Subjects: Biology >> Botany >> Applied botany submitted time 2024-02-07 Cooperative journals: 《广西植物》
Abstract： In this study, we sought to investigate the correlation between endophytic bacteria colonizing the leaves of Loropetalum chinense var. rubrum and the seasonal abnormal leaf coloration characteristic of this plant. Hence, we performed plate isolation and culturing and subsequent 16S rDNA sequence analysis to isolate and identify endophytic bacteria from leaves with five abnormal colors and normal red-colored leaves of L. chinense var. rubrum; we also analyzed differences in bacterial diversity, community structure, and functional levels among differently colored leaves. The results were as follows: (1) Compared with the normal red-colored leaves, we detected higher biomasses of endophytic bacteria in the five types of abnormally colored leaves. Among the isolated bacteria, 16S rDNA sequence alignment and phylo-genetic tree analysis revealed the presence of 906 bacterial strains classified into 26 genera and 40 species. (2) While the smaller leaves were colonized by the largest number of endophytic bacterial species with a relatively uniform community structure, the opposite was true for bacteria isolated from the redand yellow-pigmented leaves. (3) Comparison of the bacterial community data for abnormally colored leaves and those with the normal red color revealed that not only were there significant differences with respect to the dominant genera and species but also an enrichment of numerous bacterial species in the genera Methylobacterium and Pseudomonas in the five types of abnormally colored leaves. Particularly, we detected significantly larger numbers of Pseudomonas oryzihabitans. (4) We established that abnormally colored leaves (smaller, red spotted, and the red and yellow types) were characterized by an enrichment of bacteria with phosphorus solubilization, nitrogen fixation, IAA production, and salt tolerance functions, among which, four strains were found to have all four of these functions. Accordingly, we speculate that the abnormal leaf coloration of L. chinense var. rubrum is closely associated with the activities of these enriched functional bacteria. Our findings in this study indicate that the abnormal leaf coloration of L. chinense var. rubrum is closely associated with the enrichment of specific endophytic bacterial communities, which can thus provide clues for elucidating the mechanisms underlying the development of abnormal leaf pigmentation in this plant. Moreover, this may have important application value for the efficient cultivation of high-quality L. chinense var. rubrum.
Subjects: Biology >> Botany >> Applied botany submitted time 2024-02-07 Cooperative journals: 《广西植物》
Abstract： In order to investigate the impact of climatic factors on the quality of Siraitia grosvenorii fruits pollinated in different seasons and the underlying molecular mechanism involved, the differences in climate factors, quality traits, and gene expression between fruits of the main cultivar S. grosvenorii “Qingpiguo” pollinated in summer and autumn were statistically analyzed by monitoring climate factors at different developmental stages, measuring morphological changes, detecting mogroside metabolism, and analyzing gene expression using qRT-PCR. The results were as follows: (1) compared to summer-pollinated fruits, the average temperature and effective accumulated temperature of autumn-pollinated fruits decreased significantly after 35 d. Additionally, the temperature difference between day and night increased significantly before 65 d. However, this difference was still less than that of the average temperature and effective accumulated temperature. The light intensity and air humidity remained similar. (2) The transverse diameters, longitudinal diameters, and single fruit weights of autumn-pollinated fruits increased compared to those of summer-pollinated fruits, however, these differences were not statistically significant. (3) Mogroside V and 11-O-mogroside V in autumn-pollinated fruits accumulated slowly from 55 d with a delay of about 10 days, moreover, the content of both compounds in ripe fruits decreased by 40.66 % and 46.07 %, respectively. (4) The number and extent of up-regulated mogroside V genes were relatively lower, and their co-expression consistency was poorer. Furthermore, the glucosyltransferase gene SgUGT94-289-3, responsible for the final step in mogroside V biosynthesis, exhibited down-regulation at all time points of 55 d. In summary, the shape and size of S. grosvenorii fruits pollinated in different seasons were not significantly affected by climatic factors; however, the content of mogroside V was significantly influenced by the temperature, which potentially influences these variations in mogroside V by regulating both the co-expression consistency and expression level of mogroside V genes. The results of this study can provide theoretical basis for high-quality cultivation and genetic breeding of S. grosvenorii.
Subjects: Biology >> Botany >> Applied botany submitted time 2023-09-20 Cooperative journals: 《广西植物》
Abstract： Saxifraga L. is rich in species diversity with about 440–500 species and broad distribution. The taxonomical issues of this genus have been continuously concerned by the botanists. Saxifraga has important ornamental and medicinal values. Some of European countries have made great efforts on the exploitation and utilization of its ornamental resources. China is one of the diversity centers of Saxifraga, but it has been lagged far behind Europe, USA and even Japan in exploitation and utilization on ornamental value of this genus. The world breeding work in Saxifraga started 150 years ago. By the end of 2022, the 1 692 names of cultivars had been on-line listed by The Saxifrage Society, but only one came from China. In this paper, the germplasm resources of Saxifraga, and progress on its classification and breeding were reviewed, and also the utilization of its ornamental resources was briefly introduced, which will provide an important reference for taxonomical research, breeding and horticultural application of this genus in China. The results were as follows: (1) Saxifraga is rich in germplasms, but many scientific issues remain in the evolutionary relationships of its subordinate systems, which require a systematic and in-depth investigation by integrating morphological and molecular biology methods. (2) The cultivars of this genus are mainly raised through cross-breeding and mutant selection, and the majority of cultivars produced from the UK, Czech Republic, Germany, and the Netherlands. (3) The breeding of Saxifraga started very late in China, with only few cultivars from one breeding method.
Subjects: Biology >> Botany >> Applied botany submitted time 2022-05-21 Cooperative journals: 《广西植物》
Abstract： As a shade plant with high ornamental value, Saxifraga stolonifera is often used in landscape of courtyards and gardens. The light intensity may have an important impact on its growth performance, especially on leaf color, formation and coloration of leaf variegation, which subsequently affects its ornamental value. However, the related study has not been reported before. In order to explore the adaptability of different cultivars of S. stolonifera to light intensity and understand their light or shade tolerance, three internationally-registered cultivars raised in China were used as the experimental material, the effects of five light intensity treatments (100%, 85%, 60%, 40% and 15%) on plant growth and development and photosynthetic physiological indexes were investigated. The suitable indexes of light intensity for Saxifraga were screened by the principal component analysis, and the light tolerance of the cultivars was evaluated by membership function analysis. The results were as follows: (1) The number of stolons, number of blades, leaf length, leaf width, leaf area, specific leaf area, chlorophyll a, b and total chlorophyll contents increased with shading. (2) The fresh and dry weight above ground, stolon diameter, and the contents of carotenoid and flavonoids increased first and then decreased. (3) The initial fluorescence values and the contents of soluble sugar, soluble protein and malondialdehyde of the leaves decreased with shading. (4) By analysis of principal component and membership function, the significant differences were found in the adaptability of the three cultivars to light intensity, ‘Xue Wen’ > ‘Tianmu Enci’ > ‘Hei Kui’. In which, 40% light intensity is optimal for ‘Xue Wen’, and 15%-40% light intensity is optimal for ‘Tianmu Enci’ and ‘Hei Kui’. Therefore, in horticultural practice, the suitable light intensity should be considered according to the cultivars of Saxifraga.
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