AM真菌和磷对小马安羊蹄甲幼苗生长的影响

Impacts of arbuscular mycorrhizal fungi and phosphorus on growth dynamics of Bauhinia faberi seedlings

丛枝菌根(arbuscular mycorrhizal,AM)真菌在退化生态系统恢复与重建实践中具有重要作用。采用盆栽模拟方法,重点分析不同土壤磷条件下小马鞍羊蹄甲(Bauhinia faberi)幼苗接种AM真菌后,幼苗的形态、生物量积累、菌根侵染率和菌根效应(mycorrhizal growth response,MGR)在一个生长季内的动态变化。结果表明,Glomus mosseae和Glomus coronatum能较好地侵染幼苗,两种AM真菌显著地增加幼苗根系、叶片数和生物量;接种AM真菌显著影响幼苗的生物量分配,而土壤磷对幼苗的生物量分配影响不明显,AM真菌和土壤磷对幼苗生长的交互作用显著;G.mosseae是小马鞍羊蹄甲的优势AM菌,其接种的幼苗根长、叶片数、生物量、侵染率和菌根效应都显著高于G.coronatum处理的幼苗;菌根效应显著,接种AM真菌能有缓解土壤磷素缺乏的限制作用,且随着苗龄增大促生作用表现更为明显。不同AM菌种对小马鞍羊蹄甲幼苗生长的促生作用表现出的差异,提示在多元资源限制的干旱贫瘠环境中进行生物修复须为目标恢复物种筛选出高效的优势AM真菌。

Arbuscular mycorrhizal （AM） fungi play key roles in ecological restoration and ecological reconstruction of degraded ecosystems in arid and semi-arid lands. Based on the previous results of limiting soil moisture and soil available phosphorus （AP） deficit in the arid valley of Mingjiang River, which is one of the main branches of Yangtze River and located in the north of the Hengduan Mountain Systems, a full factorial and completely random pot experiment in a greenhouse was designed and conducted to understand the influence of two AM fungi （Glomus mosseae and Glomus coronatum） on dynamics of Bauhinia faberi seedling growth. We calculated biomass production and its partitioning, inoculation rate, and mycorrhizal growth response （MGR） across one growth season with two soil AP concentration （P1：6.0 and P2： 24.0 mg P/kg soil）. The following results were obtained： （1） Irrespective of both low and high soil AP concentration （6.0 mg/kg and 24.0 mg P/kg soil）, both AM fungi could well colonized root of B. faberi seedlings. Under two soil AP conditions, growth promotion effects on seedling root, leaf number and biomass production were significantly increased marked when inoculating B. faberi seedling roots with both AM fungi （G. mosseae or G. coronatum）; （2） inoculation with G. mosseae or G. coronatum on seedling root significantly impacted on root biomass accumulation and its partitioning （P 〈 0.05）. However, soil AP did a little effect on biomass accumulation and its partitioning （P 〉 0.05）, the coupling interaction between inoculated with AM fungi and soil AP was obvious （P 〈 0.05） by multivariate analysis of variance （MANOVA）; （3） The inoculation rate of G. mosseae ranged from 51% to 71% under low soil AP condition and ranged from 60% to 74% under high soil AP condition, the inoculation rate of G. coronatum did from 30% to 31% under low soil AP condition and from 35% to 58% under high soil AP condition. Therefore, seedling inoculated with G. mosseae had absolutely higher the root length, leaf number, total biomass, inoculation rate, and MGR than those of seedlings inoculated with G. coronatum. The result suggested that G. mosseae is the more appropriate host for B. faberi in poor arid environment; （4） MGR of G. mosseae and G. coronatum was marked increasing, Inoculation with AM fungi can decrease the limiting strengthen of soil AP. Moreover, the extent with age of seedlings （both 48 and 86 day） was apparently more stronger than those seedlings of 104 day. However, no significant higher of inoculation rates for both AM fungi under 6.0 and 24.0 mg P/kg soil condition demonstrated that the impacts of soil AP on inoculation rate of AM fungi was weakly. The different abilities of both AM fungi （G. mosseae or G. coronatum） could improve growth on B. faberi seedling, which indicated that it is important and necessary to select beneficial AM fungi for vegetation restoration practice in multi-resource limiting regions.