Effects of Soil Moisture Stress On Free Proline And Chlorophyll Contents in Tomato

Abstract

A study was conducted in the Agronomy farm of the Faculty of Agriculture, Eastern University, Sri Lanka to investigate the biochemical responses of moisture stress clur ing the vegetatir,e, flowering, early fruiting and fruit ripening stages of tomato (cv. KCI-1)" This experiment was layed out in the RandomizedComplete BlockDesign with five treatments and four replications. Moisture stress was imposed for different treatments for a period of ,{ days per treatment dnring the above growth stages. Moisture stress increased the proline content of tomato leaves. An increasing trend in proline content was obsened with the age of plants when sub.jected to moisture stress. There was a decrease in the proline content 5-6 hours after supplying water and the values returned to normal after 48 hours of re-rvatering. Moisture stress reduced the chlorophylls a and b contents oftomato leaves. Plants which experienced moisture stress during the vegetative and flowering stages showed greater reduction in the chlorophyll content thap those ofthe other growth stages. It was also observed that moisture stress caused higher reduction in chlorophyll a than chlorophyll b. The reason for this reduction needs to be investigated. There was a partial recovery in the chlorophylls a and b contents of plants after re-watering. The rate of recovery of chlorophyll content was faster during the vegetative stage than the flowering stage.