Responses Of Peanut Hydraulic Traits To Water Resource Supply In North China Plain

Water resource is one of the key factors that determine plant growth.Plants adapt to different water resource supply using different strategies so as to avoid adverse effects on plant growth.Based on hydraulic traits of plant organs such as root,stem,and leaf,more research has been conducted on plant water regulation strategies.However,it is unclear whether plant root and leaf,which are two important organs at the end of vascular tissues,respond independently or relevantly to changes in water availability.Additionally,the impact of plant-soil microbial interactions on the response of plant root and leaf hydraulic traits to changes in water availability is poorly understood.In order to understand the adaptation mechanism of peanut to changes in water resource supply,a pot manipulative experiment was conducted to examine the effects of inculcated soil microbe and water resource supply on peanut root and leaf hydraulic traits in the North China Plain.In this study,inoculated soil microbe included arbuscular mycorrhizal fungi and rhizobia.Water resource supply included 70% maximum field capacity(70% FC)and 35% maximum field capacity(35% FC).The results of the study showed that:(1)Compared with the 70% FC treatment,the 35% FC treatment significantly reduced peanut vein density(VD)by 0.8%,but had no significant effect on leaf tissue tightness ratio(CTR)and upper stomatal density(USD).In addition,under inoculated rhizobia,inoculated mycorrhizal fungi increased VD by81.8%,but reduced VD by 4.9% in the absence of rhizobia inoculation(2)Compared with 70% FC,35% FC reduced the periderm thickness(Pe T)and total vessel area(TVA)of taproot by 4.3% and 17.5%,respectively,but had no significant effect on the cortical thickness(CT)and fine root diameter(FRD).Inoculated arbuscular mycorrhizal fungi significantly increased the ratio of fine root length to fine root biomass(RLB)and TVA by 93.8% and 67.3%,respectively.Inoculated rhizobia did not affect root hydraulic traits.In addition,there was also a interaction between water supply and inoculation of soil microorganisms on taproot diameter(RD).(3)For the intercorrelations among leaf hydraulic traits,water resources supply did not affect the trade-off between VD and CTR,but changed the correlation between VD and USD.For the intercorrelations among root hydraulic traits,water resources supply altered the relationships of RD with Pe T,TVA,and RLB.For the intercorrelations between root and leaf hydraulic traits,water resources supply changed the between Pe T-VD,RD-VD,RLB-VD,RD-CTR,RD-USD,and TVA-USD correlations.(4)For the interrelationships among leaf hydraulic traits,inoculated arbuscular mycorrhizal fungi changed the relationships of VD and CTR with USD,while inoculated rhizobia did not affect the trade-off relationship between VD and CTR.For the interrelationships among of root hydraulic traits,inoculated arbuscular mycorrhizal fungi did not affect the synergistic RD-TVA and CT-FRD relationships,but altered the Pe T-RLB,TVA-RLB,and TVA-USD correlations.Inoculated rhizobia did not affect the synergistic relationship between RD and TVA.For the interrelationships between root and leaf hydraulic traits,inoculated arbuscular mycorrhizal fungi changed the RD-VD,RD-USD,Pe T-VD,Pe T-CTR,TVA-USD,and TVA-VD correlations,while inoculated rhizobia changed the TVA-VD,RD-VD,RLB-VD,RD-CTR,TVA-CTR,and TVA-USD correlations.In general,water resource supply and inoculation with soil microorganisms could alter root and leaf hydraulic traits of peanut,and there were synergistic or trade-off relationships between root and leaf hydraulic traits in response to water resources supply and inoculation with soil microorganisms.In addition,inoculated arbuscular mycorrhizal fungi could mitigate the negative effects of water resource supply reduction on hydraulic traits.The findings enhance the understanding of plant adaptation strategies to water resources supply changes.