Magnolia lucida (Magnoliaceae) is classified as an endangered species by the International Union for Conservation of Nature. It has high commercial value owing to its attractive tree shape and flowers. We adopted an excellent genotype of M. lucida as the parent material and established a mini-cut orchard through grafting to provide trunk shoots explants over the long-term. Optimal sterilization was achieved using a combination of 75% ethanol for 30 s, one percent benzalkonium bromide for five minutes, and 0.1% mercuric chloride for five minutes. Modified Murashige and Skoog medium (ML) was the optimal medium for the growth of M. lucida. Addition of one mg/L of 6-benzyl adenine (BA) and 0.05 mg/L of α-naphthaleneacetic acid (NAA) to the medium increased the shoot induction rate to 95.56%, and the ML medium containing 0.4 mg/L BA and 0.04 mg/L NAA achieved the maximum multiplication rate (284.56%). Dark treatment for seven days, followed by continuous light treatment could better resolve the challenge of difficult rooting in M. lucida plants. Using random amplified polymorphic DNA and inter simple sequence repeat markers, we confirmed the genetic uniformity and stability of the regenerated plants. Our protocol should be helpful for the propagation and conservation of this endangered plant.

Bretschneidera sinensis is a monotypic species of rare and tertiary relic trees mainly distributed in China. B. sinensis is a potentially valuable horticultural plant, which has significant ornamental and research value, and is a crucial tool for the study of phylogeography. The artificial cultivation of B. sinensis is of great scientific value and practical significance. In this study, we developed a direct organogenesis process of B. sinensis using mature zygotic embryos as initial materials. The highest sterile germination induction (54.5%) from the mature zygotic embryo was obtained in a Murashige and Skoog (MS) medium with 2.0 mg·L⁻¹ 6-benzylaminopurine (6-BA) and 0.2 mg·L⁻¹ α-naphthaleneacetic acid (NAA). The highest percentage of shoot regeneration (90.37%) was attained using 1.0 mg·L⁻¹ 6-BA and 0.01 mg·L⁻¹ NAA in the MS medium. The Woody Plant Medium (WPM) had the greatest adventitious shoot elongation rate of 93.33%. The most optimized rooting rate was 88.89% in a half-strength MS medium containing 2.0 mg·L⁻¹ indole-3-butyric acid (IBA) and 1.0 mg·L⁻¹ NAA. The genetic fidelity of in vitro regenerated plantlets was assessed using inter-simple sequence repeats and random amplified polymorphic DNA molecular markers, confirming the genetic uniformity and stability of regenerated B. sinensis plantlets. Our research presents an effective in vitro propagation system for B. sinensis, laying the groundwork for its germplasm conservation and large-scale production while maintaining high genetic integrity.

Mango (Mangifera indica L.) is one of the most significant tropical and subtropical fruit species, with high ecological and economic value. However, research on the in vitro culture of mangoes is relatively weak, so establishing an efficient and stable mango plant regeneration system is of great significance. In this study, a preliminary mango regeneration system was established with Mangifera indica L. cv. Keitt from young branches as the starting explants. The results showed that the optimal plant growth regulator (PGR) formula for direct adventitious shoot induction on the branches was 1 mg/L 6-benzylaminopurine (6-BA) + 0.1 mg/L a-naphthaleneacetic acid (NAA), with an adventitious shoot induction rate of 73.63% and an average of 6.76 adventitious shoots. The optimal basal medium for adventitious shoot induction was wood plant medium (WPM), with an adventitious shoot induction rate of 63.87% and an average of 5.21 adventitious shoots. The optimal culture medium for adventitious shoot elongation was WPM + 1 mg/L 6-BA + 0.5 mg/L NAA, with an adventitious shoot elongation rate of 89.33% and an average length of 5.17 cm. The optimal formula for the induction of mango rooting was Douglas fir cotyledon revised medium (DCR) + 3 mg/L indole-3-butyric acid (IBA), with a maximum rooting rate of 66.13% and an average rooting quantity of 6.43. The genetic fidelity of the in vitro-regenerated plants was evaluated using inter-simple sequence repeat (ISSR) molecular markers. There was no difference between the in vitro-regenerated plants and the parent plant. This study provides an efficient and stable propagation system for Mangifera indica L., laying the foundation for its rapid propagation and genetic improvement.

The deciduous conifer larch has been widely distributed around the world, which is a high-quality wood species and is also used to extract industrial raw materials and medicines. In this study, we developed an organogenesis protocol for Larix olgensis from both mature zygotic embryos and needles, and analyzed the content of taxifolin in different tissues. The highest callus induction (96.8%) from mature zygotic embryo was got in the Douglas-fir Cotyledon Revised (DCR) medium augmented with 2.0 mg/L 6-Benzylaminopurine (6-BA) and 0.2 mg/L α-Naphthaleneacetic acid (NAA), while from needles the highest callus induction (92.03%) was got in the Murashige and Skoog (MS) medium augmented with 3 mg/L 6-BA and 0.3 mg/L NAA. The best shoot regeneration capacity from zygotic embryo-derived calli (83.3%) was obtained in DCR medium augmented with 1.0 mg/L 6-BA and 0.01 mg/L NAA, and needle-derived calli were 77.3%. The shoots achieved the highest elongation (75.6%) in the DCR medium supplemented with 0.5 mg/L 6-BA, 0.05 mg/L NAA and 2g/L activated charcoal (AC). The rooting rate was 62.8% in DCR medium augmented with 3 mg/L Indole-3-butyric acid (IBA) and 100 mg/L phloroglucinol (PG). The accumulation of the taxifolin in elongation shoots and lignified elongation shoots have greatly improved along with the development process, were 28.6 µg/g, and 53 µg/g respectively. The content of the taxifolin in callus was 1.99-5.26 µg/g, adventitious shoots were 4.8µg/g, and adventitious roots were 2.86 µg/g. To date, we reported an efficient organogenesis and taxifolin production protocol in larch for the first time.