Chin J Plant Ecol ›› 2022, Vol. 46 ›› Issue (9): 1038-1049.DOI: 10.17521/cjpe.2021.0399

• Research Articles • Previous Articles     Next Articles

Radial growth and its low-temperature threshold of Abies georgei var. smithii at different altitudes in Jiaozi Mountain, Yunnan, China

ZHU Ming-Yang1, LIN Lin1, SHE Yu-Long1, XIAO Cheng-Cai1, ZHAO Tong-Xing1, HU Chun-Xiang2, ZHAO Chang-You2, WANG Wen-Li1,*()   

  1. 1School of Ecology and Environment Science, Yunnan University, Kunming 650500, China
    2Jiaozishan National Nature Reserve, Kunming 651500, China
  • Received:2021-11-08 Accepted:2021-12-13 Online:2022-09-20 Published:2022-10-19
  • Contact: WANG Wen-Li
  • Supported by:
    National Natural Science Foundation of China(32160354);National Natural Science Foundation of China(31500174)

Abstract:

Aims In view of the overarching significance for tree function and survival, it is essential to explore the environmental influences on tree development. Our objective was to clarify the altitudinal differences in the onset and offset of each stage of tree radial growth, to analyze the response of cambium activity and xylem differentiation to temperature at different altitudes, and to identify low temperature threshold for radial growth of trees.

Methods Weekly microcores and hourly in situ climate data were collected at 3 600, 3 800 and 4 000 m along the altitude gradient of Abies georgei var. smithii forest in Jiaozi Mountain, Yunnan.

Important findings The results showed that: (1) There were differences in the phenology of radial growth at three altitudes. The onset of radial growth was delayed by 4.7 d per 100 m, the end of radial growth was advanced by 7.2 d per 100 m, and the growing season was shortened by 12.8 d per 100 m with increasing altitude; (2) The radial growth of Abies georgei var. smithii at different altitudes had similar low temperature thresholds (about 5 °C), and temperature controlled the onset of cambium activity and the end of xylem differentiation; (3) The degree of cell division activity at different altitude decreased at higher temperatures (around the summer solstice), and photoperiod was involved in the regulation of the end of cambium activity to ensure the completion of cell mature before the freezing. The relationship between the cambium activity and altitude-induced temperature change is weak. The photoperiod may be involved in regulating the end of cambium activity to ensure the completion of cell mature before the freezing. This study contributes to understand the response mechanisms of tree growth dynamics to climate change and provides a scientific basis for better adaptation and response to climate change.

Key words: radial growth, temperature threshold, cambium activity, xylem differentiation, micro-core