Dynamic changes of photosynthetic properties and chemical compositions of Eucommia ulmoides Oliver under two planting models

Photosynthesis is a fundamental and complex physiological process for the biosynthesis of secondary metabolites in the green plant species. In this study, the dynamic changes of photosynthetic properties, chemical compositions and cumulative production between the traditional arbor forest model of Eucommia planting (AFMEP) and using leaf model of Eucommia planting (ULMEP) were systematically investigated. The photosynthetic properties were plotted using a portable photosynthesis system. Chemical composition and structural characterization of the EUO wood were comparatively investigated by a combination of HPAEC, Raman images, Elemental analysis, and 2D-HSQC NMR. Meanwhile, the composition and content of secondary metabolites in EUO leaves from different planting models were determined by the HPLC. Besides, the water content in leaves, barks and wood were calculated by the gravimetric method. Results showed that the light-saturated net photosynthetic rate in ULMEP was significantly higher than that in AFMEP. The content of lignin in AFMEP wood was higher than that of ULMEP wood, while the amounts of beta-O-4 linkages were abundant in lignin from ULMEP wood, which was beneficial to utilize the ULMEP wood. By contrast, the content of carbohydrates in ULMEP was slightly higher than that of AFMEP wood. Besides, the contents of various secondary metabolites (chlorogenic acid, geniposidic acid, eucommiol and gutta percha) in the leaves from AFMEP and ULMEP varied with the seasonal change, respectively. Moreover, the cumulative production of dry biomasses in wood, leaves and barks of EUO at the same periods (10 years) were all significantly higher in ULMEP than those in AFMEP, which indicated that the ULMEP was a promising planting model to solve the source of the EUO resources in industrial scenario. (C) 2016 Elsevier B.V. All rights reserved.