Peculiarities of transpiration in plants Pisum sativum L.

Field and vegetative experiments were carried out to identify the species characteristics of transpiration in Pisum sativum L . plants. The transpiration was determined on intact plants using portable gas analyzers of the brand LI-6400 XT and GFS-3000 FL. The research has shown that the evaporation rate of water molecules by culture leaves significantly depends on the weather conditions of the growing season: varied by year from leaflets from 3.14 to 12.67 mmol H2O/m2s, from stipules - from 2.25 to 13.45 mmol H2O/m2s. Its lowest values (2.70-3.39 mmol H2O/m2s) were noted in conditions of low humidification and high air temperature, and the highest values (9.76-12.91 mmol H2O/m2s), when the weather conditions promoted active growth of plants. The dependence of the intensity of leaf transpiration on light was weak. An increase in insolation from 300 to 1000 µmol/m2s of leaflets led to an increase in transpiration by only 5%, and with a further increase in light intensity, its decline decreased by an average of 15%. In the 8-leaf phase, the evaporation rate of water by the leaves was 3.99, the stipules - 4.94 mmol H2O/m2s, and in the flat-bob phase its value in these plant organs increased to 9.07 and 10.42 mmol H2O/m2s, respectively. But, by the phase of green ripeness of the beans, it again decreased -2.1 times on average. High transpiration activity was characterized by leaflets and stipules, primarily located in the upper nodes of the plants. At the 3rd top, the evaporation rate of water was 9.55 and 11.08 mmol H2O/m2s, respectively, which was 30% and 40% more compared to the lower ones.