Influence of exogenous melatonin and arbuscular mycorrhizal fungi on growth and physiological characteristics of Rosa chinensis seedling under salt stress
[Objective]Salt stress leads to poor growth and development and decreased ornamental quality of Chinese rose(Rosa chinensis Jacq.),and seriously affects their outdoor greening applications in high salt environments or coastal areas.This study explores the effects of exogenous melatonin(MT)and inoc-ulation with arbuscular mycorrhizal fungi(AMF)on seedling growth,chlorophyll fluorescence parame-ters,and cytokinin metabolism,and analyzes their physiological and the biochemical mechanisms that pro-mote rose to adapt to salt stress,in order to enhance salt resistance and expand the application of rose.[Methods]The seedling of Chinese rose variety'Yueyue Hong'was used as experimental material to con-duct indoor potting experiments.In addition,control(CK),100 mol/L NaCl stress,root administration of MT,and root inoculation of AMF larvae of the genus Claroideoglomus etatunicum and their combina-tion were set to investigate the effects of each treatment on the growth of rose seedlings,chlorophyll fluo-rescence parameters,hormone metabolism,and antioxidant system.[Results](1)Application of MT pro-moted AMF infestation of the roots of rose seedlings and increased the infection rate,bush growth rate,number of vesicles,and invasion points.(2)Under salt stress,the growth of rose seedlings was inhibited,and plant height,stem thickness,and biomass were decreased significantly.MT and AMF treatments in-creased the height,stem thickness,and biomass of rose seedlings,whereas AMF+MT treatment had no significant difference in plant height and stem thickness,aboveground dry weight and underground dry weight were increased by 24.1％ and 37.0％.(3)Under salt stress,the chlorophyll content of rose seed-lings was decreased significantly while chlorophyll fluorescence parameters were decreased,and MT and AMF treatments could improve the chlorophyll content and chlorophyll fluorescence parameters.Under AMF+MT treatment,the total amount of chlorophyll and chlorophyll a/b was increased by 46.2％ and 67.2％,respectively.PS Ⅱ maximum photochemical efficiency(Fv/Fm),potential activity(Fv/Fo),ac-tual photochemical efficiency(ΦPSⅡ),effective photochemical quantum efficiency(Fv'/Fm'),and photo-chemical quenching coefficient(qP)were increased by 4.9％,51.0％,175.0％,168.7％,and 92.5％,re-spectively,whereas NPQ was decreased by 42.7％.(4)Under salt stress,zeatin(ZT),gibberellin(GA),auxin(IAA)content in leaves were decreased,whereas the abscisic acid(ABA)content was in-creased.MT and AMF contributed to the increase in ZT,GA,and IAA content and the decrease in ABA content.Under AMF+MT treatment,ZT,GA,and IAA content were increased by 146.9％,116.9％,35.7％,respectively,while ABA was decreased by 21.1％.(5)Under salt stress,the activity of SOD and CAT were increased,and the rate of superoxide anions(O2(·-))production and H2O2 accumulation was in-creased.MT and AMF treatments decreased O2(·-)production rate and H2O2 content,while AMF+MT treatment activated SOD and CAT activity,and reduced the rate of O2(·-)production and H2O2 accumula-tion.[Conclusion]Inoculation with AMF,addition of MT,or AMF+MT treatment could increase the chlorophyll content of rose seedlings under salt stress,protect the chlorophyll fluorescence system,main-tain the balance of endogenous plant hormones,activate the activity of antioxidant enzymes such as SOD and CAT,and reduce lipid peroxidation and H2O2 accumulation,thereby reduce the damage caused by salt stress to rose seedlings,promote rose growth,and enhance the salt resistance of rose seedlings better with AMF+MT treatment.
Rosa chinensis Jacq.salt stressmelatoninarbuscular mycorrhizal fungi(AMF)growthchlorophyll fluorescence parametershormone metabolismantioxidant enzymes
NETL
NSTL
万方数据
维普
