Characterization of Changes in Photosynthetic Rate, Transpiration and Chlorophyll Content during the Hop Growing Season

The paper evaluated changes in the rate of photosynthesis, transpiration and chlorophyll content during the hop growing season. The device LC pro+ (portable infrared gas analyzer) and Chlorophyll spacemeter SPAD-502 was used for the measurement of physiological processes. The generic model of the photosynthetic rate was defined in relation to the growth phase of the hop during the growing season. The results of measuring of photosynthetic rate (2007 to 2009) showed that photosynthesis gradually increased during the rapid growth and photosynthetic activity increased in the flowering stage of hop plants. On the contrary, hop plants reduced assimilation as the hop cones matured. A similar trend was found for measurement of chlorophyll in the leaves. The transpiration rate decreased with the course of hop plant ontogeny. The average rate of photosynthesis during the growth season in 2007 to 2009 ranged from 5.61 to 7.82 mu mol CO2.m(-2).s(-1). The average transpiration rate ranged from 1.02 to 1.21 mmol H2O.m-2.s(-1). The average values of chlorophyll ranged from 36.78 to 44.07.