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Zelkova sinica Schneid. is a popular landscape plant in China because of its wide adaptation, strong disease resistance, large crown, and beautiful fall color. Immature embryos from Z. sinica seeds were cultured on woody plant medium (WPM) supplemented with 4.5 μM 6-Benzylaminopurine (BA) and 5.4 μM α-naphthaleneacetic acid (NAA) to induce callus, and 60% of immature embryos formed callus. The cream-white, friable, nodular callus with proembryogenic structures was then cultured on WPM containing 5.4 μM NAA in combination with 9.0 or 11.2 μM BA to regenerate shoots; approximately five shoots per explant were induced on 70% callus. Shoots were rooted on WPM containing 0.5 μM indole-3-butyric acid (IBA), on which 62.3% shoots developed roots with an average of 4.2 roots per shoot at 4 weeks. The regenerated plantlets were acclimatized and transplanted into the field. This protocol could be used for mass production for field plantation, genetic improvement, and germplasm exchange of Z. sinica.
To shorten Ilex seed germination time and speed up breeding cycles, immature embryos of Ilex crenata ‘Sky Pencil’ seedlings were removed from fruits at their heart-shape stage and cultured in vitro on Murashige and Skoog (MS) medium or Woody Plant Medium (WPM) with 3% sucrose and 0.65% agar. Cultures were incubated at 27 °C for 2 weeks in darkness and subsequently moved to a growth chamber with 14-hour photoperiod (115 μmol⋅m−2⋅s–1). Embryos began to germinate 2–3 weeks after culture. The highest germination rate was 91.67% under 1/4 MS medium. Embryos cultured on MS medium also had high germination rates and produced the longest seedlings to 8.02 mm. Nodal segments with one axillary bud taken from embryo germination seedlings were cultured on MS medium with various concentrations of cytokinins and auxins for micropropagation. Zeatin (ZT; 4-hydroxy-3-methyl-trans-2-butenylaminopurine) increased the number of shoots and shoot lengths significantly more than 6-benzylaminopurine (6-BA). The recommended ZT concentration should be 2.28 µM. Rooting induction could be established on 1/4 MS medium with various concentrations of indole-3-butyric acid (IBA) or 1-naphthaleneacetic acid (NAA). IBA at 4.14 µM produced the best rooting percentage (91.67%) and good-root quality. All rooted plantlets were transplanted into a mixture of peatmoss and perlite (1:1 v/v) and acclimatized in a mist system. The average survival rate was 88.8%. The rapid embryo germination protocol for Ilex crenata could save Ilex breeders at least 2 years compared with traditional seed germination.
Lagerstroemia is a genus with a wide geographical range extending from Southeast Asia to Australia, and it plays a significant role in many aspects of urban life, including supporting ecosystems, beautifying cities, and affecting human health. To gain insights into the current state of Lagerstroemia research, a bibliometric analysis was conducted using 138 publications from the Web of Science core database between 2002 and 2022. The analysis involved co-occurrence analyses of authors’ affiliated institutions, a keyword co-occurrence analysis, and a timeline view of keywords. The results of the analysis revealed three stages of Lagerstroemia research: the initial stage (2002–04); the rapid growth stage (2005–13); and the in-depth stage (2014–present). Furthermore, 335 keywords from 10 clusters were identified, which indicated that genetic diversity, breeding, and landscape utilization were the three main research areas of Lagerstroemia. Collaboration among authors mainly occurred within major natural and cultivated regions, such as China and the United States. Based on the bibliometric evaluation, future research of Lagerstroemia should focus on areas such as whole-genome sequencing, male sterility problems, resistance, ornamental characteristics, and landscape utilization guidelines. The findings of this study provide an important reference for further studies and can guide the development, innovation, and application of Lagerstroemia.
Karyotype comparison and fluorescence in situ hybridization (FISH) were conducted to analyze the wild Lilium species distributed in China. The karyotype results revealed that all species except Lilium lancifolium (2n = 3X = 36) were diploid and had two pairs of metacentric or submetacentric chromosomes. The karyotypes of all species are similar. FISH analysis revealed that there are 5–12 45S rRNA gene loci dispersed on the chromosomes of the 14 diploid species, and 15 45S rRNA gene loci were detected in the triploid species L. lancifolium. Most of the FISH signals were detected on the long arms and the centromeric regions. Three samples of L. brownii [Hubei, China (lat. 31°28′N, long. 110°23′E); Liaoning, China (lat. 40°07′N, long. 124°19′E); and Guangxi, China (lat. 25°06′N, long. 107°27′E)] showed very similar chromosome patterns in both the karyotype and the FISH analyses, further demonstrating that these samples belonged to the same species. L. brownii is widely distributed in China from latitude 25°06′N to 40°07′N, indicating that it is highly adaptable to the environment.