库布其沙漠几种植物的光合蒸腾及水分利用效率

采用Li-6400便携式光合测定系统,在自然条件下测定了内蒙古库布其沙漠北缘试验地4种沙生植物(沙米、苦豆子、油蒿、沙柳)连体叶片的光合、蒸腾速率及相应环境因子的日变化.结果表明:沙柳和沙米具有较高的光合能力,而且沙米对高温、低湿和强光的耐受性比其他3种植物强;气孔的开张程度与湿度的关系更密切,且叶内外水气压差是气孔导度变化的主导因子;4种植物蒸腾速率日变化曲线有明显的"午休"现象,沙米的蒸腾速率要高于其他3种植物,属于高蒸腾植物;苦豆子水分利用效率较低,沙米居中,油蒿和沙柳水分利用效率较高;油蒿和沙柳在该地区生产力较高;油蒿对干旱环境的反应要比其他3种植物敏感.

Diurnal Variations of Moisture Physiology Characteristic of a Few Plants in Hobq Desert

Diurnal variations of photosynthetic and transpiration rate and the relevant environment factors of four kinds of sandy plants(Agriophyllum arenarium,Sophora alopecuroides,Artemisia ordosica,Salix psammophila),with leaves connecting the body were measured with portable Li-6400 photosynthetic measure system under natural conditions in the experiment area of the north in Hobq desert in Inner Mongolia.The results showed: The net photosynthetic of A.arenarium and S.psammophila was higher,it showed that they had a higher photosynthetic ability. The resistance ability of A.arenarium to the high temperature and low humidity or strong light was more strong than the other three plants. The relation between the open degree of stomatal conductance and humidity was closer,and vapor pressure deficit was the main factor of the change of stomatal conductance. Four plants had significant midday depression.Transpiration rate of A.arenarium was higher than the other three plants,so it belonged to high transpire plants. S.alopecuroides had low water use efficiency,A.ordosica and S.psammophila had high water use efficiency,and A.arenarium was between them.A.ordosica and S.psammophila had higher productivity in the region.The reaction of A.ordosica to dry environment was more sensitive than the other three plants.