尾叶桉Eucalyptus urophylla对8种乡土树种的化感作用

测试了尾叶桉叶片水提取液和叶片挥发物对8种乡土树种的种子萌发和幼苗根茎生长的影响,包括鸭脚木Schefflera octophylla,肖蒲桃Acmena acuminatissima,水翁Cleistocalyxoperculatus,三花冬青Ilextriflora,荷木Schima superba,小叶青冈Cyclobalanopsis myrsinaefolia,拐枣Hovenia dulcis和火力楠Michelia maclurei,结果表明:①水提取液的母液对这8种植物的种子萌发都没有显著影响,但在幼苗的根茎生长方面,对其中的鸭脚木、肖蒲桃和三花冬青产生了显著的抑制作用,对小叶青冈和拐枣则产生了显著的促进作用;3种水提取稀释液则对所有受体植物都没有显著影响。②叶片挥发物在150 g处理以下对所有物种的种子萌发均没有显著抑制作用,在较高浓度的处理中对部分植物的种子发芽率产生了显著或极显著的抑制作用,如肖蒲桃在350 g处理时,荷木在250 g和350 g处理时都受到极显著抑制;在幼苗根茎生长方面,肖蒲桃、三花冬青、荷木、拐枣和火力楠都受到了挥发物的显著抑制作用,而鸭脚木和水翁在250 g和350 g处理中受到了显著抑制,小叶青冈只在350 g处理中受到显著抑制。总之,尾叶桉叶片挥发物的化感作用强度比水提取液的高,而幼苗根茎生长比种子萌发更易受化感物质的抑制。

Allelopathy of Eucalyptus urophylla on Eight Native Tree Species

Aqueous leaf leachate and leaf volatile of Eucalyptus urophylla were used to test their effects on seed germination and seedling growth of eight native tree species, including Schefflera octophyllaAcmena acuminatissima,〖WTBX〗Cleistocalyx operculatus,Ilex triflora, Schima superba,Cyclobalanopsis myrsinaefolia, Hovenia dulcis, Michelia maclurei. The results showed that aqueous leaf leachate had no suppression on the seed germination of all receptors. Aqueous leaf leachate had inhibition on the seedling growth of Schefflera octophylla,Acmena acuminatissima and Ilex triflora, while it had a promotion on that of Cyclobalanopsis myrsinaefolia and Hovenia dulcis at higher concentration. Leaf volatile had inhibitory effect on the seed germination of Acmena acuminatissima and Schima superba at higher concentration of 350 g leaf weight per desiccator, and Schima superba at 250 g leaf weight. However, it had no suppression on them under 150 g leaf weight treatment. On the other hand, leaf volatile had a significant suppressive effect on the seedling growth of Acmena acuminatissima,Ilex triflora,Schima superba, Hovenia dulcis and Michelia maclurei at all concentrations. Leaf volatile also effectively decreased the seedling growths of Schefflera octophylla and Cleistocalyx operculatus at 250 g and 350 g leaf weight. It did not inhibit the growth of Cyclobalanopsis myrsinaefolia utill at the concentration of 350 g leaf weight. With these results, we can conclude that Eucalyptus urophylla has allelopathy and the allelochemical effects of the donor varies with the dose.It seems that allelopathy of leaf volatile is more intense than that of aqueous leaf leachate. Nevertheless, seedling growth is more easily suppressed than seed germination.