Volume 14, Issue 3 (10-2024)                   2024, 14(3): 37-52 | Back to browse issues page


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Respectively, Faculty of Agriculture and Natural Resources, University of Mohaghegh Ardabili, Ardabil, Iran. , raouf_ssharifi@yahoo.com
Abstract:   (627 Views)
Extended Abstract
Introduction
Water deficit is one of the most important factors limiting crop production under rainfed condition. Several methods have been proposed to increase the resistance of crops against water deficit. In this regard, foliar application of methanol and nano zinc oxide can improve the performance of crop plants under water limitation conditions. Zinc deficiency is recognized as a critical problem in plants, especially when grown on soils with high pH values. But, recent researches have shown that application of micronutrients, including Zn, in the form of nano-fertilizers is a viable criterion for growing plants under water deficit condition, as it increases resource use efficiency and reduces environmental pollution. Also, foliar-applied methanol can increase the concentration of CO2 inside the plant tissue and promote photosynthesis rate and growth under water deficit conditions. On the other hand, water deficit is mitigated by stress modulators such as methanol and nano zinc oxide through a variety of mechanisms, including increased photosynthetic efficiency and nutrient acquisition in plants, and enhancement of the antioxidant system towards preventing damage from reactive oxygen species. Considering the above fact, the present study was undertaken to evaluate the effects of nano zinc oxide and methanol foliar application on grain yield and some physiological traits (i.e, relative water content, electrical conductivity of flag leaf, dry matter remobilization from plant’s above-ground parts and hence contribution of photoassimilates remobilization in grain yield) of wheat under rainfed conditions.
Materials and Methods
A factorial experiment was conducted based on a randomized complete block design with three replications in Sarab in north-west of Iran, in 2018-2019. Experimental factors included nano zinc oxide foliar application at four levels (foliar application with water as control, 0.3, 0.6, and 0.9 g L-1) and methanol application at four levels (foliar application with water as control, 10, 20, and 30% v/v). Methanol was prepared from Mojallal Co. and  nano zinc oxide from Pishgaman Nanomaterials Co. Nano zinc oxide consisted of particles of  less than 30 nm. Foliar application of nano zinc oxide and methanol were done in stages of tillering and boot stage. Relative water content (RWC) and electrical conductance (EC) of flag leaves was calculated based on the given formula Kheirizadeh Arough et al (2015):
RWC (%) = [(FW-DW)/(TW-DW)] × 100  (1)
where FW is the fresh weight; DW is the dry weight; and TW is the turgid weight. From each plot, the samples of  developed flag leaf were randomly selected and after placing them in aluminum foils, they were transferred to the laboratory very quickly, then the flag leaf samples were kept in flasks containing 25 ml of distilled water. It was then placed at room temperature for 24 hours and then the electrical conductivity was measured by an EC meter (Mi 180 Bench Meter).
Dry matter and remobilization of stem reserves to grain yield were evaluated as follows:
Dry matter remobilization from shoot (g plant-1) = maximum of  dry matter of shoot after anthesis (g plant-1) - shoot dry matter (grains excluded) in maturity (g plant-1).

Contribution of dry matter remobilization to grain (%) = [dry matter remobilization from shoot (g plant-1) /grain yield (g plant-1)] × 100.

Contribution of dry matter remobilization from stem to grain yield (g plant-1) = [maximum  of stem dry matter after anthesis (g plant-1) - stem dry matter in maturity (g plant-1) ] × 100.

Analysis of variance was done by SASv9.12. The main effects and interactions were compared by LSD test at the 0.05 probability level.
Results and Discussion:
Mean comparison showed that the least of dry matter remobilization from above-ground parts (0.21 g plant-1) and contribution of remobilization to grain yield (23.6%), dry matter remobilization from stem (0.17 g plant-1) and contribution of stem reserves to grain yield (10.3%) were obtained at the highest level of nano zinc oxide application. Similar results were obtained in these traits at the highest level of methanol application. Foliar spraying of high rates of nano zinc oxide and methanol increased the relative water content of flag leaf in ear emergence (17%) and grain filling stages (11%), zinc content (62%), protein content (14%) and grain yield (33%) in comparison to control.
Conclusions
Results of this study taken together, it seems that application of 0.9 g L-1 nano zinc oxide with 30% v/v of methanol can be suggested for improvement of physiological traits and thereby increase in grain yield of wheat under rainfed conditions.
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Type of Study: Research | Subject: General

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