PJB-2017-212
EFFECTS OF DIFFERENT JUVENILE MIXED PLANTATIONS ON GROWTH AND PHOTOSYNTHETIC PHYSIOLOGY OF PINUS YUNNANENSIS FRANCH.
YUAN ZHENG, GUANG-LONG OU, JIN-LONG CHEN, DAN-DAN CHEN, GUO-YUAN LIU, QI-QIN LI, SHI-HAO ZHANG AND MING-YUE HAN
Abstract
The growth characteristics, photosynthetic gas exchange features, physiological and biochemical resistance, and soil nutrition contents of different juvenile mixed plantations were analyzed. Moreover, the synergic effect mechanism of the different species was elucidated to improve the stand quality of Pinus yunnanensis Franch. plantations and guide the screening of P. yunnanensis mixed plantations. The mixed plantations were P. yunnanensis–Alnus nepalensis–Quercus acutissima, P. yunnanensis–A. nepalensis–Cyclobalanopsis glaucoides, and P. yunnanensis–Q. acutissima–C. glaucoides. Individual juvenile plantations of pure P. yunnanensis, A. nepalensis, Q. acutissima, and C. glaucoides were used as control groups. Results showed that pure P. yunnanensis juvenile plantation consumed more soil organic matter, total nitrogen (TN), total phosphorus (TP), and total potassium (TK) than the other plantations. This plantation also showed poorer growth characteristics, poorer photosynthetic capability, lower water utilization efficiency (WUE), and biochemical resistance in infertile soil, as shown by the nutrition and water competition. Increasing soil organic matters, TN, TP, and TK of the different mixed plantations evidently enhanced height, ground diameter growth rate, net photosynthetic rate (Pn), transpiration rate (Tr), WUE, carboxylation efficiency (CE), soluble sugar (SS) content, and superoxide dismutase (SOD) activity. Moreover, different mixed forests slightly influenced the characteristics of photosynthetic gas exchange and physiological and biochemical resistance of A. nepalensis. All stand types facilitated growth of tree height and basal diameter of Q. acutissima sapling. Although Q. acutissima inhibited physiological and biochemical resistance of leaves to a certain extent, they increased WUE significantly. Different stand types slightly influenced growth features, Pn, Tr, and WUE of C. glaucoides sapling. Moreover, they inhibited the osmotic adjustment system and SOD activity of C. glaucoides to a certain extent, indicating that C. glaucoides was not a well-associated broad-leaf species of P. yunnanensis juvenile mixed plantations. Therefore, P. yunnanensis–A. nepalensis–Q. acutissima is an optimal mixed plantation, which is beneficial for increasing growth rate, Pn, and WUE, as well as for recovering soil fertility.
To Cite this article:
Download
