不同林分枯落物浸提液对柠条种子萌发与幼苗生长的化感效应研究

Allelopathic Effects of Different Forest Litter Extracts on Seed Germination and Seedling Growth of Caragana korshinskii

为了解黄土丘陵沟壑区不同林分枯落物的化感效应,该研究以2022年度内蒙古呼和浩特市和林格尔县盛乐经济园区秋季造林期9月降雨量为基础数据,采用室内模拟方法,根据单位面积上枯落物储量和降雨量进行换算得出不同林分枯落物浸提液的浓度,以2021年在该地区收集的柠条Caragana korshinskii种子作为受试种子,对樟子松Pinus sylvestris var.mongolica、蒙椴Tilia mongolica、山杏Armeniaca sibirica、白桦Betula platyphylla、华北落叶松Larix principis-rupprechtii和小叶杨Populus simonii 6种林分枯落物浸提液对柠条种苗的化感作用进行分析。结果表明:(1)不同林分枯落物浸提液浓度对柠条种子发芽率有显著影响,化感效应均表现出抑制作用,抑制作用也随浓度的增加而增加,其中小叶杨林枯落物抑制作用最弱,柠条种子发芽率达到了41%,樟子松林枯落物抑制作用最强,柠条种子发芽率仅为29%。(2)不同林分枯落物浸提液浓度对柠条种子芽长具有化感抑制作用,化感作用下芽长生长长度依次为小叶杨(41.38 mm)>华北落叶松(38.68 mm)>白桦(35.45 mm)>山杏(32.23 mm)>蒙椴(28.17 mm)>樟子松(24.38 mm)。(3)不同林分枯落物浸提液浓度对柠条种子根长有化感抑制作用,抑制作用下根长生长长度依次为小叶杨(50.13 mm)>华北落叶松(46.53 mm)>白桦(41.6 mm)>山杏(37.58 mm)>蒙椴(30.47 mm)>樟子松(27.17 mm)。(4)不同林分枯落物浸提液对柠条种子发芽指数有显著抑制作用,抑制作用依次为小叶杨(0.69)>华北落叶松(0.64)>白桦(0.47)>蒙椴(0.39)>山杏(0.32)>樟子松(0.27)。6种林分枯落物浸提液对柠条种子萌发和生长存在化感效应,且化感效应表现为抑制作用,随着浸提液浓度的增加,抑制作用增强。总的来说,小叶杨林比山杏林和蒙椴林的抑制作用弱,建议在内蒙古呼和浩特和林格尔地区柠条人工造林优先选择小叶杨林。

To study the allelopathic effects of different forest stands of litter in the loess hilly and gully area,the study used September rainfall during the autumn afforestation period in Shengle Economic Park,Helingeer County,Hohhot City,Inner Mongolia in 2022 as the basic data,and used indoor simulation methods to convert the concentration of litter extract from different forest stands based on the litter storage and rainfall per unit area,Using Caragana korshinskii seeds collected in the region in 2021 as test seeds,the allelopathic effects of litter extracts from six forest stands,including Pinus sylvestris var.mongolica,Tilia mongolica,Armeniaca sibirica,Betula platyphylla,Larix principis-rupprechtii and Populus simonii on Caragana korshinskii seedlings were analyzed.The results showed that:(1)Different concentrations of litter extract from different forest stands had a significant impact on the germination rate of C.korshinskii seeds,and the allelopathic effects showed inhibitory effects.The inhibitory effect also increased with the increase of concentration.Among them,the litter inhibition effect of Populus simonii was the weakest,and the germination rate of C.korshinskii seeds reached 41%.The litter inhibition effect of Pinus sylvestris var.mongolica forest was the strongest,and the germination rate of C.korshinskii seeds was only 29%.(2)Different concentrations of litter extracts from different forest stands have allelopathic inhibitory effects on the sprout length of C.korshinskii seeds.Under allelopathic effects,the growth length of the sprouts is in the following order:P.simonii(41.38 mm)>L.principis-rupprechtii(38.68 mm)>B.platyphylla(35.45 mm)>A.sibirica(32.23 mm)>T.mongolica(28.17 mm)>Pinus sylvestris var.mongolica(24.38 mm).(3)Different concentrations of litter extracts from different forest stands have allelopathic inhibitory effects on the root length of C.korshinskii seeds.Under the inhibitory effect,the root length growth length is in the following order:Populus simonii(50.13 mm)>L.principis-rupprechtii(46.53 mm)>B.platyphylla(41.6 mm)>A.sibirica(37.58 mm)>T.mongolica(30.47 mm)>Pinus sylvestris var.mongolica(27.17 mm).(4)The extract of litter from different forest stands has a significant inhibitory effect on the germination index of C.korshinskii seeds,with the inhibitory effects in the following order:Populus simonii(0.69)>L.principis-rupprechtii(0.64)>B.platyphylla(0.47)>T.mongolica(0.39)>A.sibirica(0.32)>Pinus sylvestris var.mongolica(0.27).Six types of forest litter extracts have allelopathic effects on the germination and growth of C.korshinskii seeds,and the allelopathic effects are manifested as inhibitory effects.With the increase of extract concentration,the inhibitory effect is enhanced.Overall,the inhibitory effect of Populus simonii forest is weaker than that of A.sibirica forest and T.mongolica forest.It is recommended to prioritize Populus simonii forest for artificial afforestation of C.korshinskii in Hohhot and Linger areas of Inner Mongolia.