盐胁迫下丛枝菌根网络介导的两种典型荒漠植物幼苗抗逆生理响应OA

Arbuscular mycorrhizal fungi(AMF)enhance the stress resistance of desert plants through symbiosis.This study focused on Glycyrrhiza inflata and Lycium ruthenicum,two typical desert plant species from the lower reaches of the Tarim River,and established conspecific(GG)and heterospecific(GL)plant combinations.The plants were treated with NaCl at concentrations of 0,150,250,and 350 mmol·L-1.A two-chamber device was used,with donor plants(inoculated with AMF)subjected to salt stress and receptor plants(not inoculated with AMF)kept under nonstress conditions.The experiment measured plant biomass;chlorophyll content;photosyn-thetic fluorescence parameters;antioxidant enzyme activity;osmotic regulators;and the levels of plant hormones such as abscisic acid(ABA),salicylic acid(SA),and jasmonic acid(JA).The results were as follows:(1)Salt stress significantly reduced the mycorrhizal infection rate in donor plants(P<0.05).(2)As salt concentration in-creased,both donor and receptor plants showed a significant reduction in chlorophyll content(SPAD values)and maximum photochemical efficiency(Fv/Fm)and an initial increase followed by a decrease in nonphotochemical quenching(NPQ).(3)Under salt stress,receptor plants showed a significant increase in superoxide dismutase(SOD)and peroxidase(POD)activity as well as soluble sugar(SS)and proline concentrations(P<0.05).The in-crease in SOD and POD activity in receptor plants was significantly higher in the GL group than in the GG group(P<0.05),and malondialdehyde(MDA)accumulation was also higher(P<0.05).(4)In the GG group,the receptor plants showed significantly increased ABA and SA levels and significantly decreased JA levels,whereas in the GL group,the receptor plants showed significantly increased ABA and JA levels and significantly decreased SA levels(P<0.05).The receptor plants,which were not under direct salt stress,exhibited synchronized hormonal changes,photosynthetic inhibition(decrease in SPAD and Fv/Fm),photoprotective activation(increase in NPQ),and systemic defense responses(increase in SOD and POD activity and proline and SS accumulation).These changes suggest that donor plants transmit"warning"signals to receptor plants via the common mycorrhizal net-work(CMN).In the GG combination,the ABA and SA levels were primarily enhanced,which protects the photo-synthetic apparatus.In the GL combination,the ABA and JA levels were enhanced-which activated the antioxi-dant system-but with higher MDA accumulation.This regulatory pattern highlights the central role of CMN in interplant communication and collaborative adaptation to salt stress,providing important theoretical insights into symbiotic mechanisms in desert plants and ecological restoration.