Kovalyov M., Plugatar Yu., Ilnitsky O. The dependence of drought resistance Aucuba japonica Thunb. from environmental factors in conditions of Southern Coast of the Crimea . Electronic science-productive magazine "AgroEcoInfo", 2017, N 3

2017, N 3 (29)

ECOLOGY

*Kovalyov M., Plugatar Yu., Ilnitsky O.*
*The dependence of drought resistance Aucuba japonica* Thunb. from environmental factors in conditions of Southern Coast of the Crimea**
Authors have studied the drought resistance of Aucuba japonica Thunb. in the conditions of dry subtropics on the Southern Coast of the Crimea. Studies have shown that young leaves of A. japonica are highly vulnerable to soil drought. During the dehydration of the plant the intensity of net photosynthesis decreased from 8 to 2 μmol/m2•s. Soil drought leads to a decrease in the intensity of transpiration from 40–60 to 18–20 mg/m2s in 18 days. During the first day after watering, the intensity of transpiration remains at 20 mg/m2s. Only the next day it increases to 30 mg/m2•s. Complete restoration of the initial transpiration intensity occurs on the second day after watering. The growth of the plant stem is closely correlated with soil moisture. While the soil moisture content decreased from 19 to 3%, the intensity of plant stem growth decreased insignificantly. A slow and insignificant decrease in the rate of plant stem growth during dehydration indicates that the growth processes continue despite dehydration of the plant. The surfaces of the response function Pn = f(I, W), E = f(I, W), constructed in the XYZ coordinates, allowed us to determine the conditions and levels of potential maxima and the boundaries of the photosynthetic and transpiration optimum areas: the optimum Pn = 8…9 μmol/m2•s, with I = 600…1200 μmol/m2•s, W = 18…20%, and the optimum E = 50…56 mg/m2•s, with I = 1150…1400 μmol/m2•s, W = 18…20%. The values of optimal illumination (I, μmol/m2•s) obtained by us for A. japonica confirm the data of other researchers. Registration of the main processes of plant life, as well as their reaction to dehydration of the plant can serve as a prerequisite for the creation of an ecophysiological plant passport. Keywords: Aucuba japonica, DROUGHT RESISTANCE, MAIN PROCESSES OF PLANT LIFE, WATER REGIME, PHYTOMONITORING