Protective effect of jasmonic acid and potassium against cadmium stress in peas (Pisum sativum L.)

A combination of mineral nutrients and plant growth regulators should be assessed to improve crop performance under various abiotic stresses. There is a need to include plant growth regulators in fertilization regime of various crops along with essential mineral nutrients, especially when they are irrigated with polluted water with higher levels of heavy metals. The performance of pea was evaluated under cadmium (Cd) stress coupled with potassium (K) and jasmonic acid (JA) supplementation. The Cd stress (50 μM) was applied to soil (sandy loam) grown pea plants as basal dose after a month of sowing. The control and stressed plants were then supplemented with K (5 M), JA (0.5 mM) and their collective application along with control as distilled water. Cd stress showed a marked reduction in growth pattern, however, the collective supplementation sufficiently improved the growth pattern of stressed peas plants as evidenced by improvement in shoot length (cm), root length (cm), number of leaves per plant, leaf area (cm²), plant fresh and dry weight (gm). Potassium application under Cd stress significantly enhanced internodal distance (cm) while the number of seeds per pod and relative water contents remained nonsignificant. The applied treatment (JA + K) under Cd stress prominently improved enzymatic activities, which were measured as nitrate reductase activity (NRA), nitrite reductase activity (NiRA), superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT). Cd stress impacted the biochemical profile by enhancing antioxidant capacity (AC), antioxidant activity (AA), total phenols (TP), while reducing total soluble protein (TSP), chlorophyll 'a', chlorophyll 'b' and carotenoids. The combined application of JA and K under Cd stress enhanced AC, AA, TP, Chl a and b, TSP and carotenoids. The results indicate that foliar application of JA and K efficiently negated the harmful effects of Cd stress on peas.

A numerical analysis of calendering of Oldroyd 4-constant fluid

We investigate the effects of non-Newtonian parameters on the exiting sheet thickness in the calendering of Oldroyd 4-constant fluid. The governing equations are first converted into dimensionless form and then simplified under lubrication approximation theory. A complete numerical approach is developed based on Matlab built-in routine “bvp4c” in order to obtain stream function and pressure gradient. The pressure is computed using Runge-Kutta method. The effects of involved material parameters on various quantities of interest are highlighted through graphs. The results indicate that Oldroyd 4-constant model predicts lower pressure in the nip region than that of the Newtonian model. The force and power for Oldroyd 4-constant model are also lower than their counterparts for Newtonian model. Moreover, the leave-off distance is nearly independent of the material parameters of the Oldroyd 4-constant model for larger value of the entering sheet thickness.