Maintenance and variation of chromosome ploidy under tissue culture conditions of different Camellia germplasms

Abstract

The maintenance and variation of ploidy in plants are influenced by environmental factor, and the tissue culture regeneration can often cause changes of chromosome structures and ploidy levels. In order to explore the ploidy variation of Camellia germplasm under tissue culture conditions, the callus induction system of Camellia germplasm was used to analyze the ploidy changes by flow cytometry, and the stability and variation of the ploidy under tissue culture generation were analyzed in combination with colchicine treatment. The results were as follows:(1)Six of ten of Camellia germplasms were diploid, two of them were tetraploid, one hexaploid and one decaploid, and the germplasm materials largely maintained stable ploidy levels during the tissue regeneration processes.(2)The optimum conditions for colchicine treatment were obtained, that is, the callus was cultured in treatment medium containing colchicine at 20 mg·L-1 for 10 d, followed by regeneration in tissue-differentiation culture.(3)The ploidy analyses were carried out on the treated tissues in different differentiation states, and the results showed that most of the independent tissues(including 56 callus and shoots)were found to be aneuploids, 38 tissues had ploidy between 1.5 to 2.5, and 11 tissues produced less than 1.5. This study further explores the ploidy relationship between different Camellia germplasms, and provides a reference for an in-depth study of ploidy regulation and polyploid induction of Camellia.

Keywords

• camellia
• chromosome ploidy
• tissue culture
• colchicine