Chapter 12 Plant k nutrition and K fertilizers
Chapter 12 Plant K nutrition and K fertilizers
Plant K A Potassium content of plants 1.20-50gkg1 2. Plants take up a large amount of K. Only N is taken up more 3. In some plants(sugar beets and potatoes) K uptake is greater than n uptake
Plant K A. Potassium content of plants 1. 20-50 g kg-1 2. Plants take up a large amount of K. Only N is taken up more. 3. In some plants (sugar beets and potatoes) K uptake is greater than N uptake
Plant K B Potassium movement to roots 1. Diffusion of k to plant roots accounts for >75% of plant upta ke. The diffusion distance is very small 2.k dissolved in soil water can also reach the plant root by mass flow
1. Diffusion of K to plant roots accounts for >75% of plant uptake. The diffusion distance is very small. 2. K dissolved in soil water can also reach the plant root by mass flow. B. Potassium movement to roots Plant K
Plant K C Potassium movement in the plant 1. Mobile in the plant. Translocated from older leaves to young growing points 2. The concentration of K in the phloem sap is high. The sap can be translocated for relatively long distances in the plan either upward or downward
c. Potassium movement in the plant 1. Mobile in the plant. Translocated from older leaves to young growing points. 2. The concentration of K in the phloem sap is high. The sap can be translocated for relatively long distances in the plant, either upward or downward. Plant K
Plant K D. Form of potassium in plants 1 K+ remains in its ionic form in the plant(remains as K+) 2. K+ may also be bound to negative charges on the surface of plant tissue
D. Form of potassium in plants 1. K+ remains in its ionic form in the plant (remains as K+). 2. K+ may also be bound to negative charges on the surface of plant tissue. Plant K
Function of potassium in plants 1. Activation of enzymes The main function of K+ in biochemistry is its activation of various enzyme system a) Starch synthesis b) ATP production Photosynthesis (Rubisco); d) Protein synthesis In vitro experiments have shown that maximum K+ activation is obtained within a concentration rang of 40 to 80 mol/m K+ can bring about conformational changes of enzymes
Function of potassium in plants 1. Activation of enzymes The main function of K+ in biochemistry is its activation of various enzyme system. a) Starch synthesis; b) ATP production; c) Photosynthesis (Rubisco); d) Protein synthesis In vitro experiments have shown that maximum K+ activation is obtained within a concentration rang of 40 to 80 mol/m3. K+ can bring about conformational changes of enzymes
Effects of K+ on the incorporation of 15N into grains proteins of wheat (seer 1980) K1(0.3mM in the medium) K2(1. 0mM in the medium) Amn(清蛋白), mg N/kg 424 670 Globulin(球蛋白), mg N/kg 364 492 Prolamin(谷醇溶蛋白), mg N/kg 1080 151.0 Glutelin(谷蛋白), mg N/kg 1300 1940 K-concentration mg KDM 4.9 5.0 Polypeptide synthesis in the ribosomes requires high K concentration(40-50mM) and Kt is essential for protein synthesis
Effects of K+ on the incorporation of 15N into grains proteins of wheat (seçer 1980) K1(0.3mM in the medium) K2 (1.0mM in the medium) Albumin(清蛋白), mg 15N/kg 42. 4 67.0 Globulin（球蛋白）, mg 1 5N/kg 36.4 49.2 Prolamin（谷醇溶蛋白）, mg 1 5N/kg 108. 0 151.0 Glutelin（谷蛋白）, mg 1 5N/kg 130.0 194.0 K-concentration mg K/DM 4.9 5.0 Polypeptide synthesis in the ribosomes requires high K+ concentration(40-50mM) and K+ is essential for protein synthesis
K increases the N efficiency optimum N rate content mg/g 45 adequate K 40 low K 3 3 deficient K amino acids caffeine N rate ■NP口NP+KNP+K+Mg
K increases the N efficiency
Function of potassium in plants 2. Water regime(水分状况 a) K controls cell water potential and osmosIs (1)A large concentration of potassium in the cell sap creates conditions that cause water to move into the cell(osmosis) through the porous cell wall and membrane. This process is related to the movement of nutrients and sugars throughout the plant
Function of potassium in plants 2. Water regime(水分状况) a) K controls cell water potential and osmosis (1) A large concentration of potassium in the cell sap creates conditions that cause water to move into the cell (osmosis) through the porous cell wall and membrane. This process is related to the movement of nutrients and sugars throughout the plant
Potassium - chlorine Phosphorus Note different scales for Potassium ond for chlorine and Phosphorus Guard cells Cuticular Ledges 88×5a0585 i=4 F M4 lon contents of guard cells with closed and open stomata(after HUMBLE and RASCHKE