水分和土壤微生物对干热河谷山合欢和银合欢生长性状的影响

Effects of water and soil microorganisms on the growth traits of Albizia kalkora and Leucaena leucocephala in a dry-hot valley

关键词:  干热河谷, 山合欢, 银合欢, 土壤水分, 土壤微生物

Key words:  dry-hot valley, Albizia kalkora, Leucaena leucocephala, soil water, soil microorganisms

摘要:

植被恢复是干热河谷自然植被恢复的有效途径,干热河谷自然植被修复的同时也引进了很多外来种。为比较本地种和外来引进种对水分与微生物的响应差异,该文选取当地乡土种山合欢(Albizia kalkora)和外来种银合欢(Leucaena leucocephala),采用气候箱模拟云南干热河谷地区条件,通过土壤水分控制和微生物接种研究了水分和各自的土壤微生物对两种豆科植物生长发育的影响。结果表明:(1)山合欢的种子发芽率、根生物量、根冠比和植株氮磷比较银合欢高58.82%、76.13%、90.59%和18.42%(P<0.05)。(2)干旱条件下山合欢的根生物量和植株氮含量比湿润条件低33.67%和8.65%(P<0.05),银合欢的株高、地上生物量、根生物量在干旱条件下较湿润条件低39.32%、40.06%和39.61%(P<0.05),表明干旱抑制了两种植物生长和养分吸收。(3)山合欢在干旱条件下的根瘤数量多于湿润条件(P<0.05),而银合欢在湿润条件与干旱条件下的根瘤数量没有显著性差异。(4)除枯叶比例外,土壤微生物接种、土壤微生物与水分的交互作用对山合欢和银合欢的生长并没有造成显著影响。以上研究结果表明山合欢较银合欢可能更适宜干旱环境,为干热河谷植被恢复物种选择提供了一定的理论依据,但土壤微生物对植物生长的影响还值得进一步探索和研究。

Abstract:

Vegetation restoration is an effective way for ecological restoration in the dry-hot valley, and many alien species are introduced along with natural vegetation restoration. In order to compare the responses of native and alien species to water and microorganisms, the native Albizia kalkora and alien Leucaena leucocephala were selected as our research objects, and the effects of water and soil microorganisms on the growth and development of the two plants were studied by soil water control and soil microbial inoculation under climate chamber conditions. The results were as follows:(1)Compared with Leucaena leucocephala, the seed germination rate, root biomass, root-shoot ratio and plant N:P ratio of Albizia kalkora were significantly increased by 58.82%, 76.13%, 90.59% and 18.42%, respectively(P<0.05).(2)Under drought conditions, the root biomass and plant nitrogen content of Albizia kalkora were significantly lower than those under moist conditions by 33.67% and 8.65%(P<0.05), and the plant height, aboveground biomass and root biomass of Leucaena leucocephala under drought conditions were 39.32%, 40.06% and 39.61% lower than those under moist conditions(P<0.05), indicating that drought inhibited the growth and nutrient uptake of both plants.(3)The quantity of root nodules in Albizia kalkora under drought conditions was higher than that under moist conditions(P<0.05), and the quantity of root nodules in Leucaena leucocephala under moist conditions was higher than that under drought conditions, but no significant difference.(4)Except for the litter proportion, soil microbial inoculation and the interaction between soil microorganisms and water had no significant effect on the growth of Albizia kalkora and Leucaena leucocephala. The above results suggest that Albizia kalkora is more suitable for drought environment than Leucaena leucocephala, which provides a theoretical basis for the selection of species for vegetation restoration in dry-hot valley, but the effects of soil microorganisms on plant growth are worthy of further exploration and research.