WATER RELATIONS IN THE RELICT SAVANNA EDIFICATORS OF SOUTH TAJIKISTAN

Some water relation characteristics in the edificators [Imperata cylin drica (L.) Beauv. and Erianthus ravennae (L.) Beauv.] of unique savann a-like vegetation grown in the arid subtropical zone of South Tadzhiki stan were studied. These characteristics include transpiration rate, w ater content in the leaves, water-retaining capacity, osmotic pressure , suction force, midday and residual water deficit, and the water expe nditure rate. Due to the shallow bedding of groundwater and efficient use of water by the plants, both species can maintain their water econ omy. Their characteristics did not increase up to the critical values even at the highest summer temperatures. Because of this, both plant s pecies produce stable, highly productive savanna-like communities in t he flood-plain ecosystems of the Central Asian arid zone.