The survey will be conducted in order to place physio-morphological, attributes which can be used for word picture of salt tolerance in onion ( Allium cepa ) in a pots civilization. The experiment will be conducted in vegetable country, Institute of Horticulture Sciences, University of Agriculture, Faisalabad. Twelve genotypes will be grown in fictile pots, utilizing all right sand as growing medium. One month after transplanted workss will be treated with 0, 2, 4, 6 and 8 decimal/cm saline H2O and Hoagland solution will be used as alimentary solution. The experiment will be laid out in Wholly Randomized Design ( CRD ) with six reproductions and each reproduction contains three pots. Data pertaining to assorted physio-morphological and parametric quantities will be collected and analyzed statistically utilizing standard statistical processs.
IV. NEED FOR THE PROJECT:
Salt has been a menace to agriculture in some parts of the universe for over 3000 old ages ; in recent times, the menace has grown ” . As the universe population continues to increase, more nutrient demands to be grown to feed the people. This can be achieved by an addition in cultivated land and by an addition in harvest productiveness per country. The former has brought agribusiness to marginal, salt-affected lands. Furthermore, the salt job has been aggravated by the demand of irrigation for harvest production in waterless and semiarid environments ( Anonymous, 1999 )
Salinization normally occurs as an result of agricultural patterns, either associated with irrigation or due to long-run alterations in H2O flow in the landscape that can follow land clearance or changed H2O direction. Salinization associated with agribusiness occurs when salts build up in the root zone, either because the dirt is per se saline, or because the drainage of H2O from the sub-soil is non sufficient to forestall saline Waterss lifting into the root zone. It hence tends to be common in waterless and semi arid parts where leaching of salt is hapless due to low rainfall ; where there are strongly saline sub-soils formed from Marine sedimentations or where irrigation alterations H2O tabular arraies and salt flow. The ionic balance differs harmonizing to the salts in the sub-soils or H2O ( Kanber et al.,1992 ) . However, Salinization besides can be a portion of natural landscapes and saline pockets may happen where hapless drainage and high dirt salt come together. In these countries salt tolerant species have become established that may hold other utilizations. For illustration, the salt tolerant grass species Diplachne fusca, used as cut fresh fish in Pakistan, grows of course in semitropical saline countries in Australia from where it is believed to hold been introduced to Pakistan ( Anonymous, 2002 ) .
The entire planetary country of salt-affected dirts has late been estimated to be about 830 million hectares ( Martinez-Beltran and Manzur, 2005 ) . The different types of dirt salt that impact agricultural productiveness, i.e. irrigation-induced salt and ‘transient ‘ dry-land salt have been characterized in item by Rengasamy ( 2006 ) . Clearly, dirt salt is one of the major environmental emphasiss that limit agricultural productiveness worldwide.
Salt is a major restraint to harvest production which is frequently observed under natural environmental conditions. Increased salinization of cultivable land is expected to hold devasting planetary effects, ensuing in 30 % land loss within following 25 old ages and upto 50 % by the center of 21thA century. It is a job of great importance, because many agricultural countries antecedently fertile became saline due to irrigation with unfit H2O. Salinization of belowground H2O resource is another major job impacting the agricultural productiveness. It is really of import to prolong the dirt birthrate and quality of H2O resources to carry through the nutrient, provender and fiber demand of ever-growing population of the universe. Salinity limits the production of about over 6 % of the universe ‘s landA and 20 % of the irrigated land ( 15 % of entire cultivated countries ) and negatively impacts agricultural output throughout the universe ( Cramer and Nowak, 1992 ) . A In Pakistan, a loss of about 20 billion rupees ( 350.88 million US $ ) yearly has been estimated from the salt-affected irrigated countries of the Indus Basin on history of lessening in harvest output. Salinization of good cultivable land in Pakistan is making a job with huge socio-economic losingss. The loss of first-class natural resource is another job, because the population depends for its support on these lands, which are bit by bit dwindling through the spread of salt ( Anonymous, 2005 ) .
Salt emphasis causes many-sided drastic effects in workss and among these factors production of reactive O species ( ROS ) is a common phenomenon. These ROS are extremely reactive because they can interact with a figure of cellular molecules and metabolites and finally leads to cellular harm. In saline environment, works growing is affected by complex interaction of endocrines, osmotic effects, specific ion effects and nutritionary instabilities, likely all occur at the same time ( Dubey, 1999 ) . In pea, it affects the foliage growing, photosynthesis, mineral nutrition, stomatous conductance, transpiration, H2O and ion conveyance and increases sugars, aminic acids and different ions along with acute effects on output and quality. Salinity induced symptoms such as nonspecific greensickness, stunted leaf size and impaired shoot growing.
They nevertheless, under salt emphasis follow different mechanisms to set the osmotic and ionic emphasiss caused by salt. These mechanisms include osmotic accommodation by accretion of compatible solutes such as Proline, Glycine-betaine and Polyols. Proline accretion is known as the version of salt and Glycine-betaine is one of the most abundant quaternate ammonium compounds produced in higher workss due to salt ( Munns and Tester, 2008 ) .
