兰州主要阔叶造林树种凋落物对火炬树种子萌发的影响

Effects of litter of main afforestation tree species on seed germination of Rhus typhina in Lanzhou

为探讨兰州主要造林树种的凋落物对外来植物火炬树(Rhus typhina)种子萌发的影响,采用双层滤纸培养方法,以刺槐(Robinia pseudoacacia)、国槐(Sophora japonica)、臭椿(Ailanthus al⁃tissima)、白蜡(Fraxinu schinensis)、新疆杨(Populus alba)、垂柳(Salix babylonica)的凋落物浸提液作为化感物质来源,对火炬树种子进行萌发试验。结果表明:各树种不同浓度的浸提液对火炬树种子萌发均有显著影响,随着浸提液浓度增加(至中浓度0.050 g/mL)抑制作用随之增强,刺槐、新疆杨相比于其他树种,显著抑制了火炬树种子的萌发;随着浸提液浓度的增加,对火炬树苗高增长的抑制作用逐渐增强,新疆杨抑制效果最显著;而对根的生长则呈低浓度促进高浓度抑制的趋势,相比于其他树种,新疆杨显著抑制了火炬树根长的增长。几种树种浸提液在低浓度(0.025 g/mL)时对火炬树幼苗抗逆生理指标影响较小,与对照无显著差异,随着浓度的升高,火炬树幼苗丙二醛含量增加,过氧化氢酶、过氧化物酶、超氧化物歧化酶和可溶性蛋白含量均下降,新疆杨浸提液对火炬树幼苗抗逆生理指标的影响最为显著。刺槐、新疆杨凋落物的化感物质可在一定程度上抑制火炬树种子萌发和幼苗生长,并影响其生理活性;在兰州引种火炬树时,可以选择刺槐或新疆杨与其混交,对其进行生态管理和控制,预防其入侵。

In order to investigate the effect of litter of the main afforestation species in Lanzhou on the germination of seeds of the exotic plant Rhus typhina,a double‐layer filter paper culture method was used to test the germination of R.typhina seeds by using the litters extracts of Robinia pseudoacacia、Sophora japonica、Ailanthus altissima、Fraxinus chinensis、Populus alba and Salix bobylonica willow as allelochemical sources.The results showed that the leaching solution and its concentration of each species had significant effects on the germination of R.typhina seedlings,With the increase of extraction concentration,the inhibition effect was increased.R.pseudoacacia and P.alba significantly inhibited the germination of R.typhina seedlings compared with other tree species.with the increase of leaching solution concentration.the inhibition effect on the seedling height growth of R.typhina was gradually increased,and P.alba inhibited the most obvious effect;while the root length showed a trend of low concentration The inhibition of root length was more pronounced in P.alba than in other species.The effect of the extracts of several species on the resistance physiological indexes of R.typhinaseedlings at low concentrations was small and did not differ significantly from the control,and as the concentration increased,the MDA content of R.typhina seedlings increased and the CAT,POD,SOD and soluble protein contents decreased,and the effect of the extracts of P.alba on the resistance physiological indexes of R.typhina seedlings was the most significant.Therefore,when introducing R.typhina in Lanzhou,we can choose R.pseudoacacia and P.alba to mix with them for ecological management and control to prevent their invasion.