干旱胁迫下接种菌根真菌对滇柏和楸树幼苗根系的影响

Effects of mycorrhizal fungus inoculation on the root of Cupressus duclouxiana and Catalpa bungei seedlings under drought stress

在正常水分(25%～30%)、中度干旱(15%～20%)、重度干旱(5%～10%)3种水分条件下,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)4个处理,利用盆栽实验研究了菌根真菌对滇柏、楸树地下生物量和根系N、P含量以及根系形态的影响。结果表明:接种菌根真菌后,根系生物量都有所增加,但滇柏以外生菌和混合菌接种的效果更显著,而楸树以内生菌的效果最为显著。除重度干旱以外,滇柏接种处理的氮和磷含量都要高于对照处理,楸树B和D处理的氮磷含量要高于对照。其中滇柏根系的平均直径、总长度以及表面积都有所增加,接种效果表现为D>C>B>A。接种内生菌根对楸树影响明显,根系形态和对照组相比呈显著性差异,外生菌根无明显作用。重度干旱条件下,接种处理对两种树种各指标的影响都较小。可见,接种菌根真菌能够提高滇柏、楸树的抗旱性。

The potted seedlings of Cupressus duclouxiana and Catalpa bungei were used to examine their response under different moisture content conditions,including normal moisture（25 %-30 %）,moderate drought（15 %-20 %） and severe drought（5 %-10 %）.The inoculated groups were the control group（A）,VAM group（B）,ectomycorrhizal（C） and mixture group（D,VAM＋Ectomycorrhiza）.After 150 days of treatment,the root biomass,root morphology and contents of nitrogen and phosphorus were measured.The results showed that after the seedlings were inoculated with mycorrhizal fungi,root biomass increased.The root biomass of Cupressus duclouxiana seedlings increased significantly under C and D treatments,however,B and D treatment significantly increased the root biomass of Catalpa bungei.Except severe drought,N and P contents in roots of Cupressus duclouxiana with mycorrhizal fungus inoculated were higher than those of control,whereas only with B and D treatment,the N and P contents of Catalpa bungei roots were higher than those of CK.After the seedlings inoculated with mycorrhizal fungi,the mean root diameter,total root length and root surface area of Cupressus duclouxiana increased;meanwhile,endomycorrhiza can positively affect the growth of the roots of Catalpa bungei seedlings.Our research showed that mycorrhizal fungus inoculation could enhance the drought resistence ability of Cupressus duclouxiana and Catalpa bungei seedlings in varying degrees.