Effect of foliar spray of nutrient solutions on photosynthesis, dry matter accumulation and yield in seawater-stressed rice

The effects of seawater salinity and foliar application of nutrient solutions on rice in the early tillering stage and early reproductive phase of growth were investigated in a glasshouse. During early tillering stage, from 10 to 35 days after transplanting (DAT) and the early reproductive phase, from 75 to 100 DAT, potted rice plants were irrigated with Japan seawater of 0, 8.8, 17.5 and 35% (equivalent to an EC of 0.9, 5.7, 11.5 and 21.5 ms cm−1, respectively). The nutrient solution of 1 mM Ca(NO3)2, MnSO4 or K2HPO4 was sprayed twice a week until the solution ran off the leaves. Photosynthesis and its related parameters were measured at 30 and 95 DAT in the early tillering stage and in the reproductive growth phase, respectively. Seawater salinity diminished photosynthesis rate and photosynthesis-related parameters, such as stomatal conductance, intercellular CO2 concentration, leaf water and osmotic potential and relative leaf water content in both growth stages and have reduced tiller number, leaf area and top dry matter content in tillering stage. We have also studied the effect of salt-stress on the mineral content at 35 DAT. Na+ concentration increased, whereas Ca2+, Mn2+ and K+ concentration were decreased with increasing stress. Seawater decreased fertile spikelets in the panicle, decreased accumulation of dry matter in the grain and concomitantly decreased grain yield. Foliar spray of Ca(NO3)2, MnSO4 or K2HPO4 partially minimized the salt-induced nutrient deficiency, increased photosynthesis, dry matter accumulation, number of fertile spikelet in the panicle and grain yield. Among the nutrient solutions, Ca(NO3)2 seemed to be the most effective, followed by MnSO4 and K2HPO4. These results suggested that foliar application of nutrient solutions partially alleviates the adverse effects of salinity on photosynthesis and photosynthesis-related parameters, yield and yield components through mitigating the nutrient demands of salt-stressed plants.[1]

Potassium Silicate as Foliar Spray and Rice Blast Control

Silicon (Si) is known as a “beneficial element” for plants. The direct and indirect benefits of the element for crops (especially grasses) are related to resistance to diseases, pests, and drought. Since most studies were done with fertilizers applied to the soil, new studies on the efficacy of silicon absorption through the leaves are required. The effect of silicon absorption through the leaves on rice blast (Pyricularia oryzae) control was studied using potassium silicate (K2SiO3) in different doses (0, 1, 2, 4, 8, or 16 g L− 1 Si), number of sprayings at two solution pHs. Rice (Oryza sativa), cultivar ‘Metica 1’ (susceptible to blast), was grown in pots in a completely randomized experimental design. Silicate was applied beginning at the 22nd day after emergence (DAE). The pathogen was inoculated on the 25th DAE. Disease incidence was evaluated ten days after inoculation. Potassium silicate pulverization on the leaves did not increase Si absorption or accumulation by the plant; however, there was a reduction on blast incidence. The greatest reduction on blast incidence was observed at 4 g Si L− 1, regardless of solution pH. [2]

Effect of nanoparticles suspension on the growth of mung (Vigna radiata) seedlings by foliar spray method

The present experimental investigation demonstrates the effect of nano-ZnO, nano-FeO and nano-ZnCuFe-oxide particles on the growth of mung (Vigna radiata) seedling. The study was carried out by spraying optimum concentrations of nanoparticles in suspension form on hydroponically grown test units and examining the effect on the shoot growth of seedlings. Based on biomass assay, it was found that the seedlings displayed good growth over control, demonstrating a positive effect of the nanoparticle treatment. The best performance was observed for nano-ZnCuFe-Oxide followed by nano-FeO and nano-ZnO. Absorption of nanoparticles by plant leaves was also detected by inductive coupled plasma/atomic emission spectroscopy.[3]

Carbohydrates in plant immunity and plant protection: roles and potential application as foliar sprays

Increasing interest is devoted to carbohydrates for their roles in plant immunity. Some of them are elicitors of plant defenses whereas other ones act as signaling molecules in a manner similar to phytohormones. This review first describes the main classes of carbohydrates associated to plant immunity, their role and mode of action. More precisely, the state of the art about perception of “PAMP, MAMP, and DAMP (Pathogen-, Microbe-, Damage-Associated Molecular Patterns) type” oligosaccharides is presented and examples of induced defense events are provided. A particular attention is paid to the structure/activity relationships of these compounds. The role of sugars as signaling molecules, especially in plant microbe interactions, is also presented. Secondly, the potentialities and limits of foliar sprays of carbohydrates to stimulate plant immunity for crop protection against diseases are discussed, with focus on the roles of the leaf cuticle and phyllosphere microflora.[4]


Effect of Foliar Spray of Nano Silver and Organic Fertilizer (Algastar) and Salicylic Acid on Some Morphological Characteristics and Carbohydrate Content in (Helianthus annuus L.)

An experiment was conducted to check the effect of foliar spray of nano and organic fertilizers and a growth regulator on vegetative growth of sunflower crop. Sunflower (Helianthus annuus L.), Spanish class (Viki) was cultivated from march 2013 to June 2013 at College of Agriculture, University of Wasit, Iraq. Three levels of nano silver viz., control, 25 and 50 mL/L; three levels of organic fertilizer (Algastar) viz., control, 0.75 and 1.5 g/L and three levels of salicylic acid viz., control 60 and 120 mg/L were foliar sprayed at 65 days old sunflower crop. Results showed that foliar spray of 50 mL/L of nano silver, 1.5 g/L of organic fertilizer (Algastar) and 120 mg/L of salicylic acid have a positive effects on average number of leaves, number of branches and leaf contents of carbohydrate. There was no significant interaction among nano silver, organic fertilizers and salicylic acid on all studied traits of sunflower.[5]

Reference

[1] Sultana, N., Ikeda, T. and Kashem, M.A., 2001. Effect of foliar spray of nutrient solutions on photosynthesis, dry matter accumulation and yield in seawater-stressed rice. Environmental and Experimental Botany, 46(2), pp.129-140.

[2] Buck, G.B., Korndörfer, G.H., Nolla, A. and Coelho, L., 2008. Potassium silicate as foliar spray and rice blast control. Journal of Plant Nutrition, 31(2), pp.231-237.

[3] Dhoke, S.K., Mahajan, P., Kamble, R. and Khanna, A., 2013. Effect of nanoparticles suspension on the growth of mung (Vigna radiata) seedlings by foliar spray method. Nanotechnology development, 3(1), pp.e1-e1.

[4] Trouvelot, S., Héloir, M.C., Poinssot, B., Gauthier, A., Paris, F., Guillier, C., Combier, M., Trdá, L., Daire, X. and Adrian, M., 2014. Carbohydrates in plant immunity and plant protection: roles and potential application as foliar sprays. Frontiers in plant science5, p.592.

[5] Agung, I.G.A.M.S. and Nurjaya, I.G.M.O., 2016. Foliar Spray of Rice Rinsed Water to Tropical High Elevation Grown Strawberry (Fragaria ananassa Duch.) Increased Sugar Content of Ripe Fruits. Journal of Experimental Agriculture International, pp.1-9.

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