紫茎泽兰叶片水浸液对蚕豆的化感效应

Allelopathic effects of Eupatorium adenophorum leaf aqueous extracts to Vicia faba

关键词:  外来入侵植物, 染色体畸变, 根尖微核, 叶片N含量, 潜在最大净光合速率

Key words:  exotic invasive plants, chromosomal aberration, root tip micronucleus, leaf nitrogen content, maximum net photosynthetic rate

摘要:

外来入侵植物可以通过淋溶、自然挥发、根系分泌和植株凋落物分解等途径向周围环境释放化感物质,抑制伴生植物的生长、发育。该研究以不同浓度紫茎泽兰(Eupatorium adenophorum)叶片水浸液处理蚕豆(Vicia faba)种子,研究紫茎泽兰叶片水浸液对蚕豆根尖细胞微核、染色体畸变、细胞凋亡、蚕豆幼苗叶片叶绿素和N含量、光合生理特性、生物量的影响。结果表明:(1)紫茎泽兰叶片水浸液处理显著抑制蚕豆根尖的伸长和细胞的有丝分裂,并诱导蚕豆根尖细胞染色体畸变和细胞微核的产生,有丝分裂指数随着叶片水浸液浓度增加而减小,根尖细胞微核率随叶片水浸液浓度增加而增大,高浓度叶片水浸液处理对蚕豆根尖细胞的凋亡及坏死有明显影响。(2)紫茎泽兰叶片水浸液处理引起蚕豆幼苗叶片的叶绿素和N含量显著降低,并导致蚕豆幼苗最大净光合速率和生物量的显著下降。总之,紫茎泽兰叶片水浸液可能引起蚕豆根尖的氧化损伤和抑制根尖的伸长,且叶片水浸液的抑制作用呈现一定的剂量效应。紫茎泽兰叶片水浸液对蚕豆根尖的损伤和抑制作用可能影响了植株对氮素的吸收,进而对蚕豆幼苗光合生理表现以及生物量积累产生显著负面效应。

Abstract:

Exotic invasive plants can alter ecosystem and displace the native plants by releasing allelochemicals to the surrounding environment by means of leaching, natural volatilization, root exudation and plant litter decomposition. In this study, Vicia faba seeds were treated with different concentrations of Eupatorium adenophorum leaf aqueous extracts. The effects of E. adenophorum leaf aqueous extracts on the micronucleus, chromosome aberration, apoptosis, chlorophyll and nitrogen content and photosynthetic physiological characteristics of Vicia faba were studied in this paper. The results were as follows:(1)The treatment of Eupatorium adenophorum leaf aqueous extracts significantly inhibited the root tip elongation and cell mitosis of Vicia faba, and induced chromosome aberration and cell micronucleus in the root tip cells of V. faba. With the increasing concentration of leaf water extracts, mitosis index significantly decreased and micronucleus rate of root tip cells significantly increased. In addition, the treatment of high concentration leaf aqueous extracts significantly affected apoptosis and necrosis of V. faba root tip cells.(2)The content of chlorophyll and nitrogen in leaves of V. faba decreased significantly, and the maximum net photosynthetic rate and biomass of V. faba seedlings were significantly decreased. In conclusion, Eupatorium adenophorum leaf aqueous extracts may cause the oxidative damage of the root tip of Vicia faba and the elongation of the root tip, and the inhibitory effect of leaf water extract showed a certain dose effect. At the same time, the damage and inhibition effects of Eupatorium adenophorum leaf aqueous extracts on the root tip of Vicia faba might affect the uptake of nitrogen, and thus had a significantly negative effect on the photosynthetic physiological performance and biomass accumulation of broad bean seedlings.