Sedum dormiens (Crassulaceae, Sempervivoideae, Sedeae): a new species from the Sierra de Manantlán, Mexico

Sedum dormiens (Crassulaceae) from the Sierra de Manantlán in Jalisco, Mexico, is described. The distinctive characters of the species are its chamaephytic nature, capillary roots, formation of large colonies, tetramerous flowers with white petals, dormant terminal and lateral buds in the mother plant and connate fruits of ½–¾ its length. The habitat and morphology of the species is illustrated and its relationships with close species presented. Its conservation status was categorized as Endangered (EN).

Cyclanilide Induces Lateral Bud Outgrowth by Modulating Cytokinin Biosynthesis and Signalling Pathways in Apple Identified via Transcriptome Analysis

Cyclanilide (CYC), a plant growth regulator, is a potent shoot branching agent in apple. However, its mechanism remains unclear. The current study revealed that CYC treatment resulted in massive reprogramming of the axillary bud transcriptome, implicating several hormones in the response. We observed a marked increase (approximately 2-fold) in the level of zeatin riboside and a significant decrease (approximately 2-fold) in the level of abscisic acid (ABA). Zeatin metabolism gene cytokinin (CTK) oxidase 1 (CKX 1) was down-regulated at 168 h after CYC treatment compared with the control. Weighted gene co-expression network analysis of differentially expressed genes demonstrated the turquoise module clusters exhibited the highest positive correlation with zeatin riboside (r = 0.92) and the highest negative correlation with ABA (r = −0.8). A total of 37 genes were significantly enriched in the plant hormone signal transduction pathway in the turquoise module. Among them, the expressions of CTK receptor genes WOODEN LEG and the CTK type-A response regulators genes ARR3 and ARR9 were up-regulated. ABA signal response genes protein phosphatase 2C genes ABI2 and ABI5 were down-regulated in lateral buds after CYC treatment at 168 h. In addition, exogenous application of 6-benzylaminopurine (6-BA, a synthetic type of CTK) and CYC enhanced the inducing effect of CYC, whereas exogenous application of lovastatin (a synthetic type of inhibitor of CTK biosynthesis) or ABA and CYC weakened the promoting effect of CYC. These results collectively revealed that the stimulation of bud growth by CYC might involve CTK biosynthesis and signalling, including genes CKX1 and ARR3/9, which provided a direction for further study of the branching promoting mechanism of CYC.

Primary morphogenesis of Sorbus Torminalis L. (Grantz) into in vitro culture

Nowadays in vitro methods, combined with ex situ and becoming an increasingly important means of preserving and maintaining the level of phytodiversity stability. Sorbus torminalis L. is a tree of the Rosaceae family, which grows on the territory of Ukraine, belongs to rare, valuable aboriginal species and is listed in the Red Book of Ukraine, with its protection status - endangered. The peculiarities of introduction of in vitro culture of perennial representatives of S. torminalis with the use of different types of explants, sterilizing substances, cultivation conditions and nutrient medium composition are presented in the paper. For in vitro culture of S. torminalis, annual shoots with apical and lateral buds 15-25 cm long are optimal. The influence of different sterilization options on the development of primary microshoots has been studied. For sterilization of artificially awakened and young shoots it is most effective to use 0.1% solution of AgNO3 (7 min) and 15% solution of H2O2 (10 min). The developed method of sterilization of S. torminalis explants provided 80-90% yield of aseptic plant material. It was found that the sterilization regime did not significantly affect the primary morphogenesis of explants and was uniform. The optimal components of nutrient media at the stage of introduction into vitro culture and primary morphogenesis of S. torminalis have been established. For the cultivation of different types of explants of S. torminalis, used WPM nutrient media with the addition of synthetic plant growth regulators 6-benzylaminopurine, thidiazuron, kinetin 0,5-1,5 mg mg∙l-1 and α-naphthylacetic acid 0,01-0,05 mg∙l-1 both alone and in combination with each other. In particular, for the regeneration of plants from the lateral and apical buds of explants is effective WPM medium with the addition of BAP 1,5 mg∙l-1 + 0,5 mg∙l-1 NAA and WPM + TDZ medium 0,5 mg∙l-1 with adding PVP 200 mg∙l-1. To induce the laying of additional buds and shoots on the explant from the apical meristems in the medium should be added 4,0 mg∙l-1 BAP + 0,01 mg∙l-1 NAA with the addition of PVP 200 mg∙l-1.

