Contribution to the ecology of the steppe vegetation of the Tihany Peninsula III. Estimation of drought resistance based on the saturation of water deficit

Rychnovská, Milena and Květ, Jan (1965) Contribution to the ecology of the steppe vegetation of the Tihany Peninsula III. Estimation of drought resistance based on the saturation of water deficit. A Magyar Tudományos Akadémia Tihanyi Biológiai Kutatóintézetének évkönyve, 32. pp. 289-296. ISSN 0365-3005

Preview

Text 317_cut_MTA_TihanyiBiologiaiKutIntEvkonyve_32.pdf Download (3MB) | Preview

Abstract

Reversibility of the water deficit in leaves of some characteristic steppe grasses growing at Kiserdőtető on the Tihany Peninsula was compared with that found in the same species from Szentendrei-sziget and Csornád. With each species tested a series of different water-deficit values were induced by drying the intact leaves at constant temperature for periods varying from 0 to 9 hours. Segments cut from these water-deficient blades were then saturated with water through both their cut surfaces for 2 hours. The initial water content, the water deficit and the water content after saturation of the segments were determined by weighing. The grass species tested were found to fall into two groups: 1. Stipa-type. The leaf segments fully recover from their water deficit by regaining their initial water content, but beyond a certain water deficit, irreversible changes seem to occur in the leaf tissues which prevent the segments from fully saturating their water deficit. 2. Chrysopogon-type. Increase in water deficit brings about an increase in the water-holding capacity of the leaf tissues. In general, the water content of the leaf segments after saturation is higher than it was initially. As with the Stipa-type, irreversible changes seem to occur, with the same consequences, when the water deficit reaches a certain value. These findings have been compared with the phytogeographical distribution of the species studied which is supposed to be in accordance with their ecological amplitude. The Stipa-type of water deficit saturation seems to be advantageous to plants that have to survive long rainless periods in regions with continental conditions. The Ghrysopogon-type seems to be favourable to plants in mesophytie conditions, or those having a rather oceanic distribution,where only short periods of drought have to be survived. The plants of this type can undoubtedly make full use of occasional rainfall, especially if it follows a dry period.

Actions (login required)

Edit Item