The Effects of Low Potassium Stress on Root Growth and Potassium Absorption of Maize Seedling

The article studied stress response on root system growth and potassium absorption of maize seedling at K+ deficiency. Two inbred lines of maize seed, A which sensitive to K+ deficiency and B which tolerant to K+ deficiency, were cultured in nutrient solutions of three different K+ concentration(5, 100, 1 000 μmol/L). After 4 weeks, the maize seedling had been cultured, the plants were transplanted into culture barrel and then cultured for 50 days. Sampling was made near by root tip 2 cm on time(0, 3,10, 25, 50 days), when to observed root system morphological character and dissection structure, and determined its root system vigor, Imax, Km. The results showed that under lower K+ concentration, root hair number of B was increased and growed near by the root tip. Xylem canal differentiation enhancive at dissection structure, and it improved transportation ability of leading organization. Root top ratio of length and weight increases, root system vigor and Imax of B obviously increased while Km obviously decreased. B improved potassium absorption through synergistic action both root system morphological character and active potassium absorbency.