基于叶片SPAD 值的微型盆栽月季氮素营养诊断研究

氮素是微型盆栽月季生长发育的必需元素，实时监测植株生长过程中氮素的变化，精准估测氮素含量尤为重要。设置4个施氮水平(包含高氮处理)，分析施氮量对微型盆栽月季生长发育的影响，测定不同施氮水平下4种微型盆栽月季在不同生长时期、不同叶片层位的SPAD值，利用线性及非线性回归分析等方法，构建基于叶片SPAD值的单一品种和混合品种叶片氮含量估测模型，并对此模型进行检验和通用性评价，利用SPAD氮饱和指数评估临界氮含量。结果显示，4个不同微型月季品种在整个生长发育时期的营养生长趋势相似，且在不同施氮水平下性状指标具有差异。随着施氮量的增加，叶片氮含量和叶片SPAD值均呈先上升后平稳的趋势。叶片SPAD值与叶片氮含量之间存在显著相关性，且不同层位的叶片SPAD值与叶片氮含量的相关性存在差异。多品种混合构建的综合模型在通用性上优于单一品种模型，S1和S2时期的下层叶片、S3和S4时期的上层叶片SPAD值与叶片氮含量回归决定系数较高，构建的模型分别为y=0.0009x²+0.6115x+0.8047、y=0.002x²+0.7118x+2.3382、y=0.1...

A study on nitrogen nutrition diagnosis based on leaf SPAD value in miniature potted rose

Nitrogen was an essential element for the growth and development of miniature potted roses. It was very important to monitor the changes of plant nitrogen nutrition in real time and accurately estimate the nitrogen nutrition content in the cultivation and production. Four nitrogen application treatments were set up to analyze the impact of nitrogen application amount on the growth and development of miniature potted roses. The leaf SPAD values at different growth stages and different leaf layers of four different miniature potted roses were measured. Linear and nonlinear regression analysis methods were used to structure leaf nitrogen content estimation models for single and mixed cultivars based on leaf SPAD values. The critical nitrogen content was evaluated by the nitrogen saturation index. The results showed that the vegetative growth tendency of four different miniature potted roses cultivars during the whole growth period wassimilar，and the character indexes were different under different nitrogen application levels. With the increase ofnitrogenapplication，both the nitrogen content in leaves and the SPAD value in leaves increased first and then stabilized. There was a significant correlation between the leaf SPADvalue and the leaf nitrogencontent，and it was different in different layers. The comprehensive model constructed by using four varieties was better than the single model in generality. The lower leavesat S1 and S2stages，and the upper leaves at S3 and S4 stages had higher regression coefficient between SPAD values and leaf nitrogen content. The constructed models were y=0.0009x2+0.6115x+0.8047，y=0.002x2+0.7118x+2.3382，y=0.1279x1.4938，y=-0.0015x2+0.5204x+3.7738，respectively. It was reliable to estimate the nitrogensaturation index by the polynomial model. Inconclusion，nitrogen applicationlevels， growth period and leaf position all affect the correlation between SPAD value and leaf nitrogen content. The comprehensive model of leaf nitrogen content estimation established by using four varieties could be used as a universal model. The polynomial equation of the nitrogen saturation index was more accuratein nitrogendiagnosis，and provides theoretical data for real -time diagnosis of nitrogen nutrition in miniature potted rose.