毛乌素沙地优势种在高CO_2浓度条件下对土壤干旱胁迫的响应

Responses of some dominant species in Maowusu sandland under high CO_2 concentration to drought stress

采用人工模拟试验方法研究了毛乌素沙地沙生植物群落优势种沙柳、油蒿、柠条、杨柴对高CO2浓度(700μmol/mol)和土壤干旱胁迫的响应。试验结果表明,CO2浓度升高有利于4种植物的生长,根、茎、叶生物量均呈增加趋势;土壤干旱胁迫对4种植物都产生显著的不利影响,且均随干旱程度的加重而负效应加重;在高CO2浓度条件下,土壤干旱胁迫的不利影响仍较明显,但与本底CO2浓度条件下相比,CO2的"施肥效应"依然存在。通过对4种植物生物量的比较,沙柳在高CO2浓度条件下对干旱更为敏感,而柠条对CO2浓度的升高更为敏感。

Using the artificial experiment, the response of soil drought stress and high CO2 concentration (700 μmol/mol)on some dominant species in Maowusu sandland plant community, such as Salix psammophila, Artemisia ordosica, Caragana intermedia and Hedysarum mongolicum. was studied. The results showed that the increase of the CO2 concentration was in favor of the biomass increasing trend of the root, stem, leaf of the four species. Soil drought stress put remarkably adverse impact on all of them, and the negative impact increased with drought degree aggravating. Under the condition of high CO2 concentration, the negative impact was still existing, but compared with the condition of normal CO2 concentration, the 'fertilization function' was existing also. By the comparing, we found that S.psammophila was more hypersensitive to drought stress under high CO2 concentration and C.intermedia was most hypersensitive to an increase in CO2 concentration.