水质条件对外来入侵生物水葫芦生长的影响
本文关键词：水质条件对外来入侵生物水葫芦生长的影响，由笔耕文化传播整理发布。
水质条件对外来入侵生物水葫芦生长的影响
水质条件对外来入侵生物水葫芦生长的影响
水葫芦（Eichhornia crassipes （Mart．）Solms．）（学名：凤眼莲），原产于南美洲，约上世纪初传入中国的水生草本植物现已成为世界十大恶性杂草之一。目前在我国的福建、广东、云南、江苏、浙江、湖北、河南等17个省市均有分布。水葫芦在江河湖与池塘的水面大量滋生，抑制了其它水生植物的正常生长，堵塞航道，威胁渔业的发展，污染环境，对环境、经济与社会发展带来了重大的损失。当前，国内外相继采用物理防治（人工或机械打捞）、化学防除（除草剂）和生物防治（引进天敌、病原菌和化感作用）的策略来制约水葫芦的疯长，但都没有取得理想的效果。因此，进一步研究可持续性，防治效能高的治理措施对于水葫芦的防治具有重大意 义。探讨水葫芦与周围生境的关系，通过生境调控的策略从根本上治理水葫芦泛滥的报道甚少。为此，本研究通过对福建省水葫芦分布地的调查，浅析浅析导致水葫芦滋生的主要水质因子和环境条件，并探讨了水体中不同N、P浓度及pH对水葫芦生长的影响，从而为福建省水葫芦的综合治理提供科学依据。主要结果如下：1．福建省水葫芦的分布及为害情况从全省范围来看，南平，福州，漳州3地受水葫芦危害程度比较严重，闽江流域和九龙江流域水葫芦分布广泛。三明、龙岩、泉州和莆田的水葫芦主要分布在鱼塘、水坝以及部分内河，一定程度上影响了当地水产养殖业的发展与水电站的正常运行。宁德、厦门两地水葫芦危害程度较轻。2．福建省水质条件与水葫芦生长的关系对水体质量的调查表明：福建省内水葫芦发生地水体总氮和总磷含量较高，水中溶解氧较低，水体质量下降，富营养化的水体为水葫芦的成功入侵及蔓延提供了优越条件。从各观测点的调查得出，在我省各水域水质条件下，随着总氮和总磷含量的增高，水葫芦的长势逐渐增强。N是影响水葫芦生长的关键因素，主要推动水葫芦的向上生长，提高总生物量；P推动水葫芦分裂和横向生长，提高水葫芦匍匐茎数和叶柄数。3．三种不同水质对水葫芦生长发育的影响处理Md(TN：13．8 mg·L-1，，TP：0．614 mg·L-1)在总N浓度上远大于处理CK(TN：1．17 mg·L-1，TP：0．014 mg·L-1)和处理Ro(TN：0．156 mg·L-1，TP：<0．005 mg·L-1)，但三者的总P浓度均小于0．1 mg．L-1。培养60日后从水葫芦的形态上看，在缺N、P（处理Ro）条件下，生长明显受到抑制；从水葫芦的生物量增长情况来看，水葫芦在缺N缺P条件下，生长发育速率缓慢，在培养60日后与处理Md（含N缺P）生物量增加值的差值达到最高。这进一步表明水体中N浓度是限制水葫芦生长的最主要因素，而水葫芦的生长对P浓度的需求比较低。4．水体不同营养条件对水葫芦生长发育的影响（1）生长特性水葫芦分别在水体N浓度25-30 mg·L-1、P浓度5．7-7 mg·L-1或水体pH值7-9的范围内生长情况最佳，高于或低于这个范围，水葫芦的生长发育均受到不同程度的抑制。（2）生物量水葫芦分别在水体N浓度30 mg·L-1、P浓度6．33 mg·L-1或水体pH值7-9的条件下，生物量增加值最大，高于或低于这个值或范围，水葫芦生物量的增加均受到不同程度的抑制。（3）叶绿素含量叶绿素含量分别在各营养条件下均有不同程度的下降，其中，N和P高浓度处理的叶绿素含量下降程度甚至超过了低浓度处理。在水体N浓度20-30 mg·L-1或水体P浓度4-5 mg·L-1范围内，水葫芦叶绿素含量下降值较低；pH为3和5的两个处理溶解氧浓度下降速度快于其他浓度处理。在水体pH值在7-9的范围内，水葫芦叶绿素含量下降值较低。（4）覆盖率水葫芦分别在水体N浓度25 mg·L-1、水体P浓度7 mg·L-1或水体pH值7时，试验前后覆盖率差值达到最大。（5）溶解氧浓度在不同营养条件转变着水葫芦生长发育情况的同时，水葫芦的生长也导致水体溶解氧浓度的不断下降。高浓度处理N6(30 mg·L-1)、N7(35mg·L-1)的溶解氧浓度下降幅度明显大于N1(5 mg·L-1)、N2(10 mg·L-1)等低浓度处理；处理P2(5 mg·L-1)和P5(8 mg·L-1)的溶解氧浓度下降幅度略大于其他浓度处理；pH为3和5的两个处理溶解氧浓度下降幅度略快大其它pH处理。
【Abstract】 Water hyacinth （Eichhornia crassipes （Mart.） Solms.） , which originated from South America and was first introduced into China in 1900’s, has become one of the most invasive aquatic weeds in the world. It is now widely spreading in many Chinese provinces, like Fujian, Guangdong, Yunnan, Jiangsu, Zhejiang and Henan. Water hyacinth growes mainly in rivers, lakes and ponds to form a monotonous dominant population, which suppressed the growth of other aquatic plants and has caused serious social, economic and environmental losses with its fast extending distribution and development. In places infested with the weed, waterways are often blocked and thus water transportation for industry and tourism affected. At present, mechanical control （e.g. hand-pulling and use of draglines）, chemical control, and biological control （introducing natural enemies, pathogens and plant allelopathy） have been used to control water hyacinth in most countries affected by the infestation of the weed. However, these control measures have each their own disadvantages or setbacks to put them into practice. To develop a more sustainable and effective control strategy of water hyacinth, further research will be needed on both the methods now available and the methods with potentials. There is no report about controlling water hyacinth using ecological measures and exploiting the relationship between water hyacinth and its environment in China. Therefore, this paper mainly analysed the relationship between the predominant water quality, environmental factors, and the growth status of water hyacinth. The effects of different nutrient levels, such as, N, P and pH, on water hyacinth were measured, thus providing a solid and scientific base for developing an integrated control system of water hyacinth in Fujian Province.The results were as follows:1. Distribution and severe damage of water hyacinth in FujianAcross the Fujian province, water hyacinth had caused severe damage in Nanping, Fuzhou and Zhangzhou. It’s also widely distributed along the Min River and Wu Long River. Water hyacinth mainly grows in ponds, lakes and in some inland rivers that inhibited the aquiculture life and the function of waterpower station to a certain extent in Sanming, Longyan , Quanzhou and Putian. There was also a slight damage caused by the infestation of water hyacinth in Ningde