In searching for information on getting rid of bugs from my vegetable garden, I came across some really valuable information from many online sources. I should start by saying that I have just started using some of these suggestions, and do not assure you 100% effectiveness, yet. That information will have to follow in a few weeks.
My search originally started by looking for chemical-free products to kill off any unwanted pests. I was quickly swayed by all of the information available about companion planting. Companion planting involves planting differing plants around the plant you wish to protect. Each pest has a plant it doesn’t like, this works in our favor when we know which pest we’re dealing with. It is imperative to keep the additional plants localized to the protected plant. Bugs are smart enough to go another route or even jump from plant to plant to get its fix. It’s best to surround the protected plant with the deterrent plants listed. For example, to get rid of ants with aphids, plant pennyroyal and spearmint around the stalk of the protected plant. A few feet to each side will not deter the ants from going right through the middle.
Here are some simple rules to follow when protecting your vegetable garden from pests:
Ants (carrying aphids) then plant pennyroyal, spearmint, southernwood, tansy,
Aphids plant pennyroyal, spearmint, southernwood, tansy, garlic, chives, coriander, anise, nasturtiums and petunias.
Asparagus beetles apparently do not like tomatoes
Borers dislike garlic, tansy, and onion
Cabbage maggots are stopped if you plant alternating rows of mint, tomato, rosemary, sage.
Cabbage moths apparently do not like mint, hyssop, rosemary, southernwood, thyme, sage, wormwood, celery, catnip and nasturtiums.
Carrot Fly dislikes rosemary, sage, wormwood, salsify, onions, coriander
Chinch bugs don’t like soy beans so surround your lawn with them.
Colorado Potato Beetle doesn’t like green beans (me neither), horseradish, dead nettle and flax.
Cucumber Beetle is repelled by radish and tansy
Cutworms are driven to distraction by tansy
Eelworms are repelled by big stinky marigolds
Flea beetle wormwood, mint, catnip, tomatoes
Fruit tree moths of all sorts don’t like southernwood
Groundhogs castor beans and human urine although the latter is enhanced by imbibing products made from hops
Japanese Beetles garlic, larkspur/delphiniums, tansy, rue, geraniums
Leafhopper petunias and geraniums
Mexican bean beetle marigold, potatoes, rosemary, summer savory, and petunias
Mice don’t like mint (mice hate fresh breath)
Mites are repelled by onion, garlic and chives
Moles don’t like spurge, castor plants and castor oil, fritillaria bulbs
Nematodes stinky marigolds, salvia, dahlia, calendula, asparagus
Plum curculio are supposedly repelled by garlic – don’t ask me how you get it into the tree but I’ve read this more than once. (maybe all copying from one source)
Rabbits don’t like onions or the onion family (garlic/chives etc)
Rose chafer geraniums, petunia and onion family
Slugs don’t like rosemary, wormwood and that might be the only two plants they wont’ eat
Squash bug don’t like tansy and nasturtiums
Pumpkin beetle doesn’t like nasturtiums (and nasturtiums don’t like it either)
Tomato hornworm is deterred by borage, marigolds and basil.
White fly won’t go near nasturtiums, marigolds, nicandra
Wireworms apparently don’t like mustard and buckwheat.

A lot of people, myself included, are growing our own vegetables to beat the credit crunch. And why not? Planting a few seeds in containers on your patio or in your backyard yields delicious, organic results – and money savings, too! Growing organic vegetables is easier than you think. Here are the 12 vegetables you will have no problem planting, tending for and harvesting in your own garden, even if you are a first-time gardener!

#1 Radish

Radishes are particularly easy to grow and can be intercropped with rows of lettuce to take up a minimum amount of space! Great thing about radishes is that very few pests bother them. Choose a sunny, sheltered position in soil, well fed with organic matter. Sow the seed thinly, evenly at ½ inch below the soil’s surface with one inch of space between each. Water the soil thoroughly before sowing and after the seeds emerge water them lightly every couple days. Radishes are a great source of potassium, folic acid, magnesium and calcium, and are perfect in salad dressings or as a garnish for salads. Radishes are fast growers and should be ready to pull in several weeks.

#2  Zucchini/ Squash

Zucchini and squash do well in most climates and they need very little special attention. If you plant zucchini you’ll probably end up with way more than they can even eat!

Zucchini and squash are very low in calories but full of potassium, manganese and folate. Sow several zucchini seeds in a heap pile of composted soil a foot high and a couple feet wide. Space each heap pile approximately 3 feet apart, water them heavily every other day and wait for them to sprout in a couple weeks. They should be ready to harvest about a month later. For any early start sow the seeds singly about ½in (1.25cm) deep, in small pots and place in a temperature of 65-70F (18-21C). After germination of seeds, grow on in a well lit spot, harden off and plant out after the last spring frost when the weather is warm.

#3 Carrots

Carrots tend to be pest free and need little attention. Carrots are rich in vitamin A, antioxidants, carotene and dietary. Dig a hole less than an inch deep and plant a couple of seeds in each, and leave several inches in between holes. Thin out in stages to 4-6in (10-15cm) apart. Keep the soil moist but remember to water the carrots less as they begin to reach maturity.

#4 Spinach

A highly nutritious and easily grown crop, high in both calcium and iron. Spinach can be eaten plain, cooked, and made into a chip dip. Turn over the soil with compost and plant seeds less than an inch deep, placing them at least 4 inches apart to give room for growth. Pick young leaves regularly. Sow the soil a couple more times in the first month and keep this area well-watered.

#5 Peas

Peas are another high-yield crop, both sweet peas and sugar peas. Other than fruit flies, these guys attract very few pests. A good source of vitamins A, B and C. Cultivate the soil just prior to sowing top dress with a balanced fertilizer. Keep in mind that your soil must drain well in order for peas for flourish. Space each seed several inches apart and sow them one inch deep. Freshly planted seeds require ½ inch of water every week, while more mature plants need a full inch. Any surplus peas can be frozen very successfully.

#6 Peppers

Peppers contain nutrients like thiamin and manganese. Peppers can be stuffed with meat and rice or used in salsa and pasta, and raw in salads. Till the soil with compost and Epsom salts, this will make it rich in magnesium to help the peppers develop healthily. Peppers can be produced outside in growing bags, large pots etc. Since they grow best in warm soil, sow the seeds a foot or more apart in raised beds or containers. Water them frequently, keeping the soil moist, or they may taste bitter once harvested.

