宁夏灌区春小麦光合作用对光强的响应

在田间条件下，研究了宁夏灌区历年主栽春小麦品种的光合作用对光强的响应，结果表明：不同年代主栽品种不同生育期对光强的响应不同，孕穗期和灌浆期要求较高的光强，开花期对光强的要求较低。最大光合速率表现为孕穗期〉开花期〉灌浆期，呼吸速率则表现为孕穗期〉灌浆期〉开花期．随品种的更替，光饱和点呈现降低的趋势，光补偿点呈现有规律的增加，最大光合速率则呈现减小趋势，呼吸速率呈现增大趋势．

Responses of Spring Wheat on Various Light Intensities Along Years In Irrigation Area of Ningxia

Under the field conditions, the light response of photosynthesis of spring wheat varieties during last 50 years was studied in the irrigation area of Ningxia. The result indicated that the responses toward the intensity of light at different growth stage were different when different spring wheat varieties were grown along years concerned. Both booting and grouting stages required for a higher intensity of light, on the contrary, a relative lower intensity of light was suitable for anthesis. The highest ratios for photosynthesis and respiration occurred at the stage of booting, the lowest ratios for photosynthesis and respiration at the stages of grouting and anthesis, respectively. During turnover of spring wheat varieties, light saturation point showed a trend of decrease, in contrast,the light compensation point and the respiration ratio increased regularly. The maximum photosynthetic ratio showed a trend of decrease.