The dependence of intensity of photosynthesis in Nerium oleander L. and Laurus nobilis L. on environmental factors (Ta, I-PAR., Da.), leaf temperature, transpiration and their changing during the growing season under the conditions of the Southern Coast of the Crimea

Abstract

The dynamics of change of optimum net - a photosynthesis, a transpiration, temperature of a leaf and factors of an external environment throughout the period of vegetation (August-October, 2016) was studied. Best value of Pn for Laurus nobilis L. during August-October period decreased by 21%, intensity of a transpiration for 40%, air temperature for 16%, an air humidity deficit for 87,14%, leaf temperature for 26% and illuminance for 17,8%. For Nerium oleander Pn during this time it decreased by 51,73%, intensity of a transpiration - for 78%, air temperatures - for 17%, an air humidity deficit for 89,14%, leaf temperature for 28,58% and illuminance for 31,58%. It was determined that if air temperature was above optimum the intensity of a photosynthesis sharply fell, for N. oleander it was equal to 36,5 °C, for L. nobilis it was equal to 32 °C. The wide range of their ecological plasticity with further saving a tendency of warming and climate aridization makes them competitive with the types having small ecological amplitude. The acquired information is an important potential characteristic of these types during creation of their ekologo-physiological passports.