连作对黄花蒿生长及土壤细菌群落结构的影响

Influence of continuous cropping on growth of Artemisia annua and bacterial communities in soil

试验采集未种植、种植1年、3年和5年的黄花蒿土壤,利用常规分析和Illumina Mi Seq高通量测序技术,研究了连作对黄花蒿生长、青蒿素含量、土壤有效养分和细菌群落结构的影响。结果表明,连作显著抑制黄花蒿生长,降低叶片生物量、青蒿素含量和产量,最大降幅依次为30.20%,7.70%,35.58%。黄花蒿连作不同程度地降低土壤有机质、有效氮、有效磷含量和细菌16S rRNA序列数。高通量测序结果显示,在不同种植年限的黄花蒿土壤中,共有634-812种细菌,归属于21个门类,代表不同处理年限细菌群落的点在主成分坐标系中分布距离较远,群落结构发生了显著变化（P〈0.05）。随黄花蒿连作年限增加,放线菌门、绿弯菌门和芽单胞菌门的丰富度降低,但变形菌门、酸杆菌门和疣微菌门丰度增加。与未种黄花蒿的土壤相比,在种植土壤的前20种优势细菌中,硝化螺旋菌和根瘤菌消失,仅有芽单胞菌、微单孢菌、亚硝化单胞菌、黄色杆菌和不可培养细菌JG30-KF-AS9等5种相同。说明种植尤其是连作黄花蒿选择性抑制了土壤细菌的生长繁殖,影响土壤养分的转化供应,导致黄花蒿生长不佳,青蒿素含量和产量降低。因此,在种植黄花蒿的过程中,提倡轮作很有必要。

In this study,several types of Artemisia annua in soil,including the soil which had not been planted,or planted for one year,or continuously planted for three or five years were collected,in order to study the influences of continuous cropping on the growth of A. annua,content of artemisinin,available nutrient of soil,and bacterial community structure through adopting routine analysis and Illumina Mi Seq high-throughput sequencing. The results showed that continuous cropping inhibited significantly the growth of A. annua and reduced leaf biomass,content and yield of artemisinin,with the maximum decreasing amplitude of 30. 20%,7. 70% and 35. 58%respectively. The content of soil organic matter,available nitrogen,available phosphorus and 16 S rRNA sequence number were increased to different extents after continuous cropping of A. annua. According to the results of high-throughput sequencing,634-812 types of common bacteria belonged to 21 categories were planted in different soil of A. annua with different planting years,which represented that the distribution distance of the point of bacterial community with different years among coordinate system of principal component was relative distant,and community structure had significant changes（ P〈0. 05）. As the planting years increased,the abundance of Actinobacteria,Chloroflexi,Gemmatimonadetes decreased in contrast to Proteobacteria,Acidobacteria and Verrucomicrobia.In the top 20 types of predominant bacteria,Nitrospira japonica and Nitrospira disappeared,among which,only Gemmatimonadaceae,Micromonosporaceae,Nitrosomonadaceae,Xanthobacteraceae,and unculture bacterium JG30-KF-AS9 were similar,indicating that the planting and continuous cropping of A. annua selectively inhibited the growth and reproduction of soil bacteria,and influenced the supply and transform of soil nutrient,leading to a poor growth and resulting in reduction of artemisinin content and yield. Therefore,it is necessary to advocate crop rotation in the process of planting A. annua.