Muhammad Rashid Shaheen

Zinc-cadmium interactions: Impact on wheat physiology and mineral acquisition.

Increasing concentration of Cd in soil is of great concern due to risk of its entry into food chain. Zinc (Zn) being antagonist to Cd is an important micronutrient to ameliorate its toxic effects on plants and to limit its entry into food chain. A pot experiment was conducted using Cd contaminated soil (30 mg Cd kg(-1) soil as 3CdSO4 · 8H2O) to investigate the effect of soil and foliar applied Zn on physiological response and Cd concentration in wheat. In soil, Zn was applied at 15 and 30 mg Zn kg(-1) soil as zinc sulfate (ZnSO4 · 7H2O). For foliar applications, 3 and 6 g L(-1) ZnSO4 solution was sprayed on completing eight weeks of growth. Results indicated that Zn application could effectively improve physiological performance and mineral content of wheat grown on Cd contaminated soils. Among different Zn fertilization treatments, foliar application of 3 g L(-1) ZnSO4 solution recorded the maximum soluble proteins and the minimum grain-Cd concentration. Soil application of ZnSO4 or foliar application at 6 g L(-1) did not affect Cd concentration in grains. Zinc application through both the methods significantly increased phosphorus (P), potassium (K) and Zn concentrations in shoots. Concentration of P and K in grains showed positive relationship with that of Zn. In crux, present study suggests that foliar application of Zn at booting stage in a suitable concentration (3 g L(-1) ZnSO4 solution) can effectively ameliorate the adverse effects of Cd and decrease grain-Cd of wheat grown in Cd contaminated soil.

Morpho-physiological evaluation of tomato genotypes under high temperature stress conditions

BACKGROUND Tomato (Solanum lycopersicum L.) is an important but heat-sensitive vegetable crop. The losses in tomato production associated with heat stress are aggravating further under a global warming scenario. The present study was designed to investigate the comparative performance of tomato genotypes under high temperature stress. Tomato genotypes (191) were exposed to the controlled conditions of high temperature (40/32 °C day/night temperature). Different morphological (shoot length, root length, shoot fresh weight, root fresh weight, shoot dry weight, root dry weight and number of leaves), physiological (photosynthetic rate, transpiration rate, water use efficiency, stomatal conductance to water, sub-stomatal CO2 and leaf temperature) and SPAD value (chlorophyll content) were recorded to check the diversity among genotypes against heat stress. RESULTS All the genotypes showed a significantly variable response in almost all the attributes under high-temperature conditions. Correlation among the variables provided a clear understanding of the phenomena involved. Based on all the attributes studied, genotypes L00090 and L00091 were found to be the most heat tolerant compared to other genotypes, whereas CLN1462A and CLN 1466E were found to be comparatively sensitive. CONCLUSION It was concluded that the studied attributes were genotype dependent, and significant diverse performance was noted. The findings of this study pave the way towards the selection of tolerant genotypes, not only for use under high-temperature conditions but also to employ them in breeding programs to produce heat-tolerant hybrids.

Salicylic acid confers salt tolerance in potato plants by improving water relations, gaseous exchange, antioxidant activities and osmoregulation

BACKGROUND Potato is an important vegetable; however, salt stress drastically affects its growth and yield. A pot experiment was therefore conducted to assess salicylic acid efficacy in improving performance of potato cultivars, grown under salt stress (50 mmol L-1 ). Salicylic acid at 0.5 mmol L-1 was sprayed on to potato plants after 1 week of salinity application. RESULTS Salt stress effects were ameliorated by salicylic acid effectively in both the studied cultivars. N-Y LARA proved more responsive to salicylic acid application than 720-110 NARC, which confirmed genetic variation between cultivars. Salicylic acid scavenged reactive oxygen species by improving antioxidant enzyme activities (superoxide dismutase, catalase, peroxidases) and regulating osmotic adjustment (proline, phenolic contents), which led to enhanced water relation and gaseous exchange attributes, and thereby increased potassium availability and reduced sodium content in potato leaves. Moreover, potato tuber yield showed a positive correlation with potassium content, photosynthesis and antioxidant enzyme activities. CONCLUSION Salt tolerance efficacy of salicylic acid is authenticated in improving potato crop performance under salt stress. Salicylic acid effect was more pronounced in N-Y LARA, reflecting greater tolerance than 720-110 NARC, which was confirmed as a susceptible cultivar. Hence salicylic acid at 0.5 mmol L-1 and cultivation of N-Y LARA may be recommended in saline soil.

Study of Efficacy of Various Split Applications of Inorganic Nitrogen on Potato Crop

Series of experiments have been conducted to find the optimized dose and efficacy of nitrogen to fulfill the requirements of plant at each level by making split doses. Being most important macro nutrient, afield trial was conducted to study the effect of without applying nitrogen (control) single nitrogen (N) application at planting time on yield and nitrogen uptake of potato in comparison to various split applications. Data were collected about plants vegetative growth, total yield and qualitative factors (TSS, nitrogen, phosphorus, potassium and protein percentage in tuber). Experimental design used was Randomized Complete Block Design (RCBD) having seven treatments with three replications. Data were analyzed by using standard statistical techniques. Overall, qualitative characters of tubers and yield enhanced with split nitrogen application as compared to all nitrogen applied once at planting time whereas, there was no significant difference between tuber nitrogen, potassium, phosphorus and protein contents.

Exploring the better genetic options from indigenous material to cultivate tomato under high temperature regime

Screening test was conducted on 54genotypes of tomato to analyze the effect of heat stress and categorize them as heat tolerant or heat susceptible ones. Seedlings were grown at temperatures of 28/22oC day/night. Four weeks after sowing, plants were exposed to high temperatures of 40/32oC day/night for one week. Data for various morphological (root and shoot length, root and shoot fresh and dry weight, number of leaves) and physiological parameters (chlorophyll contents, sub-stomatal CO2, transpiration rate, stomatal conductance, photosynthetic rate, water use efficiency and leaf temperature) were recorded. Heat stress had a negative effect on all physiological and morphological processes of the genotypes. However, “Parter Improved”, “Legend” and “Roma” were the most tolerant genotypes whereas “Grus Chovka”, “Nepoli”, “Tima France”, “Kaldera” and “Cold Set” were susceptible to heat stress.