行间种不同草后对幼龄苹果树光合特性的影响

Effects of the Orchard-planted Grasses on the 1-year-old Apple Photosynthesis Characteristics

为了解果园种草后不同草种对苹果树光合特性的影响,于苹果园建植第1年春季,果树行间分别种植不同草种,以不种草为对照,在7月高温干旱时研究种草后对苹果树光合作用的影响。结果表明:除百脉根(Lotus cornic-ulatus)外,种其他草后苹果树叶片净光合速率(Pn)均显著提高(P<0.05);百脉根、多年生黑麦草(Lolium pe-renne)和匍匐翦股颖(Agrostis stolonifera)对苹果树叶片蒸腾速率(Tr)无显著影响,而种其他草种后苹果树的Tr显著高于对照(P<0.05);种大部分草后使苹果树叶片气孔导度(Gs)显著升高(P<0.05);种狗牙根(Cynodon dac-tylon)后,会使苹果树叶片胞间二氧化碳浓度(Ci)显著升高(P<0.05),其余种草处理均对苹果树Ci无显著影响;种草后,苹果树的水分利用效率(WUE)由高到低的顺序依次为:白三叶(Trifoliumrepens)>匍匐翦股颖>马蹄金(Dichondra repens)>草地早熟禾(Poa pratensis)>多年生黑麦草>狗牙根>草地早熟禾+多年生黑麦草>高羊茅(Festuca arundinacea)+草地早熟禾>红三叶(Trifoliumpratense)=百脉根>紫羊茅(Festuca rubra)>对照,但只有50%与对照达显著差异(P<0.05)。说明果园种草后对苹果树光合特性的影响及程度与所生草种及其组合的不同有关,草种的选择是提高果园生草效益的重要环节。

Planting grasses between fruit trees can improve the soil fertility,orchard micro-ecology,and the growth of the fruit trees.However,effects depend on grass species.Though the research of the photosynthesis characteristics can provide evidences of tree growth changes,these reports are not common.The effects of the grasses planted between the apple tree lines in the spring of the 1-year-old orchard on the photosynthesis characteristics was studied here in July.Trees without grasses between their lines were used as control.Results showed the photosynthetic rate（Pn） of all treatments except for Lotus corniculatus significantly increased（P〈0.05）.There was no significant change for the transpiration rate（Tr） of Lotus corniculatus,Lolium perenne and Agrostis stolonifera,wheras the Tr of others significant increased（P〈0.05）.The stomatal conductance（Gs） of the most treatments went up significantly（P〈0.05）.Internal CO2（Ci） for planting Cynodon dactylon treatment significantly increase（P〈0.05）.Consequently,planting the grasses made the water use efficiency（WUE） of the trees increased but only 50% treatments reached significant differences（P〈0.05）.The order of WUE is： Trifolium repens〉Agrostis stolonifera〉Dichondra repens〉Poa pratensis〉Lolium perenne〉Cynodon dactylon〉Poa pratensis ＋ Lolium perenne〉Festuca rubra ＋ Poa pratensis〉Trifolium pretense = Lotus corniculatus〉Festuca rubra〉control.In conclusion,the effects of the grasses on the photosynthesis characteristics varied among grass species and different combinations,so the selection of the grass species are the important factor to increase the efficiency of the grass-planted orchard.