#7 Lettuce/ Baby Greens

Lettuce is one of the easiest vegetables to grow; you just have to plant the seeds, water and watch how fast it grows. Lettuce is a good source of folic acid and vitamin A, used as the main ingredient mostly in salads, but also can be stuffed with various ingredients to make a lettuce wrap or top sandwiches, hamburgers and tacos. When cultivating the soil with nutrient-rich compost, break up any chunks and remove debris. Make sure that seeds are planted between 8 and 16 inches apart and water them every morning. Avoid doing so at night because this could cause disease. Loose-leaf varieties are ready to start cutting about seven weeks after sowing.

Baby greens are simply greens that are harvested while they are still young and tender. They are true instant gratification vegetables – you’ll be harvesting your first salad in under a month! Sprinkle the seeds as thinly as possible across the soil in a 2- to 3-inch wide band. Space rows of baby greens 6 to 8 inches apart. Or plant baby greens in a pot, and cut your salad fresh every night!

#8 Onion

Rich in dietary fiber, folate and vitamin C, onion need little care – just give them plenty of water. Plow the soil a foot deep and get rid of debris. The easiest way to grow onions is from sets which are small onions. Plant sets so that the tip is showing about 5in (13cm) apart in rows 12in (30cm) apart. Or, plant the seeds a couple centimeters deep and several inches apart. Weed this area frequently but gently and provide them with about an inch of water every week.

#9 Beets

The beet (beetroot) can be peeled, steamed, and then eaten warm with butter; cooked, pickled, and then eaten cold as a condiment; or peeled, shredded raw, and then eaten as a salad.. Betanin, one of the primary nutrients in this deep red or purple vegetable, can help lower blood pressure. Clean and strengthen the seeds by soaking them in water at room temperature for a day. Plow the soil and remove any stones from the top 3 feet. Plant each seed 2in (5cm) apart, thin out to 4in (10cm) apart and water them at least once every day.

#10 Broccoli

For the most part doesn’t need a lot of special care, broccoli is easily grown vegetable that gives the best return for the space it occupies and is cropped when other green vegetables are in short supply. One row of 15ft (4.5m) will accommodate six plants to give self-sufficiency for a family of four. Sow broccoli seed in spring in a seed bed ½in (1.25cm) deep and transplant when the seedlings are about 4in (10cm) tall 2ft (60cm) apart each way.

#11 Tomatoes

There are many benefits to growing tomatoes – they’re good for you, they’re tasty, and the dollar value of the yield can be very significant. Tomatoes are rich in nutrients like niacin, potassium and phosphorous, antioxidants like lycopene, anthocyanin and carotene, and vitamins A, C and E.

Sow the seed just below the surface in a tray of peat-based compost. When the seedlings have made two pairs of true leaves prick them out into 3in (7.5cm) pots and place them in a light, warm place indoors (like windowsill). After the last danger of frost has passed, pick a spot in your garden that receives at least 6-8 hours of sunlight and test the soil’s pH level – needs to be between 6 and 7. (To decrease pH level add sulfur, to increase it add lime). Spread compost over this area and mix it with the soil. After hardening off, set tomato plants 2ft (60cm) apart in rows 3ft (90cm) apart, bush plants 3ft (90cm) apart. Water them a couple times per week. Tomatoes do need a little more attention then the other vegetables on the list. However, for the little bit attention that tomatoes do need, you get an incredible reward in the large amount of fruit that they produce. Here are a few tricks for growing tomatoes.

#12 Herbs

There are many herbs including thyme, rosemary, basil, mint, sage, chives, parsley and oregano that need very little attention and can be grown successfully in containers on a patio, balcony or terrace. Purchase some of your favorite small herb plants from your local nursery and get a container that is at least 6-12 inches deep. You can plant multiple herbs in a wide or long container or use at least a 6″ pot for individual plants and you will enjoy not only their fragrance and beauty but also their culinary benefits. Water sparingly because herbs don’t like to sit in wet soil.

If you are a little apprehensive about planting an organic garden, start slow with any of the veggies I’ve mentioned. Soon you will gain confidence and have a beautiful organic garden, complete with delicious vegetables and bragging rights!

INTRODUCTION

India has to support 16% of world food needs in the available less than 2 % land of the country. Hence agriculture has to maximize its efficiency. Which can be achieved only by understanding and engineering the plants to make them survive in the adverse condition.Plant growth requires not only carbon dioxide and oxygen from the air but also water and mineral nutrients from the soil. Soil has been called the “placenta of life”, because it supplies essential nutrients to all land plants and the plants in turn feed all the terrestrial ecosystem. Throughout the history, humanity standard of living has depended on the fertility and productivity of the soil.Soil erosion and salinization are accelerated by poor agronomic practices. Mismanagement and neglect of soil can ruin the arable land, which is a fragile and precious resource. The harappan civilization in western India, Mesopotamia in Asia minor , and the mayan culture in central America all collapsed partly because of soil degradation. Maintaining productive should be one of society’s important goals. Most crops are salt sensitive or hypersensitive (glycophytes ) in contrast to halophytes , which are native flora of saline environment , halophytes have the capacity to accommodate extreme salinity , because of various special anatomical and morphological and physiological adaptation or avoidance mechanism.Approximately 330 species of vesicular plants (i.e.<0.15% of total number), have been demonstrated as desiccation tolerant. The majority of bryophytes which represent 30,000 spp of mosses , liverwort , hornworts are postulated to tolerate at least brief desiccation of low intensity.

HALOPHYTES :

Plants which grow and complete their life cycles in a habit with a high salt concentration are commonly designated as halophytes these are the specialized plants growing under saline environment commonly found near sea shore where the concentration of salts ( NaCl , MgSo4 , MgCl2 etc ) are relatively high. Although such plants grow in water or in area well saturated with water , water absorption is extremely difficult process , thus halophytes are physiologically dry but physically wet habitants. For this reason they have under gone a detail morphological physiological and anatomical adaptation , during their life cycle.

