钾元素对植物光合速率、Rubisco和RCA的影响

Effects of potassium on Rubisco,RCAand photosynthetic rate of plant

钾离子可提高叶肉细胞渗透势 ,增加植物叶片水势 ,减少气孔阻力 ,增多叶绿体内基粒 ,促进光合电子传递及光合磷酸化 ,提高光合关键酶二磷酸核酮糖羧化酶 /加氧酶(Rubisco)和Rubisco活化酶 (RCA)的含量和活性 ,明显降低量子需要量 ,提高光合速率。Rubisco是光合速率的关键酶 ,RCA对Rubisco活性有重要的调节作用。低钾主要导致Rubisco及RCA含量均降低 ,限制了体内Rubisco的活化和Rubisco总活性 ,降低了Rubisco的初始活性 ,使CO2 固定作用低于Rubisco的最大能力 ,制约了光合速率和生物产量的提高。同时钾离子对Rubisco和RCA没有直接的活化作用。参 5

Potassium resulted in high osmotic potential and water potential,low stomatal resistance,increasing chloroplast grana,activities of electron transport and photophosphorylation,activities and contents of Rubisco and Rubisco activase,and net photosynthetic rate.Rubisco is the key enzyme of photosynthesis,and RCA regulates the activities of Rubisco.The contents of Rubisco and RCA in plant leaves sharply decreased with decreasing potassium nutrition,as a results,the initial Rubisco activity,total Rubisco activity and RCA activity decreased.Potassium ion on the activity of pure Rubisco and RCA in vitro was unavailable.The reseach progress about the effect of potassium on photosynthesis and its key enzymes of plant is discussed.