火炬树根蘖幼苗对3种草坪草种子萌发和幼苗生长的化感效应

Allelopathic effects of Rhus typhina tillering seedlings on seed germination and seedling growth of three common turf species

以白三叶、苇状羊茅和多年生黑麦草3种北方常见草坪草为对象,通过室内砂培试验,研究了火炬树幼苗根、皮和叶的水浸提液在12.5、25.0和50.0 g·L^(-1)浓度下对受体植物种子萌发、幼苗生长以及生理指标的影响。并基于不同指标对应化感效应指数进行主成分分析获取的综合主成分值(F)评价各处理对3种草坪草的综合抑制程度,以期明确火炬树幼苗的潜在化感效应及其作用规律。结果表明:火炬树幼苗对受体植物各类指标的化感效应普遍受到化感物质来源器官、浸提液浓度和受体植物种类,以及上述因素交互作用的显著影响(P<0.05)。其中,火炬树所有器官的浸提液在各浓度下均使白三叶在苗期全部死亡。其根、皮和叶浸提液均显著抑制了苇状羊茅的种子萌发和幼苗生长,但仅后两者的综合抑制程度随浸提液浓度增加持续增强(F值降低1.07~2.77);浓度一致时,火炬树对苇状羊茅的综合抑制程度均为叶和皮>根(F值较后者低0.98~3.23)。火炬树根和皮浸提液对多年生黑麦草的综合抑制程度随浓度增加呈先增后降趋势,叶浸提液的抑制程度则随浓度增加呈持续增强趋势(F值降低1.11),且所有器官浸提液对多年生黑麦草的化感抑制普遍强于其对苇状羊茅的抑制(F值较后者低0.64~2.96);浓度一致时,在12.5和50.0 g·L^(-1)浓度下叶浸提液的综合抑制程度强于其他器官(F值较其他器官低0.44~1.55),而在25.0 g·L^(-1)浓度下皮浸提液的抑制程度最强(F值低0.51~0.69)。综上所述,在火炬树下种植草坪植物时建议优先考虑苇状羊茅而应避免种植白三叶。

We aimed to clarify the allelopathic effects of Chinese sumac(Rhus typhina)seedlings on common turf species and the underlying mechanisms of such effects.Three common turf species,namely Trifolium repens,Festuca arundinacea,and Lolium perenne,were cultivated in sand,and were treated with aqueous extracts of the root,bark,and leaf of R.typhina tillering seedlings.Seed germination,seedling growth,and physiological traits such as chlorophyll content,root activity,and antioxidant indexes were measured for all of the turf species.Aqueous extracts of the root,bark,and leaf of R.typhina were prepared at three concentrations:12.5,25.0,and 50.0 g·L^(-1)(dry weight/volumewater).A principal component analysis was used to calculate the integrated principal component value(F)based on the allelopathic effects of each extract on each index.These values were then used to assess the comprehensive inhibitory effects of each treatment on each turf species.The results indicated that the allelopathic effects of R.typhina extracts on the turf species were significantly affected by the organ the extract was prepared from,the concentration of the extract,and the type of turf species being treated,and there were significant interactions among these factors(P<0.05).All T.repens seedlings died after being treated with any of the extracts at any concentration.The seed germination and seedling growth of F.arundinacea were significantly inhibited by the root,bark,and leaf extracts of R.typhina.The effect of the root extract did not change as its concentration increased,but the inhibitory effects of bark and leaf extracts increased as their concentrations increased,with the F value decreasing by 1.07-2.77.The leaf and bark extracts of R.typhina had stronger inhibitory effects on F.arundinacea than did the root extract at the same concentration,with F values 0.98-3.23 lower in the leaf and bark extract treatments than in the root extract treatments.The inhibitory effects of R.typhina root and bark extracts on L.perenne first increased and then decreased as their concentrations increased.However,the inhibitory effect of the R.typhina leaf extract continuously increased as its concentration increased,with the F value decreasing by 1.11.In addition,extracts from all organs exhibited greater inhibitory effects on L.perenne than on F.arundinacea,with F values that were 0.64-2.96 lower in L.perenne than in F.arundinacea.Generally,the leaf extracts had stronger inhibitory effects than the root and bark extracts at concentrations of 12.5 and 50.0 g·L^(-1),with F values that were 0.44-1.55 lower in the leaf extract treatments than in the root and bark extract treatments.However,the bark extract had a stronger inhibitory effect than the leaf and root extracts at a concentration of 25.0 g·L^(-1),with F values that were 0.51-0.69 lower in the bark extract treatments than in the leaf and root extract treatments.In conclusion,these results show that F.arundinacea is the most suitable of the three tested turf species to be planted under R.typhina,and T.repens should be avoided.