Roles of Micronutrients and Plant Growth Regulators on Abiotic Stresses Management of Pistachio Trees: A Review

Abstract

One of the most valuable nut fruits in arid and semi-arid regions is the Pistachio (Pistacia vera L.). Biotic and abiotic stresses affect crop productivity worldwide. Pistachio trees are tolerant to abiotic stress conditions to some extent. However, imbalance of nutrients, heat stress, low-quality irrigation water, salinity, and soil drought are the most limiting factors in pistachio production. Pistachio cultivation is possible in soils with high pH, high carbonate, and low organic matter, however, micronutrient deficiency and low yield often occur. Preharvest pistachio fruit abscission is one of the problems related to micronutrient deficiency, leading to yield reduction and alternate bearing. The parent material of the soil, low rainfall, and high evaporation have caused large areas to become salty and calcareous. These physicochemical properties stabilize nutrients and reduce their absorption by the plant. On the other hand, the occurrence of physiological drought affects optimal growth by reducing root growth and nutrient absorption. Meanwhile, the management of nutrients plays a vital role in resistance against abiotic stresses and determines the survival and distribution of plant species. Therefore, nutrient management is essential for sustainable production. Additionally, management methods such as the external application of osmotic compounds, antioxidants, and plant growth regulators are beneficial for resistance against abiotic stresses. Nutrients and plant growth regulators induce stress resistance by changing the growth pattern of plants. The interplay between plant growth regulators and their synergistic or antagonistic interactions, mediated by phytohormones, plays a major role in abiotic stress tolerance.