Salinity is a serious threat to crop production in Pakistan and all over the world. It imposes severe reduction in horticultural crop yield and production. Proline is reported to involve in salt tolerance in various crops. It was hypothesized that proline could ameliorate the salinity induced damages in physio-chemical attributes against salt stress. Therefore, a pot experiment was conducted to assess the role of foliar application of proline to improve the salt tolerance in chilli genotypes. Two chilli genotypes namely; Plahi and A-120 were grown under 50 mM NaCl saline condition. Various concentrations of proline (0.4, 0.6, 0.8, 1.0 and 1.2 mM) were applied as a foliar spray on one month old seedlings. Salt stress imposed negative impact on growth (Shoot and root length, plant fresh and dry mass), ionic (K +) and physiological (photosynthetic rate and transpiration rate) attributes in both the studied chilli genotypes except Na + which increased under salinity stress. However, maximum reduction was observed in A-120 as compared to Plahi genotype. In contrast, foliar application of proline under salt stress conditions stimulated shoot and root length, plant fresh and dry mass, photosynthetic rate, transpiration rate and antioxidant enzyme (SOD and CAT) activities were noted under salt stress in both the genotypes. However, maximum increase was observed in Plahi genotype relative to A-120. Moreover, among all proline concentrations, 0.8 mM proved to be the best concentration regarding growth, physiological, ionic and biochemical attributes in both the genotypes.

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 and cultivation of N-Y LARA may be recommended in saline soil. © 2016 Society of Chemical Industry.

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Wheat is an important global staple food crop; however, its productivity is severely hampered by changing climate. Erratic rain patterns cause terminal drought stress, which affect reproductive development and crop yield. This study investigates the potential and zinc (Zn) and silicon (Si) to ameliorate terminal drought stress in wheat and associated mechanisms. Two different drought stress levels, i.e., control [80% water holding capacity (WHC) was maintained] and terminal drought stress (40% WHC maintained from BBCH growth stage 49 to 83) combined with five foliar-applied Zn-Si combinations (i.e., control, water spray, 4 mM Zn, 40 mM Si, 4 mM Zn + 40 mM Si applied 7 days after the initiation of drought stress). Results revealed that application of Zn and Si improved chlorophyll and relative water contents under well-watered conditions and terminal drought stress. Foliar application of Si and Zn had significant effect on antioxidant defense mechanism, proline and soluble protein, which showed that application of Si and Zn ameliorated the effects of terminal drought stress mainly by regulating antioxidant defense mechanism, and production of proline and soluble proteins. Combined application of Zn and Si resulted in the highest improvement in growth and antioxidant defense. The application of Zn and Si improved yield and related traits, both under well-watered conditions and terminal drought stress. The highest yield and related traits were recorded for combined application of Zn and Si. For grain and biological yield differences among sole and combined Zn-Si application were statistically non-significant (p>0.05). In conclusion, combined application of Zn-Si ameliorated the adverse effects of terminal drought stress by improving yield through regulating antioxidant mechanism and production of proline and soluble proteins. Results provide valuable insights for further cross talk between Zn-Si regulatory pathways to enhance grain biofortification.

Maize (Zea mays L.) is one of the most important food and feed cereals of the world, but its production is threatened by sudden climate change especially drought. While, low organic matter in soils increases the drought severity. Therefore, study was planned to investigate the interactive effect of biochar and silicon (Si) nutrition on morpho-physiological and biochemical traits under water-deficit environment. Drought stress was applied subsequent 15 days of seedlings development. Experimental treatments comprised of CK (controlled soil no drought stress nor amended), only drought (40% water holding capacity (WHC)), drought + Si (40% WHC with 100 mg Si kg −1 soil), drought + biochar (40% WHC with 4 t ha −1), and drought + Si + biochar (40% WHC + 100 mg Si kg −1 soil +4 t ha −1). Data were collected after 15 days of treatment application. Drought reduced the growth of maize seedlings by reducing shoot biomass (38%), seedling weight (37%), photosynthetic rate (29%), transpiration rate (28.7%), and relative water contents (23.8%) and increased the activities CAT (30%), SOD (38.5%), and POD (33%). The positive effect of sole application of biochar and silicon was observed in improving physio-biochemical traits. In addition, better results were obtained with combined application of biochar and Si in enhancing maize growth such as shoots (25%), roots (40%), and seedlings (27%) as compared with drought. Combined application of biochar and Si may be a viable option to alleviate adversities of drought stress for maize growth and development.