八倍体小偃麦和普通小麦旗叶及叶鞘光合日变化比较研究

以温室大棚中栽培的普通小麦'中国春'(对照)及八倍体小偃麦'小偃7430'(染色体组为ABDE_1)、'小偃693'(染色体组为ABDF_1)为材料,采用TPS-1光合作用测定系统及FMS-2荧光仪测定了开花期旗叶和叶鞘的净光合速率、气孔导度和叶绿素荧光参数的日变化,以揭示普通小麦与八倍体小偃麦旗叶及其叶鞘的光合作用差异.结果表明:八倍体小偃麦与普通小麦'中国春'的旗叶和叶鞘光合作用均有午休现象,净光合速率于上午11:00左右出现高峰,午间下降,下午又呈现上升趋势,且'小偃693'叶片在上午时上升较快;气孔导度和荧光参数F_v/F_m、Fv/F_o、 Φ_(PS)Ⅱ、ETR的变化趋势与净光合速率相似,而NPQ的变化趋势则相反.各光合作用和叶绿素荧光参数在材料间表现为八倍体小偃麦高于普通小麦'中国春',器官间表现为旗叶高于相应叶鞘,而'小偃693'的叶鞘和'中国春'叶片的相似.研究发现,八倍体小偃麦旗叶和叶鞘的光合效率优于普通小麦'中国春';'小偃693'的光合效率因其较高的光反应活性表现得尤为突出,其叶鞘的光合能力也不容忽视.

Diurnal Variation of Photosynthesis of Flag Leaf and Sheaths of Octoploid Tritielytrigia and Triticum aestivum

Octoploid Tritielytrigia types ('Xiaoyan 7430' and 'Xiaoyan 693') and Triticum aestivum (Chinese spring) were planted in greenhouse to study the diurnal variation characteristics of photosynthesis of flag leaf and sheath in anthesis using TPS-1 photosynthesis system and FMS-2 chlorophyll fluorescence system.The results showed that the photosynthetic rate of flag leaf and sheath either Triticum aestivum (Chinese spring) or octploid Tritielytrigia types showed midday depress,the daily progress of net photosynthetic rate (P_n) was an obvious double-peak curve.The peak values were at 11:00 am and 3:00 pm respectively. The photosynthetic rate of flag leaf of 'Xiaoyan 693' rose quickly in the morning,stomatal conductance (G_s),chlorophyll fluorescence parameters(F_v/F_m,Fv/F_o,Φ_(PSⅡ),ETR) showed similar characteristics,but NPQ was opposite.The parameters values of flag leaf and sheath of octoploid Tritielytrigia types were higher than that of Triticum aestivum (Chinese spring) and the parameters values of flag leaf were higher than that of sheath except NPQ. The parameter values of sheath of 'Xiaoyan 693' were similar to the flag leaf of Chinese spring.All of the results showed that the photosynthetic efficiency of octoploid Tritielytrigia types were higher than that of Triticum aestivum (Chinese spring), especially 'Xiaoyan 693'.It may be related to their higher light reaction activity.The photosynthesis of sheath of 'Xiaoyan 693' is also important.