| Solidago canadensis L., a perennial composite plant originating from NorthAmerica, was introduced into China as a horticultural plant in1935. S.canadensis isthe most devastating invasive plant in China.With high reproductive capacity and fastspread speed, this exotic plant has changed the constitution of ecosystem, destroyedthe biodiversity and soil utility in the places it invaded and caused serious damage toagricultural production and ecosystems in several provinces of China. S.canadensiswas introduced into Xinjiang arid region as desert afforestation plants because of itshigh ornamental value and it was growth well. This paper focuses on some aspectsrelated to breeding habits and allelopathy after being Xinjiang, such as seedgermination and pollination detection; Measurement of rhizomes, stem and leafgrowth, neuter proliferation ability and salt tolerance under different conditionprocessing; Allelopathy activity measurement of different parts of the different phaseof different concentrations of water leaching solution to several common crop seedsand weed seeds of Xinjiang; The anatomy of the root, rhizome, stem and leaf ofdifferent habitats were compared.The main results were concluded as follows:(1) S.canadensis through sexual reproduction and asexual reproduction forreproduction. The studies to the sexual reproduction include: thousand seed weight,the seed germination under natural conditions and investigation of pollination insects.The mean weight of1000-seed was about0.0436g, natural seed germination rate wasabout14.5%, it was declined relative to zhejiang’s. Average seed setting rate was about8.04%±2.05%, showed that the seed setting rate is low. Both set of mesh bagand not bagged seed can germination, and no significant difference, so S. canadensisnot only wind pollination but also insect pollination. Although the seed setting rate isrelatively lower, the whole plant seed amount is large, still need to prevent its throughsexual reproduction produce seeds for remote diffusion. The rhizomes of S.canadensis still have strong clone ability after being introduced in Xinjiang that canbreeding a large number of rhizomes and fibres in the time of half an year underenough moisture. It can resistance to dystrophic, can growth well in sand that hasfew nutrition, it verified the previous research results, and it has salt resistance afterintroduced Xinjiang, it can maintain basic survival in a certain range of saltconcentration; And stems and leaves can take root in fresh water and normal growth,could be able to accomplish a growth cycle, and has certain salt resistance in a certainrange of salt concentrations. The test results showed that, S. canadensis graduallyadapted to the climate environment in Xinjiang, Xinjiang still has invasiveness.(2) Allelopathic effect is one of the mechanisms why plants can successfullyinvade and disperse fastly. By using the same method with Fangfang’s, we studied theallelopathy of S. canadensis that introducted to Xinjiang, and compared theexperiment results of mine with Fangfang’s. Allelopathy to several common cropseeds and weed seeds germination, seedling growth in different periods of differentconcentrations of different parts of the water leaching solution of S. canadensis inxinjiang were studied and the allelopathy of the dry material and fresh material ofdifferent parts were compared. The results showed that the effects of water extractsfrom S. canadensis of Xingjiang still has strong allelopathy. Different parts of thewater leaching solution of S.canadensis have different degrees of allelopathy on thetest plant seed germination and seedling growth that is low concentration to promoteand the high concentration to inhibition. Eg, with facilitating effect on growth of cropseedling under treatment with0.025g/mLwater extracts from S. canadensis and theinhibiting effect with0.050g/mL or more. The inhibiting effects become stronger withthe concentration increase of the water extracts from S. canadensis, even killed theseeds with the treatment of0.100g/mL; Vegetative phase underground part of theleaching solution in0.025g/mL are promoting seedling growth of both five kinds ofweed seeds, When the leach liquor concentration higher than0.050g/mL, weed seedsgermination and growth were restrained, The inhibiting effects become stronger withthe concentration increase of the water extracts from S. canadensis, even killed thesmall seed plants with the treatment of0.100g/mL. The strength of the allelopathy ofS. canadensis are different, such as the effects of the leaves and inflorescences of S.canadensis were stronger than those from the stems; Allelopathy of acrial part stronger than underground part. Besides, allelopathy of dry material stronger thanfresh material. This is different with previous research results, But with the sameresult is: allelopathy of leaf is stronger than stem whether dry material or freshmaterials. The experiment results of crop seeds compared with Fangfang’s, the resultsshowed that the allelopathy of S. canadensis of Xinjiang stronger than Zhejiang’s, itmeans that the allelopathy become more powerful of S. canadensis after introduced inXinjiang.(3) The morphological features and anatomical structures of two differenthabitats of S. canadensis in Xinjiang were studied by the methods of traditionalparaffin wax sections with light and electron microscopy. Aims to reveal its basedstructure of invasion and adapt to the environment in Xinjiang. The results showedthat anatomical structure is different in two habitats, especially the roots and rhizomes.Different vegetative organs have the structure characteristics of drought environmentin drought habitat, eg. the skin of leaf, stem with a thick cuticle, with developedvascular bundle and bundle sheath outspread inside leaf, developed root of xylem anda lot of catheter distributed in it, the biggest pipe diameter is153.3μm, Rhizomesmore like root structure, For complex skin epidermis(2～3layers), Also has developedxylem and catheter; But vegetative organs of each measurement of moist habitat isrelatively small, Rhizomes like stem structure and completely different with dryhabitat, it is distributed a large number of secretory cavity in the cortex and pith of therhizomes. |
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