小麦和大麦果皮的光合功能研究

Photosynthesis in the Pericarp of Wheat and Barley

为了探讨小麦和大麦子粒各组织呼吸耗氧和光合放氧速率的差异,取花后25 d的小麦和大麦子粒,剥除颖壳(包括内稃和外稃)、果皮外侧透明层和果皮内侧绿色层后,用氧电极测定其呼吸耗氧和光合放氧速率。结果表明,无论是小麦还是大麦,未去壳的完整子粒、去壳后的完整颖果、颖壳与果皮透明层都去除的剩余组织均具有净光合放氧活性;剥除颖壳和将颖壳与果皮透明层都剥除均提高了颖果呼吸速率;而去除绿色层则导致光合放氧停止。果皮光合作用产生的氧气主要留在果皮中,用于胚乳的呼吸消耗。

Rates of oxygen exchange in light and dark were recorded for immature detached barley and wheat grain both before and after successive removal of the husk （palea and lemma）, transparent layer of the pericarp, and green layer of the pericarp. Results showed that removal of the husk increased the rate of measured oxygen uptake in both light and dark. With normal barley and wheat, net oxygen evolution in the light was observed in intact grain, as well as after husk removal and after both husk and transparent layer removal. Additional removal of the green layer of the pericarp resulted in a dramatic changeover from oxygen evolution in the light to oxygen uptake. The results suggested that some of the oxygen generated by pericarp photosynthesis remained within the grain.