International Letters of Natural Sciences Vol. 76

Abstract: This study was carried out during the winter seasons of 2016 and 2017 at private farm in Beni Suief Governorate, Egypt to investigate the integrative use of potassium levels (24, 48, 72 and 96 kg K₂O fed^-1) and soil mulching (rice straw and bare soil) on growth and productivity of garlic under three levels of surface irrigation (60, 80 and 100 % of crop evapotranspiration (ET_C)). The experimental layout was a spit-spilt plot system based on Randomized Complete Blocks Design. Irrigation levels, potassium rates and mulch types were randomly allocated in the main, sub and sub-sub plots, orderly. The obtained results showed that, the amount of irrigation at 80 and/or 100 % ET_C was accompanied increases by plant height, leaves number, leaf area and dry weight plant^-1, total bulbs yield, individual bulb weight, cloves weight and number bulb^-1 compared to irrigation 60 % ET_C. The application of potassium from 24 to 48 and further to 72 and 96 kg K₂O fed^-1 gave gradual increments in the aforementioned growth and productivity of traits. The rice straw mulch augmented all previous growth, total bulbs yield and its components compared to bare soil. Generally, the 1^st order interaction between irrigation percent at 100 and/or 80 % ET_C × potassium rate at 96 and/or 72 kg K₂O fed^-1, irrigation percent at 80 and/or 100 % ET_C × rice straw, potassium rate at 96 kg K₂O fed^-1 × rice straw and the 2^nd interaction of irrigation percent at 100 % ET_C × potassium rate at 96 kg K₂O fed^-1 × rice straw mulch had pronounced effects on morphological characters and bulbs yield and its components compared to other combined treatments.

Abstract: The leafy vegetable Telfairia occidentalis is a tropical vine grown in West Africa; it is indigenous to Southern Nigeria and is usually subjected to extreme salt stress in Southern Nigeria as well as in the world that results in significant loss of T. occidentalis production. Therefore, the present investigation was aimed at evaluating the response of T. occidentalis seedlings inoculated with arbuscular mycorrhizal fungi (Glomus geosporum) in saline soil and further to determine the threshold of T. occidentalis salinity tolerance in association with G. geosporum. The total photosynthetic pigments contents in saline soil treatment were significantly (p=0.05) reduced as well as percentage arbuscular mycorrhizal fungi colonization (53.97 to 22.41%). Mycorrhizal dependency was significantly (p=0.05) higher in saline soil treatments compared to control (100.00% to 15.13%). Mineral analysis of T. occidentalis leaves revealed increased uptake and accumulation of Na⁺ (500.00 mg/kg in control to 2920.13 mg/kg in saline soil treatment). Saline soil treatments significantly (p=0.05) reduced the K, Mg, N, P and Ca. AM Fungi significantly (p=0.05) increased the photosynthetic pigments and minerals both in saline and non-saline soil treatments. Using different mechanisms T. occidentalis by association with G. geosporum showed better salt tolerance thank the uninoculated plants. G. geosporum was able to impose some physiological and root morphological changes such as an extensive network of the mycorrhizal-plant roots to improve water and mineral nutrient uptake. Physiologically G. geosporum inoculation enriched T. occidentalis vigour, attuned the rate of K⁺/Na⁺ which restored nutrient and water balance in the plant and directly resulting in the enhancement of salt tolerance in T. occidentalis seedlings, thus improving growth and yield.

Abstract: Two pot experiments were conducted during the two successive seasons of 2014 and 2015 to study the effect of propolis extract at the rates 0, 6000, 7000, 8000 and 9000 ppm solution used as seed soaking to spinach seedlings on growth, yield and some chemical constituents of spinach plants (Spinacia oleracea L.) grown under saline soil conditions. The obtained results indicated that increasing the rates of propolis extract as seed soaking application increased the growth parameters of the treated plants. The best result was obtained by the middle rate (7000ppm) as seed soaking in both seasons of the study. The same trend was also observed regarding all studied chemical constituents, i.e. chlorophyll a, b and total caroteniods concentration, anthocyanine, total carbohydrates, total and reducing sugars, total free amino acid, free proline, crude protein, total indoles, total phenols, N, P and K in leaves. Moreover, soaking seeds in propolis extract before planting improved the metabolic activity of seeds through the increase in seed values from total and reducing sugar, total free amino acid, total indoles and total phenols as well as the lowest values from , total carbohydrate. Thus, the coincident application of propolis extract at (7000ppm) as seed soaking is recommended for improving growth, yield and chemical composition of spinach plants and to overcome the adverse effect of salinity conditions.

