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2012 - 20132
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Subject: Botany × End date: 2013 × Start date: 2012 × Thesis Type: M.Sc ×
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    SALICYLIC ACID INDUCED CHANGES IN SOME PHYSIOLOGICAL AND BIOCHEMICAL PARAMETERS IN MASHBEAN (Vigna mungo L. Hepper) GENOTYPES GROWN UNDER SALINITY
    (PAU Ludhiana, 2012) Manpreet Kaur; Navita Ghai
    The present investigation was undertaken to study the effect of salicylic acid on physiological and biochemical parameters in salt sensitive (KUG 363 and KUG 310) and salt tolerant (KUG 529 and KUG 502) mashbean genotypes, along with a check variety (UL 338) grown under NaCl (30mM and 45mM) stress. The plants were grown in plastic pots kept under a rain-out shelter. NaCl was applied in split dose: 50% at the time of sowing and remaining 50% at 15 days after sowing (DAS). Salicylic acid (SA) @ 0.5 mM and 1.0 mM was applied as a foliar spray at 25 DAS. Data on various physiological and biochemical changes was recorded at 35 (vegetative stage), 50 (flowering stage) and 65 (pod setting stage) DAS. Salt stress decreased the leaf area and plant dry biomass of all the genotypes at various stages of development. The decrease in plant dry biomass led to reduction in relative growth rate and crop growth rate. Sensitive as well as tolerant genotypes showed a sharp increase in membrane permeability under saline conditions. NaCl caused a decrease in photosynthetic pigments and increase in levels of hydrogen peroxide and malondialdehyde content. Under saline conditions, all the genotypes showed a higher accumulation of osmotic solute proline, with tolerant genotypes accumulating more amount than sensitive ones. Antioxidant enzymes like catalase and ascorbate peroxidase showed a decrease under saline conditions. However, peroxidase activity was increased under salt stress. Maximum increase was shown in salt sensitive genotypes. Reduction in yield contributing parameters like number of pods plant-1, number of seeds per pod, 100 seed weight and seed yield plant-1 was observed at both the levels of salinity. SA treatments had a pronounced ameliorative as well as, growth promoting effect under saline conditions. The ameliorative effect of SA was observed as increase in leaf area, relative leaf water content, water potential of leaves and photosynthetic pigments in salt-stressed plants. SA treatments increased the biosynthesis of proline under salt stress. Foliar application of SA enhanced the level of antioxidant system (catalase and ascorbate peroxidase) in mashbean plants under NaCl stress and reduced the hydrogen peroxide and malondialdehyde content. The reduction in yield and yield contributing parameters was also less in SA-treated salt-stressed plants as compared to non saline controls. However, tolerant genotypes (KUG 529 and KUG 502) and check variety (UL 338) were able to tolerate high salinity and responded better to the application of SA as compared to sensitive genotypes probably due to improved growth, metabolism and enhanced antioxidant system. Lower concentration of SA (0.5 mM) proved to be more effective to ameliorate the adverse effects of salt stress.
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    Screening of chickpea (Cicer arietinum L.) genotypes to salinity tolerance
    (Punjab Agricultural University, Ludhiana, 2013) Pavneetpal Kaur; Jagmeet Kaur
    The present investigation was undertaken to screen the chickpea genotypes for the growth behavior and alteration in yield contributing traits during salinity stress. Twenty two diverse chickpea genotypes were evaluated for salinity tolerance. The experiment was conducted in plastic pots raised under rain out shelter. The treatments comprised of control, 20mM and 30mM NaCl applied in split doses: 50% at the time of sowing and remaining at 15 days after sowing. The observations on various physiological and biochemical traits were recorded at 65 DAS (vegetative stage), 90 DAS (flower initiation) and 110 DAS (pod initiation) and yield attributes at maturity. Salt stress profoundly affected the growth attributes. All the genotypes depicted reduction in plant height, leaf area and biomass efficiency. The photosynthetic pigments, activity of nitrate reductase and relative leaf water content was also reduced in response to salt application with effect being more pronounced in identified salt sensitive genotypes (ICC15868 and GL26054) as compared to salt tolerant ones (BG1053, L550, ICC8950 and ICCV10). Lipid peroxidation increased with both the salinity levels. Under saline conditions higher accumulation of osmotic solute proline, total proteins and protein fractions was observed with tolerant genotypes in contrast to sensitive genotypes. Salt imposed stress finally caused a higher decline in yield attributes of sensitive genotypes as compared to tolerant. The genotypes viz. BG 1053, L550, ICC8950 and ICCV10 were identified as salt tolerant.