南洋楹无性系抗寒性研究

Physiological analysis on cold resistance of Albizia falcataria clones

【目的】南洋楹属典型热带树种,抗寒性较差,严重制约其推广应用。开展南洋楹无性系抗寒性评价,对于提高其造林成效、拓广其栽培区域具有重要意义。【方法】以生长较好的9个南洋楹无性系组培苗为研究对象,通过系列低温处理,观测幼苗叶片形态变化,分析测定叶片相对电导率(REC)、脯氨酸(PRO)含量以及超氧化物歧化酶(SOD)的活性,揭示南洋楹无性系在低温胁迫下的生理响应,并进行无性系抗寒性评价。【结果】在2℃时,所有无性系均出现不同程度落叶;0℃时所有无性系均出现顶芽死亡,其抗寒性差异主要表现在0~2℃温度区间;9个无性系的REC随温度降低呈单调上升和先上升后下降再上升的2种变化趁势,属于后者的无性系抗寒性更强,0℃下S5、S7的REC最低;PRO含量随温度降低整体上呈现递增趁势,TL18、S7、S5、A8的PRO含量增幅最大,均在1倍以上;SOD活性在同一温度下无性系之间差异显著,但随温度降低无明显变化规律。应用REC进行聚类分析,将9个无性系分为3类,S7、S5、TL18抗寒性最强,A8抗寒性最差,其它6个无性系抗寒性居中。【结论】建议生产上推广S7、S5和TL18无性系。

【Objective】Albizia falcataria(Linn.) Fosberg is a typical tree species in the tropics, and its plantation development was severely restricted by its poor cold-resistance. It is thus important to evaluate cold resistance of clones for purpose of raising planting successfulness and enlarging planting area of this species.【Method】Morphological properties of nine A. falcataria clones with good growth performance were observed under a serial of low temperature treatments, and relative electronic conductivity(REC), total soluble protein(PRO) contents and superoxide dismutase(SOD) activity of seedling leaves were analyzed in order to reveal physiological responses under low temperature stress and assess cold resistance of this species.【Result】The results showed that different levels of defoliation occurred under 2 ℃, and withered top buds were seen under 0 ℃ for all clones, indicating that difference of seedlings in cold-resistance mainly demonstrated from 2 ℃ to 0 ℃. There existed both trends for these nine clones: REC of some clones increased with declination of treated temperature, and those of other clones increased first, then declined, and increased finally. Clones with the latter trend seemed to be of higher cold-resistance. The REC of S5 and S7 were the highest under 0 ℃. PRO content increased with declination of treated temperature as a whole, and the increases of TL18, S7, S5 and S8 clones from 25 ℃ to 0 ℃ were more than one time, the highest among these clones. SOD activity differed significantly among clones under the same temperature, while it changed irregularly with declination of temperature. Clustering analysis was conducted on basis of REC, and nine A. falcataria clones could be divided into three clusters: S7, S5, TL18 clones were of the highest cold resistance;A8 was of the lowest;and other six clones were of the middle level.【Conclusion】As a whole, S7, S5 and TL18 clones were recommended for application in practice.