Résumé
An attempt has been made to assess the response of Phaseolus mungo L. under influence of cadmium chloride (Cd Cl2) with special reference to growth, morphology, yield and biochemical aspects. Surface sterilized seeds of Phaseolus mungo L. cv. T-9 were exposed to various concentrations of Cd Cl2 solution (10-2 M, 10-4 M, 10-5 M, 10-8 M and control) for 12 hr at room temperature and these seeds were transferred to petriplates and polythene bags in triplicate. 10-2 M conconcentration was found to have deleterious effects on seed germination, germination relative index, length and dry weight of root and shoot, shoot root ratio and seedling vigour index, plant height, phytomass, number of leaves and branches, leaf area and chlorophyll contents while 10-8 M revealed slightly promotory effects. Phytotoxicity percentage and chlorophyll stability index were maximum in (10-2 M) concentration, while minimum in 10-8 M conconcentration of Cd Cl2. Nitrate and nitrite reductase activity was markedly inhibited at higher conconcentration. Low dose of Cd (10-8 M) did not affect soluble sugar contents of seeds but it induced a significant increase at higher conconcentration (10-2 M). It however, did not affect protein contents of seeds accept at higher concentration.
Résumé
An experiment was conducted to see the impact of osmotic stress as it is one of the main cause in various soil and water disorders in agricultural field crops, specially the seed germination and seedling growth. The osmotic stress was generated using PEG-6000 and the seed germination, seedling growth were evaluated including the status of pigments i.e. chlorophyll (a, b and total), total carotenoids, pheophytin (a, b and total) and different enzymes like amylase, peroxidase, catalase and superoxide dismutase. The various osmotic potentials generated (-2, -5 and -10 bars) showed significant decrease in germination percentage as at the osmotic potential of -10 bars it was observed 70 in comparison to 90% of control. All the seedling growth parameter also showed inhibition with increase in osmotic potential. Increase in osmotic stress decreased Chlorophyll ‘a’, while Chlorophyll ‘b’ was increased in -5 bars while total chlorophyll showed decrease in -5 bars osmotic potential. Total carotenoids and pheophytin (a, b and total) were highly increased in -5 bars and decreased in -10 bars osmotic concentration. Enzymatic activity was found to be decreased in amylase while peroixidase, catalase and SOD were increased at different osmotic gradients in comparison to control. The data observed in the experiment can be helpful to assess the impact of any kind of osmotic stress on plant growth and development in crops.
Résumé
The various dilution levels of treated tannery effluent (T.E.) (10, 25, 50 and 100 %) and Cr 6+ (0.5, 2.0, 5.0 and 10 ppm) were used in experiment to know their effect on seed germination, seedling growth, pigments and enzymes content in Black gram (Phaseolus mungo Roxb.). Chromium is known as the main toxic component of tannery effluent so its various concentration were given to know their effects. For the recovery of plant damage, protective value of 10 and 25 ppm of zinc, potassium and iron sulphate were also given with 50 % treated tannery effluent and 10 ppm Cr 6+ levels in separate petridishes. The different concentrations of tannery effluent and Cr 6+ showed significant reduction in germination percentage, seedling growth (plumule and radicle length, number of lateral roots, fresh and dry weight, and moisture %) and pigments (chlorophyll, pheophytin and carotenoids) with increase in concentrations. The lower doses of tannery effluent (10%) and Cr 6+ (0.5, 2 and 5 ppm) slightly increases the pigments concentration. The amylase activity and total sugar contents were also significantly decreased while catalase and peroxidase activity showed significant increase with rise in concentrations of treatments. The lower concentrations of tannery effluent (dilution 10 and 25%) and Cr 6+ (0.5 and 2 ppm) showed significant increase in total protein contents while decrease at higher concentrations. The zinc, potassium and iron treatments led to recover the damage caused by chromium and tannery effluent in all parameters. In recovery treatments zinc showed highest and significant recovery in maximum parameters. Iron also showed almost similar effect to the zinc while potassium showed minimum recovery.