Abstract: To investigate whether the fungicide Azoxystrobin improves the potential to maintain physio-biochemical functions under drought, tomato plants were applied with Azoxystrobin under either well-watered and deficit irrigation conditions. Drought-stressed tomato plants showed significant reductions in most tested parameters of physiology [cell membrane stability (CMS), relative water content (RWC), relative water loss (RWL) and chlorophylls], growth attributes and leaflet and main stem anatomical features, while exhibited increases in contents of proline and total phenols, activities of catalase (CAT), peroxidase (POD) and polyphenol oxidase (PPO), fresh (FW) and dry (DW) weights of roots, and leaflet spongy tissue thickness compared to well-watered control plants. Under full irrigation, Azoxystrobin treatment significantly increased RWC and chlorophyll content, POD and PPO activities, root DW, number of fruits per plant and many features of leaflet and main stem, while significantly decreased CMS and RWL, root, shoot and plant lengths, shoot and plant FW, and stem xylem tissue thickness compared to the control plants sprayed with water. However, Azoxystrobin treatment ameliorated drought stress in tomato plants and significantly increased CMS and free proline content, activities of CAT, POD and PPO, and contents of free and total phenols, and root DW and number of fruits per plant, in addition to spongy tissue thickness of leaflet, but not affected chlorophylls and carotenoids contents, root FW, plant DW and most of anatomical features compared to the stressed plants without Azoxystrobin treatment. These results support that Azoxystrobin foliar application may have a positive effect on well-watered and drought-stressed tomato plants.

Abstract: Low-temperature results in various physiological and metabolic disturbances in cells of plants which are sensitive to low-temperatures. Moringa is getting popularity as a field crop because of its multipurpose usage. There is no information available about effects of low-temperature (14-18°C) on moringa seedlings and its mitigation. Present study was conducted to test the performance of moringa seedling grown in wire house under low-temperature conditions in response to foliar application of moringa leaf extract (3% solution), hydrogen peroxide (5 ml L^-1), ascorbic acid (50 mg L^-1) and salicylic acid (50 mg L^-1). Seeds of six moringa accessions [Local landrace grown at Agronomic Research Area, Z.A Hashmi Hall, Firdous Colony. Exotic landrace grown at Lalazaar Colony, Department of Agronomy and Agronomic Research Area.] were collected and grown in polythene bags filled with equal ratio of compost, sand, silt and clay. All foliar treatments were applied twice; first round at the seedling age one month and second round at the seedling age two months. Foliar application of moringa leaf extract significantly enhanced number of branches (92%) and leaves (39%), leaf total chlorophyll contents (73%), leaf phenolic contents (53%) and membrane stability index (57%) of moringa seedlings compared to control. Healthy and vigorous growth of moringa seedlings with higher concentration of antioxidants ensured the defensive potential of moringa leaf extract against low-temperature condition.

Abstract: Pots experiment was carried out during season 2017 at greenhouse of the Agric. Bot. Dep., Fac. of Agric., Zagazig Univ., Egypt to evaluate the effect of glycine betaine (GB) application under salinity stress (50 and100 mM NaCl) on growth, physio-chemical analysis and yield of snap bean cv. Bronco. A complete randomized blocks design was used in this search with three replications. Growth parameters, chlorophyll content and green pod yield were significantly decreased with subjecting plants to NaCl. However foliar application of GB detoxified the stress generated by NaCl and significantly improved the above mention parameters. Salinity stress increased the electrolyte leakage (EL) and decreased membrane stability index (MSI) and relative water content (RWC). While foliar application of GB was improved MSI and RWC and minimized EL. Proline content and antioxidant enzymes significantly increased in the response to NaCl stress as well as GB application.

