Study of drought tolerance in selective clones of tea (Camellia sinensis L.)

Increasing the activity of antioxidant defense system against harmful agents such as reactive oxygen species، resulting from drought، is a common response in plants. In order to study these responses، the effects of two withholding irrigation in treatments (10 and 20 days) on the progress of the phenolic and flavonoid compounds activity malondialdehyde rate and also the amounts of chlorophyll a، total and carotenoids in three clone of tea (DN، 100 and 258) were investigated. Results showed that the amounts of phenol had the most increase in clones DN and 100 in 20 and 10 day-treatments respectively. However، changes in neither of the treatments had no significant effect in clone 258. The amounts of flavonoid and antioxidant capacity increased in clone DN with 20 day-treatment however; it decreased in clone 258 and stayed constant in clone 100. The most values of proline appeared in 20 day-treatments in all clones. Results of malondialdehyde contents were increased in clones 258 and 100، but it did not change in clone DN. Decreasing in amount of chlorophyll a and total chlorophyll were observed in clones DN and 100 with 20 day-treatments and remained unchanged in clone 258. Carotenoids remained constant in clones and treatments. On the basis of obtained data it seemed that clone DN had more ability against drought and consequently its defense mechanism was excited more than others.