梭梭(Haloxylon ammodendron)叶片气孔导度与气体交换对典型降水事件的响应  

Responses of Leaf Stomatal Conductance and Gas Exchange of Haloxylon ammodendronto Typical Precipitation Event in the Hexi Corridor

作　　者：杨淇越[1,2] 赵文智[1] 

机构地区：[1]国科学院寒区旱区环境与工程研究所中国生态系统研究网络临泽内陆河流域研究站/中国科学院内陆河流域生态水文重点实验室,甘肃兰州730000 [2]中国科学院大学,北京100049

出　　处：《中国沙漠》2014年第2期419-425,共7页Journal of Desert Research

基　　金：国家杰出青年科学基金项目(41125002)资助

摘　　要：C4植物以其较高的水分利用效率而表现出较强利用荒漠环境有限降水的能力,但对其气孔行为和气体交换对降水响应的理解并不深入。本研究选择荒漠区沙丘上6~7年生的梭梭(Haloxylon ammodendron),利用自制的降水拦截设施,将每次降水事件后样地中接受的降水量分别减少和增加10%、20%和30%,形成包括对照在内的7个降水梯度,研究梭梭气孔导度(Gs)与净光合速率(Pn)对典型降水事件的响应。结果表明:6~12mm的降水对土壤水分的补给集中在50cm土壤深度范围内。降水量每增加10%,Gs和Pn分别增加9.17%和4.17%;Gs和Pn在降水前后呈现先增加后降低的单峰型趋势,峰值出现在降水后第1天,两者与土壤水分含量(SVWC)、空气相对湿度(RH)以及水汽压差(VPD)显著相关。降水后梭梭黎明前叶水势在-2.08^-2.74 MPa时叶片气体交换主要受气孔因素影响,而当叶水势降至-3.16MPa以下时主要受非气孔因素控制。C4 plants have strong ability to use limited precipitation in desert environment due to higher water use efficiency, but it is not understanding of stomatal behavior and gas exchange response to precipitation thoroughly. Here the responses of leaf stomatal conductance （Gs） and gas exchange （Pn） of 6-7 year-old Haloxylon ammodendron in desert-sand to seven rainfall treatments （±30%, ±20%, ±10%, CK） which were applied by rainfall manipulative experiments were evaluated. The results showed that the supply of 6-12 mm rainfalls to soil moisture concentrated within 50 cm soil depths. Gs and Pn increased by 9.17% and 4.17% with the increase of precipitation by 10%, respectively. Gs and Pn showed a trend of unimodality which increased to a peak value at 1d after precipitation and then decreases. Both were correlated significantly to Soil moisture content （SVWC）, Air relative humidity （RH） and Vapor pressure deficit （VPD）. Leaf gas exchange was mainly affected by stomatal factors when predawn leaf water potential of H. ammodendron between -2.08 MPa and -2.74 MPa after precipitation, while by non- stomatal factors when predawn leaf water potential dropped to below -3.16 MPa.

关 键 词：河西走廊 梭梭(Haloxylon ammodendron) C4植物 气孔导度 气体交换 

分 类 号：Q945.79[生物学—植物学]