مطالعه تنش آبي بر بيوماس، قندهاي محلول، پرولين، آنزيم ها و يون ها در گياه آفتابگردان .HELIANTHUS ANNUS L

Study of water stress on biomass, soluble sugars, proline, enzymes and ions in Helianthus annus L.

In order to have adaptation and tolerance for the environmental stresses, different plant species show different physiological responses. In this study, the effect of water stress on biomass, change in content of soluble sugars , proline , K+ , Na+ and activity of peroxidase and catalase was investigated in one sunflower (Helianthus annuus L.) cultivar including of Record . An experiment was carried out under potting conditions and 5 treatments (10, 20, 30, 40 and 50% of water saturation capacity) and 4 replicates of CRD was used. Total dry weight, total leaf chlorophyl, total soluble sugars and proline, Na+, K+ in leaf and enzymes activity of catalase and peroxidase in leaf were measured. Results showed that total chlorophyll and K+ in leaf significantly decreased in comparison to control sample (50% of water saturation capacity) by increasing water stress. Dry weight decreased with increasing water stress and significantly decreased in treatments of 10 and 20% of water saturation capacity in comparison to control sample. Na+ in leaf significantly increased with increasing of water stress. Total soluble sugars and proline increased by increasing water stress. Enzyme activity of catalase in leaf increased with increasing water stress and significantly increased in treatments of 10 and 20% of water saturation capacity in comparison to control sample. Also in the leaf, peroxidase activity significantly increased in treatments of 10, 20 and 30% in comparison to control sample. Sugars and proline accumulation probably play an important role in osmoregulation and tolerance to water stress conditions. In addition, the increase of enzymes activity in leaf is necessary for protecting against oxidative damages and defense against the water stress.