In addition, the effect of nitrogen status on leaf SPAD was quantified by the value of leaf nitrogen concentration, and the relationship between SPAD and RGB was described with linear equation.

• 并基于叶片氮含量表达了氮素供应水平对叶片SPAD值变化规律的影响，同时用线性方程描述了叶片SPAD值与RGB值之间的定量关系。