Leaf Traits And Cutting Propagation Of Four Lianas

Lianas are essential components of urban vertical greening, playing a significant role in increasing the diversity of landscape and improving the ecological environment. Leaf traits affected the basic behavior and function of plants directly, which strongly linked to the growth strategy of plants’ acclimatization and the ability to access resources. How good quality continued, involving the cultivation of plants. The application of matrix composition and growth regulating substances was the important factor affecting cuttage rooting. To explore the influence by different types of matrix, concentrations of IBA and NAA on cuttage propagation, the study provided a scientific basis for propagation and popularizing application of plants. Study on the growth characteristics and the plasticity of seedlings, with great significance for seedling cultivation and management, reflected the ecological adaptation strategy of plants to different environments.Based on four common species of landscape lianas in South China, the study took some measurements of leaf traits from mature blades to explore the relationship of leaf growth and the relationship between leaf traits, and assess plant’s adaptation ability to the environment. Clustering analysis was carried out on the leaf functional traits and species; Cuttage experiment was carried out with orthogonal design(3×3), analyzing the influence by different combinations of matrix, concentrations of IBA and NAA on cuttage propagation, to find out optimal treatment of cuttage propagation of different species by estimating the cuttage effect by membership function value. Measurements of seedling morphology and biomass components were taken to analyze the plasticity index and the correlation between different characters, to construct models for predicting the plant biomass components using morphological characteristics as the independent variable.The main results were as follows:(1)Clerodendrum speciosum had larger specific leaf volume, higher leaf water content and dry weight water content, also lower value of chlorophyll a/b, and strongest shade tolerance. Hetcropterys angustifolia obtained more light resources with larger specific leaf area, improving the adaptability to the environment. Mansoa alliacea improved leaf toughness by higher leaf density and leaf dry matter content to resist physical abuse. Pyrostegia venusta resisted physical coercion by larger leaf thickness. Leaf growth mainly conformed to linear relationships and power function relationships, and the leaf volume and leaf dry weight were in power function relationship in all species, presenting the law of allometry. Clerodendrum speciosum, Mansoa alliacea and Pyrostegia venusta mainly presented allometry relationship, while Hetcropterys angustifolia presented isogony relationship. Based on leaf functional traits, the plants were divided into two types that Mansoa alliacea and Pyrostegia venusta were in one type, while Hetcropterys angustifolia and Clerodendrum speciosum were in one type.(2)Species with the best cuttage result was Mansoa alliacea, followed by Clerodendrum speciosum with more adventitious roots. Ranking as the third, Hetcropterys angustifolia had more roots, the worst was Pyrostegia venusta. Indexes with more important weight were retaining rate of old leaves, rooting index, number of total roots, rooting rate and number of adventitious roots, which can be used to evaluate the cuttage result in future experiments. Concentration of IBA, matrix and concentration of NAA respectively played a leading role in Clerodendrum speciosum, Hetcropterys angustifolia and Pyrostegia venusta, while all factors played their role in Mansoa alliacea equally. The optimal treatment for Clerodendrum speciosum and Hetcropterys angustifolia was river sand+150 mg·L-1 IBA+50 mg·L-1 NAA. The optimal treatment for Mansoa alliacea and Pyrostegia venusta was the 3:2 matching for river sand and peat soil+100 mg·L-1 IBA+ 50 mg·L-1 NAA.(3)Clerodendrum speciosum had better morphological characteristics, with larger specific leaf area, leaf area to root mass ratio, root shoot ratio, all biomass components and root biomass fraction. In the biomass model constructed by morphological characteristics as independent variable and plant biomass components as dependent variable, the impact factor of all species was plant height. The plasticity index of biomass allocation was the highest in 4 parameters, reflecting that plants adjusted themselves in the different habitats mainly by biomass allocation adjustment. Pyrostegia venusta had the strongest plasticity, followed by Clerodendrum speciosum, Mansoa alliacea was the next, and Hetcropterys angustifolia was the weakest.The correlations of leaf functional traits, effect of each factor in cutting experiment, biomass allocation characteristics of seedlings and so on were also discussed at the end of the thesis.