MORPHOLOGICAL ADAPTATIONS :

A ) ROOT:

1.In halophytes in addition to normal roots , many stilt or prop roots develops from the aerial branches of the stem. Example? Rhizophora mucronata. 2.Some times a large number of root buttresses develops from the basal part of the tree trunks.Example ? Dischidia numularia 3.In order to compensate lack of soil aeration they develop special type of negatively geotropic roots , called pneumatophores , this peg like structures causes numerous lenticells inner surface.

B) STEM:

Stems of several halophytes are succulent. Which is induced only after the accumulation of free ions in this organs. They are either hard or tough or swollen or fleshy and are usually covered with hairs.

C ) LEAVES

1.The leaves of most halophytes are thick , succulent , genrally small sized and glassy in appearance 2.Leaves of aerohalopytes are densely covered with trichomes on their surface , 3.Leaves of submerged marine halophytes are thin , thorny with thick cutinized cuticle,

D) FRUITS & SEEDS Fruits, seeds and pollen grains usually light in weight, surface of fruit have waxy covering that prevents damage during their transportation through water medium. Halophytes specially mangroves growing in the tidal region shows the phenomenon of viviparous germination which can be defined as the process of germination of seeds while the fruit is still attached with the mother plant.

ANATOMICAL ADAPTATION

1.Epidermis is highly cutinized and covered with epidermal outgrowths like hairs which prevents transpiration and salt spray into the plant body. Both dorsiventral and isobilateral leaves shows sunken and reduced stomata 2.Cortex shows mucilage cavities , tannin cells , spicule , lacuna , schlerides , salt glands which are very important characteristic modification of the cortical regions in such plants which are adapted in this saline environment. 3.Vascular bundles are very poorly developed and they are conjoint collateral with exarch xylum strands.4.stele is well liginified.5.Most of the cell have elastic cell walls.6.mesophyll cells are differtiated into palisade and spongy parenchyma. 7.Cholorophyll content is very low within the cells among these halophytes.

diagram [ A ] attached in the blog address given below

PHYSIOLOGICAL ADAPTATION

1.salinity reduces the rate of cell division which promotes the rate of cell elongation , 2.The cells of free ions which improves its turgidity and increases its adaptability from salinity. 3.The plants show high rates of transpiration which is helpful to tolerate saline condition and to maintain normal rate of metabolism.4.Halophytes shows exudation of sap that contains dissolved salts.5.Some halophytes have salt secreting glands and water storage tissues.6.The viviparous of mangrove plants is one of the most important physiological adaptations responsible for normal growth and development of new seedling.

GENETIC DIVERSITY FOR SALT TOLERANCE IN PLANTS

The extensive genetic diversity for salt tolerance that exists in plant texa is distributed over numerous genera , researchers of recent decade established that most halophytes and glycophytes tolerate salinity by rather similar strategy often using analogous tactical processes. The cytotoxic ions in saline environments , typically Sodium ion and Chloride ion are compartmentalized into the vacuole and used as osmotic salts , the fact that cellular ion homeostasis is controlled and effected by common molecular entity for the dissection of the plant salt stress response .

GENETICS OF STRESS:

To breed or genetically engineer plant stress tolerance , it is imperative to identify the genes that control these traits and to understand how these genes work and their products are regulated. The products of some of the stress inducible genes may play role in stress signaling and stress tolerance .Example : enzymes that function in the biosynthesis compatible solutes ( osmolytes ) or either directly in detoxification of reactive oxidants or in the biosynthesis antioxidant compounds ion transporters , ABA biosynthetic enzymes etc..The products of some other genes may also have protective roles against stress damage. These are mainly “late embryogenesis abundant” ( LEA) like proteins.

In some cases genes that are physically associated with certain key stress induced genes in a chromatin region may be regulated by stress , although these genes may not be related otherwise.Example : UFC { upstream of FLC (flowering locus )gene } gene. FLC is a flowering repressor whose transcript level is down regulated by cold treatment (vernalization ). Interestingly, UFC is similarly regulated by vernalization yet it does not relate to FLC either in sequence or function. They are merely neighboring genes on the same chromosome. This suggests that chromosome location has a strong influence on the induction of certain genes.

SIGNAL TRANSDUCTION.Signal transduction is required for many cellular activites and their coordination. Some signal trasduction process are simple but most others are complex , involving multiple components occurring in time and space dependent manner.Generally signal transduction starts with the perception of the stimulus by a specific cellular molecule(s). The sensors or receptors may differ in their molecular identities, mode of signal perception and output , as well as subcellular localization. In plant cells , it is also common for receptor activaton to result in the generation of secondary messenger , so called because they represent intracellular signals being translated form the primary external signal. The intracellular signals are interpreted further by other signals component(s) and result in the activation of down stream pathways that may have multiple outputs.

signal transduction diagram [ B ] given in the blog , link given below

A conceptual signal transduction pathway for drought , cold , and salt stress in plants. Secondary molecules can cause receptor mediated calcium ion release(indicated in feed back arrow ). These partners that modulate the components in the main pathway can be regulated by the main pathway. signalling can also bypass calcium ions or secondary signaling molecules in early signaling step.GPCR ? G-protein coupled receptor.RLK ? receptor-like kinase.InsP ? inositol pol phosphate.

Ca2+ Signaling and the Activation of the Salt Overly Sensitive (SOS) Signal Transduction Pathway

