Nanomaterials. Effective tools for field and horticultural crops to cope with drought stress: A review

Drought is the most serious environmental challenge that limits plant growth and causes more severe yield losses than other abiotic stress factors resulting in a serious food shortage. Nanomaterials (NMs) are considered as vital tools to overcome contemporary and future challenges in agricultural production. Recently, NMs have been applied for enhancing seed germination, growth, physiology, productivity and quality attributes of various crops under normal or stress conditions. Up to date, there is no a comprehensive review about the potential role of NMs in attenuating the drought-induced adverse effects in crop plants. Thus, this review will highlight this issue. Generally, NMs minimize drought-induced osmotic stress by accumulation of osmolytes that result in osmotic adjustment and improved plant water status. In addition, NMs play a key role to improve root growth, conductive tissue elements and aquaporin proteins facilitating uptake and translocation of water and nutrients. Furthermore, NMs reduce water loss by stomatal closure due to abscisic acid signaling. However, this leads to reduced photosynthesis and oxidative stress damage. At the same time, NMs increase the content of light-harvesting pigments, enzymatic and non-enzymatic antioxidants leading to enhancing photosynthesis with reducing oxidative stress damage. Overall, NMs can ameliorate the deleterious effects of drought stress in crop plants by regulation of gene expression and alternation of various physiological and biochemical processes

The demographic characteristics of Palestinian refugees in Syria, 1949-1992

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Agar-agar a promising edible coating agent for management of postharvest diseases and improving banana fruit quality

This study was executed to investigate the potential of agar-agar, a nontoxic and non-degradable gelling agent, as a promising coating agent to improve and protect banana fruit against fungal postharvest diseases i.e., crown, finger, neck and flower end rots which are caused by fungal isolates of Colletotrichum musae and Fusarium moniliforme. Coated-banana fruit samples with different concentrations of agar-agar suspension particularly at 2.0 g · l−1 exhibited a significant reduction in incidence and severity of postharvest diseases compared to untreated fruit. Banana fruits dipped in agar suspension at 2.0 g · l−1 for 5, 10 and 15 min showed significant reduction in disease incidence and severity. Moreover, application of agar suspension as a coating agent at 2.0 g · l−1 significantly decreased weight loss (%), firmness loss (%), and soluble solid concentration of banana fruit for 15 days at 25 ± 2°C. Scanning electron microscopy observation confirmed that the fruit coated with agar colloid at 2.0 g · l−1 had significantly fewer cracks and showed smoother surfaces than untreated fruit. This explains the quality improvement in agar-coated fruit compared to uncoated fruit. Overall, agar colloid, a safe coating agent, could be used to protect banana fruit against postharvest rot diseases and extend fruit storage life during ripening and storage

Nanomaterials. Effective tools for field and horticultural crops to cope with drought stress: A review

Drought is the most serious environmental challenge that limits plant growth and causes more severe yield losses than other abiotic stress factors resulting in a serious food shortage. Nanomaterials (NMs) are considered as vital tools to overcome contemporary and future challenges in agricultural production. Recently, NMs have been applied for enhancing seed germination, growth, physiology, productivity and quality attributes of various crops under normal or stress conditions. Up to date, there is no a comprehensive review about the potential role of NMs in attenuating the drought-induced adverse effects in crop plants. Thus, this review will highlight this issue. Generally, NMs minimize drought-induced osmotic stress by accumulation of osmolytes that result in osmotic adjustment and improved plant water status. In addition, NMs play a key role to improve root growth, conductive tissue elements and aquaporin proteins facilitating uptake and translocation of water and nutrients. Furthermore, NMs reduce water loss by stomatal closure due to abscisic acid signaling. However, this leads to reduced photosynthesis and oxidative stress damage. At the same time, NMs increase the content of light-harvesting pigments, enzymatic and non-enzymatic antioxidants leading to enhancing photosynthesis with reducing oxidative stress damage. Overall, NMs can ameliorate the deleterious effects of drought stress in crop plants by regulation of gene expression and alternation of various physiological and biochemical processes

Biological control of Podosphaera xanthii the causal agent of squash powdery mildew disease by upregulation of defense-related enzymes

Abstract Squash (Cucurbita pepo L.), one of the most important vegetable crops for human nutrition all over the world, is infected by many diseases, particularly powdery mildew caused by Podosphaera xanthii (syn. Sphaerotheca fuliginea), which is considered the most serious disease causing yield losses. This research study was conducted to investigate the role of Bacillus subtilis, Bacillus chitinosporus, Bacillus pumilus, Bacillus megaterium, Bacillus polymexa, Trichoderma harzianum, and Trichoderma viridi on squash leaves infected with P. xanthii under laboratory and greenhouse conditions. Results indicated that all treatments significantly inhibited the conidial germination of P. xanthii than the control. A significant decrease in the disease symptoms, severity, and the area under disease progress curve (AUDPC) was registered in squash plants sprayed with the tested bio-agents, particularly B. subtilis, B. pumilus, and T. harzianum. The activity of defense-related enzymes, i.e., catalase (CAT), peroxidase (POX), and polyphenol oxidase (PPO), were significantly upregulated as results of most treatments. Light and scanning electron microscopic (SEM) investigation showed that the morphological shape of P. xanthii was abnormal and the pathogen growth was limited in bio-agent-treated plants compared to control plants that showed dramatic infection. Bio-agent treatments significantly increased growth and yield attributes of squash plants over control. Overall, the results showed possibility of using the tested bio-agents to control squash powdery mildew disease as an alternative to fungicides’ use that is harmful for human health and polluting the environment