木薯栽培种与野生种叶片光合器官结构和酶学差异

为探究栽培型木薯高光效的机理，采用石蜡切片法和酶活测定等方法分别对木薯栽培品种Arg7(Manihot esculenta)和野生种W14(Manihot esculenta subsp. flabellifolia)进行了叶片解剖结构、光合淀粉累积关键酶活性、净光合效率和叶绿素含量的测定。对比分析两木薯种试验结果，发现栽培型木薯较野生种具有独特的叶片维管束鞘细胞结构，较高的PEPCase(50.41NADHμmol/(mg protein?hr)活性和净光合速率(36.82μmol/(m2s))以及低于野生种的叶绿素含量。另外，木薯种Arg7叶片中Rubisco、PEPC、AGPase和SuSy这4个酶活性动态变化与净光合速率变化趋势基本一致，表明木薯光合作用、淀粉合成以及光合产物的运输是个协同作用的过程。最后推断出栽培型木薯高光效的原因可能是叶片中存在一定程度的C4光合模式以及较野生种通畅的光合产物运输通路。

Differences in Anatomical Photosynthetic Structure and Enzyme Activity of Leaves Between Cultivar and Wild Species in Cassava

In order to seek the the mechanism of high photosynthetic efficiency in cassava, paraffin sectioning and activity detection had been used to detect the differences of leaf anatomical structure, the activities of key enzymes in photosynthesis and starch accumulation, net photosynthetic efficiency and chlorophyll content between cassava cultivar Arg7 （Manihot esculenta） and its wild ancestor species W14 （Manibot eseulenta subsp. 11abellifolia）. It had been discovered that Arg7 leaves owned unique vascular bundle sheath cell structure, higher PEPCase activity （50.41 NADH μmol/（mg·protein·h）], higher net photosynthetic rate 36.82 μmol/（m2·s）] as well as lower chlorophyll content than W14. Furthermore, the activities dynamic changes of Rubisco, PEPC, AGPase and SuSy were almost the same with the trends of net photosynthetic rate. It was indicated that cassava showed a high synergy in the process of starch synthesis, photosynthesis and photosynthesis product transportation. A conclusion could be draw that the high photosynthetic efficiency in cassava maybe due to the existing of C4 photosynthesis mode in leaves to some degree and a better route for photosynthesis product transportation than W14.