It was identified that three genetically linked Arabidopsis loci (SOS1, SOS2 and SOS3), which are components of a stress-signaling pathway that controls ion homeostasis and salt tolerance . Genetic analysis of Na+/Li+ sensitivity established that sos1 is epistatic to sos2 and sos3 . These sos mutants also exhibit a K+ deficient phenotype in medium supplemented with ?M [K+]ext and [Ca2+]ext. Na+ and K+ deficiency of sos2 and sos3 is suppressed with mM [Ca2+]ext . sos1 exhibits hyperosmotic sensitivity unlike sos3 and sos2. Together, these results indicate that the SOS signaling pathway regulates Na+ and K+ homeostasis and is Ca2+ activated. SOS3 encodes a Ca2+ binding protein with sequence similarity to the regulatory B subunit of calcineurin (protein phosphatase 2B) and neuronal Ca2+ sensors Interaction of SOS3 with the SOS2 kinase and SOS2 activation is Ca2+ dependent The in planta function of SOS3 as a salt tolerance determinant is dependent on Ca2+ binding and Nmyristoylation . The SOS2 serine/threonine kinase (446 amino acids) has a 267 amino acid N-terminal catalytic domain that is similar in sequence to yeast SNF1 (sucrose nonfermenting) kinase and the mammalian AMPK (AMP-activated protein kinase). The kinase activity of SOS2 is essential for its salt tolerance determinant function . The SOS2 C-terminal regulatory domain interacts with the kinase domain to cause autoinhibition. A 21 amino acid motif in the regulatory domain of SOS2 is the site where SOS3 interacts with the kinase and is the autoinhibitory domain of the kinase . Binding of SOS3 to this motif blocks autoinhibition of SOS2 kinase activity. Deletion of the autoinhibitory domain results in constitutive SOS2 activation, independent of SOS3. Also, a Thr168 to Asp mutation in the activation loop of the kinase domain constitutively activates SOS2.Genetic and biochemical evidence indicates that components of the SOS signal pathway function in the hierarchical sequence . Ca2+ binds to SOS3, which leads to interaction with SOS2 and activation of the kinase. Among the SOS signal pathway outputs are transport systems that facilitate ion homeostasis. The plasma membrane sited Na+/H+ antiporter SOS1 is controlled by the SOS pathway at the transcriptional and post-transcriptional level Recently, functional disruption of AtHKT1 was shown to suppress the salt sensitive phenotype of sos3-1, indicating that the SOS pathway negatively controls this Na+ influx system. Also, the SOS pathway negatively controls expression of AtNHX family members that are implicated as determinants in the salt stress response.[Ca2+]ext enhances salt tolerance and salinity stress elicits a transient [Ca2+]cyt increase, from either an internal or external source, that has been implicated in adaptation . Yeast has provided insight into Ca2+ activation of salt stress signaling that controls ion homeostasis and tolerance.The hyperosmotic component of high salinity induces a short duration (1 min) rise in [Ca2+]cyt that is due substantially to influx across the plasma membrane through the Cch1p and Mid1p Ca2+ transport system. The transient increase in [Ca2+]cyt activates the PP2B phosphatase calcineurin (a key intermediate in salt stress signaling controlling ion homeostasis) leading to the transcription of ENA1, which encodes the P-type ATPase that is primarily responsible for Na+ efflux across the plasma membrane .The model proposes that the hyperosmotically-induced localized [Ca2+]cyt transient activates calmodulin that is tethered to Cch1p-Midp. Calmodulin in turn activates signaling through the calcineurin pathway, which mediates ion homeostasis and salt tolerance. From these results, a paradigm for salt-induced Ca2+ signaling and the activation of the SOS pathway can be suggested. Components of the SOS pathway, either SOS3 or upstream elements, might be associated with an osmotically responsive channel through which Ca2+ influx could initiate signaling through the pathway. These are constituent of signal pathways that respond to different inducers but are still components of the plant response to salt stress. SOS signaling transduction by physical interaction with the positive effectors or competition for substrate required for signaling. Such positive and negative regulation of signal modulation constitute a fine tuning necessary to achieve the appropriate plant response for stress adaptation and ill stability.

CELLULAR MECHANISMS OF SALT STRESS SURVIVAL RECOVERY AND GROWTH Plant are either dormant during the salt episode or they must they be cellular adjust to tolerate saline environment. The chemical potential of the saline solution initially establishes a water potential imbalance between the apoplast and the symplast that leads to turgor decrease , which is severe enough to cause growth reduction . cellular dehydration begins when the water potential difference is greater than can be compensated for by the tugor loss. The cellular response to turgor response is osmotic adjustment which is achieved in this compartments by accumulation of compatible osmolytes . however Na + and Cl – are energetically efficient osmolytes for osmotic adjustment and are compartmentalized into the vacuole to minimize cytotoxicity.Compartmentalization of Na+ and Cl – facilitates osmotic adjustment that is very essential for cellular development. Movement of ion into the vacuole might occur directly from the apoplast into the vacuole through membrane vesicles or a cytological processes through the plasma membrane to the tonoplast. The bulk of Na+ and Cl- from the apoplast to the vacuole is mediated through ion transport system located in the plasma membrane and tonoplast. The SOS signallig pathway is the key transport system required for ion homeostasis.

OSMOLYTES AND OSMOPROTECTANTS

Some compatible osmolytes are essential elemental ions such as K+ but the majority are organic solutes. The major cateogory of organic osmotic solutes consists of simple sugars like fructose and glucose : sugar alcohols like glycerol , inositols: complex sugars like raffinose. Other include quaternary amino acids like proline , glycine, beta alanine : tertiary amines and sulfonium compounds like dimethyl sulfonium , propyronate.An adaptable biochemical function of osmoprotectants is scavenging of reactive oxygen species that are by product of hyper osmotic and ionic stresses which causes cell death.Compatible solutes have the capacity to preserve the activity of enzymes in saline conditions. The synthesis of compatible osmolytes is often achieved by diversion of basic intermediately metabolites into unique biochemical reactions often stress triggers this metabolic diversions.

ION HOMEOSTASIS – TRANSPORT DETERMINANTS AND THEIR REGULATIONS.

Intracellular Na+ homeostasis and salt tolerance are modulated by ca++ and high Na+ concentration which effects K+ acquisition. Na + competes with K+ for uptake through common transport system , and does this effectively since the Na+ oncentration in saline environment is usually greater than extracellular K+ concentration , Ca++ enhances K+/Na+ selective intracellular accumulation. The molecular entitites that mediate Na+ and K+ homeostasis is one of the function of Ca++ in the regulation of these transport systems. The SOS stress signaling pathway is identified to be a important regulator of plant ion homeostasis and salt tolerance.ION TRANSPORT SYSTEM : Na + HOMEOSTASIS

( a ) H+ pumps ( proton pumps)

H+ pumps in the plasma memebrane and tonoplast fecilitate solute transport necessary to compartmentalize cytotoxic ions away from the cytoplasm and the function of ions as signal determinants. These pumps provide the driving force ( H+ electro chemical potential ) for secondary active transport and function to establish membrane potential variants that facilitate electrophoretic ion flux. The plasma membrane loclised H+ pump is a p-type ATPase and is primarily responsible for the large membrane potential gradient across the gradient. A vacuolar type H+ ATPase generate the membrane potential across the tonoplast. The activity of the H+ pumps is increased by salt treatment and induced gene expression. The plasma membrane H+ ATPase is confirmed as a salt tolerant determinant based on analysis of phenotypes caused by the semidominant “aha4-1″ mutation. The mutation to aha4 which is expressed predominantly in the root causes a reduction in root and shoot and root growth. The decreased root length of salt treated “aha4-1″ plants is due to reduced cell length. It is postulated that leaves of “aha4-1″ plant accumulate more Na + and less K+ than those of wild type. So it can be said that “aha4-1″ functions in the control of Na+ flux across the endodermis.

