关键词: 刺蓬（Cornulaca alaschanica), 冰草（Agropyron cristatum）, 干旱胁迫, 生长

Abstract:

For understanding regional desert ecosystem process of drought causing disaster and the influence of drought on growth of Agropyron cristatum and Cornulaca alaschanica, three treatments including continuous drought stress, supplement irrigation and natural growth were designed firstly. Then the changes of two desert herbaceous plants’ morphology and dry matter yield were compared under different soil moisture conditions. The results show that the continuous drought stress made the vegetative growth stage of Cornulaca alaschanica and Agropyron cristatum extend, the reproductive stage and the whole growth period shorten. As affected by drought stress, the growth height, dry matter and cover of Cornulaca alaschanica and Agropyron cristatum decreased, and the effects of drought stress gradually increased. As affected by the continuous drought stress, when volumetric soil water content was only 0.4-0.6 mm, the period of 64 to 73 days after turning green was the inflection point of growth height of Cornulaca alaschanica, and when volumetric soil water content went down to 0.3-0.4 mm, the period of 130 to 135 days after turning green was growth height inflection point of Agropyron cristatum. The period of 106 to 121 days after turning green was the critical stage of drought stress influence on dry matter accumulation of Cornulaca alaschanica when volumetric soil water content decreased to 1.0-1.1 mm. While the period of 181 to 197 days after turning green was key stage of dry matter accumulation of drought stress effect on Agropyron cristatum when volumetric soil water content was about 1.5 mm.

Key words: Cornulaca alaschanica, Agropyron cristatum, drought stress, growth