比较了小麦不同基因型籽粒生长期旗叶与穗、茎、鞘等非叶绿色器官光合速率及光合碳同化酶活性的变化,结果表明, 存在显著的基因型差异。籽粒生长早期非叶器官净光合速率最大值低于旗叶，但后期的净光合速率下降幅度小于旗叶。各器官RuBPC活性和PEPC活性的变化均呈单峰曲线，RuBPC活性表现为旗叶>芒>叶鞘>穗下节间>颖片(护颖、外颖),其中芒的酶活性与叶片差异很小； PEPC活性表现为穗颖、叶鞘、穗下节间均明显高于旗叶。各基因型各非叶器官不同时期PEPC/RuBPC活性平均比值均明显高于旗叶, 后期非叶器官中PEPC活性甚至超过RuBPC活性。暗示在小麦生长后期的碳同化、特别是非叶器官的碳同化过程中，PEPC可能发挥着重要作用，后期非叶器官光合速率的相对稳定性可能与其较高的PEPC活性及活性下降缓慢有密切关系。在小麦品种改良过程中，不仅要重视叶片而且要重视非叶绿色器官光合性能、特别是PEPC活性的选择。
The photosynthesis of flag leaf and non-leaf green organs (sheath, peduncle and ear parts) makes a major contribution to final grain yield in wheat; however, there have been the few attentions paid to photosynthetic characteristics of the non-leaf green organs other than flag leaf. In order to increase wheat productivity through improving photosynthetic capacity of the whole plant, it is important and necessary to understand photosynthetic characteristics of the non-leaf green organs. In the present experiment, net photosynthetic rate and carbon assimilation enzyme activities in different green organs (flag leaf blade, sheath, peduncle and ear parts) after anthesis were studied with five genotypes of wheat. The results showed that the net photosynthetic rate and RuBPC and PEPC activities were different among green organs or genotypes. Compared with flag leaf blade, non-leaf organs (sheath, peduncle and ear parts) had lower net photosynthetic rates in the early stage of grain growth, but more slowly decreased ones in the later stage of grain growth. RuBPC activity was highest in flag leaf blade, then in awn, sheath, lemma, peduncle and glume in turn; PEPC activity was higher in every non-leaf organs than in flag leaf blade. The ratio of PEPC/RuBPC activities in various organs of all genotypes gradually increased from 0 to 23d after anthesis, and that of every non-leaf organs was higher than that of flag leaf blade. All of these showed that the non-leaf organs are very important in the photosynthesis of whole plant in the later growth stages, and PEPC may play an important role in maintaining carbon assimilation activity of the non-leaf organs. It is suggested paying more attentions to photosynthetic traits of the non-leaf organs in wheat breeding.
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