Effects of Fragmentation Intensity of Perennial Roots and Their Burial Depth on Sprouting and Early Growth of Alternanthera philoxeroides(Mart.)Griseb

[Objective] The aim was to provide theoretical basis for the prevention and control of the invasion of Alternanthera philoxeroides（Mart.）Griseb.[Method] Effects of fragmentation intensity of fresh roots and their burial depth on sprouting and early growth of A.philoxeroides were studied by control test.[Result] More sprouts of A.philoxeroides emerged when the fragmentation intensity of fresh roots was higher,while if the fragmentation intensity of fresh roots was lower,the early growth of A.philoxeroides was more rapid.The soil buried depth had significant effect on fresh root sprouts＇ emergence,but once fresh root sprouts could reach the soil surface and were given enough growth time,even if the fresh roots were buried in different depths,soil buried depth had no significant effect on its young plant growth.[Conclusion] If different fragmentation intensities of fresh roots present,there is a kind of trade-off strategy between root sprouts＇ emergence and plant＇ early growth,by which A.philoxeroides can invade new habitat successfully.To control the invasion of A.philoxeroides,it is critical to prevent its fresh root sprouts from emerging to soil surface,that is,to bury the fresh roots at a further soil depth.

Effect of Lead Stress on Growth Characteristics and Physiological Indexes of Alternanthera philoxeroides

[Objective] The paper aimed to discuss effects of different concentrations of lead stress on Alternanthera philoxeroides growth and physiological indices,to explore phytoremediation methods for removal of lead pollution. [Method] A. philoxeroides in water culture was treated with different concentration of lead,and then,its external injury was observed,its growth and physiological indexes were measured. [Result] A. philoxeroides biomass and chlorophyll content decreased; conductivity and malonaldehyde （MDA ） content were increased; the SOD,POD and CAT activities showed a trend of first increase and then decrease with increase in concentration of lead stress. [Conclusion] With increase in lead concentration,the cell membrane permeability increased and MDA had a higher accumulation,antioxidant enzymes activity decreased,the normal oxidative metabolism of A. philoxeroides was severely affected,leading it to wilt.

添加蚯蚓后入侵植物喜旱莲子草的生长状况

由于入侵生物自身体内的化学物质影响到土壤动物和土壤过程,试验采用土壤常见动物蚯蚓和重要入侵植物喜旱莲子草[Alternanthera philoxeroides(Mart.)Griseb.]为材料,研究蚯蚓对喜旱莲子草生理生化指标及生长的影响。结果表明,喜旱莲子草叶片中叶绿素a、叶绿素b、类胡萝卜素的含量和叶绿素总量随着添加蚯蚓数量的增加而增加;喜旱莲子草叶片淀粉和非结构性碳水化合物(NSC)的含量随着添加蚯蚓数量的增加呈递增趋势;随着添加蚯蚓数量的增加,喜旱莲子草单位面积质量和分蘖数呈上升趋势。由此可知,土壤动物蚯蚓有利于入侵植物喜旱莲子草生长。