转CryIAb水稻对稻田杂草群落组成及多样性的影响

Composition and diversity of weed community in transgenic CryIAb rice field

尽管基因工程技术可以增加作物产量,但转基因作物是否对农田生态产生影响受到广泛关注。本研究通过田间定位试验,应用群落生态学方法研究了转CryIAb基因抗虫水稻"Mfb"连续2年在传统栽培和半野生条件下对稻田杂草群落组成及多样性的影响。调查结果显示:转CryIAb基因稻"Mfb"与非转基因稻"明恢86"田间杂草种类没有显著差异。稻田杂草的频度和密度与栽培方式有关,半野生稻田杂草的频度和密度显著高于传统稻田,但相同栽培条件下,转基因稻"Mfb"与非转基因稻"明恢86"田间杂草频度和密度在整个生长期内均无显著差异。半野生稻田物种丰富度(Sr)指数明显大于传统稻田;相同栽培条件下,相同生长时期抗虫转基因水稻"Mfb"与其非转基因对照"明恢86"对稻田杂草群落丰富度的影响差异不显著。稻田杂草群落优势度(D)、均匀度(J)以及多样性(H)各处理、各生长时期内转基因稻与非转基因稻相比均没有显著差异。稻田杂草Shannon-Wiener多样性指数变化无明显规律,相同栽培方式相同生长期的抗虫转基因水稻"Mfb"与其非转基因对照"明恢86"的Shannon-wiener指数差异不显著。综合上述分析,转CryIAb基因抗虫稻对稻田杂草群落的组成及多样性没有显著影响。

Although crop yields can be improved by engineered genetic modification of plants, ecological concerns remain about persistence of such crops in the wild in the event of dispersal from cultivated habitats with unintended effects, like adverse impacts on weed community composition and diversity in the fields. This study aimed to assess the effects of GMC （genetically modified crop） rice with CrylAb gene on the diversity, structure and composition of weed communities in rice fields and using conventional indica rice （＂MH86＂） as the control. A total of 16 plots in semi-wild cultivation and conventional cultivation conditions were analyzed. The conventional cultivation treatment was in accordance with local farming practice, while in the semi-wild cultivation was non-farming practice with irrigation. All weed species and numbers collected from five sample spots per plot were investigated. An investigated sample spot was 0.25 m2 in the semi-wild plots and 1.0 m2 in the conventional cultivation plot. The results showed： no significant difference in weed species between transgenic CrylAb （＂Mfb＂） rice and non-transgenic （＂MH86＂） rice fields under the same cultivation pattern. While high weed fi＇equency and density were observed in semi-wild plots compared to conventional cultivation plots, no differences in frequency and density were noted between two varieties. Statistical analysis suggested that species richness and Shannon-Wiener diversity index were greater in semi-wild plots than in conventional cultivation plots. All the applied multivariate methods of analysis revealed that weed community composition was significantly different between the two cultivation conditions. There was an unobvious difference between transgenic and non-transgenic rice communities in terms of the indices of weed species richness, evenness, dominance and diversity. The results suggested that the diversity and stability of weed community in transgenic rice fields did not significantly differ from those in traditional rice fields.