桂西南不同种源蚬木光合和生长特征的研究

为选择喀斯特特有树种蚬木(Excentrodendron hsienmu)优良种源,采用完全随机区组试验设计,研究了不同种源蚬木光合生理和生长特征的月动态变化。结果表明,蚬木光合生理特性在不同月份、不同种源间差异显著,净光合速率、气孔导度、蒸腾速率和水分利用效率表现出对气候变化的适应,均随月份发生变化。各种源蚬木净光合速率、气孔导度和蒸腾速率均在8月份最高,4月份和12月份较低。水分利用效率则在8月份最低,4月份和12月份较高。相关分析表明,蚬木各种源苗高与地径、净光合速率均显著正相关,而净光合速率与地径也表现一定的正相关关系,说明净光合速率可作为蚬木生长过程中的指示性监测指标。蚬木大新、武鸣、隆安种源在整个生长季节均表现较高的净光合速率和生长量,以及较低的蒸腾速率,因此,这3个蚬木种源更适合在南宁地区引种种植。

Photosynthetic and Growth Characteristics of Different Excentrodendron hsienmu Provenances from Karst District of Southwestern Guangxi, China

In order to selection of excellent provenance of Excentrodendron hsienmu, the monthly changes in photosynthetic and growth characteristic were studied by using a completely random zone experiment design. The results showed that the photosynthetic and growth characteristics of E. hsienmu had significantly differences among different months and different provenances. The net photosynthetic rate, stomata conductance, transpiration rate and water use efficiency (WUE) changed with the month, indicated the adaptability to climate changes. The net photosynthetic rate, stomata conductance and transpiration rate of different provenances were the highest in August, but low in April and December. However, the WUE were the lowest in August, and high in April and December. The seedling height had significant positive correlation with ground diameter and net photosynthetic rate and seedling height, as well as the net photosynthetic rate and ground diameter. The net photosynthetic rate could be used as indicative monitoring indicators in the growth process of E. hsienmu. The provenances of Daxin, Wuming and Long''an had high net photosynthetic rate and growth increment and low transpiration rate during whole growing season. Therefore, the three provenances of Daxin, Wuming and Long''an were more suitable to introduction planting in Nanning area.