Vanadium (V) as minor concentration is present in various plants and extensively found in soils. The current study was established to assess the response of rice seedlings to different V concentrations and also investigated its toxic effect on growth, photosynthetic assimilation, relative chlorophyll content, SPAD index, ion leakage, enzyme activities, hydrogen peroxide (H 2 O 2), and cell death. The rice seeds were sown in Petri dishes for 8 days, and after that, rice seedlings were grown hydroponically in a climate-controlled growth chamber. After 15 days of V-treatment, antioxidant enzyme activities, H 2 O 2 , protein contents, photosynthetic assimilation, relative chlorophyll content, and cell death were determined by utilizing the Spectrophotometer (Lambda 25 UV/VIS Spectrophotometer), and V accumulation (roots and shoots) was determined by GFAAS (GTA 120). The obtained results showed that all V concentrations significantly decreased the biomass (dry and fresh) and root growth as a result of the reduction in total root length, root tips, root fork, root surface area, and root crossing, and V was more accumulated in roots than shoots. Besides this, enzymatic activities were significantly enhanced under V stress. The findings also confirmed that seedling exposed to V stress had lower tolerance indices, photosynthetic activity, and protein contents while the ion leakage was consistently increased by increasing the V concentrations. The viability of plant cells severely damaged in response to high V stress, and H 2 O 2 induction might be responsible for cell death. Generally, all V doses had a drastic effect on enzyme activities and caused cell death of rice plans. Moreover, the current study demonstrated that V ≥ 35 mg L −1 caused damaging effects on rice plants.

Understanding the impact of the warming trend on phenological stages and phases of cotton (Gossypium hirsutum L.) in central and lower Punjab, Pakistan, may assist in optimizing crop management practices to enhance production. This study determined the influence of the thermal trend on cotton phenology from 1980–2015 in 15 selected locations. The results demonstrated that observed phenological stages including sowing (S), emergence (E), anthesis (A) and physiological maturity (M) occurred earlier by, on average, 5.35, 5.08, 2.87 and 1.12 days decade−1, respectively. Phenological phases, sowing anthesis (S-A), anthesis to maturity (A-M) and sowing to maturity (S-M) were reduced by, on average, 2.45, 1.76 and 4.23 days decade−1, respectively. Observed sowing, emergence, anthesis and maturity were negatively correlated with air temperature by, on average, −2.03, −1.93, −1.09 and −0.42 days °C−1, respectively. Observed sowing-anthesis, anthesis to maturity and sowing-maturity were also negatively correlated with temperature by, on average, −0.94, −0.67 and −1.61 days °C−1, respectively. Applying the cropping system model CSM-CROPGRO-Cotton model using a standard variety in all locations indicated that the model-predicted phenology accelerated more due to warming trends than field-observed phenology. However, 30.21% of the harmful influence of the thermal trend was compensated as a result of introducing new cotton cultivars with higher growing degree day (thermal time) requirements. Therefore, new cotton cultivars which have higher thermal times and are high temperature tolerant should be evolved.

Abstract:Resources are limited, thus improving resource use efficiency is a key objective for cereal-based cropping systems. This field study was carried out to quantify resource use efficiencies in selected C 3 and C 4 cereals under split nitrogen (N) application regimes. The study included the following treatments: six cereals (three C 3 : wheat, oat, and barley; and three C 4 : maize, millet, and sorghum) and four split N application regimes (NS 1 = full amount of N at sowing; NS 2 = half N at sowing + half N at first irrigation; NS 3 = Results revealed that C 4 cereals out-yielded C 3 cereals in terms of biomass production, grain yield, and resource use efficiencies (i.e., radiation use efficiency (RUE) and nitrogen use efficiency (NUE)), while splitting N into three applications proved to be a better strategy for all of the selected winter and summer cereals. The results suggest that C 4 cereals should be added into existing cereal-based cropping systems and N application done in three installments to boost productivity and higher resource use efficiency to ensure food security for the burgeoning population.

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