Impact of osmotic stress on seed germination and seedling growth in black gram (Phaseolus mungo).

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.

Interactive studies of potassium and copper with cadmium on seed germination and early seedling growth in maize (Zea mays L.).

In the present study a novel approach has been made to evaluate the toxicity of cadmium in maize (Zea mays L. cv. KJ9451) in terms of germination, seedling growth, pigment development and relevant enzyme activity,and the possible remedial approach using potassium and copper to reduce cadmium toxicity. For the present investigations maize seeds were sown in petridishes on filter paper in triplicate containing different doses of cadmium viz. 0.05, 0.10, 0.25, 0.50, 0.75 and1.0 mM and for interactive studies maize seeds sown in 0.50, 0.75 and 1.00 mM Cd concentration were subjected to 0.50 and 1.00 mM concentration of potassium and copper respectively. At the high cadmium concentrations, germination percentage was decreased. I also showed considerable reduction in plumule length, radicle length and number of lateral roots while the potassium and copper combination with cadmium increased the seedling growth. The calculated values of SVI were found to be decreased with increase in the concentration of cadmium. Decreased GRI values were observed in maize treated with three higher concentrations of cadmium but the combination of potassium and copper showed recovery in GRI values. The fresh weight, dry weight and moisture contents were also found reduced with higher cadmium concentrations but the potassium and copper combination showed recovery when used with higher concentration of cadmium. Declined chlorophyll contents were noticed under the influence of higher cadmium concentrations. Both the combination of potassium and copper used with 0.50, 0.75 and1.00 mM cadmium concentrations resulted in increased chlorophyll and pheophytin contents and decreased in Cu combination respectively. The potassium and copper (both 0.50 and 1.00 mM) with 0.75 and 1.00 mM cadmium increased the carotenoid contents although lone cadmium decreased it. Amylase activity was found to be gradually reduced at all concentrations of cadmium. The 0.50 mM and 1.00 mM potassium combination improved amylase activity. Marked increase in catalase and peroxidase activity by the application of test chemical was observed in different doses of cadmium. The potassium and copper combination used with cadmium concentration reduced catalase activity while peroxidase activity was promoted.

Combinatorial effects of distillery and sugar factory effluents in crop plants.

Under the reutilization and recycling strategy of industrial effluents, treated distillery and sugar factory mixed effluent was used in petridish culture experiments to investigate its effect on seed germination and seedling growth in wheat, garden pea, black gram and mustard. The seed germination and seedling growth were significantly reduced with increase in concentration of the effluent. The fresh matter was found significantly increased in barley (1.16 g per seedling in 25% dilution level of effluents in comparison to 0.93 in control), while other higher dilution levels reduce it. Wheat, garden pea, black gram, mustard invariably showed inhibition in fresh weight. Dry weight was found consistently reduced or unchanged in different treatments. Total chlorophyll contents in barley were significantly increased in different treatments (2.351 and 2.721 mg/g fresh weight of tissue at 25, 50% dilution levels in comparison to 1.781 of control) while in other crop it was reduced alloverthe treatments. Amylase activity in wheat, garden pea, black gram and mustard was reduced in all the treatments. Only in barley its level was enhanced from 0.76 to 0.85, 0.96, 0.81 in 25, 50, 75% dilution levels of the effluent mixture respectively Based on the data of different crops barley was found to be highly tolerant as the 25 and 50% dilution levels of combined effluents. It showed no change in germination %, while seedling growth was increased in lower dilution levels of combined effluent as compared to control Barley>garden pea>wheat>black gram>mustard gradually showed increased level of sensitivity respectively Most detrimental effects were seen in mustard. This toxicity might be due to excess of nutrients, beyond the limits of tolerance. Therefore, the higher concentration of mixed effluent was not advisable for irrigation purpose, however it could be used for irrigation purpose after proper treatment and dilution (one part treated effluent and five parts of available irrigation water), as this dilution level was found growth and yield promotory

Response of wheat seed germination and seedling growth under copper stress.

The experiment was performed to study the seed germination and seedling growth in wheat under the influence of different concentrations of copper. The germination %, plumule and radicle length, and number of lateral roots decreased with increase in copper concentration (5, 25, 50 and 100 mgl(-1)). Total chlorophyll contents declined on 14th day from 1.605 of control to 1.581, 1.242, 1.275 and 1.107 mg g(-1) fresh weight in respective treatments. Similarly, on 21st day the decline in total chlorophyll contents was 1.288, 1.123, 1.077 and 0.985 mg g(-1) fresh weight in respective treatments against 1.724 of control. Likewise the pheophytin contents also declined showing the same pattern. However, carotenoid contents increased in different treatments, ranging between 0.366 to 0.464 mg g(-1) fresh weight in comparison to control (0.328) on 14th day, but showed adverse effects on 21st day as the carotenoid contents decreased in different copper treatments. The activity of amylase was found to be gradually reduced 14th day from 29.73 of control to 27.80, 27.33, 21.86 and 20.00 mg g(-1) and at 21st day from 14.40 of control to 11.46, 11.01, 9.86 and 5.60 mg g(-1) fresh weight with increase in concentrations of copper The catalase activity increased 14th day from 97.33 of control to 134.66, 161.33, 216.00 and 232.00 and on 21st day from 140.00 of control to 245.33, 274.66, 278.66 and 300.66 ml H2O2 hydrolyzed/g fresh weight in different increased concentrations of copper Similarly the peroxidase activity was also increased with increase in copper concentration. Likewise fresh weight and moisture contents decreased with increase in copper concentration. The dry weight was increased with increase in concentration of copper treatment. Total protein contents were initially decreased on 14th day from 80.69 of control to 66.75, 60.41, 56.41 and 48.48 microg/mg and on 21st day 81.37 of control to 67.06, 62.31, 54.92 and 46.47 microg/mg fresh weight in different copper concentrations respectively Sugar contents were significantly decreased in all the doses of copper on both 14th and 21st days i.e. (5.53 of control to 4.76, 3.69, 3.68 and 2.86 microg/mg in different copper treatments on 14th day and 4.81 of control to 4.49, 3.40, 2.79 and 2.15 microg/mg on 21st day respectively.

Chromium in tannery industry effluent and its effect on plant metabolism and growth.

Different dilution levels of tannery treated effluent and their corresponding concentration of chromium (Cr6+) were studied in a petridish culture experiment on seed germination and seedling growth in radish (Raphanus sativus L). The different concentrations of Cr6+ (2, 5 and 10 ppm) and treated tannery effluent (10, 25 and 50%) showed reduction in seedling growth and related enzymatic activities with increase in concentration of Cr6+ in treatments and effluent both. The low concentration of chromium (2 ppm) and effluent dilution (10%) showed significant growth reduction separately. At this concentration of chromium and effluent dilution chlorophyll content, amylase, catalase and protein contents remained unchanged while with increase in Cr6+ concentration (>2ppm) and effluent dilution (> 10%) in treatments showed growth inhibitory effects.

Metabolism of mycobacteria.

The metabolism of mycobacteria have been studied with reference to carbohydrate, lipids, nitrogen metabolism and oxidative phosphorylation. Some of the enzymes of glycolytic pathway, tricarboxylic acid cycle and lypogenic enzymes were purified, characterized and their kinetic properties investigated. The effect of age of the culture and environmental factors on different aspects of metabolism of mycobacteria were also studied. A comparison of lipid profile in various species of mycobacteria grown in different culture conditions were made. The metabolism of spheroplasts isolated from mycobacteria has been established with respect to their energy charge and to synthesize peptidoglycan using D-alanine as the precursor.