Photoassimilatory and Photorespiratory Behaviour of Certain Drought Tolerant and Susceptible Tea Clones

Net photosynthetic rate (P _N) in the mother leaves was higher in the drought tolerant (DT) clones of tea (Camellia sinensis) while liberation of the fixed ¹⁴C in light from the mother leaves was higher in the drought susceptible (DS) clones. The DT clones translocated more photosynthates to the crop shoots (three leaves and a bud) from the mother leaf than the DS clones. Concentrations of RuBP carboxylase (RuBPC) or oxygenase (RuBPO) had no relationship with the drought tolerant nature of tea clones but their ratio correlated with the same. DT tea clones had higher catalase activity that could scavenge the hydrogen peroxide formed in the photorespiratory pathway and thereby reduced photorespiration rate (P _R). The ratio of RuBPC/RuBPO had a positive correlation with P _N and catalase activity. Negative correlation between RuBPC/RuBPO and P _R and between catalase activity and RuBPO activity was established.