丛枝菌根真菌对元宝枫枯叶分解及其生长的影响

Effects of arbuscular mycorrhizal on litter decomposition and growth of Acer truncatum

【目的】探究丛枝菌根(arbuscular mycorrhizal,AM)真菌对元宝枫生长以及枯叶分解的影响,明确其与元宝枫生长状况间的关系。【方法】以元宝枫(Acer truncatum)幼苗为试验材料,采用盆栽试验,设置接种AM真菌(AMF)和不接菌(CK)2个处理,其中AMF处理灭菌基质中加入根内根孢囊霉(Rhizophagus intraradices,Ri),CK中加入灭菌Ri和菌剂过滤液,同时在2个处理供试的花盆中放置2个装有元宝枫枯叶的分解盒,待元宝枫幼苗生长180 d后,测定元宝枫幼苗生长指标、养分含量以及枯叶中的养分含量,计算元宝枫枯叶的分解量以及不同粒径剩余枯叶质量,并采用冗余分析研究元宝枫生长状况、养分含量与枯叶养分间的相关性。【结果】(1)与CK相比,AMF处理元宝枫的地上部、地下部鲜质量和干质量以及根全氮、全磷、全钾和叶全磷含量显著增加,但二者的株高、地径和叶全氮含量无显著差异,叶全钾含量显著降低。(2)与CK相比,AMF处理元宝枫枯叶总分解量显著增加,粒径>0.15 mm枯叶质量显著降低,粒径0.25μm~0.15 mm枯叶质量显著增加。(3)与CK相比,AMF处理促进了枯叶中多酚的释放,降低了枯叶全氮积累,但对枯叶单宁、纤维素、全磷、全钾和有机碳含量无显著影响。(4)相关性分析发现,枯叶全氮累积系数与叶全钾含量呈显著正相关,与元宝枫生物量以及根和叶养分含量呈负相关;而枯叶多酚累积系数的表现则与之相反。【结论】接种AM真菌促进了元宝枫枯叶的分解,影响了元宝枫枯叶中有效养分的含量,从而促进了元宝枫的生长发育。

【Objective】 This study explored the effects of arbuscular mycorrhizal(AM) fungi on the growth and decomposition of dead leaves of Acer truncatum and determined the relationship between AM fungi and the growth status of Acer truncatum.【Method】 The Acer truncatum seedlings were subjected to two treatments of arbuscular mycorrhizal fungi(AMF) and control without fungi(CK).In the AMF treatment,Rhizophagus intraradices(Ri) was added to the sterilized substrate.In the CK treatment,sterilized Ri and fungicide filtration were added.At the same time,two decomposing boxes containing dead leaves of Acer truncatum were placed in two pots for both treatments.After 180 days of growth,growth index and nutrient contents of seedlings,as well as nutrient contents of dead leaves of Acer truncatum were determined.The decomposition amounts of dead leaves at different particle sizes and their remaining quantities were calculated.Redundancy analysis was conducted to examine the correlations between growth status,nutrient contents and decomposition rates of dead leaves.【Result】(1) Compared to CK,AMF treatment significantly enhanced fresh and dry masses and contents of total nitrogen,total phosphorus and total potassium roots and total phosphorus in leaves.There were no significant differences in plant height,ground diameter and leaf total nitrogen content.Total potassium content in leaves was significantly decreased.(2) Compared with CK,total decomposition capacity of dead leaves treated with AMF was significantly increased.The mass of dead leaves with size larger than 0.15 mm was notably reduced while that of 0.25 μm-0.15 mm showed significant increases.(3) Compared to CK,AMF treatment enhanced the release of polyphenols and mitigated the accumulation of total nitrogen in withered leaves,while it had no significant impacts on tannin,cellulose,total phosphorus,total potassium and organic carbon.(4) The correlation analysis revealed that total nitrogen in dead leaves had a positive association with total potassium content in leaves and negative correlations with biomass and nutrient contents in roots and leaves.The accumulation coefficients of polyphenols in dead leaves exhibited inverse relationships.【Conclusion】 The ino-culation of AM fungi enhanced the decomposition process of dead leaves,influenced the nutrient availability in dead leaves,and facilitated the growth and development of Acer truncatum.