棉花学报    COtton Science 2005，17(3)：165-170

Preliminary Study of K⁺ Uptake Kinetics of Cotton (Gossypium hirsutum L. ) and its Application
ZHANG Zhi-yong，WANG Gang-wei，TIAN Xiao-li，LI Zhao-hu，DUAN Liu-sheng，ZHAI Zhi-xi， HE Zhong-pei
(College of Agronomy and Biotechnology，China Agricultural University，Beijing 100094，China)

Abstract：It has been a main problem in cotton production that transgenic insect-resistant cotton is prone to premature senescence induced by K⁺ deficiency, which makes it necessary to study K⁺ uptake characteristics and, on the basis of it, to screen cotton cultivars with high K⁺ uptake efficiency. This experiment studied the factors influencing K⁺ uptake kinetic parameters of cotton, preliminarily identified the conditions of K⁺ uptake kinetic applied to cotton, and compared the K⁺ uptake characteristics of transgenic insect-resistant cotton cultivar, DP99B, and conventional cotton cultivar, CCRI 35 , at seedling stage. The results showed that K⁺ uptake kinetic parameters were significantly affected by seedling stage, initial K⁺ concentration in depleting solution and K⁺ concentration in culturing solution. Higher K_m. and C_min resulted from younger seedling (3-4 vs. 4-5 leaf stage) , higher initial K⁺ concentration in culturing solution (0.35 vs. 0.2 mmol• L^-1) and higher K⁺ concentration in culturing solution (2.0 vs. 0.5mmol• L^-l)but higher I_max was produced under the two former conditions, and lower I_max came into being under the last situation. Compared with CCRI 35, DP99B had significantly lower I_max and higher K_m and C_min(O.5 mmol• L^-1 K⁺ in culturing solution and 0.2 mmol• L^-l initial K⁺ in depleting solution) at 5-6 leaf stage, which indicated that the ability of DP99B to uptake limited K⁺ was weaker than that of CCRI 35.
Key words：cotton；K⁺；uptake kinetics      [Full Text, 658KB]