( b ) Na+ influx & Efflux across the plasma membrane

Transport system with greater selectivity for K+ are presumed to facilitate Na+ leakage in cells. Na is a competitor for uptake through plasma membrane K+ inward rectify channels. K+ outward rectifying channels also facilitate Na+ influx. Na+ when expressed in heterologous systems providing evidence of the function as a Na+ , H+ dependent K+ transporter.Energy dependent Na+ transport across the plasma membrane is also mediated by the secondary active Na+/ H+ antiport.

( c ) Na+ vacuolar compartmentalization

Na+/ H+ antiport across the tonoplast facilitate vacuolar compartmentalization of the cation. The SOS pathway negatively regulates transcriptional expression of these Na+/H+ antiporter genes.

DROUGHT RESISTANT PLANTS ( XEROPHYTES )

Plants which grow in dry habitats or xeric conditions can with stand low humidity ,high temperature are called as xerophytes. Xerophytic plants are characteristics of desert and semi desert regions. These plants develops certain structural , anatomical physiological adaptations to absorb as much as water possible they can get from the surrounding and to retain water in their organs for long time by reducing the transpiration rate.

EFFECT ON PLANTS:

o Decrease in growth ( Ex: limitation in leaf expansion).o Decrease in leaf area decreases the photosynthetic activities.o Decrease in water content increases the solute concentration.o The first effect on root system is the death of root hairs, which decreases the capacity of the roots to absorb water.o Production of phytohormones like cytokinins and gibberlic acid decreases.o It decreases the production of secondary metabolites, which leads to decrease in the defense mechanism against certain insects and diseases.MORPHOLOGICAL ADAPTATIONS

A ) ROOT

Xerophytes have well developed root system which may be profusely branched and more elobarate than shoot system. The roots of perennial xerophytes grow very deep in soil and reach the layer where water is available in plenty.

B) STEM

1. Hard and woody stem are covered with thick coating of wax and silica or may be cover with hairs ( Calotropis sp ).2. In some xerophytes stem may be modified with thorns. Example? Ulex sp3. Stem of some extereme are modified to leaf like , flattened and fleshy structures , which are called phylloclades. Example? Muehlenbeckia sp 4. In some plants a number of axullary branches become modified into small needle like green structure which looks like leaves and are called cladodes. Example ? Asparagus sp

C) LEAVES.

1.In some xerophytes the leaves fall early in the season , but in majority of plants leaves are generally reduced to scales. Example? Casuarina equisitifolia, 2.Some ever green have needle shaped leaves. Example? Pinus roxburghii3.In some species the leaves become succulent and swell remarkably and becomes very fleshy for the storage of excess amount of and latex in them. Example? Aloe spinossina4.Leaves may be reduced to spines and are provided with thick coating of wax or silica. Example? Opumtia polardii.5.Leaves blades have thick network of veins, In some cases the green petiole swells and becomes flattened to form phyllode. Example? Acacia auriculiformis.6.Many xerophytic plants shows trichophylly for protecting the stomatal guard cells against stong winds. Example? Zizyphus numularis.7.Leaves in some extreme xerophytic grasses have the capacity for rolling and folding.

D) FRUITS & SEEDS.

Flowers usually develop in favourable conditions and they complete their reproduction in very short period of time. Fruits and seeds are protected by very hard coverings and they can remain dormant for a long period of time.

ANATOMICAL ADAPTATIONS

1.Epidermal cells are small compact with thick cuticle and it is single layered. 2.Wax , tannin , rasin , cellulose etc. are deposited on the surface of epidermis this forms a protective measure against high intensity of light. 3.Some of the epidermal cells found in the depression become more enlarged are called motor cells or hinge cells which felicitates the rolling of leaves by becoming flaccid during dry period. Example? Amnophilla.4.The hypodermal cells are thick walled and compactly grouped and may be filled with tannin and mucilage. 5.Stomatal number per units area is reduced and they are sunken type. Walls of the guard cells and subsidiary cells are heavily cutinized and lignified. Such specialized stomata reduces the rate of transpiration. 6.In case of reduced leaves the photosynthetic activity is taken up by outer Chlorenchymatous cortex. Example? Capparis. Decidua7.In succulent stem the ground tissue is filled with thin walled parenchymatous cells which store excess quanitity of water , mucilage , latex. Example? Agave americana.8.The mesophyll cells are very compact , intracellular spaces are reduced. Palisade tissue develops in several layers and in some cases mesophyll is surrounded by a sheath of sclerenchyma.9.In Pinus sp spongy cells in the mesophyll cells are star shaped.10.Both the conducting tissues xylum & phloem are very well developed in the xerophytes.

Diagram [ C ] given in the blog , link given below.

PHYSIOLOGICAL ADAPTATION

1. Xerophytes have high osmotic pressure which increases the turgidity of the cell sap exerts tension force on the cell wall. In this way wilting of cell is prevented.2. Presence of cuticle, sunken stomata protected with stomatal hair regulates the transpiration.3. The capacity of xerophytes to survive during dry period lies not only on the structural features but also in the resistance of hardened protoplasm to heat and dessication.4. Some enzymes such as catalases, peroxidases are more active in xerophytes. Low concentration of hydrolytic enzymes prevents higher rate of water consumption.5. In xerophytes conversion of chemical compounds of cell sap such as polysaccharides into anhydrous forms like cellulose suberin etc are noted.6. In some xerophytes stomata opens during night hours and remain closed during the day. These unusual features are associated with the metabolic activity of thee plants.7. In these plants some polysaccharides are converted into pentosens which have water building capacity. 8. In xerophytes respiratory carbon dioxide release during night leads to the biosynthesis of large amount of organic acids which are helpful for the plants to survive in extreme draught condition.