Expression Analysis of DgD14, DgBRC1 and DgLsL in the Process of Chrysanthemum Lateral Bud Formation

The growth of lateral bud can greatly affect the development of apical bud and reduce the quality of single-flower cut chrysanthemum. However, the wide use of artificial bud removal in production leads to the increase on production cost. Therefore, it is important to study the lateral bud development mechanism in chrysanthemum for plant type regulation and genetic improvement. Auxin (IAA), cytokinins (CKs) and strigolactones (SLs) have direct or indirect effects on the formation of lateral buds. D14, BRC1 and LsL are key factors regulating the signal pathways of hormones, but their regulation mechanisms on the development of lateral buds in chrysanthemum are still unclear. In this study, single-flower cut chrysanthemum ‘Jinba’ and spray cut chrysanthemum ‘Fenyan’ were used as experimental materials. Quantitative real-time PCR was used to observe the effects of apical bud removal and exogenous hormones on the growth of lateral buds and the expression levels of DgD14, DgBRC1 and DgLsL, so as to clarify the expression characteristics of three genes in the process of lateral bud formation. The results showed that GA was effective in promoting the growth of lateral buds, whereas IAA and ABA had little effects on lateral bud growth or even inhibited. Removing apical dominance can significantly affect the expression levels of three genes, which regulated the formation and elongation of lateral buds. Additionally, the three genes showed different responses to different hormone treatments. DgD14 had a significant response to GA, but a gentle response to ABA. The expression levels of DgBRC1 varied in different trends, and it responded to IAA in a more dramatic way. The levels of DgLsL reached the peaks quickly before decreased in most experimental groups, and its response to GA was extraordinary severe.

Cercetări privind diversitatea genofondului nucului (Juglans regia L.) în Republica Moldova

In the article there are presented some results of morphological and ecological researches of wal-nut (Juglans regia L.) genotypes, selected in different pomological zone of Rep. Moldova. Obtained data shows manifestation of different characteristics like flowering period, dichogamous types, manifestation of capacity to develop pistillate flowers from lateral buds, as well as capacity of formation of fruits from lateral buds.

Modified Atmosphere Packaging Maintains the Sensory and Nutritional Qualities of Post-harvest Baby Mustard During Low-Temperature Storage

Baby mustard is a popular, yet highly perishable, Brassica vegetable. There is a need to develop effective methods for maintaining post-harvest qualities of baby mustard. Here, the lateral buds of baby mustard were packed in transparent polyethylene bags with no holes (M0), 6 mm in diameter holes (M1), or 12 mm in diameter holes (M2) and stored at 4°C. The effect of different modified atmosphere packaging (MAP) treatments on the sensory quality, health-promoting compounds, and antioxidant capacity was investigated by comparison with non-wrapped baby mustard. M1 and M2 delayed sensory quality deterioration and slowed declines in the content of ascorbic acid, total phenolics, and glucosinolates and antioxidant capacity during storage. M1 was most effective in prolonging the shelf life (three additional days compared with control lateral buds) and maintaining the content of glucosinolates. However, M0 accelerated the decline in the odor score, acceptability score, and ascorbic acid content and shortened the shelf life of baby mustard by more than 5 d compared with the control. These findings indicate that the effect of MAP treatment depends on the size of the holes in the bag. Based on these results, M1 was an alternative method for prolonging the shelf life and maintaining post-harvest qualities of baby mustard stored at 4°C.

Morphological, phenological, and transcriptional analyses provide insight into the diverse flowering traits of a mutant of the relic woody plant Liriodendron chinense

Flowering is crucial to plant reproduction and controlled by multiple factors. However, the mechanisms underlying the regulation of flowering in perennial plants are still largely unknown. Here, we first report a super long blooming 1 (slb1) mutant of the relict tree Liriodendron chinense possessing a prolonged blooming period of more than 5 months, in contrast to the 1 month blooming period in the wild type (WT). Phenotypic characterization showed that earlier maturation of lateral shoots was caused by accelerated axillary bud fate, leading to the phenotype of continuous flowering in slb1 mutants. The transcriptional activity of genes related to hormone signaling (auxin, cytokinin, and strigolactone), nutrient availability, and oxidative stress relief further indicated active outgrowth of lateral buds in slb1 mutants. Interestingly, we discovered a unique FT splicing variant with intron retention specific to slb1 mutants, representing a potential causal mutation in the slb1 mutants. Surprisingly, most slb1 inbred offspring flowered precociously with shorter juvenility (~4 months) than that (usually 8–10 years) required in WT plants, indicating heritable variation underlying continuous flowering in slb1 mutants. This study reports an example of a perennial tree mutant that flowers continuously, providing a rare resource for both breeding and genetic research.