【摘要】 A染色体组的野生一粒小麦（T.boeoticum）比D染色体组粗山羊草小麦（Ae.squrrosa）的光合速率高11.3—12.9％,从叶片全展到光合速率下降到50％的天数短11.1—15.4％。有D染色体组小麦种叶片的光合速率高于无D染色体组的小麦种,但光合速率在高水平上的持续时间则后者比前者长。叶片展开后叶绿素含量变化可以分为缓降期和速降期两个阶段,缓降期长短与光合速率下降到50％所需天数的相关系数为0.9810,与单位叶面积同化CO₂总量的相关系数为0.9001,所以叶绿素含量缓降期可以作为诊断指标加以应用。不同染色体组小麦种叶（?）叶肉细胞的总环数,每个环的平均面积,叶绿体的数目,基粒片层数等与叶片的光合速率有关。叶片一生中叶绿体超微结构的变化不仅影响光合速率而且与叶绿素含量缓降期有关。更多还原

【Abstract】 In this study, the photosynthetic rate of T. boeoticum (A genome) measured 11.3-12.9% higher than that of T. squarrosa (D genome); the duration from leaf expansion to the date when the photosynthetic rate declined to 50% (high photosynthesis duration, denoted by P~A50, ) was 11.1-15.4% shorter in T. boeoticum than in T. squarrosa. The photosynthetic rate of leaves in wheat species possessing D genome was higher than that in those devoid of D genome, but as for P~A50, it was longer in the latter than in the former. The change of chlorophyll contents after leaf expansion was divided into two phases-the relatively steady phase ( RSP ) and the sharp fall phase ( SFP ) . The correlation coefficients between RSP and P~A50, and between RSP and the total amount of CO~2 assimilated by unit leaf area were 0.9810 and 0.9001, respectively,both highly significant.Therefore RSP could be used as a diagnostic index for high photosynthesis duration and the total amount of CO2 assimilation of leaf. There were close relationships between photosynthetic rate and the total arm number of mesophyll cells per viewing screen, the average area of mesophyll cell arms, the number of chlorop-lasts per viewing screen, and the number of grana lamellas. The change of ultrastructure of chloroplasts during the leaf life span not only affected photosynthetic rate but also was connected with the duration of RSP.更多还原