Abstract: Salt stress restricts plant performance by disrupting various physio-biochemical processes like photosynthesis. Plants growing in saline substrates show deficiencies in absorption of some essential elements due to the presence of excessive sodium (Na⁺) in the rhizosphere, which antagonizes beneficial cations and causing toxicity in metabolism. Cyanobacteria (CB; a natural biofertilizer) play a fundamental role in building-up soil fertility, thus increasing plant performance. Glutathione (GSH) is a well-known antioxidant, which contributes to increase salt tolerance in the plant. This work was conducted as a pot experiment (sand culture) in 2017 to study the combined effect of CB, applied as seed inoculation, and GSH, applied as foliar spray, on growth, pods and seed yields, the contents of antioxidants, osmoprotectants, and nutrients, and the antioxidative enzymes activities of soybean (Glycine max L., cv. Giza 111) plants grown under saline conditions. At fourth leaf stage (21 days after sowing; DAS), CB-pretreated seedlings were supplemented with NaCl (150 mM) along with Hoagland′s nutrient solution, and at the same time seedlings were sprayed with 1 mM GSH. Samples were taken at 60 DAS to assess morphological, physio-biochemical and antioxidant defense systems attributes. Results showed that the integrative application of CB and GSH under saline conditions was effective in improving significantly the growth characteristics, yield components, photosynthetic efficiency (pigments contents and chlorophyll fluorescence), membrane stability index, relative water content, contents of soluble sugars, free proline, ascorbic acid, glutathione, α-tocopherol, and protein, and activities of superoxide dismutase, catalase, and guaiacol peroxidase. The contents of macronutrients (N, P, K⁺, and Ca²⁺) were also increased significantly in Glycine max plants compared to the stressed control. In contrast, Na⁺ content and electrolyte leakage were significantly reduced. Our results recommend using the combined CB (as seed inoculation) and GSH (as foliar spray) application for soybean plantss to grow well under saline conditions.

Abstract: The objective of this investigation was to study the helpful effects of foliar application with antioxidant citric acid in combos with some micronutrients on growth, yield and a few chemical constituents of maize (Zea mays L.) plants. The plants were grown up in clay soil, and foliar sprayed with eleven treatments (0, 0.05, 0.1, 0.15, 0.2, 0.25, 0.3, 0.35, 0.4, 0.45 and 0.5%) of combined fertilizer (citrine) which contains (15% citric acid, 2% Fe, 2% Mn and 2% Zn). The obtained results indicated generally that each one studied vegetative growth parameters (i.e. plant height, stem diameter, number of leaves /plant, dry weight of leaves) similarly as grain yield /fed. and some of their components (i.e. ear length, ear diameter, number of rows/ear, number of grains/row, grain weight/ear, weight of 100 grain and ear weight/plant) and some chemical constituents of leaves (chlorophyll a, b, total caroteniods, anthocyanin, total carbohydrates, total and reducing sugars, total free amino acids, total indoles, nitrogen, phosphorous and potassium) and grain protein %, were accrued with application of the various treatments. The maximum values were obtained from the treatment of 0.3%. On the contrary citrine treatments minimized reducing sugars and free phenol in leaves as compared to the control. The simplest results were obtained by the application of citrine treatment at 0.3%. Hence, it can recommend using citrine fertilizers as foliar application at the speed of 0.3% for improving growth, yield and chemical constituents of maize plants.

Abstract: The aim of this trial was to investigate the pre-harvest foliar application of calcium chloride and potassium thiosulfate each at 0.0, 0.2 and 0.4 % on some quality of tomato fruit (hybrid 65010) during cold storage. The experimental layout of cold storage experiments was a split-split-plot based on Randomized Complete Blocks design with three replications. Time of cold storage, calcium chloride and potassium thiosulfate levels were randomly distributed in the main, sub-and sub-sub plots, orderly. At the termination of cold storage, effect on tomato fruit titratable acidity, vitamin C and lycopene contents while, negative impact on firmness and total soluble sugars contents was obtained. At termination of cold storage, pre-harvest foliar calcium chloride at 0.2 and/or 0.4 % caused increments in fruit titratable acidity, vitamin C, total soluble sugars, lycopene and firmness contents. In addition, pre-harvest foliar potassium thiosulfate at 0.4 % enhanced fruit vitamin C, total soluble sugars, lycopene and firmness contents and also increased titratable acidity content. Generally, the interaction between cold storage × pre-harvest foliar calcium chloride or potassium thiosulfate at 0.2 and/or 0.4% increased fruit total titratable acidity, vitamin C, total soluble sugars, lycopene and firmness contents. Also, the interaction between pre-harvest calcium chloride × potassium thiosulfate at 0.4 % was distinguished and increased all studied fruit quality at the end of cold storage. The interaction treatment of cold storage × calcium chloride at 0.4 % × potassium thiosulfate at 0.4 % was the best that improved fruit quality more than others.