Changes of Germination Properties, Photosynthetic Pigments and Anti Oxidant Enzymes Activity of Safflower as Affected by Drought and Salinity Stresses
Subject Areas : Journal of Crop Ecophysiologyعلیرضا Sirousmehr 1 , J. Bardel 2 , S. Mohammadi 3
1 - Assistant Prof., College of Agriculture, University of Zabol, Zabol, Iran
2 - MSc. Student of Medicinal Plant, College of Agriculture, University of Zabol, Zabol, Iran
3 - MSc. Student of Agroecology, College of Agriculture, University of Zabol, Zabol, Iran.
Keywords: germination, Chlorophyll, Antioxidant enzymes, Safflower,
Abstract :
To evaluate the effects of drought and salinity stresses on some germination characteristics, contents of photosynthetic pigments and antioxidant enzymes (CAT, APX and GPX) in the leaves of safflower, a factorial experiment based on CRD was conducted during 2012 at both laboratory and greenhouse of Zabol University with four replications. To expose the plants to drought (0, -6 and -8 bars) and salinity stresses (5, 10 and 15 ds.m-1) PEG 6000 and NaCl were used respectively. The results indicated that the effects of factors on germination percentage and rate, chlorophyll a and b contents and antioxidants enzymes activities were significant. The result of laboratory study revealed a reduction in percentage and speed of germination when plants exposed to negative osmotic potential. Photosynthetic pigments of plant leaves grown in greenhouse significantly decreased by increasing drought and salinity stresses. Increasing drought stress along with soluble salts changed the activity of some antioxidant enzymes. Enzymes’ activity of both CAT and GPX were increased when the plants expose to PEG drought stress, but decreased against the levels of salt stress. APX activity also increased due to drought stress. Interactive effects of drought×salinity stresses indicated that under lower stress GPX enzymes increased salinity, and under severe stress APX was highly increased. It means the production and activity of plant defensive system like these enzymes in recent tensions and leads to protect or make plants tolerate against oxidative stress induced by drought and salinity.
