Root Morphology, Nutrient Absorption And Partition Of Different Maize Inbred Lines Under Low Potassium Stress

Insufficient potassium availability has seriously limited maize production.Potassium element performs the adjustment function through the promotion of plant physiologialbiochemical activity and metabolism response.Potassium deficiency affects the nutrient absorption,partition and utilization.In this experiment,maize inbred lines 90-21-3 and 91-2 (tolerant to K~+ deficiency) and D937 and N40(sensitive to K~+ deficiency ) were used to investigate and compare the effects of low-potassium stress on root morphological traits, nutrient absorption and partition in order to provide theoretical basis for further study on maize tolerance to K~+ deficiency.The results were as follows:1.Under low-potassium stress,the root length,root surface area,root volume and dry biomass of 90-21-3 and 91-2 were higher than those of D937 and N40.There were significant differences in potassium uptake efficiency between tolerant maize inbred lines(90-21-3 and 91-2) and sensitive inbred lines(D937 and N40),but there was no significant difference in potassium utilization efficiency.The high potassium efficiency of maize inbred lines 90-21-3 and 91-2 might be attributed to their higher ability to absorb potassium under plow-potassium stress.2.The plant nitrogen(N) contents increased under low-potassium stress.The shoot N contents in 90-21-3 and 91-2 were more than in D937 and N40.Low-potassium stress promoted root uptake of N and transport from root to shoot.N contents in leaf were the highest.Maize inbred lines 90-21-3 and 91-2 displayed prominently.3.The plant phosphorus(P) contents decreased under low-potassium stress.Root uptake ability of P in 90-21-3 and 91-2 was higher than that in D937 and N40.Maize has the mutual promoter action to K and P absorption.Inbred lines 90-21-3 and 91-2 had obvious superiority under low-potassium stress.Leaves contained the highest P value while the root contained the lowest.4.Along with potassium nutritional level depression,the plant sodium(Na) contents decreased,Na/K increased,and the increment of 90-21-3 and 91-2 was higher than that of Dan937 and N40.The order of Na contents in maize inbred lines differing in low-potassium tolerance were root＞leaf＞stem.5.The absorption capacity of calcium(Ca) and copper(Cu) was limited under low-potassium stress.90-21-3 and 91-2 were less affected than D937 and N40.D937 and N40 transported more calcium and copper from root to shoot.From booting to mature,the Ca/K and Cu/K in the shoot of 90-21-3 and 91-2 were higher than those of D937 and N40.