The Differences And Physiological Mechanisms On Potassium Efficiency Among Different Wheat Genotypes

Potassium is indispensable for the high yield and high quality in wheat production. It is very important to screen and breed wheat varieties with characteristics of low potassium tolerance and potassium-efficient.The study was undertaken by hydroponics, pot cultivars and field trial to study the nutrient absorption and growth, redox system and ATPase in the plasma membrane of wheat root cell aimed to elucidating the differences in potassium efficiency and its intrinsic physiological mechanism among different wheat genotypes.The increase of straw accords with the increase of potassium acquisition, indicating that potassium is a primary cause of dry matter increase. Yuanfeng898 has the higher weight of biomass irrespective of potassium stress and potassium sufficiency.Zhou13 has higher weight under potassium sufficiency but lower under potassium deficiency.Yunong015 and Bainong64 have lower weight of biomass under two conditions respectively. The content of potassium in seedlings impact on the potassium uptake successively. The Wen6-986 and ZhoulS absorb potassium rapidly and YunongO 15 and Gaoyou503 absorb it slowly.Gaoyou503,Yuanfeng898 and Wen6-986 have the higher average growth rate,Yunong015 growed slowly. The potassium uptake kinetics parameters Vmax values of Bainong64 and Zhou13 are high, the Km values of Xin9 and Wen6-986 are small. pH change concomitantly with potassium uptake, this process was identified for two phases: pH declined at primary stage coincided with potassium acquiring quickly and maintained constantly at the next stage as no potassium uptake. It is susceptible to identifying potassium uptake efficiency by pH change because no correlation exists in the process and magnitude between pH change and potassium uptake. The potassium utilization efficiency under high potassium condition is higher then that of low potassium and the rank for potassium utilization differ under two potassium level. The potassium utilization efficiency value of Xin9 is the lowest among all strains irrespective of potassium values.Zheng9023,Yuanfeng898 and Bainong64 yielded more dry matter, Xin9,WenlO and Wen6-986 yielded less dry matter under low potassium.Yuanfng898 and Zheng9023 had higher values of relative biomass compared between low potassium and high potassium and potassium utilization efficiency under low potassium.Zheng9023 and Yuanfeng898 should be identified as potassium-tolerance or potassium-efficient strains, and Xin9 be potassium -inefficient based on vegetative growth, relative biomass and potassium utilization efficiency. The amount of nitrogen and phosphorus uptake in different organs on wheat was improved with the increase of potassium employed. The amount of nitrogen, phosphorus andpotassium absorbed in Yuanfeng898 and Zhoul3 seedlings are higher among varied genotypes. The dry matter of stem plus leaf and value of nitrogen acquisition under potassium stress should be used to evaluate potassium use efficiency or degree of potassium tolerance. The variance coefficients for dry matter of stem plus leaf, value of nitrogen and phosphorus acquisition increase as potassium elevated. Rank of potassium utilization efficiency under three potassium concentration treatments show that Yuanfeng898,Gaoyou503 and Wen6-986 are higher then others, especially Yuanfeng898.To evaluate nutrition use efficiency ,We must take into account nutrition condition. It is not always the same result under high potassium supply as a certain cultivars behaves better in potassium uptake and utilization under low potassium condition. Difference of dry matter or potassium use efficiency under potassium stress mainly results from the difference of potassium utilization efficiency and not that of potassium uptake efficiency, In contrast, under potassium- sufficient the difference results from uptake efficiency and not that of utilization efficiency. Investigating the absorption, distribution and redistribution of potassium among organs in wheat at pre-anthesis and post-anthesis helps to elucidate the function of potassium o...