Effect of Cadmium Stress on the Growth,Physiology,Stress Markers,Antioxidants and Stomatal Behaviour of Two Genotypes of Chickpea(Cicer arietinum L.)

The current work was performed to know the impact of cadmium(Cd)toxicity on two different genotypes of chickpea(Cicer arietinum L.)namely Pusa-BG1053 and Pusa-BG372.Cadmium was applied in the form of cadmium chloride(CdCl_(2)),in varying levels,0,25,50,75,and 100 mg Cd kg^(-1)soil.Plant growth as well as physiological attributes were decreased with increasing concentration of Cd.Both genotypes showed the maximum and significant reduction at the maximum dose of Cd(100 mg Cd kg^(-1)soil).Results of this study proved that the genotype Pusa-BG1053 was more tolerant and showed a lower decline in growth,photosynthetic and biochemical attributes than Pusa-BG372.This later genotype showed the maximum reduction and was sensitive to Cd stress.A better activity of antioxidants protected Pusa-BG1053 from Cd toxicity;on the other hand,the activity of antioxidants was much lower in Pusa-BG372.Scanning electron microscopic studies showed differences in both genotypes.In Pusa-BG1053,stomatal quantity was higher and stomata were slightly close to the characteristic guard cells.In Pusa-BG372 stomata were lower,slightly open and with highly affected guard cells.Root cell mortality due to the harsh effects of Cd appeared to be more evident in Pusa-BG372 than Pusa-BG1053,which was visible under a confocal microscope.As a result of this study,Pusa-BG1053 was a more tolerant genotype,and exhibited a minimum reduction in terms of all studied parameters than Pusa-BG372,which was a sensitive genotype to Cd toxicity.

Changes in Growth,Photosynthetic Pigments,Cell Viability,Lipid Peroxidation and Antioxidant Defense System in Two Varieties of Chickpea(Cicer arietinum L.)Subjected to Salinity Stress

Salinity is one of the most severe abiotic stresses for crop production.The present study investigates the salinityinduced modulation in growth indicators,morphology and movement of stomata,photosynthetic pigments,activity of carbonic anhydrase as well as nitrate reductase,and antioxidant systems in two varieties of chickpea(Pusa-BG5023,and Pusa-BGD72).On 20^(th) day of sowing,plants were treated with varying levels of NaCl(0,50,100,150 and 200 mM)followed by sampling on 45 days of sowing.Recorded observations on both the varieties reveal that salt stress leads to a significant decline in growth,dry biomass,leaf area,photosynthetic pigments,protein content,stomatal behavior,cell viability,activity of nitrate reductase and carbonic anhydrase with the rise in the concentration of salt.However,quantitatively these changes were less in Pusa-BG5023 as compared to Pusa-BGD72.Furthermore,salinity-induced oxidative stress enhanced malondialdehyde content,superoxide radicals,foliar proline content,and the enzymatic activities of superoxide dismutase,catalase,and peroxidase.The variety Pusa-BGD72 was found more sensitive than Pusa-BG5023 to salt stress.Out of different graded concentrations(50,100,150 and 200 mM)of sodium chloride,50 mM was least toxic,and 200 mM was most damaging.The differential behavior of these two varieties measured in terms of stomatal behavior,cell viability,photosynthetic pigments,and antioxidant defense system can be used as prospective indicators for selection of chickpea plants for salt tolerance and sensitivity.

Day to Day Consistency and Inter-subject Variability of Neuromuscular Responses and Performance Fatigability as the Result of Maximal,Bilateral,Dynamic Leg Extensions

Purpose The purpose of the present study was to examine the day-to-day consistency and inter-subject variability of com-posite and individual,neuromuscular and torque patterns of responses as a result of a fatiguing bout of maximal,bilateral,isokinetic leg extension muscle actions.Methods Ten men (Mean ± SD =21.6 ± 2.5 years) completed two testing visits consisting of pretest and posttest maximal voluntary isometric contractions (MVIC) as well as 25 maximal,bilateral,isokinetic (180°/s),leg extension muscle actions.Electromyographic (EMG) and mechanomyographic (MMG) signals were collected from the vastus lateralis and normalized to the MVIC.Performance fatigability was defined as the percent decline in torque between the average of repetitions 1,2,and 3 and repetitions 23,24,and 25.Polynomial regression was used to examine the individual and composite relation-ships between EMG amplitude (AMP),EMG mean power frequency (MPF),MMG AMP,MMG MPF,and torque versus repetitions.Results There was no significant difference (d =0.80;P =0.17) in the performance fatigability between Day 1 (19.3% ± 7.1%)and Day 2 (26.9% ± 11.3%).Polynomial regression indicated substantial inter-subject variability,but high day-to-day consistency.Conclusion The composite EMG AMP,MMG AMP,and MMG MPF patterns of responses demonstrated consistency across days.The composite EMG MPF patterns of responses,however,were not consistent between Day 1 and Day 2.In addition,based on the high inter-subject variability,future studies should present both composite patterns of neuromuscular responses and the patterns of responses on a subject-by-subject basis to make inferences regarding fatigue-induced changes in motor unit activation strategies.