Effects of UV radiations on growth and some physiological and biochemical parameters of Portulaca oleracea L.

The increased effects of UV radiation are observed as a result of the reduced ozone layer with increasing atmospheric pollution. The aim of this study was to investigate the effects of UV radiations on growth and some physiological and biochemical parameters of Portulaca oleracea L. Experiments were performed under controlled greenhouse conditions using a completely randomized design with three replications. Purslane plants were treated with UV rays (UV-A at three times 20, 40 and 60 minutes, UV-B at three times 20, 40 and 60 minutes, and UV-C at five times 10, 20, 30, 40, 60 minutes). The results indicated that changes in root growth were not significant, but shoot length, wet and dry weight of plant increased compared to control in the three groups treated with 60 min UV-A, 60 min UV-B and 10 min UV-C. the treatment with 60 min UV-B increased the activity of defense enzymes, phenolic, flavonoid and antioxidant contents significantly more than the other UV treatments. In general, the results indicate that the purslane plant is sensitive to UV radiation. However, applying controlled UV light can provide a new alternative strategy to increase crop productivity, that is the same application of 60 min UV-B as a novel plant growth booster, in comparison with UV-A and UV-C treatment.