Plants have assorted mechanisms to cut down the drastic effects of salt and these mechanisms take topographic point at three degrees of organisation i-e. whole works, cellular and molecular degree. Assorted scientists have described the physiological mechanisms at whole works degree. Salt tolerance of works depends upon its ability to look into the motion of salt at five sites i-e. selectivity of uptake by root cells, burden of xylem, remotion of salt from xylem in the upper portion of the roots, root and leafstalk, burden of the bast and elimination through salt secretory organs ( Shafqat et al.,1998 ) .
All halophytes have good developed mechanisms to supervise the consumption, conveyance and elimination of salt. Glycophytes use first three mechanisms. As pea is non a halophyte so the above mechanisms are non good established in it. There are many other characteristics that work to keep low rates of salt accretion in foliages. High shoot/root ratios and high intrinsic growing rates and absence of apoplastic tract in rootsA all serve to cut down the rate at which salt enters the transpiration watercourse and sedimentation in the shoot. As these characteristics are non efficient in salt sensitive workss like pea so there is a demand to heighten their salt tolerance by exogenic application of good compounds and growing regulators. These compounds comprise of proline, glycinebetaine, salicylic acid, brassinosteroids, silicates etc. These chemicals play a critical function in osmotic accommodation under saline status and make the hinderance in the manner of ion toxicity ( Malcolm, 1993 ) .
The onion harvest is of great importance in Egypt and is one of the chief exported fresh veggies. In cultivated onion, the development of new and improved harvest genotypes is of critical importance for its turning in assorted ecological countries. The techniques of works tissue civilization may play a cardinal function in the development of new cultivars. Aseptic civilization technique offers a potency for choice of salt-tolerant lines of onion. The present work was planned to analyze the influence of different salt degrees on growing and chemical contents of onion tissue civilizations and in vitro choice for salt emphasis tolerant genotypes ( Rhoades el al. , 1992 ) .
Vegetable species, in general, differ greatly in their ability to digest drought conditions depending on their familial do up and evolutionary versions. Basic works construction and development besides contribute to drought tolerance among species. Since onion is a shallow rooted harvest, a terrible impact ofdrought on growing and physiological procedures are expected. Continued transpiration under worsening dirt wet position will ensue in terrible H2O emphasis in workss during their development. Among the growing processes, leaf enlargement is perceived extremely sensitive to H2O shortage ( Kriedmann, 1986 ) . Continued suppression of leaf enlargement reduces net photosynthetic capacity of the workss, taking to eduction in biomass production ( Kriedmann, 1986 ) . A lessening in root zone H2O potency would ensue in partial or complete closing of pore ( Kaufmann, 1981 ) .
Reappraisal of Literature:
Ahmad and Riffat, ( 2005 ) evaluated the consequence of salt on some physio-biochemical parametric quantities in pea ( Pisum sativum L. curriculum vitae. ) , under four salt interventions, 50, 100, 150 and 200A millimeter NaCl, for 30 yearss in sand civilization experiments and reported that high NaCl concentrations caused a great decrease in fresh and dry weight of foliages and roots, but insignificantly influenced the figure of foliages. They concluded that all these alterations were associated with a lessening in the comparative H2O contents and the K+ consumption. The proline and sugar contents were increased while nitrate reductase activity and chlorophyll contents were decreased.
Gad, ( 2005 ) studied the synergistic consequence of salt and Co on growing and mineral composing of two tomato assortments viz. Moneymaker ( as salt medium ) and Edcawy ( as salt tolerant ) . A pot experiment was carried out utilizing acid washed sand and 10 kilogram capacity fictile pots. It was reported that foliage chlorophyll contents were decreased in response to salt emphasis, on the other manus salt emphasis significantly enhanced the foliage H2O potency and proline contents.
Gamze, ( 2006 ) investigated the effects of salt and drouth emphasiss at the H2O potencies of -2, -4, -6 and -8 bars induced by NaCl and PEG 6000 ( polythene ethanediol 6000 ) at sprouting and early seedling growing, of three pea cultivars. Electrical conduction ( EC ) values of the NaCl solutions were 4.5, 8.8, 12.7 and 16.3 dS Garand rifle. It was reported that both NaCl and PEG inhibited sprouting and seedling growing in all cultivars, but the effects of NaCl compared to PEG were less on sprouting and seedling growing. It was concluded that suppression in sprouting at tantamount H2O potencies of NaCl and PEG was chiefly due to an osmotic consequence instead than salt toxicity.
Sato et al. , ( 2006 ) examined the consequence of NaCl on gustatory sensation scaling and chemical composing of fruit of hydroponically grown tomato workss and reported that NaCl intervention increased sugariness, sourness, umami ( i.e. the gustatory sensation of delectability ) and overall penchant. Hexose concentration of the fruit grown on NaCl treated workss significantly increased and at the same clip, chloric ion, organic and aminic acids in general had higher concentrations in NaCl treated workss than the control. It was concluded that consumer scaling of the tomato fruit was influenced non merely by sugar contents but besides by the amino acids and increased concentration of soluble solids in the fruit of NaCl treated workss was non the consequence of simple overall condensation due to the decrease of H2O conveyance.