HEAT SHOCK PROTEINS

Heat shock proteins (HSP) are a group of proteins whose expression is increased when the cells are exposed to elevated temperatures or other stress. This increase in expression is transcriptionally regulated. This dramatic upregulation of the heat shock proteins induced mostly by heat shock factor (HSF) is a key part of the heat shock response.The HSPs are named according to their molecular weights. For example, Hsp60, Hsp70 and Hsp90 (the most widely-studied HSPs) refer to families of heat shock proteins on the order of 60, 70 and 90 kilodaltons in size, respectively. The small 8 kilodalton protein ubiquitin, which marks proteins for degradation, also has features of a heat shock protein.Molecular chaperones, including the heat-shock proteins (Hsps), are a ubiquitous feature of cells in which these proteins cope with stress-induced denaturation of other proteins. Hsps have received the most attention in model organisms undergoing experimental stress in the laboratory, and the function of Hsps at the molecular and cellular level is becoming well understood in this context. A complementary focus is now emerging on the Hsps of both model and non model organisms undergoing stress in nature, on the roles of Hsps in the stress physiology of whole multicellular eukaryotes and the tissues and organs they comprise, and on the ecological and evolutionary correlates of variation in Hsps and the genes that encode them. This focus discloses that (a) expression of Hsps can occur in nature, (b) all species have hsp genes but they vary in the patterns of their expression, (c) Hsp expression can be correlated with resistance to stress, and (d) species’ thresholds for Hsp expression are correlated with levels of stress that they naturally undergo. These conclusions are now well established and may require little additional confirmation; many significant questions remain unanswered concerning both the mechanisms of Hsp-mediated stress tolerance at the organismal level and the evolutionary mechanisms that have diversified the hsp genes.Upregulation through stressProduction of high levels of heat shock proteins can also be triggered by exposure to different kinds of environmental stress conditions, such as infection, inflammation, exercise, exposure of the cell to toxins (ethanol, arsenic, trace metals and ultraviolet light, among many others), starvation, hypoxia (oxygen deprivation), nitrogen deficiency (in plants), or water deprivation. Consequently, the heat shock proteins are also referred to as stress proteins and their upregulation is sometimes described more generally as part of the stress response.

EFFECT OF ABA IN STRESS :

STRESS-RESPONSIVE GENES ARE REGULATED BY ABA-DEPENDENT AND ABA-INDEPENDENT PROCESS.

Gene transcription is controlled through the interaction of regulatory proteins with specific regulatory sequences in the promoters of the genes they regulate. Different genes that are induced by the same signal are controlled by a signaling pathway leading to the activation of these specific transcription factors. Studies of the promoters of several stress-induced genes have led to the identification of specific regulatory sequences for genes involved in different stresses. For example, the RD29 gene contains DNA sequences that can be activated by osmotic stress, by cold, and ABA.

EFFECT OF ABA IN STOMATAL CLOSING IN DROUGHT CONDITIONS

Diagram [ D ]given in the blog , link given below.

The Acidity , alkalinity and salinity of soils are important determinants of productivity.

Because soil acidity influences the physical properties , the availability of certain plant nutrients , and the biological activity of the soil, it greatly affects the plant growth , the soils degree of acidity depends on the concentration of H+ ion dissolved in the soil water. In a neutral soil the H+ ion concentration is about one part per billion parts of water and the acid soil may have a concentration of H+ that is 100 to 1000 times higher , where as a alkaline H+ ion concentration. Neither extreme acidity nor extreme alkalinity is suitable for plant growth or for most other soil organisms. such conditions also upset soil weathering and the availability of the nutrients , although some plants can grow in strongly acidic or alkaline soil , most crop plants grow best in neutral or slightly acidic soils . just over a quarter ( 26 % )Of the worlds arable land is classified as acidic. In the tropics the % is even greater ( 43%). Acidic soils account for 68% of tropical America , 38% of tropical asia and27 % of tropical Africa.

Diagram [E ] given in the blog , link given below.

IMPROVEMENT

A)CROP RESISTANCE TO WATER DEFICIT CAN BE IMPROVED:Improving drought resistance is an important aim of plant breeders. Four basic approaches to the drought resistance are being used :1.breed for high yields under optimal condition ; i.e breed for yield potential – assuming this will provide yield advantage under suboptimal condition.2.breed for maximum yield in the target environment.3.select and incorporate morphological and physiological mechanisms of drought resistance into traditional breeding programmes.4.do not use multiple physiological selection criteria , but established without doubt that a single drought-resistance character will benefit yield under water limited conditions , and then incorporate the character into an existing yield breeding programme.

Using molecular techniques several classes of genes have been identified that confer resistance to water deficit . Some of the genes could be used to engineer plant for drought resistance and better crop yield under drought condition. First the enzymes that synthesize osmoprotectants , small molecules that accumulate in the cytoplasm of drought stress plants , have been identified.Plants genetically engineered with the genes encoding these enzymes are more drought tolerant. Second the genes that encode transcription factors that regulate entire metabolic pathways leading to drought adaptation were identified. By incorporating such genes , one can hope to ensure that plants respond rapidly and efficiently to any water deficit and continue all their developmental processes.

