三种作物茎叶枯落物水浸液对烟草幼苗生长的化感效应

Allelopathic effects of leaf-stem litter water aqueous extracts of three plant species on tobacco seedlings

为探讨玄参、川明参与烟草间套作种植过程中存在的潜在化感作用,选择烟草K126为研究对象,采用水浸液浇灌的方法,用烟草、玄参、川明参一年生茎叶枯落物水浸液培养烟草幼苗,以不加水浸液的Hogland营养液处理作为对照,对比分析质量浓度分别为0.01,0.02,0.05,0.10mg/L水浸液处理下烟草幼苗地下、地上生长指标、抗氧化酶系统及叶绿素荧光的差异。结果表明,与对照相比,烟草水浸液对幼苗地下和地上生长具有抑制作用,且随着浓度的升高,抑制作用增强;玄参水浸液对烟草幼苗地下和地上生长呈现低浓度促进高浓度抑制的双重浓度效应;川明参水浸液则对烟草幼苗生长的影响不大,偏向促进作用。玄参、川明参水浸液浇灌下,SOD、POD、CAT活性都随水浸液浓度的升高而增强,表现出一定的抗性,可溶性蛋白质以及初始荧光F0、最大荧光Fm、可变荧光Fv、PSⅡ潜在活力Fv/F0、PSⅡ最大光化学效率Fv/Fm也表现出较好的适应性。研究结果证实玄参和川明参对烟草幼苗无不良作用,可作为药烟轮(间套)作的选择作物。

Tobacco, and the two Chinese herbal medicine crops Scrophularia ningpoensis and Chuanminshen violaceum, all present husbandry difficulties under continuous cropping systems, and allelopathic effects are considered to be a significant contributing factor. There have been relatively few studies of auto-allelopathy in tobacco crops or of allelopathy between tobacco and the Chinese herbal medicine crops S. ningpoensis and C. violaceurn. To investigate problems arising in continuous cropping of tobacco, a study was conducted on leachate effects on seedlings. Flue-cured tobacco K126 and 1 aqueous extracts of leachates of tobacco （LET）, and leaf and year old leaf and stem litter were used to prepare stem litter were also used to prepare aqueous ex-tracts of S. ningpoensis （LeS）, and C. violaceum （LeC）, with pure water as control. Treatment concentra- tions were 0.01, 0.02, 0.05, 0.10 mg/L. LeT had an inhibitory effect on seedlings below ground and above ground growth, as indicated by elevated antioxidant enzyme activity. For LeS the highest concentration of 0.10 mg/L showed significant inhibition, while the lowest concentration of 0.01 mg/L had a stimulatory effect. Meanwhile, LeC had little impact on tobacco seedlings, or tended to induce positive growth promotion effects. Following application of the aqueous extracts of S. ningpoensis and C. violaceum, SOD, POD, CAT activities were increased with increasing concentration of the extracts, and soluble protein, initial chlorophyll fluores- cence （F0）, the maximum enhanced fluorescence （Fro） , variable fluorescence （Fv）, PS II potential photochem- ical activity （Fv/Fo）, and PSII maximum photochemical efficiency （Fv/Fm）, also showed better adaptation. Therefore, S. ningpoensis and C. violaceum may be an alternative rotation or intercropping plant species for tobacco, and intercropping may help ease husbandry problems encountered in continuous cropping of tobacco.