大量元素鉀ppt課件(編輯修改稿)
2025-05-30 22:05 本頁(yè)面
【文章內(nèi)容簡(jiǎn)介】 中國(guó)最大鉀肥生產(chǎn)基地的第一步，一期建成 20萬噸硫酸鉀廠，最終計(jì)劃是年產(chǎn) 220萬噸鉀肥。 K is the seventh most abundant element in the earth’s crust ranging from to %. But the available K is only 12% of total K. Potassium in soil Forms: Total K consists of four distinct forms in the soil, each of different availability to the plant: (ⅰ ) Mineral Kalmost pletely unavailable, 90~98%。 (ⅱ ) Fixed Kslowly available, 110%。 (ⅲ ) Exchangeable Kreadily available, 12%。 (ⅳ ) Soil solution Kreadily available, %. There is an equilibrium between the various forms Organic K is only a small part. Release and fixation of K+ and NH4+ ions by soil clay Section 2 Molecular and physiological aspects of potassium uptake in plants K is the most abundant cellular cation, with cytoplasmic concentrations regulated between 80 and 200 mM, and total tissue concentrations of approximately 20 mM. The transport of K+, which is mobile in plant, has been studied intensively for the last 50 years. K+轉(zhuǎn)運(yùn)進(jìn)入植物和在植物中運(yùn)輸?shù)哪Ｊ綀D 2. 1 Early Physiological and biochemical studies indicated the existence of multiple K+ transporters Excited roots (Hoaglant and Broyer， 1936） Epstein was first to treat radioisotopes to quantify ion efflux. Epstein was first to treat mineral ion transporters as enzyme kiics to studies of concentrationdependent root K+ uptake. Dual isotherm of K absorption Highaffinity K+ transport was thought to dominate at low concentration of K+ in soil, whereas as higher K+ concentrations, a lowaffinity K+ transporter operated that was less specific for K+ over other alkali cations. 硫基修飾的 N –乙基馬來亞銨（ NEM） :抑制髙親和力轉(zhuǎn)運(yùn)蛋白但不影響低親和力轉(zhuǎn)運(yùn)蛋白。 Physiological studies provided further evidence for separate high and lowaffinity K+ transporters The application of a K+ channel blocker TEA (四乙銨 ) inhibited the linear, lowaffinity transport ponent. Highaffinity K+ uptake system exhibited several properties: Increasing gene expression or transport activity induced by K+ starvation。 A very high affinity for K+ (Km=5 to 30 181
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