夏玉米叶片叶绿素含量的时空动态及其与植株含氮率关系的研究

在不同施氮水平下,研究了夏玉米郑单958叶片叶绿素含量(SPAD值)的时空动态变化及其与植株含氮率的关系。结果表明,夏玉米子粒生长期棒三叶SPAD值与棒三叶、全株总叶片及整株含氮率均有极显著线性相关关系。不同施氮水平子粒生长期叶片叶绿素含量的空间分布均以穗位叶为中心呈现出中间高两边低的趋势,SPAD值依次为中部叶>上部叶>下部叶。施氮可调节各部位叶片SPAD值或氮素含量,但并未改变其空间分布模式。不同施氮水平子粒生长期上部和中部叶片叶绿素含量随时间的动态变化总体上呈现先增大后减小的趋势,下部叶片的叶绿素含量则呈持续下降的趋势。夏玉米不同叶位叶片对氮肥的反应均表现在一定范围内(N≤207 kg/hm²),子粒生长期各叶片叶绿素含量随施氮量的增加而增加,当总施氮量增为276 kg/hm²时,各叶片叶绿素含量不再明显增加,相对来说中部叶比上部和下部叶对氮肥的反应更为敏感。

Study on Spatial-temporal Distribution of Chlorophyll Content and Its Correlation to Plant N Content in Summer Maize

The objective of experiment was to study the spatial-temporal distribution of Chlorophyll content(SPAD value) in leaves and its correlation to plant N content in summer maize cultivars,Zhengdan958,at different nitrogen levels.The results showed that there was significant liner correlation between ear-three-leaves N content,whole leaf N content or plant N content and SPAD value of the three-ear-leaves in the grain-growing period of maize.After anthesis,taking function leaves as the center,the spatial distribution of SPAD value presented a trend which was high on the middle,lower on both ends of plant.The nitrogen application could adjust SAPD value of different parts of leaves,but did not change the spatial distribution pattern.The temporal dynamic variation of N contents,in the upper and middle layer leaves,presented the trend of first increased and then decreased in all,for the lower layer leaves,the trend was decreasing.The response of all leaves to nitrogen presented N contents of different leaves in the stage of grain growth increased with increasing of nitrogen application when nitrogen application attained 207 kg/ha or less,but N content did not change significantly when nitrogen application was 276 kg/ha.Comparatively speaking,the response of middle layer leaves to nitrogen was more sensitive than that of upper and lower layer leaves in the same stage.