Abstract
ABSTRACTDrought and heat stress are significant factors limiting fruit crop yield in arid conditions. Foliar fertilization is a common practice of supplying fruit crop production with mineral nutrients, especially under limited soil nutrient availability conditions. To evaluate potential effectiveness of the foliar application of macro-, micronutrient and growth regulators on dynamics of physiological parameters of the pear and apple cultivars under abiotic stresses, three–year experiments were carried out under arid conditions at the Russian Research Institute of Arid Agriculture during the 2015–2017 growing seasons. It has been revealed that foliar nutrition reduces the negative influence of heat stress, stabilizes the functional state of plants, thereby enhancing resistance to drought. During the most severe drought periods of vegetation, under the influence of foliar nutrition, there was a significant increase in the total water content (TWC), relative leaf turgidity (RLT) and water retention capacity (WRC); and also index of leaf water deficiency (LWD) was improved as compared to the non-treated control. All foliar treatments involving the macro-, micronutrient and growth regulators significantly enhanced fruit crop yield of pear and apple varieties over the control, yield enhancement was obtained 2.7–22.0 t ha−1 for the Talgar beauty (pear variety), 2.2–19.3 t ha−1 for the Renet Symirenko (apple variety), and 1.6–10.5 t ha−1 for the Starkrimson (apple variety). The most effective treatments for water consumption coefficient (WCC) were plantafol and speedphol. The results suggest that foliar plantafol and speedfol could be used as part of an efficient, sustainable fertilizer program for apple and pear trees for maintaining or improving fruit quality, productivity, and avoiding negative efficacy of abiotic stresses.
Highlights
Perennial fruit trees are constantly exposed to various abiotic stresses during their lifetime and this has an adverse effect on fruit crop yield
The main objective of the study was to investigate the principal aspects of the foliar application of macro, micronutrients and growth regulators with regards to crucial factors of fruit cropping systems, apple and pear trees under conditions of low moisture availability and high summer temperatures
Our study demonstrates an effective approach that can significantly reduce negative influence of heat stress and stabilizes the functional state of plants, thereby increasing resistance to drought conditions
Summary
Perennial fruit trees are constantly exposed to various abiotic stresses during their lifetime and this has an adverse effect on fruit crop yield. The need for effective nutrient management is crucial for optimizing fruit crop production [1], and enhance plant ability to tolerate various environmental stresses. Foliar sprays have been employed as a significant tool to meet tree nutrient demand. This fertilization method is more target-oriented and environmentally friendly since the nutrients are applied in controlled quantities [4]. Drought and heat stresses are major abiotic factors capable of reducing photosynthetic efficiency by curtailing leaf expansion, causing premature leaf senescence, in several regions of the world, inclusive of western Asia and southern Russia [5]. Low moisture and drought stress are demonstrated as the predominant environmental factors, reducing plant productivity in many arid and semi–arid areas, which are intensively affected by climate changes [8]. Heat stress has the potential to cause serious disturbances in plant growth and development which may be due to membrane disruptions, metabolic changes and generation of oxidative stress [9]
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