Effects of potassium on the contents and activities of Rubisco, Rubisco activase and photosynthetic rate in rice leaf

Potassium deficiency resulted in low net photosynthetic rate, low activities and contents of Rubisco and Rubisco activase, and low soluble protein, especially initial activity of Rubisco, but it did not decreased in chlorophyll content at first Activities of both purified Rubisco and crude Rubisco or Rubisco activase were inhibited by addition of 0 1 0 4 mol/L of KCl to incubation reaction, suggesting that potassium ion on enzyme activation was unavailable