磷添加对不同品种苜蓿生物量及根系可塑性的影响OA

To investigate the responses of alfalfa root morphological traits to phosphorus supply,a total of 31 plant materials were selected comprising 30 varieties of Medicago sativa L.and one variety of Medicago falcata L.,and three levels of phosphorus addition treatments were set up at P5(5 mg·kg-1 KH2PO4),P20(20 mg·kg-1 KH2PO4),and P50(50 mg·kg-1 KH2PO4).To screen low phosphorus tolerant alfalfa varieties with high phos-phorus use efficiency,we measured the aboveground and belowground biomass and root morphological indices for the 31 alfalfa varieties.The results indicated that the aboveground and belowground biomass of alfalfa were lowest under P5 treatment.With increasing phosphorus supply,the aboveground biomass of alfalfa significantly increased,reaching its highest level under the P50 treatment.Under the P20 and P50 treatments,the root biomass of alfalfa was significantly higher than that under P5,but there was no significant difference between P20 and P50.However,the root morphology showed significant variation among different varieties.Among them,'HD''Algonguin''Magna Graze II'and'Longmu 801'had higher biomass than other varieties,and exhibited greater root morphological plasticity with higher root length,root volume,root surface area,and root diam-eter,which demonstrated tolerance to low phosphorus condition.The results provide a scientific basis for opti-mizing alfalfa cultivation and improving phosphorus fertilizer utilization efficiency.