C₄-Enzymes Related Photosynthetic Characteristics Of Woody Branches Chlorenchyma With Reference To Their Leaves

Trees could fix CO2 though photosynthesis to produce all kinds of organic matter nessesary to plant growth and maintenance. It is well-known that the green leaf is the main place of this photosynthetic process, so limited messages is available for the chlorenchyma underlying the bark of branches, who take large percentage of forestry biomass. Our this study mainly focused on the branch chlorenchyma with references to its own leaf. From the research of the photosynthetic characteristics between leaf and branch of Populus alba L., Syringa microphylla Diels and Larix gmellini (Rupr.) Rupr., and the research of C4 enzyme in 14 species, arid the research of saline-alkali and element influence about photosynthetic characteristics between leaf and branch, the following conclusion were found.The effect of element deficiency on photosynthetic characteristics of leaf and branch in poplar, clove and larch trees1) Lack of N treatment caused the significant reduction of N element content in leaf and branch chlorenchyma of three species of trees, lack of K treatment made larch and poplar, and lack of P treatment made poplar and clove in corresponding mineral nutrient stress state. Although lack of Ca, Mg, B treatment didn't cause the pervasively corresponding element stress in three species of trees, different element had significant relationship; 2) Although most elements lacking treatment did not make the corresponding elements within their organizations significantly reduced, but biomass and leaf-related indexes are significant. Three kinds of plants may be by adjusting the size of individual leaves and plant growth to ensure the individual elements of content necessary for growth. Such as:the individual under the condition of lacking of N treatment was short, thin and with small leaves, photosynthesis and fluorescence are relatively controlled and reduced; 3) Lacking of element treatment led escalating trend of C4 photosynthetic enzyme content in leaf and branch chlorenchyma, and different elements have different effects on different plants. Lack of P and K treatment cause rise of five enzyme (NADP-MDH, NADP-ME, PEPC, PEPCK, PPDK) in branch of larch, and Lack of Ca and B treatment cause rise of five enzyme in leaf. The content of PEPC and NADP-ME in leaf of poplar under the condition of control was higher than that in the condition of lacking K, and same trend of PEPC and PEPCK in branch. The lack of N treatment rose significantly the content of PEPC, PEPCK, NADP-MDH in leaf and branch of clove; 4) In three species of trees, negative relationship between element and C4 enzyme existed in leaf and branch. The relationship between element and ETR existed in clove and larch, not in poplar, such as:N element in leaf of clove and B element in leaf of larch had relationship with ETR. In the leaf and branch of three trees existed negative relationship between C4 enzyme and chlorophyll.The difference of C4 enzyme between leaf and branch chlorenchyma of 14 woody speciesAll the five enzymes(NADP-ME/Chl., PEPC/Chl., PPDK/Chl.) in branch chlorenchyma of 14 species were higher than in leaf, the NADP-MDH/Chl., PEPCK/Chl. in branch chlorenchyma of 12 species were higher than in leaf. Enzyme/fresh mass was the reason which reduce the differenc of enzyme/Chl., not the Chl.. From the correlation, we can detect 4 relationship of enzyme in branch chlorenchyma that is NADP-ME/Chl.& PEPC/Chl., NADP-ME/Chl.& PPDK/Chl., PEPC/Chl.& PPDK/Chl., and PEPC/Chl.& NADP-MDH/Chl., no relationship was detected in leaf.The effect of saline-alkali stress on C4 enzymes in bark chlorenchyma and leafOur findings manifest that non-photosynthetic organs (such as stem and branch) of Yinzhong poplar(Populus alba×P.berolinensis) had much higher content of C4 pathway-related enzymes (NADP-ME/Chl., PEPC/Chl., PPDK/Chl., NADP-MDH/Chl. and PEPCK/Chl.) comparing with the leaf lamina. Moreover, such differences could be adjusted by soil saline-alkali degree, i.e. the differences could be dramatically enlarged in the ameliorated saline-alkali land. Possibly, the changes in C4-related enzymes might be effective physiological paramenters for evaluating plant acclimation to saline-alkali soil.