不同品质类型小麦灌浆期旗叶Rubisco降解变化研究

Rubisco Degradation in Flag Leaf of Different Types of Wheat

为了解小麦籽粒蛋白品质的形成机制,以弱筋和强筋小麦为材料,研究了小麦灌浆期间旗叶叶绿素含量以及Rubisco(1,5-二磷酸核酮糖羧化酶/加氧酶)降解的变化。结果表明,小麦灌浆期间不同品质类型品种旗叶叶绿素含量和Rubisco含量差异明显,弱筋小麦品种宁麦9号和扬麦15花后15～25 d旗叶叶绿素含量分别降低16.8%和19.6%,而强筋小麦品种郑麦9023和镇麦168花后15～25 d叶绿素含量下降幅度分别为52.8%和34.6%;旗叶灌浆期内肽酶活性呈先升高后降低的趋势,并且2个强筋品种花后5～25 d内肽酶活性始终高于2个弱筋品种;小麦旗叶Rubisco含量在开花后呈逐渐降低的趋势,但两个弱筋小麦品种旗叶中Rubisco含量始终高于两个强筋小麦品种。此外,扬麦15花后15～20 d才可以看出Rubisco亚基出现降解现象,郑麦9023在花后15 d就已经明显出现了Rubisco大亚基降解,说明强筋小麦郑麦9023旗叶较弱筋小麦扬麦15衰老早。

In order to study the mechanism of grain quality formation,the changes of Ribulose-1,5-Bisphosphate Carboxylase/Oxygenase in different types of wheat were studied.The results showed the chlorophyll and Rubisco content in flag leaves decreased during grain filling,however,changes in the four wheat cultivars were obviously different.The chlorophyll content of two soft wheat decreased only by 16.8%and 19.6%,respectively at 15～25 d after anthesis.However,that of the two hard wheat decreased by 52.8%and 34.6%respectively.Changes of endopeptidase activity in flag leaves during grain filling were also different between different types of wheat.Besides,the rubisco content were higher in soft wheat Yangmai 15 than that in hard wheat Zhengmai 9023 during grain filling.To our interesting,the large subunit（LSU） of Rubisco was found earlier in Zhengmai 9023 than in Yangmai 15 by SDS-PAGE.It suggested that the leaf senescence in hard wheat Zhengmai 9023 might be earlier than in soft wheat Yangmai 15.