Effects of Forest Soil and Soil-borne Fungi on Seed Germination and Seedling Survival of Toona ciliata var. pubescens
Effects of Forest Soil and Soil-borne Fungi on Seed Germination and Seedling Survival of Toona ciliata var. pubescens
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DOI：
10.13275/j.cnki.lykxyj.2017.05.022
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发表时间：
2017-10-01
期刊：
影响因子：
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通讯作者：
Liang Yue-long
中科院分区：
文献类型：
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作者：
Guo Xiao-yan;Fu Li;Liang Yue-long
[目的]研究影响红椿天然更新的障碍因子。通过调查不同自然群落中的森林土壤和真菌对毛竹种子萌发和幼苗存活的影响，探讨了不同自然群落中的森林土壤和真菌对毛竹种子萌发和幼苗存活的影响。[方法]在九连山国家级自然保护区内采集距母树2.5、5.0、7.5 m 3个距离的根区土壤样品和距母树25 m的天然林分土壤样品。以非林地土壤为对照，在室内进行了种子在土壤上的萌发试验。此外，还在实验室进行了根区土壤真菌悬浮液或根分泌物灌根的土壤侵染试验。观察了种子萌发、幼苗存活和幼苗感病情况。[结果]种子在各种土壤中的发芽率均呈现先升高后降低的趋势，在播种后第8 ~ 10 d达到最高。森林土壤与非森林土壤的种子发芽率差异不显著，但森林土壤的幼苗成活率显著低于非森林土壤。根区土壤与非根区土壤的幼苗成活率差异显著，根区土壤的幼苗死亡率较高。离母树不同距离的根区土壤中的苗木成活率差异不显著。此外，不同土传真菌处理的苗木发病率差异极显著，RS 2、RS（5）土传真菌处理的苗木发病率显著高于两个空白对照、水（W）和根系分泌物（R）处理。RS 2根系分泌物悬浮液的侵染率显著高于RS（2）水悬浮液。[结论]不同自然群落的森林土壤对红豆杉种子萌发没有影响。纤毛变种但同一树种的根区土壤对苗木的定植有干扰作用，根系分泌物与病原菌的交互作用可显著降低苗木的成活率。由此推断，在番茄根区土壤中存在潜在的病原菌。纤毛变种根分泌物能增强其致病性。
[Objective] The barrier factors influencing the natural regeneration of Toona ciliata var. pubescens were explored through investigating the effects of forest soil and fungi in different natural communities on seed germination and seedling survival. [Method] Soil samples were collected from the root zone at three distances (2.5, 5.0, and 7.5 m) from the mother trees as well as the natural forest stands 25 m away from the mother trees in Jiulianshan National Nature Reserve. The seed germination trial on soils was carried out in the laboratory with non-forest soil as the control. In addition, the seedling infection trial in soil was also performed in the laboratory with root irrigation by fungi isolated from root zone soil and suspended with water or root exudates. The seed germination, seedling survival and seedling susceptibility were observed. [Result]The germination of seed in all kinds of soil revealed the tendency of increasing at initial and then decreasing, and reached the peak during the eighth to tenth day after sowing. There were no significant differences between forest soil and non-forest soil in germination rate, while the seedling survival rate of forest soil was significantly lower than that of non-forest soil. There were significant differences between root zone soil and non-root zone soil in seedling survival rate, and the seedling mortality of root zone soil was higher. It was also found that there were no significant differences in seedlings survival rate of root zone soil among different distances from the mother trees. It addition, there were extremely significant differences in seedling infection treatments, and the seedling disease incidence rates of RS2, RS(5)soil-borne fungi were significantly higher than those of the two blank controls, water (W) and root exudates (R). Moreover, the disease infection rate of RS2 root exudates suspension was significantly higher than that of RS(2)water suspension. [Conclusion] Forest soil of different natural communities has no effect on seed germination of T. ciliata var. pubescens, However, the seedling establishment is disturbed by root zone soil of the same species; the interaction between root exudates and pathogens can significantly reduce the seedling survival rate. It could be inferred that there are potential pathogens in root zone soil of T. ciliata var. pubescens and root exudates can enhance their pathogenicity.