Shibli et al. , ( 2007 ) studied the physiological and biochemical responses of open-pollinated ‘Roma ‘ and dwarf F1 loanblend ‘Patio ‘ tomato ( Lycopersicon esculentum Mill. ) cultivars to salt. Growth, foliage cell sap osmolarity, leaf tissue viability and shoot soluble protein contents were by and large depressed with elevated salt interventions, whereas, electrolyte escape, membrane hurt, raffinose and entire sugars were concomitantly increased. Integrating ethylene inhibitors CoCl2 or NiCl2 at 5.0 or 10.0A mg/l into media supplemented with 100A millimeters NaCl significantly reduced ethylene accretion in the headspace and prevented epinasty, but did non extinguish the negative impacts on growing and other physiological parametric quantities caused by salt intervention in either cultivar. It was reported that the addition in ethylene under salt emphasis is non the primary factor lending to salt ‘s hurtful consequence on tomato works growing and physiology.
Khan et al. , ( 2009 ) studied the consequence of seed priming with salicylic acid ( SA ) and acetylsalicylic acid ( ASA ) in bettering seed energy in salt tolerance of chilis seedlings. Concentrations over 1.0 millimeters of ASA or SA showed inauspicious effects on seed outgrowth. Seeds primed with SA ( 0.8 millimeter ) and ASA ( 0.2 millimeter ) were sown in medium at different salt degrees [ 0, 3, 6 and 9 dS m-1 ] . Both, SA and ASA interventions showed significantly better consequences over the control by betterment in clip taken to 50 % outgrowth, concluding outgrowth per centum, root and shoot length, seedling fresh and dry weight and seedling energy. Overall, acetylsalicylic acid exhibited high quality over salicylic acid. They reported that hormonal priming, particularly with acetylsalicylic acid, can be a good intervention for chilis to heighten uniformity of outgrowth and seedling establishment under normal every bit good as saline conditions.
Maiti et al. , ( 2010 ) used a fresh semi-hydroponic technique and evaluated that extremely signifcant differences were found among all genotypes with regard to seedling parametric quantities studied. In all vegetable harvests, in general, signifcant differences were found among genotype, NaCl concentration and interaction between genotypes & A ; NaCl concentration with regard to emergence ( % ) , outgrowth index, shoot length & A ; root length. High r2 and low CV ( % ) indicates the dependability of the technique. Emergence was extremely correlated with shoot length and root length demoing the part of shoot length and root length to salt tolerance in different vegetable harvests. With increasing salt, there was addition in root length in salt tolerant lines but there was matching lessening in root length in susceptible 1s. Salinity tolerant genotypes selected in okra at 0.1 M NaCl were: 7025, 7033 and 703. Salinity tolerant genotypes selected in tomato at 0.1 M NaCl were: 132, 113, 125, 126 and 12, besides in chili at 0.1 M NaCl.
The vegetive growing constituents and bulb output were measured in the tried cultivars. Salinity retarded onion vegetive growing. At the highest salt degree bulb fresh weight was reduced by 72.8 and 81.5 % while bulb diameter was reduced by 50.2 and 51 % in the first and 2nd experiments, severally. Contessa, Texas Grano 502 and Dorado gave the highest bulb output in both seasons. No synergistic consequence between cultivars and salt degrees was observed on the growh and output.
Vi ) Materials and Methods
The proposed survey will be carried out at vegetable country, Institute of Horticultural Scieces, University of Agriculture, Faisalabad. The undermentioned genotypes will be used as seting stuff.
Giza no. 6
Early on Grono
Swat no 1
The experiment will be laid out in Wholly Randomized Design ( CRD ) with three reproductions.
The experiment will comprised of following interventions.
T1 = Control ( No. salt intervention )
T2 = 25 millimeter NaCl
T3 = 50 millimeter NaCl
T4 = 75 millimeter NaCl
T5 = 100mM NaCl
T6 = 125mM NaCl
Seeds will be sown in 9L, underside perforated, fictile pots incorporating sand rinsed with distilled H2O. After outgrowth of first true foliages ( 15 yearss after sprouting ) , the figure of seedlings per pot will be adjusted to three and they will be irrigated harmonizing to seedlings demand. After 20 yearss of sowing, half strength ( 0.5 ) Hoagland ‘s alimentary solution will be given to workss. Salt intervention will be started one month after seeding. To avoid the osmotic daze NaCl concentrations will be adjusted, by bit by bit increasing 25 mM every two yearss until coveted concentration reached. Each pot ( three workss ) will be considered as one replicate and there will be three pots per intervention.
Parameters to be studied
I ) Morphological traits
No of foliage per workss
Weight of fresh bulb per workss
Bulb dry weight per workss
Bulb wet contents
Bulb dry affair
two ) Physiological traits