摘要
[目的]为了探明槲树(Quercus dentata)苗期生长的适宜光照强度,为其在城市森林建设应用中提供参考.[方法]以槲树幼苗为试验材料,设置全光照(CK)、75％全光照、50％全光照、25％全光照4个光照梯度,处理60 d后,测定生长指标、叶解剖结构、生理指标和光合参数.[结果]75％全光照下槲树幼苗生长状况最佳,有利于生长.随着遮阴程度增加,槲树幼苗的叶片、栅栏组织、海绵组织、主脉、上表皮和下表皮的厚度均减小,栅海比减小,而细胞疏松度增加.过氧化物酶、超氧化物歧化酶、过氧化氢酶的活性随着遮阴程度的增加先降低后升高,可溶性糖、可溶性蛋白、脯氨酸与丙二醛的含量表现出相似的变化规律.遮阴处理消除了槲树幼苗的光合午休现象,并且提高了光能利用效率,减少了暗呼吸消耗,有利于光合产物的积累.[结论]槲树幼苗具有一定的耐阴性,75％全光照是适宜槲树苗期生长的光照强度.
Abstract
[Objective]This studyaimed to determine the optimal light intensity for the seedling growth of Quercus dentata Thunb.and provide reference for its application in urban forest construction.[Methods]Q.dentata seedlings were used as ex-perimental materials.Four different light levels including full light exposure(CK),75％full light exposure,50％full light ex-posure,and 25％full light exposure were set up.After treatment for 60 days,the growth indexes,leaf anatomical structure,physiological indexes,and photosynthetic characteristics were measured.[Results]Under 75％full light exposure Q.dentata seedlings presented the best growth status,which promoted the growth.As the increase of shading levels of,the of thicknes-ses of leaf,palisade tissue,spongy tissue,main vein,upper epidermis,and lower epidermis of Q.dentata seedlings de-creased,as well as the palisade-spongy ratio,but the cell looseness increased.The activities of peroxidase,superoxide dis-mutase,and catalase initially decreased and then increased with increased shading levels.The contents of soluble sugars,solu-ble proteins,proline,and malondialdehyde followed a similar trend.Shading treatment eliminated the hotosynthetic lunch break phenomenon of Q.dentata seedlings,enhanced the light energy utilization efficiency,and reduced dark respiration con-sumption,which contributed to the accumulation of photosynthetic products.[Conclusion]Q.dentata seedlings exhibited a certain degree of shade tolerance,and 75％full light exposure was optimal for the seedling growth of Q.dentata.
基金项目
北京市教委生态修复工程学高精尖学科建设项目()
北京农学院揭榜挂帅项目(BUAJB2021010)
NETL
NSTL
万方数据