PJB-2019-587
PHYSIOLOGICAL AND ECOLOGICAL RESPONSES TO DIFFERENT ALTITUDES IN ALPINE PLANT PICEA LIKIANGENSIS ALONG YULONG SNOW MOUNTAIN, NORTHWEST YUNNAN, CHINA
Xiaoxia Huang
Abstract
Picea likiangensis (Franch.) Pritz., an endemic and evergreen alpine conifer woody plant species, plays an important role in maintaining the ecosystem stability and succession. In our study, the physiological indexes (chlorophyll content, malondialdehyde, proline, soluble protein and soluble sugar, antioxidant enzymes activities and nutrient content (C, N and P), C/N ratio and the δ13C in the needles of P. likiangensis current-year sunny branches were measured along an altitudinal gradient ranging from 2900 m to 3350 m. The average vertical distance between two adjacent collection sites was approximately 150 meters. Results showed that significant changes existed in leaf physiological and ecological traits of P. likiangensis along the altitudinal gradient. The content of pigment (including Chl a, Chl b and total chlorophyll), total phosphorus and total nitrogen concentration reached maximum at 3200 m altitude, and then decreased at an altitude 3350 m. Moreover, the higher leaf N concentration and lower C/N ratio, which indicates that P. likiangensis has high photosynthetic capacity at 3200 m altitude. In addition, the increase in proline, soluble sugar and soluble protein contents indicates that P. likiangensis resist abiotic stress by the osmotic adjustment under 3200 m altitude. Meanwhile, malondialdehyde concentration and the activities of superoxide dismutase (SOD) and ascorbate peroxidase (APX) rapidly increased from 3200 m to 3350 m altitude, which suggests that P. likiangensis suffered from heavy abiotic stress in high-altitude. Thus, we inferred that 3200 m altitude may be an optimum zone for P. likiangensis growth in the Yulong Snow Mountain, Northwest China. Moreover, the P. likiangensis population expansion was limited by the harsh environment when the altitude above 3350 m.
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