钾素营养对不同棉花品种苗期生长和叶片生理特性的影响

Effect of Potassium Nutrition on Growth and Leaf Physiological Characteristics at Seedling Stage of Different Cotton Varieties

在大田条件下,研究了施钾量对不同棉花品种苗期生长发育和叶片生理特性的影响。试验设2个施钾处理,3个棉花品种(早发型品种L21、晚发型品种L22和稳健性品种L28)。结果表明,两施钾处理均可提高各棉花苗期的株高,增加其叶片数、单株叶面积和倒四叶叶面积,促进棉株生长发育。同时,施钾还可以促进功能叶叶绿素的合成,增加叶绿素荧光动力学参数Fv/Fo、Fv/Fm、提高光合电子传递速率(ETR)和实际光化学效率(ΦPⅡ),改善其光合性能;提高功能叶片中SOD和CAT的活性,降低POD的活性,减少MDA的产生和积累,延缓其衰老。但低施钾量处理在促进棉花的生长发育和改善叶片的生理特性上效果不显著;三品种相比,L22对钾素的反应较L21和L28更敏感。

This experiment was conducted to study the effect of potassium fertilizer on growth and leaf physio -logical characteristics at seedling stage of different cotton varieties under field conditions .Two rates of potassium fer-tilizer were applied and three materials (L21,L22 and L28) were used in this design.The result showed that appli-cation of potassium fertilizer to varying degrees increased plant height ,leaf number ,leaf area per plant and the last fourth leaf area of different cultivated varieties at seedling stage .Potassium fertilizer application promoted the syn-thesizing of chlorophyll and the improvement of photosynthetic rate of functional leaf ,increased the value of Fv/Fo and Fv/Fm,and improved the effect of ETR and ΦPⅡ.Meanwhile ,when potassium fertilizer applied ,SOD and CAT activity were enhanced ,yet POD activity and the content of MDA were decreased ,which caused the long duration of functional leaf .Although characteristics improved in both potassium fertilizer application manners ,the higher quanti-ty one took a better effect .As for different cotton varieties ,L22 exhibited the most sensitiveness to potassium fertiliz-er application manners ,followed by L21 and L28 .