【摘要】 调查了广东省21市外来入侵植物的分布,对6类易入侵生境土壤氮素及14种入侵种根际土壤氮素进行了测定,结果表明:各入侵生境中分布的入侵植物优势种有所不同,在农田、果园和菜田中分布最多是菊科杂草,弃荒地分布以菊科和禾本科杂草为主,公路两侧及河道分布最多的是菊科、旋花科和豆科杂草.在6种生境中弃荒地入侵种丰富度最高,应当加强弃荒地的管理.在10种重要入侵植物中,白花鬼针草和三叶鬼针草的分布生境最广,要进行重点防范.各入侵生境土壤及入侵种根际土壤硝态氮水平均低于铵态氮,硝铵比小于1;与原生土壤相比,入侵种的根际土壤硝态氮显著降低,铵态氮显著升高,硝铵比发生了逆转.入侵种具有喜铵性,适宜在铵态氮含量较高的土壤中生存.表明入侵种对生境土壤产生了较大的影响,改变了原生土壤的氮素营养状况.更多还原

【Abstract】 The distribution of alien invasive plants in 21 cities in Guangdong Province was investigated,and the soil nitrogen content was determined in the 6 habitats subject to invasion and in the rhizosphere soils of 14 invasive plant species. The results showed that there were different dominant plants in different habitats subject to invasion. The weeds of Compositae were dominant in farmland,orchards and vegetable fields,whereas the weeds of Compositae and Gramineae were dominant in abandoned land. Further,the weeds of Compositae,Convolvulaceae and Leguminous were dominant on both sides of the roads and the rivers investigated. Of the 6 habitats investigated,the invasive plants had the highest abundance in the abandoned land. This suggests that greater attention should be payed to managing this land. Of the 10 seriously invasive plants,Bidens alba and Bidens pilosa had the widest distribution,again suggesting the importance of these weeds’ management. The concentration of nitrate nitrogen was lower than that of ammonium nitrogen( the ratio of nitrate to ammonium was less than 1) both in the 6 habitats subject to invasion and in the soil rhizosphere of 14 invasive plants. Compared with the native soil,the nitrate nitrogen decreased significantly but the ammonium nitrogen increased significantly in the rhizosphere soils of invasive plants;the ratio of nitrate to ammonium concentrations however displayed reverse quantities to that in native soil. This implies that the invasive plants may be nitrophilous,that is,capable of utilizing more nitrate nitrogen. It was concluded that the invasive plants had a great influence on the habitat’s soil and changed the nitrogen nutrition status in the native soil.更多还原