濒危植物无距虾脊兰种子无菌萌发与幼苗形成

[目的]揭示无距虾脊兰种子无菌萌发过程的形态特征和组织结构特点,为无距虾脊兰保育和离体快速繁殖提供参考依据。[方法]以浙江天目山无距虾脊兰野生居群为材料,采收其果实进行无菌萌发实验。通过形态观察和石蜡切片法,对种子萌发到幼苗初步形成过程进行细胞组织学研究,并对发育阶段进行划分。[结果]无距虾脊兰种子萌发的适宜基本培养基为VW培养基,椰子水对萌发具有促进作用,而香蕉泥对萌发具有抑制作用,在授粉后胚龄为4个月左右采收进行播种,萌发率最高。依据对其萌发过程中种胚膨胀、顶端分生组织的出现和发育、叶和根的分化等突出性状的观察,将无距虾脊兰种子萌发过程分为4个阶段。[结论]无距虾脊兰的种子无菌萌发过程主要由种胚吸水膨胀,原球茎的形成和分化2个生物学过程组成,其中,顶端分生组织、叶绿体和维管束为原球茎生长和发育过程中的重要结构。

Seed Germination and Seedling Morphogenesis of an Endangered Species Calanthe tsoongiana

[Objective] The study aims at revealing the morphological characteristics and histological structure during aseptic seed germination of Calanthe tsoongiana, so as to provide some references for its conservation and in vitro rapid propagation.[Method] This study was conducted by using wild population of C. tsoongiana distributed in Tianmushan, Zhejiang Province, aseptic germination was taken after harvesting the fruits. The process from seed germination to initial seedling formation was studied and divided into several developmental stages by morphological observation and paraffin section method.[Result] It proved that the Vacin & Went (VW) medium was the suitable basal medium for seed germination which was facilitated by coconut water. Nevertheless, the banana slurry had an inhibitory effect. The germination rate reached the highest when harvesting the fruit at the time of four months or so after pollination. The process of seed germination was divided into four stages according to the observation on swelled embryo, the presence and development of shoot apical meristem, the differentiation of young leaf and root, etc.[Conclusion] The process of aseptic seed germination is mainly composed of two biological processes, seed imbibition and the form and differentiation of protocorm. Apical meristem, chloroplast and vascular bundle are the major structures during the growth and development of protocorm.