Morphological, cytological, and pigment analysis of leaf color variants regenerated from long-term subcultured caladium callus

• Published in: In vitro cellular & developmental biology. Plant Vol. 57; no. 1; pp. 60 - 71
• Main Authors: Chen, Jin-Jin, Zhang, Yuan-Shan, Duan, Jia-Xin, Cao, Yun-Mei, Cai, Xiao-Dong
• Format: Journal Article
• Language: English
• Published: New York Springer US 01.02.2021; Springer Nature B.V
• Subjects: Anthocyanins; Biomedical and Life Sciences; Callus; Cell Biology; Cell culture; Chlorophyll; Chromosome number; Chromosomes; Color; Correlation analysis; Deoxyribonucleic acid; Developmental Biology; DNA; Flavonoids; Flowers & plants; Leaves; Life Sciences; Micropropagation; Morphology; Ornamental plants; Plant breeding; Plant Breeding/Biotechnology; Plant Genetics and Genomics; Plant growth; Plant Sciences; Ploidy; Somaclonal variation; Stomata; Subcultures; Tissue culture; China; Pigment content; Nuclear DNA content; Somaclonal variation; Color parameters; Chromosome number
• ISSN: 1054-5476; 1475-2689
• DOI: 10.1007/s11627-020-10106-8

Cultivated caladiums ( Caladium × hortulanum Birdsey) are popular ornamental plants. Although somaclonal variation occurs frequently in caladium during tissue culture, little research has been conducted on obtaining and detecting variants from long-term callus cultures. Herein, plants were regenerated from ‘Red Flash’ caladium calluses subcultured for approximately 40 mo, and 116 out of 520 established plants were grouped into 14 somaclonal variation types based on their morphological differences. Nuclear DNA content of six types (SVT1, SVT2, SVT4, SVT5, SVT8, and SVT10) varied from − 1.08% to 0.33% compared with the wild type, and these variants shared a similar chromosome number to the wild caladium (2 n  = 2 x  = 30). Three types (SVT3, SVT7, and SVT9) containing 2.82 to 5.42% less nuclear DNA content was the result of losing one or two chromosomes, and one type (SVT6) with significantly lower cellular DNA content was due to losing four chromosomes. Four types (SVT11–SVT14) contained 85.16 to 101.52% more DNA content and the SVT12 and the SVT13 had a double number of chromosomes (2 n  = 4 x  = 60), while the SVT11 and SVT14 had four more chromosomes and six less chromosomes as compared with a typical tetraploid, respectively. Correlation analysis suggested that leaf thickness, leaf index, and stomatal characteristics could be used as indicators of plant ploidy in caladium. A wide variation of pigment content was found among the variation types, and the content of chlorophyll, flavonoid, and anthocyanin had a significant positive correlation with the color parameters a* and b*. Leaf color variants created by prolonged in vitro callus cultures might hold great promise for caladium breeding.