复合群体中玉米光合特性日变化研究

通过对小麦/玉米复合群体中玉米的光合速率、光合有效辐射、蒸腾系数、水分利用率、相对湿度、叶室温度、叶片温度和二氧化碳浓度等生态生理指标在一日内的变化进行测定、分析。结果表明:Pn、PAR、Ct、Lt和Tr的日变化均“为单峰型”曲线,其变化趋势一致。CO2浓度和RH%的日变化不明显,Sr的日变化也“为单峰型”曲线,但与Pn的相反。相关分析表明,光合速率(Pn)与PAR呈极显著正相关,与Tr的相关性达显著水平,Pn与Sr呈显著负相关,PAR与Ct、Lt、Tr呈显著相关。在水肥满足的条件下,影响群体Pn的主要生态因子是PAR,要提高复合群体中玉米的经济产量主要靠调整群体结构来完成,即选择株型紧凑的玉米品种不仅能保证光合面积,而且还可改善群体内部的光照条件,从而提高群体的光合能力和经济产量。

Study on the Diurnal Variation of Photosynthetic Characteristics in Wheat/Corn Intercropping

Study on the diurnal variation of photosynthetic characteristics in wheat/corn intercropping showed that the diurnal variations of Pn,PAR,CT,LT and Tr were similar,Their curves all had one peak.The curve of Sr was also monopeaked,but it was contrary to Pn.The rang in CO2 concentrations and the RH% levels weren't significant.According to the correlativity analysis,the PAR was the key factor which affected Pn,Tr,Sr,CT and LT with sufficient water and fertilizer.There existed significant postive correlation between Pn and PAR.The corn could not only provide sufficient photosynthetic leaf area but also improve light distribution in intercropping,so adjusting the structure of intercropping could raise the yied of corn.