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【目的】研究土壤不同相对含水量,对一年生尖果沙枣幼苗生长特征参数和光合特性的影响。【方法】以一年生尖果沙枣实生苗作为研究对象,采用盆栽模拟干旱处理,测定其生长特征参数、光合特征参数和光合素色含量。【结果】随着土壤相对含水量的减少,尖果沙枣幼苗的主干、主枝的生长量和植株总生物量呈现先上升后下降趋势,其中T1处理的主干、主枝相对生长速率和总生物量均最高,值分别为(25.7±2.4)%、(194.0±32.6)%和(19.5±2.0)g,而T3处理的干物质积累率和根冠比均显著高于其它处理。与对照(CK)相比,T1处理的CO2同化效率(Pn)、蒸腾速率(Tr)和气孔导度(Gs)均显著高,T2处理的Pn、Tr和Gs均无显著差异,T3处理的Pn、Tr和Gs均显著低。【结论】尖果沙枣具有较强的抗旱性,在土壤相对含水量为50%~55%(T1)的条件下,能表现出较高的CO2同化能力和生长势,而且轻度干旱条件在一定程度上能够抑制尖果沙枣主干的顶端优势,反而促进侧枝的生长,提高尖果沙枣在生态建设中的防风固沙能力。
【Objective】 The objective of this study was to investigate the effects of soil relative water content on growth characteristics and photosynthetic characteristics of one-year-old Sabina przewalskii seedlings. 【Method】 One-year-old sauropus japonicus seedlings were used as research objects. Pot experiment was conducted to study the growth characteristics, photosynthetic characteristics and photosynthetic pigment content. 【Result】 The results showed that with the decrease of soil relative water content, the growth of main stem, main branch and plant biomass of A. sativa seedling showed the first increase and then the downward trend. The relative growth rate of trunk, main branch and the total growth of T1 (25.7 ± 2.4)%, (194.0 ± 32.6)% and (19.5 ± 2.0) g, respectively. However, the dry matter accumulation rate and root / shoot ratio of T3 were significantly higher than those of other treatments. The CO2 assimilation efficiency (Pn), transpiration rate (Tr) and stomatal conductance (Gs) of T1 treatment were significantly higher than those of CK (CK). There was no significant difference in Pn, Tr and Gs between T2 treatment and T3 treatment Pn, Tr and Gs were significantly lower. 【Conclusion】 A. japonicus has strong drought resistance. Under the conditions of soil relative water content of 50% -55% (T1), it shows higher CO2 assimilation ability and growth potential, and mild drought condition To a certain extent, it can restrain the top superiority of the main stem of Scirpusorbatus and promote the growth of collateral, and improve the windbreak and sand fixation ability of Scirpusornae verrucosa in ecological construction.