毛乌素沙地沙地柏(Sabina vulgaris)的水分生态初步研究

对毛乌素沙地沙地柏群落的水分状况作了初步研究。在典型的沙地柏群落中选取位于丘顶（水分条件较差）和丘间低地（水分条件较好）的两个样地作为研究对象，观测了植物叶子的蒸腾速率、气孔阻力及水势等生理生态指标，并结合群落特征和土壤水分状况，探讨了水分亏缺对沙地柏的影响。研究结果表明：１）虽然沙地柏具有比多数沙生灌木较小的蒸腾速率和更强的抗旱性，但是在不能利用地下水的情况下，其过大的密度可引起大量蒸腾耗水，并使植物处于严重的水分亏缺之中；２）在沙地柏群落的退化乃至于成片枯死过程中，水分胁迫是重要的因素之一；３）为了防风固沙，人工栽植沙地柏的适宜地段应选择水分条件较好的沙地（如滩地覆沙），而在高大的沙丘或梁地栽植沙地柏，应该注意规模和密度。

A PRELIMINARY STUDY ON THE WATER REGIMES OF SABINA VULGARIS IN MAOWUSU SANDLAND, CHINA

This paper deals with the water regimes of Sabina vulgaris community in China's Maowusu Sandland. In the typical sites of Sabina vulgaris community, two sample plots were selected at the top dune and the depression, standing for the poor and good water condition, respectively. The effects of water deficit on the water regimes of the plant are discussed with the aid of field collected data of transpiration rate, stomatal resistance, water potential, community characteristics and soil water conditions, etc. The main results are: 1) Although transpiration rate of Sabina vulgris was relatively low, water consumption of the community might be so remarkable that the individual plant might easily be confronted with conditions of water deficit, and 2) as a result, the degradation of Sabina vulgaris community was due partly to the shortage of water. 3) The lowland covered with sand, where water conditions is good, was more appropriate for planting Sabina vulgaris . However, in planting this shrub in the soft and hard ridges, or high moving dunes where ground water is unavailable, attentions should be paid to both the extent and density of this plant.