不同稻田生态系统周丛生物对水稻种子萌发和幼苗生长的影响

Effects of Paddy Periphyton Biofilms on Rice Germination and Seedling Growth Relative to Paddy Ecosystems

周丛生物广泛分布于稻田生态系统淹水环境中,直接影响稻田养分的迁移转化过程及其生物有效性,但其是否影响水稻的生长、发育却鲜有报道。通过室内控制试验,利用延边(YB)、鹰潭(YT)和镇江(ZJ)的水稻土培养周丛生物,并研究了三种周丛生物对水稻种子萌发和幼苗生长的影响。结果表明,不同类型土壤培养的周丛生物主要由变形菌门(Proteobacteria)、蓝细菌门(Cyanobacteria)和拟杆菌门(Bacteroidetes)组成;三种周丛生物的多样性存在显著差异,其中延边周丛生物(YBP)的物种数和Chao1指数显著高于其他两组处理(P <0.05)。皮尔森(Pearson)相关性分析结果表明,周丛生物群落物种组成和多样性与土壤pH、全磷、总有机碳和全锰含量呈显著正相关(P <0.01)。此外,三种周丛生物的碳代谢活性存在显著差异(P <0.05)。其中,延边周丛生物(YBP)在整个检测期内的碳代谢活性最高,鹰潭周丛生物(YTP)的碳代谢活性最低。种子萌发试验结果显示周丛生物的存在显著提高了水稻种子的萌发率(最高18%)和α-淀粉酶活性(P <0.05),同时提高了水稻幼苗的存活率(鹰潭周丛生物,P <0.05),增加了水稻幼苗的根生物量和根长(延边周丛生物,P<0.05)。皮尔森(Pearson)相关性分析结果表明,水稻种子萌发率和存活率与周丛生物理化特征呈显著正相关(P <0.01)。本研究明确了周丛生物与不同土壤基质间的关系,为调节周丛生物的生长进而提高作物产量提供了新视角。

【Objective】Periphyton is ubiquitously distributed in paddy fields, directly affecting nutrient cycles and their bio-availabilities. However, no study regarding effects of periphyton on rice growth has been reported. 【Method】In this study,model paddy ecosystems with three types of soils were simulated under controlled conditions to investigate the effects of periphyton on rice seed germination and seedling growth. 【Result】Results show that periphyton of three types of soils was mainly composed of Proteobacteria, Cyanobacteria and Bacteroidetes, while the diversity of periphyton of the three soils was significantly different, and that grown in soil from Yanbian(YBP) had the highest OTU number and Chao1 index. Furthermore,there were significant differences in carbon metabolic activity among the three periphyton(P<0.05). The Pearson correlations indicated that periphyton composition and diversity was positively correlated with soil pH, TP, TOC and Mn contents(P<0.05).The carbon metabolism activity of YBP was the highest during the whole growth period, while that of soil from Yingtan(YTP)was the lowest. The presence of periphyton greatly increased the germination index of rice seed(by maximally 18%), and α-amylase activity in the presence of periphyton was increased significantly(P<0.05). Besides, the periphyton covering on paddy soil surface from Yanbian(YBP) significantly promote shoot length and its biomass(P<0.05). The Pearson correlations indicated that seed germination and survival rate was positively correlated with periphyton chemical properties. 【Conclusion】To summarize, this study indicates that the presence of periphyton biofilm during seed germination period was propitious for rice growth. Results of this study provided an insight into understanding the periphyton-plant relationships with different soil-types and also new approaches to controlling plant phenology by regulating the growth of periphyton.