Effects of temperature and water limitation on the germination of Stipagrostis ciliata seeds collected from Sidi Bouzid Governorate in Central Tunisia

作     者：Lobna M FAKHFAKH Naser A ANJUM Mohamed CHAIEB 

作者机构：Department of Life Sciences Faculty of Sciences University of Sfax Centre for Environmental and Marine Studies and Department of Chemistry University of Aveiro 

出 版 物：《Journal of Arid Land》 (干旱区科学（英文版）)

年 卷 期：2018年第10卷第2期

页      面：304-315页

核心收录：

学科分类：0710[理学-生物学] 0830[工学-环境科学与工程（可授工学、理学、农学学位）] 0709[理学-地质学] 09[农学] 0708[理学-地球物理学] 0903[农学-农业资源与环境] 0815[工学-水利工程] 0705[理学-地理学] 

基　　金：supported by the Tunisian Ministry of Scientific Research  especially the arid lands program 

主　　题：Stipagrostis ciliata germination temperature water potential hydrothermal model arid zone Bou Hedma Park 

摘      要：Most ecological studies in North Africa reveal a process of continuous degradation of rangeland ecosystems as a result of overgrazing. This degradation appears across the decreasing of perennial grass diversity. Indeed, the majority of steppe ecosystems are characterized by a low density of perennial grass species at present. This study evaluated the effects of temperature and water limitation on the seed germination of Stipagrostis ciliata（Desf.） de Winter, a perennial grass species. The seeds were collected from the Bou Hedma Park, Sidi Bouzid Governorate, Central Tunisia. The thermal time and hydrothermal time models were used to describe the seed germination of S. ciliata under different water potentials and temperatures. The germination response of S. ciliata seeds in darkness was evaluated over a range of temperatures（15°C, 20°C, 25°C, 30°C and 35°C） and across a wide range of osmotic potentials（0.0, –0.2, –0.6, –1.2, –1.6 and –2.0 MPa） of the polyethylene glycol（PEG6000） solutions at each temperature level. Among the tested temperatures, 25°C was found to be the optimal temperature to the germination of S. ciliata seeds. The final germination percentage（75.2%） was obtained with distilled water. The progressive decrease of osmotic potential of the PEG6000 solutions inhibited the seed germination. However, the number of days to first germination was increased with a reduction of osmotic potential. A significant positive relationship was identified between final germination percentage of S. ciliata seeds and osmotic potential of the PEG6000 solutions, with R^2 ranging from 0.5678 to 0.8761. Furthermore, a high degree of congruency between predicted and observed germination time course curves was observed. In general, S. ciliata exhibits a significant adaptation capacity for water limitation and high temperature in arid ecosystems.