Subjects: Biology >> Botany >> Applied botany submitted time 2023-07-13 Cooperative journals: 《广西植物》
Abstract： Climate change has been observed to increase the frequency and intensity of drought, which can adversely affect plant growth and development. Therefore, it is crucial to quantify plant xylem resistance to embolism, particularly in the context of global climate change, to study the process of plant response to drought. In this study, we aimed to evaluate the drought tolerance of Rhododendron cultivars and select those with strong drought resistance by using three species of shrub rhododendrons, namely Rhododendron × pulchrum ‘zihe’, Rhododendron × hybridum ‘yangmeihong’ and Rhododendron simsii, as the materials. Optical techniques were used to construct embolism vulnerability curves in petal and leaf tissues and petal and leaf anatomical structural traits were also measured. The correlation between xylem hydraulic function and anatomical structural traits were also analyzed. The results were as follows: (1) The P12, P50 and P88 values (water potential values corresponding to the occurrence of 12%, 50% and 88% embolism) of petals in Rhododendron × pulchrum ‘zihe’, Rhododendron × hybridum ‘yangmeihong’ and Rhododendron simsii were higher than those of leaves. (2) The embolism vulnerability of petal and leaf tissues varied among the three species, and the speed of petal and leaf embolism occurrence did not coincide, which may be an important characteristic of hybridized horticultural flowering plants. (3)The correlation analysis between P50 values and their morphological characteristics showed that the P50 values of leaves were negatively correlated with leaf palisade tissue thickness, and the P50 values of petals were positively correlated with petal thickness. In conclusion, the study suggests that the petal embolism vulnerability of the three shrubs of Rhododendron is higher than that of the leaves, and the plants preferentially sacrifice the petals to protect the leaves under drought stress. Furthermore, the embolism vulnerability may be related to the leaf palisade tissue thickness and petal thickness. Our findings provide a scientific basis for selecting and configuring tree species of Rhododendron plants in arid areas, and lay the foundation for screening and cultivating drought-resistant Rhododendron varieties.
Subjects: Biology >> Botany >> Applied botany submitted time 2022-02-14 Cooperative journals: 《广西植物》
Abstract： In order to analyze the differences of metabolites and their pathways from flower opening to withering of Rhododendron delavayi, we used LC-MS/MS material separation and identification technique to non-targeted the chemical components of bud stage, dehiscence stage, pollination stage, blooming stage, senescence stage and withering stage. The results were as follows: (1) A total of 973 kinds of metabolites were detected, mainly including flavonoids, organic acids, phenolic acids, amino acids and their derivatives, lipids, alkaloids and so on. (2) Principal component analysis (PCA) shows that there were differences in metabolites among samples. Combined with orthogonal partial least squares discriminant analysis (OPLS-DA), P value of t-test and fold change (Fc) of univariate analysis, differential metabolites (VIP > 1, P < 0.05, Fc > 2 or Fc < 0.5) were screened out, involving 591 species, the quantity and expression of differential metabolites increased significantly after the Rhododendron delavayi flower stage entered the senescence stage and the withering stage, in which the expression of differential metabolites from bud stage to dehiscence stage was mainly down-regulated, while the expression of differential metabolites was mainly up-regulated after entering senescence stage and withering stage. (3) 68 differential metabolic pathways were annotated by KEGG, of which 3 pathways were significantly enriched with differential metabolites (P < 0.01), including phenylpropanoids biosynthesis, plant hormone biosynthesis and flavonoid biosynthesis. (4) Based on the analysis of biosynthetic pathways of phenylpropanoids, flavonoids and other effective components, 10 kinds of differential metabolites were screened from flowering to withering of Rhododendron delavayi, including L-phenylalanine, trans-cinnamic acid, chalcone, naringenin, p-coumaroyl shikimic acid, ferulic acid, coniferyl alcohol, sinapic acid, syringin and quercetin. In addition, the differential metabolites of effective components showed that phenylpropanoids biosynthesis and metabolism activities gradually increased with the development of Rhododendron delavayi, while flavonoid biosynthesis gradually decreased. These key differential metabolites may play an important role in regulating the development of Rhododendron delavayi. This research provides a metabonomic basis for the study of effective components in the metabolic pathway during the flowering and withering process of Rhododendron delavayi, and provides a reference for the further study of the molecular mechanism of flowering regulation of Rhododendron delavayi.
Subjects: Biology >> Botany >> Applied botany submitted time 2021-08-09 Cooperative journals: 《广西植物》
Abstract： Magnoliaceae plants have a long history of cultivation and China is rich in wild resources of them. Magnoliaceae plants have high scientific value, ornamental value, ecological value and economic value. However, the existence of many Magnoliaceae plants is threatened due to the limited reproductive capacity and habitat destruction. The traditional propagation method is inefficient. Tissue culture technology promotes the conservation and utilization of Magnoliaceae plants. It can be applied in the conservation of endangered resources, breeding and commercial production of clonal seedlings. There are many studies on the in vitro shoot propagation, and the system has been relatively perfect. Some studies can achieve rooting seedlings through this way. There are few studies on organogenesis, and the problems of callus induction and adventitious bud differentiation have not been solved effectively. Also, there are few studies on the somatic embryogenesis. This paper reviewed the research on different regeneration ways of Magnoliaceae plants such as in vitro shoot propagation, organogenesis and somatic embryogenesis. The influences of explant selection, basic medium selection, growth regulator concentration and culture condition on in vitro growth of Magnoliaceae plants were discussed. Meanwhile, the paper summarized the problems and the solutions of rooting and browning, and prospected the future research directions. It will provide theoretical basis and technical reference for rapid propagation of Magnoliaceae plants.
Subjects: Biology >> Botany >> Applied botany submitted time 2021-04-02 Cooperative journals: 《广西植物》
Abstract：生境影响植物花部特征的分化。为探究不同人为干扰强度生境是否影响杜鹃花特征分化和资源分配，以及不同颜色杜鹃花分布情况。本研究以百里杜鹃保护区高、中、低人为干扰强度生境的马缨杜鹃、迷人杜鹃和露珠杜鹃为实验材料，采用五点取样法统计不同生境杜鹃花的植株数量，游标卡尺测量花部特征，光学显微镜统计花粉数，海洋光谱仪测定花色的反射光谱，Gephi 软件绘制植株数量的网络图。结果表明：(1)迷人杜鹃植株数量显著多于马缨杜鹃和露珠杜鹃。(2)低强度干扰生境中马缨杜鹃的营养器官和繁殖器官特征指数大于高、中强度生境；不同干扰强度生境对迷人杜鹃花部特征的影响不明显；中、低干扰强度生境露珠杜鹃的营养器官和繁殖器官特征指数显著高于高强度干扰生境。(3)马缨杜鹃和迷人杜鹃的花色在 400~500 nm 波长有较高的反射，而露珠杜鹃的花色在 400~700 nm 波长有较高的反射。(4)在高、中等强度干扰生境中迷人杜鹃与其他两种杜鹃花都分布紧密，在低强度干扰生境中马缨杜鹃和迷人杜鹃分布更紧密。该研究对杜鹃花的种群管理和生物多样性保护提供重要的理论基础。
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