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SEASONAL  VARIATION  IN  PRODUCTIVITY  OF ATRIPLEX STOCKSII FROM A COASTAL MARSH ALONG THE ARABIAN SEA COAST

FARHAT AGHA¹, BILQUEES GUL² AND M. AJMAL KHAN^2*

Abstract: The productivity of Atriplex stocksii population located near the coast (Gizri Creek) of Karachi, Pakistan was studied for two years. The net biomass production showed seasonal variation and productivity appeared to be influenced by rainfall during both years. Belowground and above ground biomass showed no change during the dry year, however, considerable biomass was produced after the availability of moisture. The above ground dead biomass remained unchanged during 1997-98 but it registered a substantial promotion during the wet season. The ion concentration of root was much higher than shoot. Na⁺ and Cl^- remained high however, the concentration of other ions did not change much during both seasons. Root fresh weight was significantly promoted at low salinity and increase in salinity inhibited root and shoot growth. Fresh weight of shoots at low density was not affected by low salinities, however, at higher salinity concentrations there was no effect of density. Root fresh and dry weight were higher at low density and low salinity, however under high salinity, density had no effect. Succulence on dry weight basis was also higher at higher densities. However, succulence decreased substantially at high salinities on per plant basis. Shoots of A. stocksii accumulated large quantities of Na⁺ and Cl^- whereas other ions were found in lower amount. Na⁺ and Cl^- in root increased but were much lower in comparison to shoot.

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

¹DHA College for Women, Defense Housing Authority, Karachi, Pakistan

²Institute of Sustainable Halophyte Utilization, University of Karachi, Karachi-75270, Pakistan.

^*Corresponding author: E-mail: majmalk@uok.edu.pk; Phone: 92-21-7700930, Fax: 92-21-9261374