水分胁迫下菌根真菌对滇柏(Cupressus duclouxiana Hichel)幼苗生长和养分吸收的影响

摘要

The potted seedlings of Cupressus duclouxiana Hichel were tested to study their response characteristics under three different moisture content conditions, normal moisture(25~30%) , moderate drought (15~20%) and severe drought(5~ 10%). Accordingly, the test include four inoculated groups, control group(A), VAM groupCB, inoculated VAM), ectomycorrhizaKC, inoculated Ectomycorrhiza) and mixture groupCD, VAM + Ectomycorrhiza). The biomass,root morphology and nitrogen content, phosphorus content of Cupressus duclouxiana Hichel seedlings were measured after 150 days. The results show that when the seedlings were inoculated with mycorrhizal fungus under normal moisture, the plant biomass was increased, including above-ground biomass and under-ground biomass. The effect to the contents of nitrogen and phosphorus was mainly on the root. The nitrogen content of roots was respectively increased significantly, by 65.4%, 118. 2% and 117. 7% in B, C and D group under normal moisture, respectively. The root phosphorus content of C and D group was obivious increased 40. 4% and 49. 4% compare to contral group. The effect to root morphology was also significant, the D inoculated treatment were higher than that in controlled treatment on root length and surface area. Under mediate drought, there was significant difference a-mong B,D and A in N content in roots,but signifecant difference among C,D and A in leaves. And there was significant difference among C,D and A in P content in roots and leaves. The trend of positive effect to root morphology was D>OB>A. Under severe drought condition, the mycorrhizal fungi did not affected the plant biomass and nutrient content as well as root morphology. In brief, except for under severe drought condition, the mycorrhizal fungi would improve nutrient absorption and increase the biomass and benefit for enhancing survival rate of C. Duclouxiana Hichel.%在正常水分、中度干旱、重度干旱3个水分条件下,设对照(A)、接种内生菌根真菌(B)、接种外生菌根真菌(C)、混合接种(D)四个处理,利用盆栽实验研究了菌根真菌对滇柏生物量和N、P含量以及根系形态的影响.结果表明:在正常水分条件下,菌根真菌对滇柏的响应主要表现在生物量上,对N、P含量的影响主要体现在根上,其中滇柏的B、C、D处理根系中氮含量分别比对照显著增加了65.4％、118.2％和117.7％,而根系中磷含量只有C和D处理比对照显著增加了40.4％和49.4％.对根系形态影响显著,其中D处理的根长和表面积和对照差异显著.在中度干旱条件下,以外生茵和混合菌接种对植物的N的响应差异显著,主要体现在叶上,其中C和D处理和对照呈显著性差异.以外生菌和混合茵接种对植物的P的响应差异显著,主要体现在根和叶上.从根系形态上,接种处理的影响呈现出一个总体趋势,混合＞外生＞内生＞对照.重度干旱条件下,不论是外生菌或内生菌或混合对滇柏的影响都很小.可见,在极度缺水的条件下,菌根真菌的作用有限.总之,在一般干旱条件下,菌根真菌能够提高滇柏的抗旱能力.