Changes in Chlorophyll, Protein and Antioxidant Enzymes on Durum Wheat under Drought Stress

Drought stress as an abiotic stress causes different biochemical and physiological responses in plants. To study changes in chlorophyll، total soluble protein and antioxidant activity due to drought stress، we conducted an experiment on five durum wheat varieties (selected from the Seed and Plant Improvement Institute in Karaj) at research greenhouse of Imam Khomeini International University in 2010. Five varieties (Seymareh، Karkheh، Dena، Aria and D-79-15) were cultivated in a factorial experiment based on completely randomized design with six replicates in both normal and water stress conditions. The sampling was done at five leaf stage for measuring total soluble protein، catalase (CAT)، peroxidase (POX)، ascorbate peroxidase (APX) and super oxid dismutas (SOD) enzymes activity. Results showed that total soluble protein increased significantly، but total amount of chlorophyll decreased due to drought stress. Amount of chlorophyll a، b and total chlorophyll for cultivar Aria، was maximum. Also، the results showed that activity of CAT، SOD and POX increased due to stress، while stress caused a decrease in the activity of APX. Cultivar Aria had the highest catalase enzyme activity against drought stress and was considered as drought resistant cultivar. Seymareh had the highest POX activity under stress. The lowest POX activity was for line D-79-15 and was recorded more sensitive to stress than other varieties. Dena and Karkheh showed the highest increase in super oxid dismutas and ascorbate peroxidase enzyme activity under stress condition، respectively.