Micropropagation of Hibiscus moscheutos L. ‘Luna White’: Effect of growth regulators and explants on nuclear DNA content and ploidy stability of regenerants

Authors: Sakhanokho, Hamidou; ISLAM-FARIDI, NURUL - US Department Of Agriculture (USDA); Babiker, Ebrahiem; Smith, Barbara

Submitted to: In Vitro Cellular and Developmental Biology - Plants
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/15/2021
Publication Date: 9/3/2021
Publication URL: https://handle.nal.usda.gov/10113/7681105
Citation: Sakhanokho, H.F., Islam-Faridi, N., Babiker, E.M., Smith, B.J. 2021. Micropropagation of Hibiscus moscheutos L. ‘Luna White’: Effect of growth regulators and explants on nuclear DNA content and ploidy stability of regenerants. In Vitro Cellular and Developmental Biology - Plants. doi.org/10.1007/s11627-021-10209-w.
DOI: https://doi.org/10.1007/s11627-021-10209-w

Interpretive Summary: Common rosemallow (Hibiscus moscheutos L.) also known as hardy hibiscus is native to North America and grown as an ornamental for its showy flowers with colors ranging from white to pink. It is usually propagated via seeds or cuttings. The purpose of our study was to develop an efficient and dependable micropropagation for H. moscheutos ‘Luna White’. To that end, we used four explants or plant parts (leaf, root, node, shoot tip) and two growth regulators (BA and mT). No plants were from leaf or root in tissue culture. The other plant parts (node and shoot tip) were grown in tissue culture in the presence of the growth regulators BA and mT. For each growth regulator, four concentrations were used. To make sure that the plants produced in tissue culture remained true-to-type, we used flow cytometry, chromosome spread, and fertility test. All these methods showed that the plants obtained in tissue culture were not different from seed-derived plants. The protocol developed in this investigation can be used for industrial mass micropropagation of improved selections or cultivars of rosemallow plants.

Technical Abstract: Hibiscus moscheutos L., also known as hardy hibiscus, is valued for its medicinal and ornamental attributes. It is usually propagated via seeds or cuttings. The purpose of this investigation was to develop a dependable micropropagation for H. moscheutos ‘Luna White’. To that end, the effect of four explant types (leaf, root, node, shoot tip) and two growth regulators, 6-benzylaminopurine (BA) and meta-Topolin (mT) (6-(3-hydroxybenzylamino) purine) on in vitro growth of H. moscheutos. Genetic stability of the in vitro grown plants was assessed using flow cytometry, chromosome spread, and fertility test. No shoots were obtained from leaf or root explants. An efficient protocol for micropropagation of H. moscheutos using two explant types, 2-node and shoot tip explants, and two cytokinins (BA and mT) capable of producing true-to-type regenerants was established. Both BA and mT can be used at 2 µM or 4 µM using either 2-node or shoot tip explants. No significant difference was found between the nuclear DNA contents of seed-derived and in vitro grown plants (P < 0.05). The mean 2C DNA and monoploid 1Cx-values of seed-derived plants were 3.25 + 0.08 pg and 1.62 + 0.04 pg, respectively compared with 3.26 + 0.06 pg and 1.63 + 0.02 pg, respectively for in vitro grown plants. The chromosome number of both seed-derived plants and regenerants was determined to be 2n = 2x = 38. The mature regenerants obtained were fertile and phenotypically similar to seed-derived plants.