干旱胁迫下保水剂对络石生长和生理的影响

Effects of water retaining agent on growth and physiology of Trachelospermum jasminoides under drought stress

【目的】明确适宜络石生长的保水剂浓度,为保水剂在络石种植中的推广应用提供参考。【方法】以络石为试验对象,在自然干旱胁迫条件下,采用盆栽试验的方法,按施用保水剂质量比设置1个对照(不施保水剂)和4个处理(0.05%、0.10%、0.20%、0.40%),研究络石形态指标和生理指标的变化,并通过相关性分析和主成分分析对其影响效果进行综合评价。【结果】施加不同浓度的保水剂后,络石在不同时期的表现不同。初期各项指标差距较小,后期差异较大,对照组指标变化的时间早于试验组。干旱胁迫35 d后:添加保水剂各处理中络石的萎蔫与干枯均延缓出现,且与对照组相比,存活期延长,株高增长量和新增叶片数量均高于对照组;添加保水剂各处理中络石的叶片相对含水量、PSⅡ最大原初光化学量子效率、光合电子传递速率呈现下降趋势,叶绿素含量、可溶性蛋白含量均呈现先升后降的趋势,丙二醛含量、超氧化物歧化酶活性、可溶性糖含量、初始荧光上升。添加保水剂对络石的形态和生理指标均会有一定的正向作用。施加保水剂的络石与丙二醛含量、可溶性蛋白含量及可溶性糖含量之间的相关性较强,各处理和对照对络石干旱胁迫的缓解能力由优到劣排序依次为0.20%保水剂、0.10%保水剂、0.05%保水剂、0.40%保水剂、CK。【结论】施加一定浓度的保水剂可以延缓络石衰败、提高其保水抗旱能力以及减轻干旱胁迫对其的伤害,0.2%的保水剂可使络石的存活期延长18 d。

【Objective】This study clarified the suitable concentration of water retaining agent for the growth of Trachelospermum jasminoides,and provided a theoretical basis for the popularization and application of water retaining agent in T.jasminoides.【Method】Under natural drought stress,a pot experiment was conducted to study the effects of water retaining agent on the changes of morphological and physiological indexes of T.jasminoides under natural drought stress.One control(without water retaining agent)and four treatments(0.05%,0.10%,0.20%,0.40%)were set up according to the mass ratio of water retaining agent.The effects of water retaining agent on the morphological and physiological indexes of T.jasminoides were evaluated by correlation analysis and principal component analysis.【Result】After the application of different concentrations of water retaining agent,the performance of T.jasminoides was different in different periods.The difference of each index in the early stage was small,and the difference in the later stage was large.The index change time of the control group was earlier than that of the experimental group.After 35 days of drought stress treatment,the addition of water retaining agent delayed the withering and drying of T.jasminoides,and the average survival period,plant height growth and new leaf number were higher than those of CK.The relative water content,optimal/maximal photochemical efficiency of PSⅡand photosynthetic electron transport efficiency showed a downward trend. The contents of chlorophyll and soluble protein showed a first decreasing and then increasing trend;the contents of MDA, SOD, solube sugar and initial fluorescence were increased. The results showed that the addition of water retaining agent had a positive effect on the morphology and physiological indexes of T. jasminoides. The correlation between the application of water retaining agent and the content of MDA, soluble protein content and solube sugar content of T. jasminoides was strong, and the order of ability from good to bad of each treatment and control to alleviate drought stress in the T. jasminoides was 0.20% water retaining agent, 0.10% water retaining agent, 0.05% water retaining agent, 0.40% water retaining agent and CK.【Conclusion】A certain concentration of water retaining agent could delay the decline of T. jasminoides, improve the ability of water retaining and drought resistance, and reduce the damage of drought stress. And 0.20% water retaining agent can prolong the survival period of T. jasminoides for 18 days.