温度和风对细叶云南松幼苗生长及生理的影响

Effects of temperature and wind on 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(Pinus yunnanensis var. tenuifolia)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具有重要意义。细叶云南松是珠江上游滇、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(P. 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及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 ℃及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)。这说明高温及吹风环境有利于细叶云南松幼苗生长,通过增强根系和茎干适应干热吹风环境,实现较低抗逆响应。(3)整体上,抗氧化酶活性和丙二醛含量与年平均温度、月平均温度、风速呈负相关,与海拔、年降水量呈正相关,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,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 Pinus yunnanensis var. tenuifolia(Pyt)populations to high temperature and strong wind environment in their typical habitats is of great significance for understanding the adaptive evolution and developmental potential of this species. Pyt is one of the main tree species in the dry-hot valleys located at the junction of Yunnan, Guizhou, and Guangxi in the upper reaches of the Pearl River. It is very important to maintain water, soil, and vegetation ecology in this area. This study conducted seedling cultivation experiments using natural populations of Pyt seeds collected from the Nanpanjiang-Hongshui River basin, along with one natural 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 environment. The results were as follows:(1)Compared to Pm, Pyt seedlings exhibited superior growth and physiological performance under a temperature 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 possess superior ecological suitability compared to Pm in dry-hot habitats.(2)The 30 ℃ environment significantly increased 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 ℃ environment. A wind speed of 1.2 m·s^-1 significantly enhanced the total root average diameter(+11.1%, P < 0.05)and decreased malondialdehyde content(-44.9%, P < 0.05)compared to a windless environment, indicating that high temperature and windy environment promote the growth of Pyt seedlings by enhancing the adaptation of their roots and stems to dry-hot, and windy enviromment, thereby achieving a lower stress response.(3)Overall, antioxidant enzyme activities and peroxidation product contents showed negative correlations with annual mean temperature, monthly average temperature, and wind speed, while showed positive correlations with altitude and annual precipitation, indicating that the physiological adaptability of seedling growth was mainly influenced by the synergistic selections of temperature, precipitation, wind, and altitude. In conclusion, the dry-hot environment combined with strong wind environment in the Nanpanjiang-Hongshui River valley is a critical factor driving the development and evolution of Pyt.