摘要
研究干旱胁迫下荒漠稀有植物裸果木幼苗生物量及其分配格局,叶片和根系抗氧化特性的变化,以揭示其抗旱机理。通过盆栽实验,设置对照(CK)、轻度干旱胁迫(LD)、中度干旱胁迫(MD)、重度干旱胁迫(SD),土壤含水量分别控制在田间持水量的45%~50%、30%~35%、15%~20%和5%~10%,分析幼苗生物量、根冠比、丙二醛(MDA)含量和抗氧化酶活性的差异性。结果表明:干旱胁迫使裸果木幼苗生物量显著降低,根冠比增加,叶片MDA含量、过氧化氢酶(CAT)及抗坏血酸过氧化物酶(APX)活性均显著上升,超氧化物歧化酶(SOD)活性先显著上升后下降;根系中过氧化物酶(POD)活性显著降低,叶片中POD活性显著上升。干旱胁迫显著影响裸果木幼苗生长,但幼苗可通过增加根系生物量的分配比例来适应干旱。干旱胁迫对根系和叶片膜系统造成明显的过氧化伤害,膜伤害随胁迫程度增加而明显加重,根系抗氧化能力较叶片弱。叶片通过SOD、CAT、POD、APX酶的协同作用保护膜系统,根系主要通过SOD、CAT、APX酶减轻活性氧伤害。
[Background]Drought stress affects the biomass accumulation and distribution between the aboveground and roots,results in excessive accumulation of active oxygen and lipid peroxidation,while plants evolve antioxidant enzyme system.Gymnocarpos przewalskii originates from Tethys,is the rare relic species of the Tertiary period in the desert area of central Asia and plays an important role in keeping stable of desert ecosystem.The research is to analyze the biomass accumulation and distribution pattern of the seedlings,the antioxidant characteristics of the leaves and roots under drought stress for revealing the drought resistance mechanism and to provide some theoretical basis for rare species conservation and vegetation restoration in desert area.[Methods]Taking one-year-old seedlings of Gymnocarpos przewalskii as the experiment material and using pot experiment,four water gradients were set,including the control,light water stress,moderate water stress and severe water stress,the soil water content was kept at 45%-50%,30%-35%,15%-20%and 5%-10%of the field capacity respectively by weighing method,with 10 repetitions per pot experiment,leaves and roots were collected after being treated 90 d and the biomass and physiological indexes were measured.The difference in biomass,root-shoot ratio,malondialdehyde(MDA)content and antioxidant enzyme activities in leaves and roots was analyzed.[Results]Under drought stress,biomass of the whole plant and the aboveground significantly reduced,the underground biomass decreased remarkably under the moderate and severe stress,and the aboveground biomass decreased more,thus the root-shoot ratio increased and was significantly higher under the severe stress compared to the control.MDA content in roots and leaves increased remarkably under drought stress compared with the control,the higher the drought stress degree was,the more serious the peroxidation damage was,and the increase amplitude of MDA content in roots was higher than that in leaves under the same treatment.With the increase of the drought stress,superoxide dismutase(SOD)activity in leaves and roots first significantly increased then decreased,it was obviously higher than the control in roots but significantly lower in leaves under severe stress,which indicated that the scavenging effect of SOD to reactive oxygen was limited especially in leaves.Peroxidase(POD)activity markedly decreased in roots but significantly increased in leaves under stress treatments compared to the control,showing that POD played obvious antioxidation in leaves,and POD was not the key enzyme scavenging H2O2 in the roots under drought stress.Catalase(CAT)activity increased significantly in leaves and roots under drought stress.Ascorbate peroxidase(APX)activity showed increasing trend under stress treatment,the difference was significant among the treatments in roots,and it changed markedly under moderate and severe stress in leaves.[Conculsions]Drought stress clearly affected the growth of Gymnocarpos przewalskii seedlings,but it could increase biomass distribution to roots to adapt the drought.Drought stress caused obvious peroxidation damage to the leaf and root membrane system,and the damage was more serious in roots.The leaves protected the membrane system by synergistic action of SOD,CAT,POD and APX enzymes,and the roots mainly reduced damage of reactive oxygen by SOD,CAT and APX.
作者
崔鹏
黄海霞
杨琦琦
CUI Peng;HUANG Haixia;YANG Qiqi(College of Forestry, Gansu Agricultural University,730070, Lanzhou, China;Gansu Vocational and Technical College of Forestry, 741020, Tianshui, Gansu, China)
出处
《中国水土保持科学》
CSCD
北大核心
2020年第5期112-118,共7页
Science of Soil and Water Conservation
基金
甘肃农业大学学科建设专项基金“裸果木幼苗根系形态和生理特征对干旱胁迫的响应”(GSAU-XKJS-2018-110)
省社科规划项目“十三五”生态环境建设与保护问题研究(12032JJ)。
关键词
干旱胁迫
裸果木
叶片和根系
生物量
保护酶活性
drought stress
Gymnocarpos przewalskii
leaves and roots
biomass
protective enzyme activity
