摘要
【目的】研究外源多巴胺对干旱胁迫下枇杷幼苗光合特性及抗氧化系统的影响,明确多巴胺对枇杷幼苗耐旱性的调控作用及机理。【方法】以2年生‘大五星’枇杷盆栽苗为试验材料,设置正常水分管理下分别预喷蒸馏水(CK)和100μmol/L多巴胺溶液(DA)的处理,以及干旱胁迫10 d条件下分别预喷蒸馏水(DS)和100μmol/L多巴胺溶液的处理(DSDA)。试验结束随机选取不同处理的枇杷幼苗,分别测定其生长形态参数、光合色素(叶绿素a、叶绿素b、类胡萝卜素和总叶绿素)含量、光合作用参数(净光合速率(P n)、蒸腾速率(T r)、胞间CO_(2)浓度(C_(i))和气孔导度(G_(s)))、丙二醛(MDA)含量、相对电导率(REC)、O_(2)^(-·)产生速率、H_(2)O_(2)含量以及抗氧化酶(超氧化物歧化酶(SOD)、过氧化物酶(POD)、过氧化氢酶(CAT)和抗坏血酸过氧化物酶(APX))活性。【结果】正常水分管理下,与CK相比,DA处理的枇杷幼苗叶面积显著增加,叶绿素b含量显著提高,G_(s)显著增大,H_(2)O_(2)含量显著降低,APX活性显著增强,其余指标均与CK无显著性差异。干旱胁迫下,DS处理枇杷幼苗生长受阻,植株明显萎蔫,与CK相比,株高、叶面积及根系总长度、总表面积、总体积、平均直径和根尖数均显著减少,光合色素含量显著下降,P n、T r、G_(s)均显著降低,而C_(i)显著增加,MDA含量、REC、O_(2)^(-·)产生速率、H_(2)O_(2)含量以及SOD、POD、CAT、APX活性均显著升高。外源多巴胺预处理则可显著缓解干旱对枇杷幼苗的伤害,萎蔫程度明显减轻,与DS处理相比,DSDA处理枇杷幼苗的株高、叶面积及根系总表面积、平均直径和根尖数均显著提高,3种光合色素含量显著增加,P_(n)、T_(r)、G_(s)均显著升高,而C_(i)显著降低,MDA含量、REC、O_(2)^(-·)产生速率、H_(2)O_(2)含量显著降低,SOD、CAT和APX活性进一步显著提高,而根系总长度、根系总体积和POD活性均与DS处理无显著差异。【结论】外源多巴胺能够通过提高枇杷幼苗光合色素含量、增大气孔导度来改善光合作用效率,同时通过增强抗氧化酶活性、提高ROS清除能力减轻膜脂过氧化伤害,进而提高枇杷幼苗的耐旱性。
【Objective】This research aimed to study the effects of exogenous dopamine on photosynthetic characteristics and antioxidant system of loquat seedlings under drought stress,and to clarify the regulation effect and its mechanism of dopamine on drought tolerance of loquat seedlings.【Method】Two-year-old‘Dawuxing’loquat potted seedlings were used as experimental materials.The treatments of pre-spraying distilled water(CK)and 100μmol/L dopamine solution(DA)under normal water management were set,and the treatments of pre-spraying distilled water(DS)and 100μmol/L dopamine solution(DSDA)under drought stress for 10 days were set.After the experiment,loquat seedlings from different treatment groups were selected randomly.Growth morphological parameters,photosynthetic pigments(chlorophyll a,chlorophyll b,carotenoid and total chlorophyll contents),photosynthetic parameters(net photosynthetic rate(P_(n)),transpiration rate(T_(r)),intercellular CO_(2) concentration(C_(i))and stomatal conductance(G_(s))),malondialdehyde(MDA)content,relative electrical conductivity(REC),O_(2)^(-·) production rate and H_(2)O_(2) content and antioxidant enzymes(superoxide dismutase(SOD),peroxidase(POD)and ca-talase(CAT),ascorbic acid peroxidase(APX))activity were measured.【Result】Compared to CK,the DA treatment significantly increased leaf area,chlorophyll b content,G s,and APX activity of loquat seedlings under normal water management,and decreased H_(2)O_(2) content.There was no significant difference in other indicators compared to CK.Under drought stress,the DS treatment hindered the growth of loquat seedlings and obviously wilted the plants.Compared to CK,plant height,leaf area,total root length,total surface area,total volume,average diameter,root tips number,and photosynthetic pigment content was decreased significantly in DS treatment.P_(n),T_(r) and G_(s) decreased significantly,while C_(i) increased significantly.And the MDA content,REC,O_(2)^(-·) production rate,and H_(2)O_(2) content,as well as SOD,POD,CAT,and APX activities all significantly increased.Exogenous dopamine pretreatment significantly alleviated the damage of drought stress to loquat seedlings,and the wilting degree was obviously reduced.Compared with DS treatment,the DSDA treatment significantly increased the plant height,leaf area,total root surface area,average diameter and root tips number of loquat seedlings,and the contents of three photosynthetic pigments were also significantly increased.P n,T r and G s were significantly increased,while C_(i) was decreased.The MDA content,REC,O_(2)^(-·) production rate and H_(2)O_(2) content were significantly decreased,and SOD,CAT and APX activities were further increased in DSDA treatment.No significant difference was observed in total root length,total volume and POD activity between DS treatment and DSDA treatment.【Conclusion】Exogenous dopamine can improve the efficiency of photosynthesis by increasing the photosynthetic pigment content and stomatal conductance.Meanwhile,exogenous dopamine can reduce the membrane lipid peroxidation damage by enhancing the activity of antioxidant enzymes and improving the ROS scavenging ability,thus improving the drought tolerance of loquat seedlings.
作者
王晓莉
徐嘉宁
罗弦
罗娅
林立金
黄科文
张慧芬
邓群仙
WANG Xiaoli;XU Jianing;LUO Xian;LUO Ya;LIN Lijin;HUANG Kewen;ZHANG Huifen;DENG Qunxian(College of Horticulture,Sichuan Agricultural University,Chengdu,Sichuan 611130,China;Horticultural Research Institute,Chengdu Academy of Agriculture and Forestry Sciences,Chengdu,Sichuan 611130,China)
出处
《西北农林科技大学学报(自然科学版)》
北大核心
2025年第5期109-116,共8页
Journal of Northwest A&F University(Natural Science Edition)
基金
四川省衔接推进乡村振兴科技项目(2022ZHXC0097)
四川农业大学专业建设支持计划项目(2221998084)
四川省科技支撑计划“十四五”育种攻关项目(2021YFYZ0023-07)
国家现代化农业产业技术体系四川水果创新团队项目(SCCXTD-2024-04)。
关键词
枇杷
干旱胁迫
多巴胺
光合特性
抗氧化系统
loquat
drought stress
dopamine
photosynthetic characteristics
antioxidant system
作者简介
王晓莉(1999-),女,四川南充人,在读硕士,主要从事园艺植物栽培研究。E-mail:479774178@qq.com;通信作者:罗弦(1983-),男,四川自贡人,讲师,博士,主要从事园艺植物栽培研究。E-mail:lawxian@aliyun.com;通信作者:邓群仙(1968-),女,四川资中人,教授,博士,主要从事果树栽培理论与技术研究。E-mail:1324856299@qq.com。
