Seasonal variations in the abundance of virus-like particles and bacteria in the floodwater of a Japanese paddy field
Seasonal variations in the abundance of virus-like particles and bacteria in the floodwater of a Japanese paddy field
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DOI：
10.1111/j.1747-0765.2007.00145.x
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发表时间：
2007-08-01
影响因子：
2
通讯作者：
Kimura, Makoto
中科院分区：
文献类型：
--
作者：
Nakayama, Natsuko;Okumura, Mami;Kimura, Makoto
病毒是海洋和淡水环境中最丰富的生物实体。许多研究表明，病毒在初级生产和水环境中的微生物食物网中具有生态重要性。然而，还没有研究检查稻田洪水中的病毒丰度。本研究调查了1925年以来日本水稻种植期间，在长期化肥试验下，洪水中病毒样颗粒(VLP)和细菌的丰度。洪水中病毒样颗粒和细菌丰度分别为5.6×10~(6)~1.2×10~9VLP·L~(-1)和9.2×10~(5)~4.3×10~(8)细胞·mL~(-1)，平均丰度分别为1.5×10~(8)VLP·L~(-1)和5.1×10~(7)细胞·mL~(-1)，并随悬浮物浑浊度的增加而增加。VLP丰度的季节变化幅度是VLP的50倍以上，细菌丰度的季节变化幅度是100倍。病毒与细菌的比值在水稻栽培期间波动在0.11-72之间，它们的增加与细菌丰度的下降有关。我们的结果表明，稻田洪水中的病毒丰度高于自然海洋和淡水环境中的病毒丰度。
Viruses are the most abundant biological entities in marine and freshwater environments. Many studies have shown the ecological importance of viruses in the primary production and microbial food web in aquatic environments. However, no studies have examined viral abundance in the floodwater of paddy fields. The present study surveyed the abundance of virus-like particles (VLPs) and bacteria in the floodwater of a Japanese paddy field under a long-term fertilizer trial since 1925 during the rice cultivation period. Virus-like particles and bacterial abundances in the floodwater ranged from 5.6 x 10(6) to 1.2 x 109 VLPs mL(-1) and from 9.2 x 10(5) to 4.3 x 10(8) cells mL-1 with mean abundances of 1.5 x 10(8) VLPs mL(-1) and 5.1 x 10(7) cells mL(-1), respectively, and increased with an increase in the turbidity of the floodwater with suspended particles. The magnitude of seasonal variation was more than 50-fold for VLP abundance and 100-fold for bacterial abundance. The virus-to-bacterium ratios fluctuated over the rice cultivation period, ranging from 0.11 to 72 and their increase correlated with the decrease in bacterial abundance. Our results suggest that viral abundance in the floodwater of paddy fields is larger than in natural marine and freshwater environments.