棉 花 学 报    Cotton Science    2010，22（4）：354-359

Physiological Effects of Nitrogen and Potassium Nutrition on the Senescence of Cotton Functional Leaves
ZHU Jian-fen¹, ZHANG Yong-jiang¹, SUN Chuan-fan², LIU Lian-tao¹, SUN Hong-chun¹, LI Cun-dong^1*
（1. College of Agronomy, Agricultural University of Hebei / Key Laboratory of Crop Growth Regulation of Hebei Province, Baoding , Hebei 071001, China; 2. China Rural Technology Development Center, Beijing 100045, China ）

Abstract: Physiological effects of nitrogen and potassium nutrition on cotton functional leaves were studied by using the material of SCRC 28. Four treatments were conducted with N₂K₂, N₂K₁, N₁K₂ and N₀K₀. The results indicated that fluorescence parameters Fv/Fm , Ф PS Ⅱ and qP of the functional leaves showed “ V ” -shaped changing trend of high-low-high in a day at boll forming stage, typically the Ф PS Ⅱ . The value of each fluorescence parameter under N2K1 treatment was generally the highest, while the lowest under N0K0 treatment. Chlorophyll content under N₂K₂, N₁K₂ and N₂K₁ treatments increased by 38.0%, 24.0% and 20.7% than of N₀K₀ at the boll forming stage. In addition, the soluble protein content and SOD activity of functional leaves were lowest under N₀K₀ treatment at middle and later stages, while the MDA and ABA contents were the highest. It can be concluded that maintaining a certain level of nitrogen and potassium nutrition is helpful to improve physiological performance of functional leaves and delay in senescence.
Key words: cotton ； nitrogen and potassium nutrition ； physiological characteristics
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