Comparative studies on chlorophyll fluorescence and certain physiological features with inherent drought tolerance and quality of tea (Camellia sinensis L.)

Chlorophyll fluorescence, net photosynthesis rate, transpiration rate, water use efficiency, stomatal conductance, leaf moisture,chlorophyll content and concentration of proline of tea leaves with different stages of maturity in a shoot as well as 30 different tea clones with various levels of inherent drought tolerance and quality were studied during periods of drought. In a tea shoot, leaf maturity showed significant positive correlation with chlorophyll content, chlorophyll fluorescence (Fv and Fv/Fm), net photosyn­thesis rate and water use efficiency. In the case ofvarious clones, significant correlation could not be established between chloro­phyll content and chlorophyll fluorescence as well as net photosynthesis rate. Inherent moisture content of mother leaves of various clones showed significant positive correlation with minimal fluorescence and variable fluorescence. Leaf temperature at the time of measurement of photosynthesis exhibited significant correlation with net photosynthesis rate as well as transpiration rate. Maximal fluorescence yield and variable fluorescence of various clones showed significant negative correlation with transpiration rate. Sig­nificant negative correlation was observed between Fm and water use efficiency. Correlation between stomatal conductance as well as proline concentration, which are considered to be indicators for drought tolerance, was non-significant. There was a strong negative correlation between chlorophyll fluorescence (Fv and Fv/Fm) and transpiration rate and quality of tea produced from different leaves of a tea shoot. However, significant correlation could not be established between chlorophyll fluorescence with inherent drought tolerance as well as quality of CTC black tea manufactured from different clones.