自然入侵条件下黄顶菊丛枝菌根定殖及发育的研究

Arbuscular mycorrhizal colonization and development of Flaveria bidentis under natural invasive conditions

为探讨丛枝菌根(arbuscular mycorrhiza,AM)真菌在黄顶菊Flaveria bidentis入侵过程中可能发挥的作用,首先调查和研究了黄顶菊AM的侵入和生长表现。在黄顶菊入侵严重的河北省选择采样地点,分别从衡水地区的滨湖新区小北田村、冀州市漳下村、枣强县北王庄村、桃城区八里庄村、滨湖新区顺民庄村和滨湖新区刘家台村6个地点按黄顶菊重、中、轻3种盖度和不同生育期(苗期、花期和结籽期)采集根系和根区土样。分离根区土壤中AM真菌孢子、观察AM发育特征、测定孢子密度、AM真菌侵染率、丛枝着生率等,并与土壤理化性质进行了相关性分析。结果在各采样地点均观察到AM典型结构,不同样地菌丝侵染率、I型丛枝密度以及孢子密度的最大值均出现在八里庄村,泡囊密度和A型丛枝密度的最大值分别出现在小北田村和刘家台村;不同盖度下AM真菌侵染率最高值均出现在重度侵染区;不同生长时期黄顶菊的AM也有差异,除了丛枝密度最高值出现在花期和菌丝侵染率差异不显著外,菌丝侵染率、泡囊密度和孢子密度均在结籽期出现最大值。土壤理化特性也显著影响黄顶菊AM的发育,菌丝侵染率与土壤有机质呈显著正相关,与p H值呈显著负相关,与速效P含量呈极显著负相关;A型丛枝密度与p H含量呈显著负相关;I型丛枝密度与土壤全N含量呈极显著正相关;孢子密度与有机质含量和全N含量均呈显著正相关。因此,AM真菌侵染可能会促进黄顶菊的入侵。

In order to understand the role of arbuscular mycorrhizal（AM） fungi in the invasion process of Flaveria bidentis, a harmful introduced plant species, and the characteristics of AM on the plant grown in Xiaobeitian village of New Binhu region, Zhangxia village of Jizhou city, Beiwangzhuang village of Zaoqiang county, Balizhuang village of Taocheng district, Liujiatai village of New Binhu region and Shunminzhuang village of New Binhu region were investigated. Sample sites with heavy, medium and light coverage of Flaveria bidentis being in seedling, flowering and seed‐bearing stage period were selected and soil with root samples were collected to isolating AM fungal spores, observing the characteristics of AM, and determinating spore density and arbuscular mycorrhizal colonization. The results showed that the typical structure of AM in different regions was evident. The maximum level of hyphal colonization, intermediate‐arbuscular density and spore density appeared in Balizhuang village, and the maximum level of vesicle density and Arum‐type arbuscular density respectively appeared in Xiaobeitian village and Liujiatai village. The maximum level of AM colonization all appeared in heavy invasive plots under different cover degree of the plant. The maximum level of arbuscular density appeared in flowering stage, and the maximum level of hyphal colonization, vesicle density and spore density appeared in seeding period. Hyphal colonization was not significantly different in different growth stages. Soil properties also significantly affected mycorrhizal development. There were positive correlation between hyphal colonization and organic matter, but hyphal colonization was negatively correlative with pH value and significantly negatively correlative with available P. There were negative correlation between Arum‐type arbuscular density and pH value. A significantly positive correlation existed between intermediate‐arbuscular density and total nitrogen, and significantly positive correlation existed between spore density and total nitrogen and organic matter content. It was concluded that AM colonization would improve the invasion of the plant. The results might provide possible pathways to control this invasive alien plants.