Colchicine-Induced Polyploidy in Rhododendron fortunei Lindl.

Lan Mo,Xiongzhen Lou,Renhui Dong,Qiangwei Xu,Erpei Lin,Junhao Chen,Huahong Huang,Zaikang Tong

doi:10.3390/plants9040424

Abstract

Polyploidy in Rhododendron fortunei has great potential to improve its horticultural and commercial value, and to also meet market demands. In this study, a feasible method for polyploid induction in R. fortunei via colchicine treatment was established, and the obtained polyploid plants were identified and characterized. As a result, the stem bases of tissue-cultured plantlets treated with 0.1% colchicine for 24 h showed the highest polyploid induction with a rate of 36.67%. By flow cytometric analysis, 69 tetraploids and 29 octoploids were identified in the regenerated plants that were examined. Phenotypic analysis indicated that the leaves of tetraploid and octoploid plants were smaller, rounder and thicker with more abundant and longer epidermal hairs than those of diploids. Furthermore, the stomata of polyploids were larger and sparser than those of diploids. An increase in chlorophyll content was also detected in polyploids, which resulted in darker green leaves. In conclusion, our study established an effective method to induce polyploidy in R. fortunei, which could be used to develop new genetic resources for breeding R. fortunei and other Rhododendron species in the future.

Highlights

Rhododendron fortunei Lindl, one of the alpine rhododendrons, is an evergreen small tree or shrub of genus Rhododendron, and mainly grows at an altitude of 620 to 2000 meters in Southern China [1].Owing to the beautiful and bright color of its flowers, and their elegant shape and charming aroma, R. fortunei has a high ornamental value and great commercial potential in landscaping and horticultural markets [2]
The tissue-cultured plantlets of R. fortunei clone ZL1 were used as explants for polyploidy induction
An efficient polyploid induction method was established for tissue-cultured plantlets of R. fortunei

Summary

Introduction

Rhododendron fortunei Lindl, one of the alpine rhododendrons, is an evergreen small tree or shrub of genus Rhododendron, and mainly grows at an altitude of 620 to 2000 meters in Southern China [1].Owing to the beautiful and bright color of its flowers, and their elegant shape and charming aroma, R. fortunei has a high ornamental value and great commercial potential in landscaping and horticultural markets [2]. Occurring polyploidy is widespread in the plant kingdom, and polyploidization is often responsible for the generation of new species during plant evolution [3]. Compared with their diploid relatives, polyploid plants often exhibit advantageous features, including greater adaptability and resistance, and they have giant flowers, fruits, and other prominent features [4,5,6]. To exploit these advantages, artificial methods of inducing polyploidy have become an important tool for plant breeding and they have been widely applied in the breeding programs of crops, vegetables and flowers [7]

Objectives

Methods

Results

Conclusion