Condition of mandarin plants (Citrus reticulata var. unshiu Tan.) upon treatment using physiologically active substances

Abstract

Тhe humid subtropics of the Russian Federation constitute a conditionally suitable area for cultivating citrus crops. In recent years, low winter temperatures have been observed with increasing frequency, leading to the subfreezing of seedlings and delayed vegetation, as well as the death of plants. In addition, prolonged dry periods in summer have been recorded, contributing to a fall of leaves and fruits. One promising approach involves agricultural methods, such as the treatment of plants with regulatory and stress-protective agrochemicals. In this article, the water regime and the improvement of plant health under the influence of a number of growth regulators having a stimulating and stress-protecting effect are considered. Тhis research has been carried out at the Federal Research Centre “Subtropical Science Centre of RAS” since 2019. Тhe positive influence of such agents on the functional state of mandarin leaves was determined; the leaf health was higher (2.0–2.8 units) in the varieties treated with siliplant than that in the control (1.4-1.9 units); lower values of water deficiency (1.1-12.1 % against 13.2-15.8 % in the control) and lower content of accumulated dry matter (37-43 g against 38.5-43.8 g in the control) were noted in the same experiment. Тhe plants treated with a growth regulator yielded fruits of a higher mass (44.8-48.2 g against 41.3 g in the control). Тhe obtained data will help to develop efficient means for regulating the functional state of plants under stressful conditions.