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SEASONAL FLUX IN WATER POTENTIAL, CHLOROPHYLL AND PROLINE CONTENT IN PLANTS AT ZIARAT VALLEY BALOCHISTAN, PAKISTAN

IRFAN AZIZ

Abstract: Seasonal changes in water relations and accumulation of proline during drought stress were assessed in different plant species viz., Artemisia scopria, Juniperus exceltata, Onobrychis cornuta and Sophora alopecuroides growing under arid region of Ziarat valley. Water status of the plants was evaluated by measuring pre-dawn water potential and water use efficiency of plants. All the plant species showed higher values for both parameters during the wet period of April when soil moisture and organic matter was abundant. In general, Onobrychis cornuta and Artemisia scoparia had more negative water potential than Juniperus exceltata and Sophora alopecuroides over all seasons. A substantial decrease in water potential and water use efficiency was observed during dry period (October and January). Proline concentration peaked with a decrease in chlorophyll content during January in all species. The maximum proline concentration was observed in O. cornuta followed by A. scoparia. As soon as drought stress was released following the melting of snow and spring showers in April, an increase in chlorophyll content with corresponding decrease in proline was observed.

Department of Botany, University of Karachi, Karachi-75270, Pakistan.

Email: halophyte_irfan@yahoo.com