B) Better performance on saline soil.Salt tolerance is a complex , quantitative , genetic trait controlled by many genes. Recently a few genes have been identified that provide information useful in screening and selection programmes for salt tolerance. Four major stratergies that to develop salt tolerant crops are :1.gradually improve the salt tolerance to conventional breeding and selection.Example : development of salt tolerance in rice ( Pokkali Rice) of kerala, India has been used extensively to develop salt tolerance in other , more desirable rice genotypes.2.Introduce traits for salt tolerance from wild relatives into the crops by the process of back crossing.Example : tomato (Lycopersicon esculentum), Barley (Hordeum vulgare ) and Wheat ( triticum aestivum).3.Domesticate wild species that currently inhabit saline environment ( halophytes ) by breeding and selecting for improved agronomic characteristic. 4.use molecular techniques to identify genes associated with salt tolerance , and enhance their expression in the crop species or transfer the genes from the non crop to a crop species. Example : On the molecular front , the genes involved in sensing salt in the environment ( signal- transduction ) , transcription factor genes that turn on batteries of other genes that prepare cell to withstand a higher rate of salt influx , and genes that are a part of plant’s adaptation to the presence of salt are being identified. An example of the later category is the gene that encodes that vacuolar sodium pump. Plants that can turn this gene on rapidly when the cells are exposed to salt , will be able to transport the salt from the cytoplasm into the vacuole , there by detoxifying the cytoplasm. Example : Lycopersicon esculentum ( tomato)

CONCULSION :

Conventional and GM breeding are complementary approaches and can be expected to enhance the draught resistance and yield of crops. People have entered in new era in which enhance knowledge of both the physiology of yield accumulation and the physiological basis of genetic variation in both salt and draught resistance traits offer the potential for improving breeding efficiency for major food crops in different target environments. Using physiological knowledge and powerful tools

blog address:http://stresstolerance.blogspot.com/

Organic gardening differs from “conventional” gardening mainly in the areas of fertilization and pest control. Organic gardening is planting without chemical fertilizers and naturally building the soil to support healthy plant life. People are increasingly aware that organic food is better for the environment. This primer of organic gardening will help you get started in this fun, healthy hobby.
The main thing to remember is that organic gardening is not only about pesticide use and the soil that your garden grows in. The goal is to create an ecosystem in your back yard where every part is respected and in good shape. Robust plants can better defend themselves against pests and diseases.
Soil Is the Source of Life
The soil is the source of life for plants. Indeed, one of the problems with chemical gardening is that it sterilizes the soil and steals the life from it. Organic soil is living, and has lots of living matter in it. It is from this wellspring of life that plants create the nutrients you will eat.
At the beginning and end of every growing season, the organic gardener works the soil by adding natural garden fertilizers to enrich the soil and replace nutrients that the plants have used. You can use animal-based organic fertilizers and plant-based organic fertilizers or any combination of both. You want to add bulk to the soil along with nutrients.
Animal-Based Organic Fertilizer
Animal-based organic garden fertilizer can be reduced to one word: manure. Cow manure, chicken manure, fish emulsion and bat guano are most usually used, but you can additionally use horse and rabbit manure. Use solid animal-based fertilizers to dig into the soil, and make “manure tea” to use when transplanting seedlings.
There are some safety issues to recognize when using animal manure. All manure should be aged or composted before using it as an organic garden fertilizer to remove E. coli and other potentially troublesome pathogens. As well, you cannot use manure from humans or predator animals, such as cats. Their digestive systems contain bacteria that are pathogenic to humans, and the bacteria can get into or on food grown in soil fertilized with their feces.
Plant-Based Organic Fertilizer
Compost, seaweed, worm castings and green manure are the most standard plant-based organic garden fertilizers. Seaweed and kelp are usually purchased as dried and processed organic garden fertilizer.
Green manure is planted as a cover crop, normally in the fall after harvest. Plant a nitrogen-fixing crop, such as soybeans, and the symbiotic bacteria in the roots will add nitrogen to your soil. Then, when the cover crop emerges in the spring, dig it into the ground, and allow the plants to decompose and enrich the soil.
Compost
Far and away the most common plant-based organic fertilizer is compost. Compost is an excellent way to recycle vegetable matter. There are many theories on composting, and you can learn how to do it from community workshops, books, or other experts. Fundamentally, however, compost is not hard to make. You just save all your vegetable scraps, garden wastes, remains of plants, grass clippings, dried leaves and other vegetable matter and let it decompose. A hot compost heap that is turned frequently (so that it gets air into it) will make compost in a matter of weeks. A compost heap decomposes faster if it generates heat, and it needs to be at least three cubic feet to get good and hot. If your compost pile isn’t that big or doesn’t get very warm, or you don’t turn it, don’t despair, it will still make good compost. You can just throw your vegetable waste in a pile and leave it. If it sits for a long time, like a year, it will compost by itself.
A worm box is an alternative to a compost-pile. Worm castings are very rich in nutrients. To create worm castings, start with the right kind of worms, which you can get from any organic gardening source. Place them in a covered tub of some kind with your slightly damp vegetable matter. The worms do all the work, and you get rich organic garden fertilizer at almost no cost. Either read about how to set up a worm compost system, or you can buy a kit at your garden center. Remember to add earthworms to the soil too, as they create natural fertilizers in the soil and provide aeration.
Add natural fertilizers such as these to the soil at least twice a year and dig them into the top six inches of soil. You’ll have rich, dark, productive soil within a couple of years–even if you started out with sterile, gray, chemically treated dirt.
Water Is a Necessity of Life
All living organisms need water. It is important for the health of your plants to give them enough water to thrive. However, indiscriminate water use wastes water and washes away the soil. Watering where it is not needed encourages weeds. Water when the sun is low, early in the morning or in the evening to cut down on evaporation. It is important that the water gets to the roots of the plants without running off and taking valuable soil with it, so add water slowly and let it soak in. Use a soaker hose to water only your garden plants and nowhere else. If a soaker hose (or irrigation system) is not a choice for you, dig a shallow well around the base of each plant and fill it up and let the water soak in. Use a mulch around plants to conserve water and to prevent rain from eroding your fertile garden soil.
Don’t Let Weeds Rob Your Garden Plants
Only your cherished plants should get the advantage of the rich soil and water you provide. Therefore, it is necessary to take out all the other plants which find your garden a great place to live. That is, it is important to weed your organic garden. In the mid-twentieth century, at the height of chemical use in gardening, it became usual to spray herbicides on the soil to control weeds. But now we understand how damaging such chemical use is to the environment. Pulling out weeds by hand is neither hard nor particularly time consuming. Your organic garden is a beautiful place to spend time, why not spend it taking out the weeds that compete with your plants.
Here are the basics of weed-control. Firstly, make sure you get rid of weeds before they go to seed. Weeds routinely produce thousands of seeds in a short period of time. If there are patches of weeds growing at the periphery of your garden, make sure to mow them before they spread seeds. Second, when pulling weeds by hand make sure to pull out the roots so the plant doesn’t grow right back. Use a trowel to dig out deep-rooted weeds. Third, use mulch as a barrier to weed growth. Organic mulch will also help maintain moisture and add organic material to the soil. You can cover the entire area with plastic during the winter season to kill off weed seeds.
Control Pests without Harmful Pesticides
Pest-control is probably the biggest issue facing organic gardeners. Chemically-based pesticides are some of the most toxic substances to have on your food or polluting the environment. How, then, do you keep ravenous bugs like Japanese beetles from destroying your produce? In organic gardening you begin with the least toxic intervention and proceed from there.
Pest Prevention
The first step is to plant wisely. Remember that healthy plants will need less help from you with fighting pests, so make sure that your plants are well-fed and have adequate water. Also, use companion planting and crop rotation to discourage pests before they arrive. Some plants keep bugs away and planting them next to your tasty plants is a good idea. Garlic, onions and marigolds are commonly used to repel bugs. Plant them in a border around your garden and between your garden plants. Crop rotation is the method of planting a different crop in a given area of your garden each year. Where you put tomatoes this year put squash or corn in the next year. Crop rotation is especially helpful in preventing plant diseases.
Non-toxic Pest Controls
The next step is to remove pests when you find them. Remember that not all bugs are pests. In fact, a number of bugs are your helpers in pest control, but the wholesale use of toxic pesticides eliminates the predatory bugs as well as the harmful ones. It is important to be able to identify the good bugs and the bad bugs. Go out early in the morning or late in the evening when it’s cool, and remove any tomato hookworms, potato bugs, Japanese beetles, slugs or other harmful insects that you find. Squash them, or carry a bucket of soapy water to drown them. Better yet, feed them to your chickens. The most efficient way to remove small bugs such as aphids and mites is to spray the plants with the hose, using a strong stream of water to wash the insects off.
Physical barriers are another non-toxic method of organic pest control. They prevent pests from getting access to your plants. Some examples of barriers are to cut the top and bottom out of coffee cans and push them into the soil around tender young plants to keep cutworms away, or use fine netting to cover your plants to protect them from grasshoppers or birds.
Predatory Insects
One of the biggest defenses against pests are other bugs. Bugs that eat other bugs are a fantastic organic gardening pest control. Ladybugs, praying mantises, and lacewings are all beneficial insects. You can buy them at the garden store and release them into your garden. These predatory insects control aphids, mites and many other pests. Most spiders are bug-eaters, too, so let spiders work for you.
Using Organic Pesticides
If you are using these non-toxic pest controls and you are still faced with an overwhelming pest invasion, the last resort is to use organic pesticides. They are routinely made from plant derivatives or minerals. These natural pesticides are certified for use in natural farming and are far less dangerous than synthetic pesticides, but they are still toxic. It is important that you determine how harmful the insect pests are; you may elect to live with them rather than use something that is organic, but more toxic than you want to expose your food to.
Insecticidal soap is quite safe for food plants and the environment and works well to get rid of garden pests. Buy it at your garden supply store, or make your own by adding a few drops of liquid dish soap to a cup of water. Spray it on the plants, and then rinse off. This works great on aphids and thrips.
You can usually tell how toxic an organic pest control is by checking for a warning label. If there is no warning on the label, the substance is probably non-toxic. If the label says, “caution,” it is mildly toxic. “Warning” on the label means it is moderately toxic, and “danger” means the substance is very toxic. Organic gardening pest controls rarely have a “danger” warning on them. It is very important to apply organic pest control products exactly as the label directs. These products can be dangerous, so they must be used correctly to minimize everybody’s exposure to toxic pesticides.
For More Information
If you want to get started on your organic garden, you’ll find an abundance of help. Look for gardening clubs or workshops in your community; gardeners are always eager to give advice. Additionally, there are countless books, magazines and web sites. You can also look up your local Cooperative Extension Office, which offers advice in cooperation with local universities. Like all living processes, there is a rhythm to organic gardening. You don’t do everything at once. Begin slowly and learn as you go.

