不同气候条件下柠条锦鸡儿水力结构特征比较

Comparative Study on the Hydraulic Structural Properties of Caragana korshinskii under Different Weather Conditions

以生长在内蒙古高原荒漠区的柠条锦鸡儿为研究对象,通过观测一年生枝条在不同气候条件下的水力结构特征日变化,结合气候因子,分析旱生植物如何通过调整水分传输来适应变化着的环境条件。结果表明:不管是晴天还是阴天,柠条锦鸡儿的水力结构参数与气温呈显著线性负相关,与相对湿度呈显著线性正相关;晴天柠条锦鸡儿的导水率、比导率和叶比导率明显比阴天低。这说明柠条锦鸡儿能根据环境胁迫的变化及时调整水分运输策略,在满足枝端叶片不同需水要求的前提下,尽量减少水分丧失,达到节水的目的。

There is a range of mechanisms for desert vegetation to adapt arid conditions, such as the increase of underground part to get more water. In desert region, there is very little precipitation, high temperature and strong solar radiation. Precipitation, the most important environmental factor in desert region, affects strongly the growth and development of plants. Therefore, reducing water consumption is a key to adapt desert climate. As a typical native shrub species in the Alxa region, Caragana korshinskii has a perfect physiological mechanism and morphological characteristics to adapt arid environment in its long-term evolutionary process. Many studies have been done on physiology, ecology, molecular biology, morphology and anatomy. However, the studies on hydraulic structural properties of plants under drought stress are insufficient. In this study, the hydraulic structural parameters of C. korshinskii on sunny and cloudy days were measured to investigate their daily variation, and their response to environmental factors is researched so as to understand how the plants in desert region suffer from drought stress. In July 2008, some natural C. korshinskii plants （15 -20 years old） in the Alxa region were selected to research their hydraulic structural properties. On sunny and cloudy days, eight healthy plants were selected, and then 1-year-old twigs were picked to measure the hydraulic structural parameters. The results show that the daily variation of hy- draulic conductivity on sunny and cloudy days was similar, it was high in the morning, began to decline after sunrise, and increased to the level of that in the morning in the afternoon. The ctaily variation of specific conductivity （Ks） on sunny and cloudy days was also similar.