Abstract:

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 (Manihot esculenta subsp. flabellifolia). 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.