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• Drought stress reduced yield and nutritional content. • Drought stress reduced photosynthesis and secondary metabolites in two spinach varieties. • Amino acid application improved the osmolytes and antioxidant activities of spinach under drought stress. • Nutrient acquisition and translocation were improved by foliar spray of amino acids. As part of human nutrition, organic fertilizer decreases chemical fertilizers exposure and increases plant nutritional value, which is a major concern nowadays. This study highlights the current state of knowledge on the effect of drought stress and amino acid application to avert drought damage to two spinach (Spinacia oleracea L.) varieties at the developmental and maturation stages. Two varieties of spinach, namely Desi and VRI-2019, were exposed to different amino acid treatments such as methionine (Meth), tyrosine (Tyr), phenylalanine (Phe), proline (Pro) and mixture at 250 mg/L at 50% (drought) and 100% (control). The results showed that drought stress deteriorated spinach's growth and yield attributes and hindered the nutrient uptake of essential nutrients. However, the amino acid application improved the quantity and quality composition of secondary metabolites (flavonoids and phenolics) and enhanced the growth (root length, fresh and dry weight, shoot length, fresh and dry weight), yield attributes (number of leaves, the weight of leaf, yield per plant and leaf area), nutrient uptake (calcium and potassium) and antioxidant machinery (catalase and peroxidase), which differed depending on the spinach varieties; therefore, the use of Desi variety should be recommended under drought-prone areas with the addition of mixed emulsion of amino acids or/and separate doses according to the amino acid availability. [ABSTRACT FROM AUTHOR]

Drought is one of the major abiotic stresses which negatively affects plant growth and development. The current study evaluated the effects of drought on the growth, physiology, and biochemical attributes of wheat seedlings; and examined the role of foliar application of ZnO nanoparticles in alleviating drought-induced effects. Two wheat cultivars i.e., Anaj-2017 and FSD-2018 were grown in soil-filled pots and were subjected to 100% field capacity (FC) (well watered) and 50% of FC (drought stress). Whilst different treatments of ZnO nanoparticles spray included no spray, water spray, and 50, 100, and 150 ppm ZnO. Results demonstrated that drought caused a significant reduction in seedling fresh and dry weights, photosynthetic pigmentation, and antioxidant activities compared with a well-watered treatment. Nevertheless, the application of 100 and 150 ppm of ZnO nanoparticles effectively ameliorated the negative effects of drought and enhanced the performance of both cultivars under drought. Data revealed a significant increase in fresh and dry weight of shoot and root with the application of ZnO nanoparticles. A substantial increase of 73.68% and 28.51% in chlorophyll "a" and 26.15% and 50.02% in chlorophyll "b" was recorded with the application of 100 ppm of ZnO nanoparticles in Anaj-2017 and FSD-2018, respectively over control (0 ppm). The application of these nanoparticles also triggered the antioxidant defense system and protected the crop from oxidative damage. Averaged across different stress treatments, application of 150 and 100 ppm of ZnO nanoparticles increased the peroxidase activity by 60% and 72% in FSD-2018, and 15% and 23% in Anaj-2017, respectively compared with no spray. FSD-2018 outperformed Anaj-2017 regarding its overall performance under ZnO treatments and drought conditions. In a nutshell, it can be concluded that ZnO nanoparticles ameliorated the negative impacts of drought by improving the growth, physiology, and antioxidant defense of both wheat cultivars. • Drought reduced seedling growth, photosynthetic pigmentation, and antioxidant activities. • ZnO NPS efficiently improved growth, and photosynthetic pigments. • ZnO NPs triggered antioxidant defense system for lowering oxidative stress. • FSD-2018 outperformed Anaj-2017 regarding its overall performance under drought conditions. [ABSTRACT FROM AUTHOR]

Salinity is affecting more than 6 million hectares of cultivated area in Pakistan. The use of amino acids offers a pragmatic solution for minimizing the adverse effects of salinity on Spinacia oleracea L. (spinach). The present study evaluated the possible potential of amino acids in enhancing the salinity tolerance in spinach and identified the probable underlying mechanisms. The experiment comprised of two factors viz. amino acids with total of seven treatments; control, salinity (sal) 100 mM, Methionine + sal, Phenylalanine + sal, Proline + sal, Tyrosine + sal, Combined amino acids + sal, and two spinach cultivars (Desi Palak and VRI-2019). Salinity stress decreased the morpho-physiological attributes of both spinach cultivars, nevertheless, the application of combined amino acids effectively improved the tolerance against salinity stress. Compared with control, all applications of amino acids increased the root and shoot length, fresh and dry weight, number of leaves, and plant yield per plant of both spinach cultivars. However, the maximum was noted by the application of combined amino acids. Combined amino acids triggered the activities of antioxidants (catalase, superoxide dismutase, peroxidase), increased the contents of free proline, phenolics, flavonoids, chlorophyll a, b, carotenoids, calcium, and potassium in root and shoot while decreasing the reactive oxygen species (hydrogen peroxide) and sodium contents in both spinach cultivars under saline conditions. Overall, the VRI-2019 performed better than Desi Palak. The vigorous growth along with higher salinity tolerance because of amino acid treatments was linked to better chlorophyll contents, higher accumulation of osmolytes, maintenance of ionic balance, and an improved antioxidant defense system in Spinacia oleracea. [ABSTRACT FROM AUTHOR]

• Salinity in arable land is becoming major issue in world. • Foliar application of MLE ameliorated effects of salinity. • MLE in stressed plants c enhanced POD,SOD, GB and TSS. • MLE revealed potential as biostimulant for plants. We evaluated role of exogenous application of moringa leaf extract (MLE) in ameliorating perturbations caused by salinity (200 mM) in some physiological, biochemical and anatomical parameters of two canola varieties i.e. Super (V 1) and Punjab (V 2). Data analysis revealed significant interaction between salinity and plant attributes while MLE ameliorated effects of salinity. Both varieties exhibited an increase in shoot fresh (57%, 53%) and dry weights (37%, 19%) respectively after foliar application of MLE under salinity. In V1, particularly, this incremented growth corresponded to increase in Chl-a (33.53%), Chl-b (36.79%) under foliar application of MLE. The results presented that post MLE application in stressed plants caused comparative enhancement in H 2 O 2 , MDA, GB and TSS in both varieties but in V 1 it was particularly high (27%, 46%, 12%, 13%, respectively) when compared over control. On the other hand, TFAA (31.22%), proline (83.12%), proteins (106%), POD (81.17%), catalase (27.45%), H 2 O 2 (25.47%) and ascorbic acid (74.27%) were also boosted after MLE application in comparison with control. MLE caused a significant enhancement in leaf and stem anatomical characteristics in both varieties compared to control. Although increase was observed after MLE application but V 1 responded more strongly than V 2. Differential behavior of both varieties to MLE revealed potential of it as biostimulant for plants facing salinity. Overall, variance in photosynthetic pigments, osmoprotectants, antioxidants and changes in anatomical characteristics of leaf and stem due to MLE in V 1 and V 2 contributed in salinity tolerance. [ABSTRACT FROM AUTHOR]