棉 花 学 报 Cotton Science 2007，19(3)：173-178
Effects of Potassium Deficiency on the Transport and Partitioning of Potassium in Cotton Plant Abstract：This experiment was conducted to investigate the effects of potassium (K) deficiency in sandy loam soil on transport and partitioning of potassium in cotton plant. At full-bloom stage，86Rb+ labeled on upper part leaf (15th leaf from bottom) of CCRI 35 mainly transported to main-stem，and while 86Rb+ labeled on middle part leaf (10th leaf from bottom) mainly transported to reproductive part. Compared to control (197 mg exchangeable K per kilogram of dry soil)，K deficiency (75 mg exchangeable K per kilogram of dry soil) enhanced the transport of K from senescence leaves to functional leaves and young leaves，i.e. increased the recycle of K in cotton plant. Since transgenic insect-resistant cotton often senesce prematurely resulted from potassium deficiency in cotton production of China，comparison of K recycle between conventional cotton varieties (CCRI 12，CCRI 35) and transgenic insect-resistant cotton varieties (CCRI 41，DP 99B) was studied in present study. Under K deficiency condition，CCRI 41 and DP 99B exhibited less recycle of K from lower part leaves to other parts compared to CCRI 12 and CCRI 35，which maybe result in their premature senescence in field. Reproductive organ was the biggest and final sink for potassium in cotton plant. However，main-stem likely acted as a reserving and transferring organ for potassium. The ratio of K partitioning in reproductive organ was increased by K deficiency. When compared with other parts of cotton plant，the vibration of K concentration in seed and fiber with K availability was much less. These results indicated that cotton plant could use limited K to sustain offspring preferably under K deficiency condition.
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