欧洲鹅耳枥扦插生根及解剖特性

Rooting characteristics and anatomical structure of Carpinus betulus Cuttings

【目的】研究扦插时期对欧洲鹅耳枥(Carpinus betulus)插穗生根能力的影响,及扦插过程中不定根的发育形成过程,为了解欧洲鹅耳枥扦插生根机制提供参考。【方法】以欧洲鹅耳枥春季硬枝(采于2012-03-29)和夏季嫩枝(采于2012-06-09)为材料,进行插穗生根,观察生根过程中的外部形态;利用扫描电镜技术,对欧洲鹅耳枥扦插过程中不定根的发育形成过程进行解剖观察。【结果】嫩枝扦插的相关生根指标(如生根率、最长根长、根系效果指数)均优于硬枝扦插。随着扦插时间的延长,硬枝插穗基部出现瘤状环,中间凹陷;而嫩枝插穗基部则出现乳白色半透明凸起。欧洲鹅耳枥嫩枝扦插前在插穗内没有发现潜伏根原基;根原基细胞与愈伤组织细胞的形态解剖特征差异很大,且在愈伤组织的切片中未发现根原基的存在。【结论】欧洲鹅耳枥插穗的不定根是由诱生根原基发育形成的,诱生根原基是由初生韧皮部中的薄壁细胞、髓射线与形成层交叉处的部分薄壁细胞发育而来,不定根的形成与愈伤组织的形成关联性不大。欧洲鹅耳枥是非愈伤组织生根类型树种。

【Objective】In this article,the effects of cutting period on rooting ability of cuttings and the formation and development process of adventitious roots from cuttings of Carpinus betulus were investigated.【Method】The spring hardwood(extracted on 2012-03-29)and summer softwood(extracted on 2012-06-09)were used to conduct the rooting of cuttings and observe the external morphology.With scanning electron microscopy technology,the formation and development process of adventitious roots from cuttings of Carpinus betulus was observed.【Result】The rooting results(such as rooting rate,longest root,and root effect index)of softwood cuttings were better than those of hardwood cuttings.Nodular ring with sagged center appeared on the base of hardwood,while milky white translucent projection emerged at the base of softwood.There was no latent root primordium in cutting of Carpinus betulus.The primordium cells and callus cells were different from the morphological and anatomical characteristics,and root primordium was not found in the callus tissue slices.【Conclusion】The adventitious roots of Carpinus betulus cuttings formed from the induced root primordium.The parenchyma cell of primary phloem and the partial paren-chyma cell of pith ray at the intersection with the cambium developed into the induced root primordium and the formation of adventitious root and callus formation had little relevance.Carpinus betulus is non-callus rooting type species.