论文部分内容阅读
水是荒漠生态系统中首要限制因子。由于水分限制程度不同,植物幼苗在生长过程中表现出不同的适应策略。在塔克拉玛干沙漠南缘的沙漠-绿洲过渡带,设计了0mm(处理A)、100mm(处理B)、200mm(处理C)3种不同的灌溉量,对头状沙拐枣幼苗生长和生物量分配展开实验性研究。结果表明:①处理A比处理B和处理C地下生物量均有所增加;不同灌溉条件下,头状沙拐枣幼苗的根冠比均小于1,随灌溉量的减少头状沙拐枣幼苗的根冠比从0.19增加到0.32;即头状沙拐枣通过改变根系生物量分配适应水分条件变化。②随灌溉量的减少,头状沙拐枣幼苗主根垂直深度和水平根幅均呈增加趋势。处理A时,头状沙拐枣幼苗根系深度达180cm以上,处理B和C的根系深度均低于160cm,表明头状沙拐枣幼苗通过根系的伸长生长来适应水分减少。③在生长过程中,头状沙拐枣通过老同化枝枯落适应土壤水分减少。④株高和冠幅随着灌溉量增加呈先增加后减小趋势,基径随着灌溉量的增加而增加,地上生长指标在不同处理间均无显著差异。
Water is the primary limiting factor in desert ecosystems. Due to the different degree of moisture restriction, plant seedlings show different adaptation strategies in the growth process. In the desert-oasis transitional zone on the southern margin of the Taklamakan Desert, three different irrigation amounts of 0 mm (treatment A), 100 mm (treatment B) and 200 mm (treatment C) were designed to control the growth and biomass allocation of A. capitata seedlings Experimental research. The results showed that: (1) The biomass of underground biomass of treatment A and treatment B were increased under different irrigation conditions. The root and shoot ratio of A. capsici seedlings was less than 1 under different irrigation conditions. With the decrease of irrigation, The root-shoot ratio increased from 0.19 to 0.32; that is, the head-shaped Caragana korshinskii adapted to the change of water conditions by changing the root biomass allocation. With the decrease of irrigation, the vertical root depth and horizontal root amplitude of the main roots of jujube seedling showed an increasing trend. When treatment A was applied, the root depth of A. capitata seedlings reached more than 180 cm, and the root depths of treatments B and C were all less than 160 cm, indicating that the seedlings of A. capitata adapt to the decrease of water content through root growth. ③ in the growth process, the head of Shagu jujube through the same branch to adapt to the decline of soil moisture. The plant height and crown width firstly increased and then decreased with the increase of irrigation volume. The root diameter increased with the increase of irrigation volume. There was no significant difference in above-ground growth index among different treatments.