黑荆人工林植被稀少的成因——基于植物化感作用的研究

Formation causes of sparse vegetation under Acacia mearnsii plantation:A study based on plant allelopathy

从植物化感作用的影响与效应入手,研究了黑荆Acacia mearnsii人工林植被稀少的成因。用室内生物模拟实验法,测定了黑荆叶片的水提液原液(料液比1∶50)及其5倍、10倍、15倍稀释液对受体植物紫茎泽兰Ageratina adenophora、白三叶Trifolium repens、大叶桉Eucalyptus robusta、赤桉Eucalyptus camaldulensis的种子萌发和幼苗生长的干扰作用。实验结果表明:黑荆叶片水提液原液及其稀释液对四种受体植物的种子萌发及幼苗生长均存在抑制作用,综合效应指数S EI介于-0.246到-0.002。其中,对紫茎泽兰及白三叶的抑制作用有较明显的规律性,抑制作用随着处理液稀释倍数增加而减弱,原液对紫茎泽兰的抑制作用的S EI达到-0.246;对大叶桉、赤桉的抑制作用没有规律性,原液和10倍稀释液处理组的抑制作用较其他两组明显,5倍稀释液处理大叶桉的S EI值为-0.002。得出研究结论:黑荆人工林植被稀少可能是黑荆植株水溶物的化感作用所致。

The formation causes of sparse vegetation under Acacia mearnsii plantation were studied from the perspective of plant allelopathy. The interference effects of water extract with different concentrations （1, 5, 10, 15 times） from Acacia mearnsii leaves on seed germination and seedling growth of four receptor plants was assayed through indoor biological simulation experiments, the four receptor plants are Ageratina adenophora, Trifolium repens, Eucalyptus robusta and Eucalyptus camaldulensis, respectively. The results show that different concentrations （ 1, 5, 10, 15 times） of water extract from Acacia mearnsii leaves all had inhibitory effects on seed germination and seedling growth of the four receptor plants, the synthesized effect index （SEI） ranged from -0.246 to -0.002; there existed an obvious regularity of inhibitory effects to Ageratina adenophora and Trifolium repens, and the inhibitory effect reduced with the increase of water extract dilution ratio, the SEI of inhibitory effect on Ageratina adenophora treated with 1 times was -0.246; however, there was no regularity in inhibitory effect on Eucalyptus robusta and Eucalyptus camaldulensis, the inhibitory effects of 1 times and 10 times were more obvious than the other two groups, the SEI of inhibitory effect on Eucalyptus robusta treated with 5 times was -0.002. The possible cause of sparse vegetation under Acacia mearnsii plantation is allelopathy of Acacia mearnsii hydrotrope.