Two Groups Of Anatomical Features Of Invasive Species And Its Relatives Of Ecological Adaptability

Gaura parviflora and G. lindheimeri are herbaceous plants of Onagraceae G., and both native to North America. Xanthium spinosum and X. sibiricum are the annualherbages in Asteraceae X. X. spinosum origins in South America, and X. sibiricum is a Chinese native species. G. lindheimeri is used to be a kind of planting flower, X. sibiricum is a common weed in China. In recent years, G. parviflora and X. spinosum which have become China’s important invasive plants, quickly spread in our country and have been spread by a disaster in some areas.Exotic plant anatomy is the biological basis to test whether it can invades new habitat successfully. To eliminate the impact caused by genetic relationship, it is necessary to conduct a comparative study between the invasive plants and their relatives or an exotic species which is not strong in invasiveness. It can not only help us to contrast the study results, analysis plants’ ecological suitability, but also make the results more convincing. At present, researches about invading plant anatomy reported singularly in China, comparative study of invasive species and its relatives less. The research objects of the study are invasive plants of G. parviflora and X. spinosum and their relatives G. lindheimeri and X. sibiricum. By the methods of paraffin section, specific leaf area, leaf epidermis production method and segregation method, the vegetative organs (leaf, stem, root) of morphological anatomy structure were observed and compared, and analyzed their ecological adaptability. It provides theory basis for effective prevention and control of G. parviflora and X. spinosum. The main results were as follows:1. Characteristics of leaf tissue structureInvasive species compared with non invasive species, the leaf cell structure tightness (CTR), ratio of palisade tissue/spongy tissue, the veins of the vascular bundles and collenchyma and structure characteristics of stomatal density, etc, invasive species is more developed; non invasive species is more developed on specific leaf area and the size of the stomatal apparatus structure.2. The stem and root anatomical structure featuresCompared Invasive species to the non invasion ones, structural characteristics of the stalk and root on cuticle, xylem, catheters, vascular ray, the trend of test results shows consistency, and invasive species showed a more developed performance; Especially in the stem catheter’ molecular structure, the invaders were presented: ends on both ends of the koala proportion biger, no tail on both ends smaller. The short length, large diameter and proportion of long/straight, smaller end wall slant range from are catheter features of evolution.3. The ecological adaptabilityIn conclusion: developed palisade tissues in the leaves, xylem of stem xylem and developed vascular rays in the root, etc, especially the privileged structure characteristics of stoma and vessel elements may be related to invasive species’ tolerance ability of diverse habitats. The vegetative organs’ synergistic effect of G. parviflora and X. spinosum is the structure foundation of their strong invasion.