Water stresscauses changes in leaf chlorophyll content, proline and electrolyte leakagein ‘Shishe-kab’ pomegranate cultivar

Iran is native land of pomegranate, and the country is not only the largest producer with an annual production of 700.000 tons, but also the biggest exporter of pomegranate in the world. In this experiment the influence of different levels of irrigation regimes on ‘Shishe-kab’ pomegranate cultivar whit three replications was assessed. A factorial experiment based on a randomized complete block design was applied in the agriculture and natural resources research center of Yazd province. The three irrigation treatments were well irrigated (control), 75% of crop water requirement (moderate stress) and 50% of crop water requirement (severe stress), and trees were irrigated over the growing season. At the end of the growing season, some traits such as chlorophyll a, b, and total chlorophyll content, carotenoid content, leaf area, proline content, relative water content (RWC) and electrolyte leakage were measured. The results showed that the all traits had significant differencesexcept chlorophyll b and carotenoid content. The highest leaf total chlorophyll was recorded in control trees (9.01 mg/g fw), and the lowest leaf total chlorophyll content was recorded in severe stress (6.67 mg/g fw). Proline content was increased by decreasing irrigation levels. The highest proline content (10.43m mol/gr fw) was recorded with lowest irrigation level or severe stress. Leaf area varied from 3.62cm2 (moderate stress) to 2.69 cm2 (severe stress). Overall, with reducing the volume of irrigation, some biochemical compounds such as chlorophyll a, and total chlorophyll content decreased, but proline content increased and chlorophyll b, and carotenoid content did not change in the pomegranate leaf.