Special aspects of water exchange of Viburnum tinus L. under the conditions of progressive soil drought on the southern coast of Crimea (the SCC)

O. Ilnitsky, A. Pashtetsky, Yu.V. Plugatar, S. Korsakova
Arid phenomena are the main limiting factor for functioning of landscapes in the southern coast of Crimea. The aim of the present study was to study the eco-physiological reaction of Viburnum tinus L. on a progressive soil drought effect. The optimum thresholds and zones of soil moisture, temperature and luminance that limit photosynthesis and transpiration of V. tinus during vegetation were defined. The start point of development in the plant of water stress and inhibition of photosynthesis is soil moisture reduction to 40% FC. The optimum photosynthesis temperature which is excess leads to inhibition of an enzyme activity and reduces the rate of photosynthesis is a leaf temperature of 35°C. The growth inhibition, the turgor reduction of young leaves is a soil moisture content reduction to 25-20% of FC and less. The reduction of soil moisture to 18% FC and less results in a sharp decrease of transpiration rate of 92.3%, a visible photosynthesis rate of 95.1% and a stomatal conductance of 94.7%. The proportion of the total dark respiration from gross-photosynthesis under strong water stress is 56%, in the absence of any stress factors it is 25-30%. The beginning of a turgor recovery after watering is 40 min; the full restoration of the intensity of photosynthetic gas exchange after watering is after three days. Under strong water stress, the visual evidence of a noticeable loss of chlorophyll in leaves can be seen: the central vein acquires a yellow-green color in leaf with brownish stains. In the conditions of a cultivar, it leads to loss of the plant decorative qualities. The disclosure of leaves' functioning mechanisms, depending on the environmental impact, provides the basis for the environmental assessment of the physiology of the evergreen species and the possibilities of agricultural technology choice.
Ilnitsky, O., Pashtetsky, A., Plugatar, Yu.V. and Korsakova, S. (2021). Special aspects of water exchange of Viburnum tinus L. under the conditions of progressive soil drought on the southern coast of Crimea (the SCC). Acta Hortic. 1324, 427-432
DOI: 10.17660/ActaHortic.2021.1324.66
https://doi.org/10.17660/ActaHortic.2021.1324.66
water regime, photosynthesis, drought, environmental factors
English

Acta Horticulturae