【摘要】 【目的】建立基于叶绿素荧光参数的棉花叶片氮素营养监测模型,为棉花高效施氮及植株生长状况的无损监测提供方法。【方法】在水肥一体化滴灌条件下,以新陆早58号为试验材料,设置4个施氮水平,测定了棉花生长关键时期顶2（从顶部数起）至顶5叶的叶绿素荧光参数和氮素含量,分析了棉花叶片氮素含量与荧光参数的关系。【结果】（1）棉花出苗70 d后,叶片氮素含量以及光系统Ⅱ（PSⅡ）潜在光化学活性（F_v/F₀）、PSⅡ潜在最大光化学效率（F_v/F_m）、PSⅡ实际光化学效率(Φ_PSⅡ)、PSⅡ最大光化学效率（F_v’/F_m’）均随着棉花生长呈逐渐下降趋势。（2）不同氮素处理下,各叶片氮素含量以及叶绿素荧光参数F_v/F₀、F_v/F_m、ΦPSⅡ和F_v’/F_m’均随施氮量的增加而上升,其中N2 (240 kg·hm^-2)处理下各荧光参数值最大。（3）叶片氮含量与F_v、F_v/F₀、F_v/F_m、Φ_PSⅡ都呈现极显著正相关关系,与荧光参数ΦPSⅡ、F_v’/F_m’间呈现较好的指数函数关系,与荧光参数F_v、F_v/F_m、F_v/F₀呈现良好的线性函数关系。顶5叶可变荧光（F_v）与叶片氮素含量建立的关系模型（y=0.0022x+1.6243）的模拟效果最好,决定系数达到0.928,相关系数达到0.963,呈极显著正相关。【结论】适量施氮(240 kg·hm^-2)能够提高PSⅡ的活性及PSⅡ反应中心开放部分的比例,进而改善棉花叶片光合能力。顶5叶氮素含量与叶绿素荧光参数F_v构建的模型精确度和拟合效果较其他荧光参数好,因此可以选用荧光参数F_v来监测棉花叶片氮素含量,进而监测植株的氮素营养状况。更多还原

【Abstract】 [Objective] A monitoring model of nitrogen nutrition of cotton leaves based on chlorophyll fluorescence parameters was established for non-destructive monitoring of high efficiency nitrogen application and plant growth of cotton. [Method] A field study was conducted by using Xinluzao 58 as experimental material with four input levels of nitrogen, which were applied under the condition of mulched drip irrigation. Chlorophyll fluorescence parameters and nitrogen content of leaves in different positions of main stem were measured during the yield formation period of cotton, and the relationship between nitrogen content and fluorescence parameters of cotton leaves was analyzed. [Results]（1） After 70 days of cotton emergence, the potential photochemical activity（F_v/F₀） of photosystem Ⅱ（PSⅡ）, the potential maximum photochemical efficiency of PSⅡ（F_v/F_m）, the actual photochemical efficiency of PSⅡ(Φ_PSⅡ) and the maximal photochemical efficiency（F_v’/F_m’） of the top 2 to top 5 leaves showed a gradual downward trend with the growth of cotton.（2） The nitrogen content and fluorescence parameters（F_v/F₀, F_v/F_m,ΦPSⅡand F_v’/F_m’） of top 2 to top 5 leaves showed an upward trend with the increase of nitrogen application rate, the N2(240 kg·hm^-2) treatment had the highest values of chlorophyll fluorescence parameters.（3） The nitrogen content in leaves showedsignificant and positive correlation with F_v, F_v/F₀, F_v/F_mand ΦPSⅡ, and a good exponential function relationship with fluorescence parameters Φ_PSⅡ and F_v’/F_m’, and a good linear function relationship with fluorescence parameters F_v, F_v/F_mand F_v/F₀. The model between F_vand nitrogen content of top5 leaf（y =0.0022 x +1.6243） had the best simulation effect, showing an extremely significant correlation, with the determination coefficient reaching 0.928 and the correlation coefficient reaching 0.963.[Conclusion] Proper applying of nitrogen(240 kg·hm^-2) could increase the activity of PSⅡ and the proportion of the open part of PSⅡ reaction center and improve the photosynthetic capacity of cotton leaves. Nitrogen content in top 5 leaf was significantly correlated with chlorophyll fluorescence parameter F_v, which was therefore can be used to monitor nitrogen content in cotton leaves and further monitor nitrogen nutritional status of cotton plants.更多还原