尾巨桉叶片水提液对8种乡土树种的化感作用

Allelopathic effects of aqueous leaf leachates of Eucalyptus urophylla×E.grandis on eight native tree species

【目的】探讨桉树化感作用对华南地区乡土阔叶树种生长的影响,为桉树人工林改造提供参考依据。【方法】采用室内生物测定的方法,研究了尾巨桉叶片水提液对8种华南地区乡土树种种子萌发、幼苗根茎生长及苗期生长的影响。【结果】1)尾巨桉叶片水提液对8种受体植物种子萌发影响有限,只有高浓度(0.2 g/mL)和中高浓度(0.1 g/mL)的叶片水提液显著抑制了木荷、火力楠和枫香种子的萌发;2)尾巨桉叶片水提液显著抑制了木荷、火力楠和坡垒幼苗的根长和茎长生长,对樟树、米老排、枫香和红锥的根茎生长则表现出不同程度的促进作用;3)受体植物苗期生长过程中,木荷和火力楠在苗高生长和生物量累积方面受到桉树化感作用显著的抑制作用,而米老排、枫香和红锥的苗高、地径生长及生物量累积则在化感作用下表现为明显的促进作用,并且这种抑制或促进作用均随着尾巨桉叶片水提液浓度的提高而提升。樟树和降香黄檀苗期生长对尾巨桉叶片水提液不敏感,各处理间差异不大。【结论】通过对化感效应指数进行聚类分析,可以将8种受体植物分为化感作用抑制型、化感作用稳定型和化感作用促进型三个类别。其中米老排、枫香、红锥和樟树在桉树化感作用下表现较好,是尾巨桉人工林较为理想的混交树种。

【Objective】In order to study the allelopathic effects of Eucalyptus on the growth of native broad-leaved tree species,and provide theoretical references for the reconstruction of Eucalyptus plantation.【Method】Aqueous leaf leachate of Eucalyptus urophylla×E.grandis were used to investigate allelopathic effects on seed germination,seedling growth and plantlet growth of eight native tree species.【Result】1)Aqueous leaf leachate of Eucalyptus urophylla×E.grandis had limited influence on the seed germination of eight receptors,and only the high concentration(0.2 g/mL)and intermediate high concentration(0.1 g/mL)leaf leachate significantly inhibited seed germination rate of Schima superba,Michelia macclurei and Liquidambar formosana;2)The stem growth and root elongation of S.superba,M.macclurei and Hopea hainanensis were inhibited by aqueous leaf leachate during the seedling growth,while the leachate had promoting effects on that of Cinnamomum bodinieri,Mytilaria laosensis,L.formosana and Castanopsis hystrix at different concentration;3)Aqueous leaf leachate had inhibitory effects on seedling height growth and biomass accumulation of S.superba and M.macclurei during the plantlet growth,while it had promotion effects on seedling height growth,ground diameter growth and biomass accumulation of M.laosensis,L.formosana and C.hystrix,and the inhibitory or promoting effects were strengthening with increasing aqueous leaf leachate concentration.The plantlet growth of C.bodinieri and Dalbergia odorifera were not sensitive to aqueous leaf leachate and the treatments had no significant difference.【Conclusion】The eight native tree species can divide into three clusters by clustering analysis:inhibited species,steady species and promoting species.M.laosensis,L.formosana,C.hystrix and C.bodinieri had better growth with allelopathic effects,and thus could be used as available hybrid plantings of E.urophylla×E.grandis.