温度和风对细叶云南松幼苗生长及生理的影响

The influence of temperature and wind on the growth and physiology of Pinus yunnanensis var. tenuifolia seedlings

关键词:  生态适应性，幼苗生长，抗性生理，地理环境，细叶云南松

Key words:  ecological adaptability, seedling growth, resistance physiology, geographic environment, Pinus yunnanensis var. tenuifolia

摘要:

探究细叶云南松种群子代对其典型生境的高温、强风环境的生长生理适应性，对理解该物种的适应性演化及发展潜力有重要意义。细叶云南松（Pinus yunnanensis var. tenuifolia）是珠江上游滇、黔、桂交界干热河谷地区的主要乔木树种之一，对维持该区域的水土及植被生态极为重要。该研究以南盘江-红水河流域的细叶云南松天然种群种子及东部邻域马尾松（Pinus massoniana）天然种群种子开展育苗试验，设置25 ℃无风（对照）、30 ℃无风及25 ℃、1.2 m?s-1风速3个处理，模拟探究幼苗生长和生理对种源地高温、吹风环境因子的适应性响应。结果表明：（1）相较于马尾松，细叶云南松幼苗在30 ℃、1.2 m?s-1风速环境下有更好的生长生理表现且部分细叶云南松种群子代显著优于马尾松，说明细叶云南松更适应干热生境。（2）相比于25 ℃环境，在30 ℃环境下各种群幼苗地径（+11.9%，P＜0.05）、总根平均直径（+9.41%，P＜0.05）增长显著，过氧化物酶活性下降显著（-68.1%，P＜0.01）；相比无风环境，1.2 m?s-1风速条件使总根平均直径增长显著（+11.1%，P＜0.05），丙二醛含量显著下降（-44.9%，P＜0.05）；说明高温、吹风环境有利于细叶云南松幼苗生长，通过增强根系、茎干适应干热吹风环境且抗逆响应降低。（3）整体上抗氧化酶活性和过氧化产物与年均温、月均温、风速呈负相关，与海拔、年降水呈正相关，说明其苗木生长生理适应性主要受到温度、降水、风、海拔的协同选择。综上认为，该研究结果表明南盘江-红水河谷干热及强风环境是驱动细叶云南松发展演化的重要因素。

Abstract:

Exploring the growth and physiological adaptability of the offspring of wild Pinus yunnanensis var. tenuifolia (Pyt) populations to high temperatures and strong wind conditions in their typical habitats is crucial for understanding the adaptive evolution and developmental potential of this species. Pyt is one of the main tree species in the dry and hot valleys located at the junction of Yunnan, Guizhou, and Guangxi in the upper reaches of the Pearl River. It is very important to preserve the water, soil, and vegetation ecology in this area. This study conducted seedling cultivation experiments using wild populations of Pyt seeds collected from the Nanpan-Hongshui River Basin, along with one wild population of P. massoniana (Pm) from the adjacent eastern region. The 25 ℃ windless environment group was used as the control, while the 30 ℃ windless environment group and the 25 ℃ environment with a wind speed of 1.2 m?s-1 were established to investigate the adaptive responses of seedling growth and physiology to high temperature and wind conditions. The results demonstrated that: (1) Compared to Pm, Pyt seedlings exhibited superior growth and physiological performance under conditions of 30 ℃ and a wind speed of 1.2 m?s-1. Additionally, the offspring of certain Pyt populations performed significantly better than those of Pm. These findings demonstrate that Pyt possesses superior ecological suitability compared to Pm in dry-hot habitats. (2) The 30 ℃ environment induced significant increases in ground diameter (+11.9%, P < 0.05) and total root average diameter (+9.41%, P < 0.05), along with a marked reduction in peroxidase activity (-68.1%, P < 0.01) compared to 25 ℃ conditions. A wind speed of 1.2 m?s-1 significantly enhanced the average diameter of total roots (+11.1%, P < 0.05) and decreased malondialdehyde content (-44.9%, P < 0.05) relative to a windless environment, indicating that warm, windy conditions promoted phenotypic growth through reinforced root-stem development and reduced antioxidant demands. (3) Antioxidant enzyme activities and peroxidation product contents showed negative correlations with annual average temperature, monthly average temperature, and wind speed, but positive correlations with altitude and annual precipitation, indicating that the physiological adaptability of seedling growth is mainly influenced by the synergistic selections of temperature, precipitation, wind, and altitude. In summary, this study indicates that the dry, hot environment combined with strong winds in the Nanpan-Hongshui River valley is a critical factor driving the development and evolution of Pyt.