Determining thresholds of low soil temperature for ecophysiological traits of black spruce and jack pine seedlings |
| |
Authors: | Song Cheng |
| |
Institution: | (1) Institute of Mountain Hazards and Environment, Chinese Academy of Sciences, Chengdu, 610041, P. R. China;(2) Faculty of Forestry and the Forest Environment, Lakehead University, Thunder Bay, Ontario, P7B 5E1, Canada |
| |
Abstract: | Many studies have estimated approximately ranges of thresholds of low soil temperature in the growth and ecophysiological
traits of trees, but difficultly determined the exact values. To resolve the problem, black spruce (Picea mariana) and jack pine (Pinus banksiana) seedlings were exposed to 5, 10, 15, 20, 25, 30 and 35°C soil temperature in greenhouses. After 90 days of the treatment,
net photosynthetic rate (A), stomatal conductance (g
s), transpiration rate (E), water use efficiency (WUE) and specific leaf area (SLA) were measured. This study showed that all the traits had an asymmetrical
peak relationship with changing soil temperature, the relationship was well simulated using a cubic curvilinear model, and
the exact thresholds could be derived from the second derivative of the model. The results revealed that the thresholds varied
among ecophysiological traits and between tree species. In black spruce, the thresholds were 14.1, 14.7, 10.7, 14.4 and 16.2°C
for A, g
s, E, WUE and SLA; 15.4, 10.4, 14.7, 16.9 and 10.5°C for the corresponding traits in jack pine. The lowest thresholds of E in black spruce and g
s in jack pine were an indicator representing the minimum requirement of soil temperature for the regular processes of ecophysiology.
The highest thresholds of SLA in black spruce and WUE in jack pine suggest they are the most sensitive to decreasing soil
temperature and may play an important role in the acclimation. The averaged thresholds were at 14.0 and 13.6°C for black spruce
and jack pine, suggesting that the sensitivity of both species to low soil temperature was quite close. |
| |
Keywords: | black spruce cubic curvilinear model ecophysiological traits jack pine low soil temperature threshold |
本文献已被 CNKI 维普 SpringerLink 等数据库收录! |
| 点击此处可从《中国林学》浏览原始摘要信息 |
| 点击此处可从《中国林学》下载免费的PDF全文 |
|