玉米群体冠层内光和CO_2分布特性的初步研究

The Primary Study on the Distribution Character of Irradiance and CO_2 of Maize Canopies

为了探明玉米冠层内微环境的动态变化及其对光合特性的影响 ,用便携式红外气体分析仪和光量子探头分别测定玉米冠层内CO2 浓度和光的分布。结果表明 :3种株型玉米品种冠层内光量子密度的日变化呈早晚低、中午高的单峰曲线变化。冠层内光量子密度的分布为上层叶 >中层叶 >下层叶。高产群体穗位叶透光率大于 2 5 % ,截光率在 95 %以上。冠层内CO2 浓度的日变化呈“W”型 ,早晚高 ,上午、下午低 ,中午稍有一定回升。冠层内CO2 浓度变化为下层叶 >上层叶 >中层叶。高产群体中上层CO2 浓度较接近 ,一般为 32 0～330 μmol/mol。

The objective of experiment is to investigate the variation of microenvironmental factors and their effect on photosynthetic characteristics of maize. CO 2 concentration and irradiance in maize canopies were measured with an infrared gas analyzer and quantum sensor The results indicated that diurnal changes of photo flux density (PFD) were a single peak curve Radiation interception rate of high yield breed canopies was above 95%, and transmitting rate of light on middle layer of canopies was above 25% Irradiance of the upper layer leaves was higher than the middle layer which was in turn higher than the lower layer Diurnal variation of CO 2 concentration was a W shaped curve. CO 2 concentration was highest in lower layer and lowest in middle layer with upper layer in between them. CO 2 concentration of different layers of high yield breeds was similar with values between 320 and 330?μmol/mol.