微囊藻毒素对不同生育期水稻生长的影响

灌溉水中的微囊藻毒素不仅会影响作物生长与产量,还可能沿食物链传递而威胁人类健康。以水稻为试材,研究了不同质量浓度(1μg/L、100μg/L、1 000μg/L、3 000μg/L)微囊藻毒素(MCs)对幼苗期和孕穗期水稻生长与成熟期水稻产量的影响,以及MCs在3个生育期水稻中的积累。结果表明:处理7 d后,1μg/L MCs处理对幼苗期水稻生长有一定促进作用,而对孕穗期水稻生长没有影响,高质量浓度MCs(≥100μg/L)抑制幼苗期和孕穗期水稻的生长;胁迫结束且恢复7 d后,100μg/L处理组孕穗期水稻根长、根表面积恢复能力强于幼苗期,株高、叶面积低于幼苗期,而1 000μg/L和3 000μg/L MCs组水稻各指标不仅未恢复,且劣于胁迫期,水稻产量下降92.4%和95.2%。用酶联免疫法检测发现,胁迫后MCs均在水稻体内富集。对于相同质量浓度MCs处理,幼苗期水稻各器官富集能力最大,孕穗期次之,成熟期最小。3 000μg/L MCs处理组的水稻谷粒中MCs质量比达21.2μg/kg,使人体每天摄入MCs的量可能高于世界卫生组织规定的人体每天吸收MCs的上限值。

Effect of MCs on the growth of rice in different growing stages

This paper is aimed at making an exploration of the effects of MCs at different mass concentrations (1 μg/L,100μg/L,1 000 μg/L,3 000 μg/L) on the rice growth and its yield,in addition to its accumulation effects in different tissues of rice crops,while the main stress of the paper is to trace the contamination status-in-situ of the irrigation water with microcystins (MCs) in the influence on the crop growth and yield,as well as the potential harm on human health.The results of our study show that 1 μg/L MCs can promote the growth of the young rice after a 7-day exposure,however,it had no effect on the growth of rice at the booting stage.On the other hand,high concentrations (≥ 100μg/L) of MCs tend to inhibit the growth of the young rice during the seedling and booting stages.For example,a 7-day recovery may result in the decrease of the root length and root surface of the rice at the booting stage caused by 100 μg /L MCs were lower than those of rice at the seedlings stage caused by the same concentration of MCs.In addition,the decrease in the height and the leaf area of rice at the booting stage caused by 100 μg/L MCs could be higher than those of rice at the seedlings stage caused by the same concentration of MCs.However,the rice seedlings treated with 1 000 μg/L or 3 000 μg/L MCs prove to be lower than those of the control group,and even worse than those of the exposure period.And,the worst may be that the rice yield is likely to be reduced by 92.4％ and 95.2％,respectively.Therefore,the results measured by enzyme-linked immunosorbent assay show that MCs (1-3 000 μg/L) an be absorbed and accumulated in the rice itself.Having been treated with the same concentration of MCs,the enrichment potential of the rice at the seedlings stage turns to be the highest,whereas that of rice during the mature stage would be the lowest.Besides,the rice grains treated with 3 000 μg/L have been found that the content of MCs in the rice can be as high as by 21.2 μg/kg MCs,which should be regarded as a threat to human health,for the content rate turns to be higher than the tolerable daily intake maximum limit set by the World Health Organization under the United Nations.