种植年限对香草兰生理状况及根际土壤微生物区系的影响

对不同种植年限香草兰园植株生理指标及根际土壤微生物区系进行测定分析。结果表明:10 a以上园龄的香草兰叶片净光合速率、蒸腾速率和叶绿素含量显著降低,而0～5 a园龄香草兰叶片各生理指标并无显著性差异。平板稀释涂布结果显示:5、10和20 a园龄香草兰根际可培养细菌和放线菌数量显著低于新植园,根际细菌与新植园相比分别降低了58.4%、91.6%、96.7%;根际真菌及尖孢镰刀菌数量呈相反趋势,与新植园相比,真菌数量分别是新植园的1.6、2.1和3.4倍。综上所述,种植10 a以上的香草兰园植株生长代谢缓慢,土壤微生物由细菌型向真菌型转变,微生物区系失衡。

Effects of Planting Period on Vanilla Physiological Indices and Rhizosphere Soil Microbial Community Structure

Series of field and lab tests were carried out to investigate the effects of planting period on Vanilla growth and rhizosphere soil microbial community structure. The main results obtained were listed as follows: (1)with the planting period increasing, net photosynthesis rate, transpiration rate and chlorophyII content of Vanilla leaves were significantly decreased in over ten years plantation, however, these three physiological indices had no significant difference within five years plantation; (2)standard dilution plate count results showed that population of culturable bacteria and actinomycota in Vanilla rhizosphere soil were significantly decreased in 5, 10 and 20 years plantation compared with that of new plantation. Bacteria population was reduced by 58.4%, 91.6% and 96.7%, respectively. An opposite trend was found in fungi and Fusarium oxysporum numbers. The corresponding number of fungi in Vanilla rhizosphere soil was 1.6, 2.1 and 3.4 times higher compared with that of new plantation, respectively. In conclusion, the metabolism of vanilla plants became weak and the soil microbial community structure lost balance in the plantation of planting periods over ten years.