土壤含水量对树番茄苗木生长及非结构性碳水化合物的影响

Effect of different soil moisture content on growth and non-structural carbohydrates of Cypomandra betacea seedlings

【目的】为树番茄苗木水分管理提供参考。【方法】采用双因素随机区组试验,以1年生的树番茄苗木为研究对象,设置4个水分处理,即适宜水分含量处理、轻度亏水处理、中度亏水处理、重度亏水处理,土壤含水量分别为26.83%~30.41%、21.46%~25.04%、16.10%~19.67%、10.73%~14.31%,比较树番茄苗木在经过不同胁迫时间(15、30、45、60 d)后生长量、各器官生物量和非结构性碳水化合物(NSC)含量及积累量的变化规律,了解土壤含水量对树番茄苗木生长与NSC的关系。【结果】在适宜的水分含量和轻度亏水处理下树番茄苗高和地径持续生长,中度和重度亏水处理对苗高和地径生长有明显的抑制作用。随着土壤水分含量减少和胁迫时间的延长,茎生物量最高,各器官生物量由高到低依次为茎、叶、根;叶片可溶性糖和NSC含量逐渐增加;茎可溶性糖和NSC含量先增加后减少;根可溶性糖和NSC含量均高于叶和茎。根、茎、叶淀粉含量在适宜水分含量、轻度亏水、中度亏水处理下先减少后增加。胁迫15、30、60 d时,各处理下叶、茎可溶性糖与淀粉的含量比值高于适宜水分含量处理,胁迫45 d时,叶、茎、根可溶性糖与淀粉含量比值随土壤含水量的减少而逐渐减少。【结论】树番茄苗木生长和各器官的可溶性糖、淀粉、NSC含量随着胁迫时间延长有不同的响应,随着土壤含水量减少,树番茄苗木在一定的胁迫时间下,NSC不断积累,以此来缓解水分胁迫对树番茄苗木生存的影响。

【Objective】To provide reference for water management of Cypomandra betacea seedlings.【Method】A two-factor randomized block test was used to study 1-year-old C.betacea seedlings,and four moisture treatments were set up,i.e.,suitable moisture content treatment,mild water deficit treatment,moderate water deficit treatment,and severe water deficit treatment,with soil moisture content ranging from 26.83%to 30.41%,21.46%to 25.04%,16.10%to 19.67%,and 10.73%-14.31%,respectively,to compare the changing patterns of growth,biomass of various organs and non-structural carbohydrates(NSC)content and accumulation of C.betacea seedlings after different stress times(15,30,45,and 60 d),and to understand the relationship between soil water content on the growth and NSC of C.betacea seedlings growth and NSC.【Result】C.betacea seedling height and diameter continued to grow under appropriate moisture content and mild water deficit treatment,while moderate and severe water deficit treatments had obvious inhibitory effects on seedling height and diameter growth.With the decrease of soil moisture content and the prolongation of stress time,the stem biomass was the highest,and the biomass of each organ was stem,leaf and root in descending order;leaf soluble sugar and NSC content increased gradually;stem soluble sugar and NSC content increased and then decreased;root soluble sugar and NSC content were higher than that of leaf and stem.The starch content of roots,stems and leaves firstly decreased and then increased under appropriate water content,mild water deficit and moderate water deficit treatments.At 15,30 and 60 d of stress,the ratio of leaf and stem soluble sugar to starch content was higher than that of the suitable water content treatment under each treatment,and at 45 d of stress,the ratio of leaf,stem and root soluble sugar to starch content gradually decreased with the decrease of soil water content.【Conclusion】The growth of C.betacea seedlings and the soluble sugar,starch,and NSC contents of each organ responded differently with the prolongation of the stress time,and with the reduction of soil water content,C.betacea seedlings accumulated NSC under a certain stress time as a way to alleviate the effects of water stress on C.betacea seedlings survival.