【摘要】 采用大田试验方法,研究了模拟紫外辐射(UV-B,280～310nm)增加对40个割手密无性系土壤微生物种群数量的影响。结果表明,(1)UV-B处理条件下,土壤细菌数量、真菌数量和放线菌数量主要表现为下降,而且分别在成熟初期、分蘖期和伸长期降幅最大。36号和38号细菌数量、真菌数量和放线菌数量在3个时期下降显著。(2)UV-B处理,也会导致一些无性系在不同的时期细菌数量、真菌数量或放线菌数量上升,但没有一致的变化,其中以9号、19号上升较明显。(3)UV-B处理,土壤微生物多样性指数增高,以分蘖期变化最大。细菌的变化对多样性指数的影响较大。部分无性系的多样性指数下降,24号降低明显。UV-B辐射增加可导致割手密土壤微生物数量的降低,土壤微生物多样性增加。更多还原

【Abstract】 Field studies were conducted for a season to determine potential for alterations in the population quantity dynamics and diversity of 40 wild sugarcane clones (S. spontaneum L.) rhizisphere microorganisms under an enhanced ultraviolet-B (UV-B, 280～310 nm) radiation. 40 wild sugarcane clones were collected from different latitude and altitude, and had different UV-B background.The supplemental UV-B radiation was 5.00 kJ·m-2, simulating a depletion of 20%stratospheric ozone at Kunming (25°N, 1 950 m). Plants were irradiatedfor 7 h daily from 45 DAP to ripening stage, centered around solar noon. Out of40 wild sugarcane clones rhizosphere microorganisms tested, the quantity of bacteria, fungi and actinomyces were decreased by UV-B radiation and the lowest were in the beginning of ripening, tiller stage and elongation stage, respectively. The inhibition on bacteria was increased with the developmental stages. The order of inhibition of UV-B radiation on microbe was in an order: bacteria> fungi> actinmyces. UV-B radiation may change root secretion of rhizosphere, such as flavonoid, tannic substance, and lignin, and then indirectly affected the population quantity of rhizosphere microorganisms. The index of microbial diversityincreased under UV-B radiation and the most changes were in tiller stage. Thereason was that the bacteria quantity decreased and the change of bacteria quantity had the dominant influence on the total quantity of microbe and indicator of microbial diversity. In general, UV-B radiation decreased the population quantity and increased diversity of 40 wild sugarcane clones.更多还原