In vitro propagation and long-term observation of acclimated plants in endangered tree fern Alsophila costularis

Abstract

Alsophila costularis Barker (Cyathea costularis), an endangered tree fern with tree-like erect stem, attracts gardening enthusiasts as a special ornamental plant. In vitro propagation can be advantageous for germplasm conservation and commercial application of A. costularis. Here, we described in vitro propagation of A. costularis via spore culture and green globular bodies (GGBs) system, as well as the long-term observation of acclimated plants regenerated from GGBs. In spore culture, the low concentration of mineral salt (1/8 MS) was bene cial for sporophyte formation on gametophytes, but sporophytes per conical ask was only 8 plantlets. In GGB system, cytokinin thidiazuron (TDZ) was essential for GGB induction and multiplication. The maximum of GGB induction frequency (93.33%) was obtained on 1/2MS medium with 2.0 mg/l TDZ by using juvenile sporophytes as explants, and the same medium was optimal for GGB multiplication. 1/4 MS supplemented with 0.1% (w/v) activated carbon (AC) was appropriate for plantlet regeneration from GGB, GGB differentiation frequency was 100%, and 42.40 plantlets could be regenerated from one piece of GGBs. The maximum of plantlet height (4.64 cm) was obtained on 1/2 MS with 0.1% (w/v) AC. After 6 years of acclimatization cultivation for plantlets regenerated from GGBs, plants in the plastic pots with diameter of 60 cm showed the excellent vegetative and reproductive growth, and the mature spores of these plants could produce sporophytes. Morphological and histological observation demonstrated that A. costularis GGBs was a green structure consisting of multiple single GGBs with hair-like structures. One single GGB could develop into one plantlet.* Plantlet regeneration e ciency indicates the number of plantlets regenerated from one piece of GGBs, and the initial diameter and fresh weight of GGBs was 3.0 mm and 5.0 mg, respectively.

Distribution model and prediction of the tree fern Alsophila costularis Baker (Cyatheaceae) in China

“…The MaxEnt model showed that temperature was the key factor determining the current distribution of A. costularis . Alsophila costularis is difficult to propagate in the wild because its spore germination is impacted by environmental factors, including temperature and moisture (Cheng et al., 1990 ; Pu et al., 2023 ). Ultraviolet radiation can cause injuries to aboveground organs of organisms and limit their distribution (Wu et al., 2021 ).…”

“…Compared to other ferns of Cyatheaceae, A. costularis has been little studied, especially as regards its ecology. Previous studies have focused on tissue culture (Cheng & Liu, 1992 ), gametophyte development (Wang et al., 2007 ; Xiao et al., 2019 ), DNA extraction (Ying et al., 2009 ), chloroplast genome (Wang et al., 2019 ), and the efficient green globular bodies system (Pu et al., 2023 ).…”

In vitro spore germination and gametophyte development of two Cyathea species of South America in response to nutrient media

“…The Rodriguésia 74: e00622023. 2023 (Borelli et al 1990;Avila-Pérez et al 2011;Bharati et al 2013;Suo et al 2015;Alves et al 2019;Pu et al 2023) is related to the broad diversity of nutrients in its composition, which includes vitamins, amino acids and essential macronutrient and micronutrient salts for plant development (Rybczyński & Mikuła 2011). However, depending on the physiology of the cultivated species, metabolic processes can be impaired by this nutrient composition (Murashige & Skoog 1962;Sakuta et al 1987;Grattapaglia & Machado 1998) However, in a study carried out with Dicksonia sellowiana Hook.…”

“…Studies aimed at evaluating the influence of nutrient media focus mainly on spore germination and/or sporophyte formation (Avila-Pérez et al 2011;Suo et al 2015;Alves et al 2019;Pu et al 2023), and the development of gametophytes is lacking in discussion. However, the newly germinated spores, with chlorocyte and rhizoid, show fast growth and rapidly develop into gametophytes (Rybczyński & Mikuła 2011), and the gametophytic stage is determinant for the success of fertilization and sporophyte formation.…”