The results are as follow: (1) SPAD value increased with the rising of leaf position in the same maize variety, and reached the maximum in the leaf at middle of plant, then declined.

• 结果表明：(1)同一品种玉米叶片的SPAD值随叶位的升高而增加，至植株中间部位叶达到最大值，之后降低。