通过缩微实验,在网室中以pH值为3.5、5.0、7.0、9.0和11.0的Hoagland营养液培养水葫芦;通过测定水葫芦的形态和生理生化指标,研究了不同酸度下水葫芦的生长适应性.结果表明:在培养6周的时间内,水葫芦能够在pH值3.5-11.0的Hoagland营养液中生长,具有较宽的生存pH值范围.随营养液pH值升高,水葫芦的相对生长率从6.12倍降到3.08倍.pH值在3.5-9.0之间,水葫芦株高,叶柄长度,叶片的长度、宽度和厚度在不同酸度条件下无显著差异,根长、茎长和根系活力随pH升高明显下降.生理生化分析表明,随着营养液pH升高,水葫芦叶片的可溶性蛋白含量略有下降,MDA含量也略有变化,但不同处理间无显著差异.碱性条件下,水葫芦根系的CAT、POD活性高,MDA含量也高,CAT、POD和SOD活性失衡,表明碱性条件不利于水葫芦根系中活性氧的清除,导致自由基伤害.酸性条件下,水葫芦的根系活力和相对生长率均显著高于碱性条件,表明水葫芦更适于酸性环境生长,这是其能够在中国南方各种水域蔓延的重要原因之一.%In order to reveal the adaptation of water hyacinth at different acidity conditions, a six-week experiment, using mesocosm tanks with Hoagland's solutions, was set up in a greenhouse to investigate the adaptation of the plant exposed to different acidity conditions (pH 3.5, 5.0, 7.0, 9.0 and 11.0). The results showed that water hyacinth was able to grow in hydroponic solution at pH from 3.5 to 11.0. The relative growth rates of the plant ranged from 6.12 to 3.08 and declined as the pH level increased. Plant height, leafstalk length, leaf length, leaf width and leaf thickness of water hyacinth did not vary significantly at the range of pH 3.5 to 9.0, while root length, stolon length and root vigor declined obviously with the increasing pH. Bio-chemical analysis showed that soluble protein decreased and malondildehyde (MDA) contents changed slightly in leaves, but no significant difference was found among the five treatments. However, at basic conditions, the higher CAT, POD activities and MDA contents, as well as the imbalance between CAT, POD and SOD in roots were found, implying that the plant could not remove activated oxygen successfully and injured by radicals. The higher root vigor and relative growth rates of water hyacinth at acidic conditions than base one suggested that the plant preferred to acidic conditions. As a result, the survial of water hyacinth at a large range of pH and preferred to acidic conditions must be one of key factors for its spreading out the aquatic system in south China.
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