矮嵩草草甸植物蒸腾强度的初步研究

A PRELIMINRY STUDY ON TRANSPIRATION INTENSITY OF PLANTS IN KOBRESIA HUMILIS MEADOW

此项研究工作于1986年5-9月植物生长季节内,在海北高寒草甸生态系统定位站进行。用钻纸法测定了矮嵩草等10种植物的蒸腾强度、垂穗披碱草等3种植物的蒸腾日进程和不同植被覆盖地段的蒸腾-蒸发量,在测定时记录了气温、湿度等有关气象资料,以便分析。研究结果表明: 1.矮嵩草等10种植物的蒸腾强度随植物种和所处的物候期而变化,植物生长早期蒸腾强度较低,进入生殖阶段,蒸腾强度明显提高。2.垂穗披碱草等3种植物蒸腾强度日进程呈明显的单峰型曲线,在中午或午后出现峰值,没有午休现象。这同气孔一直开着有关,是矮嵩草草甸植物蒸腾的特征之一。3.不同植被覆盖地段的蒸腾-蒸发表明,有植被覆盖的地段的蒸腾-蒸发量较裸地的蒸发量为高。

The present study in transpiration intensity of plants in alpine Kobr-esia humilis meadows was carried out at Haibei Research Station of AlpineMeadow Ecosystem during the growing season from May to September in1986. The transpiration intensity of Kobresia humilis and plants of nineother species, the daily courses of transpiration intensity of Elymus nutansand plants of two other species as well as the evapotranspiration intensi-ty of different ground covers in Kobresia humilis meadows were measuredby method of cobalt paper. At the same time, meteorological data eweralso recorded. The study results are as follows: 1. The transpiration intensity of Kobresia humilis and plants of nineother species and their phenological phases, were lower during the earlygrowth period and higher during the growth-development period. In gene-ral, the transpiration intensity of plants in alpine meadows is higher dueto the special habitat conditions on the Qinghai-Xizang plateau. 2. The daily transpiration courses of Elymus nutans and plants ofother species showed one peak curve at noon or afternoon, due to the lon-ger time opening of the stoma to which is also one of the reasons of thehigher transpiration intensity. But on the other hand, the transpirationcoefficient is higher and the transpiration ratio is lower of the plants inKobresia humilis meadows. 3. The evapotranspiration of different ground covers showed that eva-potranspiration with ground cover is higher than that without ground co-ver (bare land).