国审品种‘苏植1号’杂交结缕草抗旱性初步评价与分析

Preliminary evaluation of drought resistance for the hybrid zoysiagrass‘Suzhi No.1'

以‘苏植1号’杂交结缕草为研究对象,‘兰引3号’结缕草为对照品种,采用沙培试验控水处理,根据叶片萎蔫度、叶片相对含水量、根系电解质外渗率和土壤含水量4个指标对‘苏植1号’的抗旱性进行了初步评价,同时分析了两个品种的根系生长特性(根系干重、比根长)和干旱胁迫下最大光化学量子产量(Fv/Fm)的变化特点。结果表明,干旱胁迫过程中,两个品种的叶片萎蔫度逐渐增大,土壤含水量逐渐下降,不同品种的变化趋势相似,胁迫结束时,两个品种的叶片萎蔫度、叶片相对含水量、根系电解质外渗率和土壤含水量均无显著差异,说明‘苏植1号’整体抗旱表现与‘兰引3号’近似。同时,相对于‘兰引3号’而言,虽然‘苏植1号’的根系干重显著较小,但是较大的比根长和干旱胁迫中期较高的Fv/Fm值很可能使‘苏植1号’在一定程度上抵消了较小的根系生物量所带来的不利影响,是其重要的抗旱机制。总体来看,‘苏植1号’与‘兰引3号’抗旱性相当,但两者具有不同的抗旱途径。

An experiment was carried out to evaluate the drought resistance of hybrid zoysiagrass ＇Suzhi No. 1 ＇ , compared with Zoysia japonica ＇Lanyin No. 3＇ as the control. Plant materials were cultured in sand in PVC tubes in a greenhouse and drought treatments were implemented by withholding water. Leaf wilting （LW）, leaf relative water content （RWC）, root electrolyte leakage （REL）, soil water content （SWC）, root growth characteristics including root dry weight （RDW） and specific root length （SRL）, as well as maximum quantum yield of PS Ⅱ （Fv/Fm） were measured under drought stress. The drought resistance of ＇Suzhi No. 1 ＇ was ini tially evaluated based on LW, RWC, REL and SWC. Both cultivars showed gradual increases in LW, exhibi ring slight wilting on the 12th day of drought stress, moderate wilting on the 29th day and severe wilting after 40 days. SWC values decreased gradually with both cultivars displaying similar trends during the stress period. Drought stress also caused significant declines in RWC and rises in REL. By the end of the treatment （40th day）, no differences in LW, RWC, REL and SWC were found indicating that the performance of ＇Suzhi No. 1＇ was similar to ＇Lanyin No. 3＇ under drought stress. Although ＇Suzhi No. 1＇ had smaller RDW to ＇Lanyin No.3＇, it also had larger SRL and could keep higher Fv/Fm values in the middle of the stress period, potentially an important drought resistance mechanism. With relatively denser roots and higher photochemical efficiency, it is probable that ＇Suzhi No. 1＇ was able to offset the adverse effects of smaller root biomass. In summary, ＇Suzhi No. 1＇ and ＇Lanyin No. 3＇ had similar drought resistance but with different resistant mechanisms.