摘 要

接种丛枝菌根真菌（Arbuscular mycorrhizal fungi，AMF）可以有效缓解盐胁迫对植物的危害，为了探究AMF是否会促进植物对氮素的吸收来提高植物耐盐性，本研究选取摩西球囊霉（Glomus mosseae）1号（GM1）、摩西球囊霉2号（GM2）、扭形球囊霉（Glomus tortuosum，GO）三种菌根真菌，接种于自培的无菌实生榉树（Zelkova serrata）幼苗，进行盐胁迫盆栽实验。通过测定根系侵染率、植物根茎叶中全氮含量、土壤中全氮和碱解氮含量，同时测定土壤电导率及总球囊霉素含量，分析盐胁迫下菌根真菌对榉树氮素吸收及其根系土壤环境的影响，结果如下：

（1）盐胁迫显著影响AMF对榉树的侵染，然而，随着盐浓度的变化，GM1和GM2对榉树侵染率的影响均不显著，而GO显著影响榉树的侵染率。与对照组相比，盐胁迫下GM1、GM2、GO处理的榉树侵染率分别降低了14.59%~16.25%、5.55%~8.39%、10.86%~30.14%。

（2）随着盐浓度增加，接种与未接种处理榉树根系氮含量、接种榉树茎内氮含量均呈现上升的趋势，而未接种榉树茎内氮含量呈先下降后上升再下降的趋势，接种与未接种处理榉树根系与茎内氮含量均无显著差异；另外，随着盐浓度增加，榉树叶内氮含量均呈下降的趋势，未受到盐胁迫以及盐浓度为100mmol/L时，接种榉树叶内氮含量低于未接种榉树，而在盐浓度为50mmol/L和150mmol/L时，接种榉树叶内氮含量高于未接种榉树，但差异均不显著。

（3）随着盐浓度增加，未接种榉树和接种GM2的榉树根际土壤中全氮含量呈现先上升后下降的趋势，而接种GM1和GO的根际土壤总体呈现上升趋势，且只有在盐浓度为50mmol/L时接种GO榉树的根际土壤全氮含量显著低于未接种榉树，低出21.46%，其余均无显著差异；随盐浓度的增加，未接种榉树和接种GM1榉树根际土壤的碱解氮含量呈现先上升后下降后上升的趋势，接种GM2榉树根际土壤碱解氮含量先上升后下降，接种GO榉树根际土壤碱解氮含量直线上升，而在盐浓度为150 mmol/L时，未接种榉树根际土壤碱解氮含量略高于接种GO榉树，显著高于接种GM1和GM2榉树，分别高出53.85%和81.82%

（4）随着盐浓度增加，榉树根际土壤的电导率呈现上升趋势，且在同一盐浓度下，接种榉树根系土壤电导率与未接种榉树均无显著差异；未接种和接种GO榉树根际土壤总球囊霉素含量随盐浓度的提高均呈现先上升后下降的趋势，接种GM1榉树根际土壤总球囊霉素含量随盐浓度的提高呈先上升后下降再上升的趋势，接种GM2榉树根际土壤总球囊霉素含量随盐浓度的提高呈先下降后上升再下降的趋势。

综上所述，盐胁迫抑制了菌根真菌对榉树的侵染，且接种菌根真菌能促进榉树对氮素的吸收，从而提高其耐盐性。

关键词：盐胁迫；榉树；丛枝菌根真菌；氮素吸收

Effect of AMF on nitrogen uptake of Zelkova serrata under salt stress

Abstract

Arbuscular mycorrhizal fungi can effectively alleviate the harm of salt stress on plants，In order to explore whether AMF can promote nitrogen uptake by plants to improve salt tolerance, three mycorrhizal fungi, GM1, GM2 and GO, were selected in this study，the seedlings of sterile Zelkova serrata were inoculated with salt stress in pot experiment. By measuring the root infection rate, total nitrogen content in plant rhizomes and leaves, total nitrogen and alkali-hydrolyzed nitrogen content in soil, as well as the soil electrical conductivity and total coccomycin content, the effects of mycorrhizal fungi under salt stress on nitrogen uptake and root soil environment of Zelkova serrata were analyzed. The results were as follows:

1. Salt stress significantly affected the AMF infection of Zelkova serrata， however, with the change of salt concentration, both GM1 and GM2 had no significant effect on the infection rate of Zelkova serrata, but GO significantly affected the infection rate of Zelkova serrata. Compared with the control group, the infection rate of Zelkova serrata treated with GM1, GM2 and GO under salt stress decreased by 14.59%~16.25%, 5.55%~8.39% and 10.86%~30.14%, respectively.
2. The nitrogen content of the roots of Zelkova serrata increased with the increase of salt concentration, but there was no significant difference between the seeded Zelkova serrata and the non-seeded Zelkova serrata；with the increase of salt concentration, the nitrogen content in the stem of the non-inoculated Zelkova serrata showed a trend of first decrease, then increase and then decrease, and the nitrogen content in the stem of the inoculated Zelkova serrata showed a trend of increase. However, there was no significant difference in the nitrogen content between the roots of the inoculated Zelkova serrata and the non-inoculated Zelkova serrata；with the increase of salt concentration, nitrogen content in Zelkova serrata leaves decreased whether inoculated or not，when no salt stress as well the salt concentration was 100mmol/L, the nitrogen content in the leaves of the inoculated Zelkova serrata was lower than that of the non-inoculated Zelkova serrata. When the salt concentration was 50mmol/L and 150mmol/L, the nitrogen content in the leaves of inoculated Zelkova serrata was higher than that of non-inoculated Zelkova serrata, but the difference was not significant.
3. With the increase of salt concentration, the content of total nitrogen in the root soil of both non-inoculated Zelkova serrata and GM2 inoculated Zelkova serrata first increased and then decreased, while the content of total nitrogen in GM1 and GO inoculated Zelkova serrata generally increased，only when the salt concentration was 50mmol/L, the total nitrogen content of the root soil inoculated with GO Zelkova serrata was significantly lower than that of the non-inoculated Zelkova serrata, 21.46% lower than that of the non-inoculated Zelkova serrata, and there was no significant difference in the rest. With the increase of salt concentration, the content of alkali-hydrolyzed nitrogen in the rhizosphere soil of both non-inoculated Zelkova serrata and GM1 Zelkova serrata showed a trend of first rising, then falling and then rising. The content of alkali-hydrolyzed nitrogen in the rhizosphere soil of GM2 Zelkova serrata rose first and then fell. The content of alkali-hydrolyzed nitrogen in the rhizosphere soil of GO Zelkova serrata rose linearly. When the salt concentration was 150 mmol/L, the content of alkaline hydrolysis nitrogen in the rhizosphere soil of non-inoculated Zelkova serrata was slightly higher than that of GO Zelkova serrata, and significantly higher than that of GM1 and GM2 Zelkova serrata, which were 53.85% and 81.82% higher, respectively.
4. No matter inoculated or not, with the increase of salt concentration, the electrical conductivity of Zelkova serrata's rhizosphere soil presented an increasing trend, and there was no significant difference between the electrical conductivity of Zelkova serrata's root system and that of non-inoculated Zelkova serrata under the same salt concentration. With the increase of salt concentration, the content of total coccytomycin in the rhizosphere soil of both the uninoculated and the GO Zelkova serrata trees showed a trend of first rising and then falling. With the increase of salt concentration, the content of total chloromycin in the rhizosphere soil of GM1 Zelkova serrata was first increased, then decreased and then increased. With the increase of salt concentration, the content of total cyclosporin in the rhizosphere soil of GM2 Zelkova serrata seedlings decreased first, then increased and then decreased with the increase of salt concentration.

In conclusion, the salt stress inhibited the infection of the Arbuscular mycorrhizal fungi on Zelkova serrata, and the inoculation of the Arbuscular mycorrhizal fungi could promote the nitrogen absorption of the Zelkova serrata, thus improving its salt-tolerance.

Key words: salt stress; zelkova serrata; Arbuscular mycorrhizal fungi; nitrogen absorption

目 录

第一章 前言 1

1.1 研究目的及意义 1