青蒿素对蔬菜种子发芽和幼苗生长的化感效应

试验以菜豆、豇豆、大白菜和小白菜为对象，用不同浓度的青蒿素浸种，研究了黄花蒿产生的化感物质??青蒿素对蔬菜种子发芽及幼苗生长的影响。结果表明，青蒿素对蔬菜种子发芽和幼苗生长的化感作用表现出浓度效应和品种差异，即浓度越高，抑制作用愈强，尤以豇豆种子发芽率和小白菜生长的表现最为明显，前者的发芽率可降低75.00%，后者的苗高降幅高达88.37%，且胚根停止生长。青蒿素抑制同季和后季作物的种子发芽和幼苗生长，有利于扩大黄花蒿的生存空间，增强生存竞争优势。在黄花蒿?蔬菜种植体系中，选择抗化感作用较强的大白菜和菜豆可提高土地利用率和整体生产水平。用青蒿素浸种后，蔬菜幼苗的根系活力降低，菜豆和豇豆叶绿素含量提高，而大、小白菜降低，均可视为妨碍生长的生理原因。此外，青蒿素浸种还提高蔬菜种子可溶性糖和游离氨基酸含量，推测青蒿素对种子水解酶活性的影响较小，但抑制合成酶催化的生化反应，导致代谢紊乱，抑制幼苗生长。

Allelopathic effects of artemisinin on seed germination and seedling growth of vegetables

Allelopathic effects of artemisinin on seed germination and seedling growth of vegetables BAI Zhen, HUANG Yue, Huang Jianguo* (College of Resources and Environment, Southwest University, Beibei, Chongqing 400716, China) Abstract: Artemisinin, being extracted from Artemisia annua L., is recommended as a firstly used drug to treat malaria by World Health Organization (WHO). During the growth and development of Artemisia annua L. in the field, a large amount of this anti-malarial compound could be released into soil ecosystems by rain leaching, root exudation and plant residues whereby to inhibit plant growth around Artemisia annua L. and microbial reproduction in soils. China is rich in cultivar resources of Artemisia annua L. and produces almost 90% of total artemisinin in the world. This medical plant is commercially grown in Three Gorges areas. Phaseolus vulgar and Vigna sinensis are grown simultaneously with this medical plant and Brassica pikenensis and Brassica chinensis after Artemisia annua L. Scientist reported previously the growth inhibition of several vegetables after growing Artemisia annua L in this areas. Therefore, allelopathic effects of artemisinin on seed germination and seedling growth of this four vegetables were studied in the present experiment. 20 healthy vegetable seeds were germinated in artemisinin solutions with variable concentrations (0, 6, 12, 24 and 48 mg L-1) at 25?C for 10 days. Germination rate, embryo activities and chlorophyll in leaves were then measured. In order to know the metabolisms in seeds under artemisinin treatments, seed respiration, free amino acids and soluble sugars in seeds were also analyzed at 48th hour after soaking the seeds in artemisinin solutions. The results showed that the allelopathic effects on seed germination and seedling growth varied with artemisinin concentrations and vegetable species. The high artemisinin concentrations led to the strong allelopathic effects, particularly on the seed germination of Vigna sinensis and the seedling growth of Brassica chinensis. The germination rate of Vigna sinensis and seedling height of Brassica chinensis were decreased by 75.00% and 88.37%, respectively. Embryo roots of Brassica chinensis ceased growing in high concentration of artemisinin. This growth inhibition on other plants could benefit the existence competition and enlarge the living space of artemisia annua L. In cultivation systems of artemisia annua L. and vegetables, to grow vegetables such as Phaseolus vulgar and Brassica pikenensis with relatively strong abilities of anti-allelopathy could increase both land use efficiencies and crop yields in the whole systems. In addition, artemisinin reduced both the root activities of the four vegetables and chlorophyll in the seedling leaves of Brassica pikenensis and Brassica chinensis but increased that in Phaseolus vulgar and Vigna sinensis. These phenomena could be considered as a physiological reason for growth retards. Simultaneously, soluble sugars and free amino acids in seeds increased significantly under artemisinin treatment. It suggests that artemisinin changed the hydrolysis reactions little if any but inhibited synthase activities in the seeds during germination, whereby to interference the metabolisms and to retard seedling growth. Further studies are necessary to detect artemisinin concentrations in the field and to understand the allelopathic effects of this anti-malarial compound on these vegetable yields. Key words: artemisia annua L.; artemisinin; vegetable; Allelopathy.