More farmers are getting into organic vegetable gardening because it is cost effective and they are able to produce almost the same yield of crops. You to can do this at home but first, you have to understand the principles of organic vegetable gardening.

First, organic vegetable gardening does not use any fertilizers, nutrients or pesticides. Nature is your partner here because you will be using two things to make it all work namely sunlight and water. We don’t produce these ourselves but you have to find the ideal area and provide adequate drainage.

Aside from sunlight and water, you can help the crops grow by using compost heap from leftover food, chipped bark, garden compost, leaf moulds and manure. You can mix these all together and then spread this throughout your garden.

A lot of people are grossed about by manure. You don’t have to scoop this from the toilet because this is sold in stores. If you have a dog, put on some gloves and put it there. Chickens are also great to have. Just let them roam around in the garden.

Some people use dead animals or meat products. You don’t put these in the soil but leave it for a couple of weeks in the bin because maggots will soon appear and this is what you use to help fertilize your garden.

Another helpful creature is the earthworm because it digs deep into the ground and aerates the soil bringing various minerals to the surface which also provides better drainage. This long pink colored creature also leaves casting behind that experts say is five times as rich in nitrogen phosphorous and potassium. Again, this can be purchased from the gardening store.

Organic garden is challenging since you have to deal with unwanted guests. Some of these pests include armyworms, crickets, gypsy moth caterpillars, slugs and squash bugs. Before, people used fertilizer to kill them but in an organic setting, the best weapon is the toad that is known to eat more almost every type of insect. If you have caterpillars or spiders lurking in the garden, get a bird because this is not in the toad’s diet.

In some cases, you don’t have to buy a toad or a bird from the pet store. They may come in to your home as long as you set the ideal environment for them. You can put up a bird house or a small pond. Within days, you will have some new occupants protecting your garden.

Other insect killers which you can get to do the job include the preying mantis and the ladybug because they mark their territory and eat anything that dares enter their domain.

Plants can also be used to protect your vegetables. For example, the rosemary, sage or thyme is an effective deterrent against butterflies. Marigolds on the other hand are effective against nematodes.

But despite all the flowers and creatures that nature has to offer, crop rotation is seen as the best way to keep the soil fertile. If you planted this kind of vegetable for this season, change it with another and the return to the first after this one is harvested.

The principles behind organic gardening are very simple. You just have to be practice it so you can harvest the vegetables you have planted weeks ago.