辣子草水浸提液对蚕豆幼苗生长和光合特性的化感效应

Allelopathic Effect of Aqueous Extract from Galinsoga parviflora on Seedling Growth and Photosynthesis of Vicia faba

为了深入探讨辣子草的化感作用机制,本研究采用盆栽试验,研究了辣子草水浸提液对蚕豆幼苗生长和光合特性的影响。结果表明:辣子草水浸提液对蚕豆幼苗叶面积影响较小,但对地上部分的高度和生物量积累具有显著的抑制效应,不同处理之间浓度效应不明显。在辣子草水浸提液作用下,蚕豆幼苗叶片的叶绿素含量、实际光化学效率(ΦPsⅡ)以及最大光化学效率(Fv_/F_m)和蒸腾速率(T_r)等与对照无显著差异,但净光合速率(P_n)随着处理浓度的增加而降低,表现出显著的浓度依赖效应,但随着处理时间进一步延长,浓度依赖效应逐渐减弱。本研究结果揭示辣子草水浸提液对光能吸收、电子传递等光反应过程影响不明显,主要是通过影响CO_2同化能力而减少积累有机物质,导致植物生长受阻。

To explore the effect of Galinsoga parviflora Cav. , an invasive plant on seedling growth and photosynthetic physiological character- istics of broad bean （ Vicia faba L. ）, the pot experiments were conducted to study the effects of plant heights, leaf areas, biomass, chloro- phyll contents, chlorophyll fluorescence parameters and gas exchange parameters of broad bean seedlings. The resuha showed that, after trea- ting with the aqueous extracts of G. parviflora, the results showed that leaf areas had little change, and the plant heights and the biomass were dramatically inhibited by the aqueous extracts in a time-dependent but not concentration-dependent manner. And net photosynthetic rate （P,） were decreased markedly（ P 〈 O. 05 ）. The chlorophyll contents, chlorophyll fluorescence parameters （~Ps II and Fv/Fm ） and tran- spiration rates （ Tr ） were not inhibited by the aqueous extracts of G. parviflora significantly （P 〉 0.05 ）. These results suggested that the a- queous extracts of G. parviflora inhibited the growth of recipient plants by inhibiting the ability of assimilation of CO2 and reducing the biomass.