and Xiamen.2. Relationship between water quality and growth status of water hyacinth Research of the relationship showed that in places infested with the weed, water quality was lower due to higher total nitrogen and total phosphorus as well as lower dissolved oxygen. Eutrophication of water provided superior and ideal condition for the growth of water hyacinth. All of these surveys indicated that water hyacinth growed well with a higher total nitrogen and phosphorus under different water qualities in Fujian province. Nitrogen was the most important factors that restricted the development of water hyacinth. The weed was not so sensitive to phosphorus. Otherwise, the total phosphorus greatly influenced the number of stolons and petioles. Total nitrogen played a significant part in the upward growth of water hyacinth.3. Effects of three kinds of water quality on the growth status of water hyacinth: In the solution, concentration of total nitrogen in treatment Md (Total N: 13.8 mg·L-1, Total P: 0.614 mg·L-1) was much higher than that of the CK (Total N: 1.17 mg·L-1, Total P: 0.014 mg·L-1) and Ro (Total N: 0.156 mg·L-1, Total P: <0.005 mg·L-1), but total phosphorus was only lowered by 0.1 mg.L-1 in each of the three treatments. After 60 days, the growth was inhibited under treatment Ro without nitrogen and phosphorus. The measured biomass of water hyacinth also had slow development under the same condition. The difference between Ro and Md （cultured with nitrogen and without phosphorus） reached the highest level after 60 days of treatment. The result indicated that nitrogen concentration was the most important factor in limiting the growth of water hyacinth, while it acquired little growth from the phosphorus.4. The impact of the water hyacinth growth and development for different water nutritional conditions （1） Growth characteristics The growth performance of water hyacinth was the best in the water of which the N concentration was in the range of 25-30 mg.L-1, P concentration was in the range of 5.7～7 mg.L-1 or the pH was in the range 7～9. The growth of water hyacinth was subject to varying degrees of restrictions if the related index of water were higher or lower than this range.（2） BiomassThe biomass of water hyacinth increased the most in the water in which the N concentration was 30 mg.L-1, P was 6.33 mg.L-1, or the pH was in7～9. The increase of the biomass was subject to varying degrees of restrictions if the related index of water were higher or lower than this range.（3） Chlorophyll contentThe chlorophyll content had different levels of drop in the nutrition conditions, in which, the chlorophyll content dropped when the N or P had a high concentration and was processed higher than when the N or P was processed in low concentration. The decreased value of water hyacinth chlorophyll content was low in the water whose N was in the range of 20～30 mg.L-1, or the P was in the range of 4～5 mg.L-1, the decreasing speed of treated dissolved oxygen concentration where the pH was 3 and 5 was faster than the others. The decreased value of water hyacinth chlorophyll content was low in the water where pH was in the range of 7～9.（4） Coverage rateD-value of the coverage, before and after the experiment reached the maximum in the water where N was 25 mg.L-1, P 7 mg.L-1 or the pH 7.（5） Dissolved oxygen concentrationAt the time of that the different nutritional conditions changed the growth and development of water hyacinth, the growth of water hyacinth had resulted in the drop of the concentration of dissolved oxygen. The decreasing range of dissolved oxygen concentration in high nitrogen concentration with N6 (30 mg.L-1) and N7 (35 mg.L-1) were faster than that in N1(5 mg.L-1) and N2(10 mg.L-1). It also showed that in treatments P2 (5 mg.L-1) and P5 (8 mg.L-1), with a pH 3 and 5 respectively, the decreasing range of dissolved oxygen concentration was little faster than other relative treatments.
【关键词】 水葫芦； 水体质量； 富营养化； 外来生物入侵； 生境调控；【Key words】 Eichhornia crassipes； Water quality； Eutrophication； Biological invasive； Habitat management；
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本文关键词：水质条件对外来入侵生物水葫芦生长的影响，由笔耕文化传播整理发布。
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