胡计红 陈桂信 杨惠婷 康建坂 甘代奎

摘  要：以屏南縣棠口乡龙源村400多年‘四季杜鹃古树的顶芽为外植体，开展离体快繁技术研究，探讨外植体消毒方式、取材时间对无菌系建立的影响，培养基中植物生长调节剂种类和配比对芽苗继代增殖的影响，以及培养基中植物生长调节剂的种类与配比对无根苗瓶内生根的影响。试验结果表明，外植体表面消毒以75%酒精作用30 s后再用0.1% HgCl2消毒8 min，消毒效果最好。外植体最佳的取材时间为5月中旬前后。在无菌系建立中污染的外植体可采用75%酒精消毒20 s，然后用0.1% HgCl2消毒5 min，再经4次转瓶后成功率可达71%。初代培养的最适培养基为WPM+3.0 mg/L ZT+0.1 mg/L NAA+0.5 mg/L GA3 ，平均有效芽数为3.45。在增殖培养中，带腋芽茎段诱导丛生芽的增殖效果优于顶芽，最适培养基组合为Anderson+0.5 mg/L TDZ+0.1 mg/L NAA，增殖系数达13.23。最适的瓶内生根培养基为：WPM+0.1 mg/L ZT+0.5 mg/L NAA，生根率达92.6%。本研究的结果可为‘四季杜鹃古树的保护与开发利用提供理论与技术支持。

关键词：屏南四季杜鹃;古树;离体快繁

中图分类号：Q813.1      文献标识码：A

Abstract： Rapid propagation in vitro was explored using the apical buds of an ancient Four-season Rhododendron tree， more than 400 years， from Longyuan Village， Tangkou Town， Pingnan County as the explants to find the effects of sterilizing methods and time of explants on the development of sterile cultures， effects of kinds and ratios of plant growth regulators added in the media on the proliferation of shoots and rooting of rootless shoots. The optimum sterilization conditions were the explants treated with 75% of ethanol for 30 seconds and then dipped with 0.1% of HgCl2 for 8 minutes. The optimum sampling period for explants was about middle to late May. After four times of bottle transfer success rate of re-sterilizing reached 71% through rescuing of the contaminated explants in the development of sterile cultures by treating with 75% of ethanol for 20 seconds and then dipping with 0.1% of HgCl2 for 5 minutes. The optimum components of the medium in the primary culture was WPM medium added 3.0 mg/L of zeatin （ZT）， 0.1 mg/L of NAA and 0.5 mg/L of GA3， on which the average number of induced valid buds was 3.45. In the proliferation culture， the clustered shoots were induced from apical and stem segments with axillary buds of sterile plant-lets inoculated on Anderson medium added 0.5 mg/L of TDZ and 0.1 mg/L of NAA， multiplication coefficient of stem segments with axillary buds was higher than that of apical buds， reached 13.23. In the rooting culture of rootless shoots， the optimum medium was WPM medium added 0.1 mg/L of ZT and 0.5 mg/L of NAA， on which the rooting rate reached 92.6%. The results would provide theoretical and technical supports for conservation， exploitation and utilization of the ancient Four-season Rhododendron tree.

Keywords： Pingnan Four-season Rhododendron; ancient tree; rapid propagation in vitro

DOI： 10.3969/j.issn.1000-2561.2020.04.017

杜鹃花是杜鹃花科（Ericaceae）杜鹃花属（Rhododendron）著名观赏植物[1]。福建‘四季杜鹃观赏价值很高，但大多处于山间野生状态，很少人工栽培，甚至有些稀有类型仅单株保存延续种性。屏南县地处闽东的宁德市高海拔山区，分布着丰富多样的‘四季杜鹃种质资源，在棠口乡龙源村村口有1株开红花的杜鹃花古树，经鉴定该树属锦绣杜鹃（Rhododendron pulchrum Sweet）变种，树龄400 a以上，该树四季开花，成为屏南县独有的、有开发利用价值的珍稀地方种质资源。……