凤眼莲等水生植物对重金属污水监测和净化作用的研究

本文研究了凤眼莲、芦苇、蒲草、杏菜、黑藻等高等水生植物对含砷、汞、镉污水的监测作用和净化能力以及温度、pH值等因子对植物的影响。初步认为凤眼莲是含砷污水的监测植物,同时又是含砷、汞,镉污水的净化植物。芦苇,蒲草是抗污能力较强的植物,并能吸收积累污水中的砷、汞、镉。水生植物对砷、汞、镉的忍耐力大小是因其植物生活型不同而异,一般为挺水植物>飘浮、浮叶植物>沉水植物。积累量为沉水植物>飘浮、浮叶植物>挺水植物。植物对重金属元素的吸收积累受温度和pH值等生态因子的制约。     

江苏省湖泊水生植被的研究

 江苏为全国多湖泊的省份之一,水生植被十分繁茂。影响湖泊水生植被生长、分布的环境因素是多方面的,湖水深度与透明度的影响最为明显。江苏湖泊水生植被的组成植物隶属30科,48属,共62种,可区分为挺水、浮叶、漂浮及沉水四类生活型植物。它们的分布有一定的规律,在沿湖岸浅水处,形成挺水植物带,向湖心方向随着湖水变深,而为浮叶植物带、沉水植物带。漂浮植物因流动性大,通常不形成独立的植物带。各植物带内分别形成相应的植物群落,在两个植物带叠接处则形成混交的群落。江苏湖泊水生植被共有16个主要群落类型。本文对湖泊水生植被的经济用途作了较详细的讨论。     

盐碱池塘水生大型植物的研究

于1998 年4 月至1998 年9 月对高青盐碱池塘的水生大型植物种类组成、生产力及其影响因子进行了野外调查和试验研究。结果表明高青盐碱池塘共有水生植物12 种。常见的优势种有沉水植物:菹草、角果藻、金鱼藻;挺水植物:芦苇、荆三棱、莲和香蒲;漂浮植物:浮萍, 以及大型藻类布氏轮藻。种类少而优势种突出是盐碱池塘大型植物的显著特点。有水草池塘与无或少水草池塘相比, 透明度大、pH 值高、浮游植物生物量和叶绿素a 含量低、营养盐含量也低。在表层光照度7200lx、水温28~30℃的条件下, 菹草、角果藻和轮藻的毛产量分别为1.70、1.56 和1.50mgO₂·L^-1·h^-1·g^-1。除光照、水温、pH 等因素外, 含盐量和碱度对大型植物的初级生产力具有重要影响, 菹草和角果藻的生产力最高时的含盐量均为3g·L^-1, 前者适宜的碱度为6.69 mmol·L^-1, 而后者则为3.82 mmol·L^-1。菹草、角果藻、金鱼藻和浮萍对NH₄-N 的吸收速率相近, 而对PO₄-P 的吸收速率则角果藻 > 菹草 > 浮萍 > 金鱼藻。文后对盐水水体大型植物特点、菹草生产力及其影响因素、如何防止养鱼池大型植物危害及大型植物与浮游植物的关系进行了讨论。     

Geographic patterns and environmental correlates of taxonomic and phylogenetic diversity of aquatic plants in China

Studies on large-scale geographic patterns of aquatic plant diversity can promote research on the generality of macroecological patterns in different ecosystems. Here, we compiled a checklist of 889 aquatic angiosperms in China, including 738 helophytes (emergent and marshy plants) and 151 hydrophytes (submerged, free-floating, and floating-leaved plants). We explore the geographic patterns and environmental correlates of aquatic plant diversity based on six metrics including species richness (SR), weighted endemism (WE), phylogenetic diversity (PD), phylogenetic endemism (PE), the standardized effect size of phylogenetic diversity (PDses), and the standardized effect size of mean phylogenetic distance (MPDses). Our results show that the diversity of aquatic plants in China is extremely uneven, with high diversity in southeastern China and low diversity in northwestern China, and the geographic patterns of taxonomic and PD are generally consistent. The pattern of helophytes differs from that of hydrophytes. Notably, the wavy-shaped pattern of aquatic plant diversity (especially SR and PD for hydrophytes) across the latitude observed in this study is not consistent with those previously observed for aquatic plants in other continents. Climatic variables and water environmental variables are the main drivers of aquatic plant diversity in China; however, the effects of individual variables differ between helophytes and hydrophytes. Water environmental variables have a greater impact on PDses and MPDses of hydrophytes than those of helophytes. Overall, our work provides insight into understanding the large-scale patterns of aquatic plant diversity and is a critical addition to previous studies on the macroecological pattern of terrestrial organisms.     

水蕹菜（Ipomoea aquatica）对含银废水的净化功能研究

 本文通过对水蕹菜净化含银废水的室内外静、动态试验研究得出：(1)水蕹菜对离子态银(Ag+)的去除速率高于对络合态银(Ag(S2O3)2)3-的去除速率即KAg+>K[Ag(S2O3)2]3-;(2)水蕹菜对银的净化率R与污水停留时间t呈指数函数关系(R=AeB/t,A、B为常数,B<0),其表面去除负荷Ps则与t呈幂函数关系(Ps=AtB B<0);(3)试验证明水蕹菜是生物净化含银废水的优良品种之一。     

Effects of stormwater sewer discharges on the aquatic community in urban canals in Lelystad

In urban areas with a separate sewerage system, the stormwater runoff is discharged into surface waters. A study on the effects of stormwater sewer discharges on the composition of the aquatic community in urban waters was carried out in two areas with a primarily residential use in the new town of Lelystad. The aquatic organisms considered included hydrophytes, epiphytic diatoms, filamentous algae and macroinvertebrates.The results indicate that the stormwater sewer discharges cause a slight change in the composition of the aquatic community. The water in the urban surface waters can be characterized as eutrophic and - toa-mesosaprobic. Near stormwater sewer outfalls the water tends to the more polluteda-mesosaprobic state. The shifts in the composition of the aquatic community could be traced primarily on the basis of a number of epiphytic diatoms and macroinvertebrates (in particular some Diptera and Trichoptera). Most hydrophytes, filamentous algae and the remaining epiphytic diatoms and macroinvertebrates (in particular water beetles and water mites) turned out to be of little or no use in this respect.Because the investigation was carried out in an unusually dry summer, the results probably underestimate the effects of stormwater discharges on the aquatic community.     

The influence of water level on the growth and photosynthesis of Hydrocotyle ranunculoides L.fil.

Floating Pennywort (Hydrocotyle ranunculoides L.fil.), a native to North America and naturalized in Central and South America, is an invasive aquatic weed in western Europe and several other regions worldwide. H. ranunculoides settles primarily in stagnant to slow-flowing waters (e.g. ditches, canals, rivers, lakes and ponds). The species prefers sunny and nutrient-rich sites and forms dense interwoven mats, which can quickly cover the surface of infested waters. In this study, the effect of three different water levels on growth of Floating Pennywort was investigated. Plants were cultivated on high-nutrient soils under waterlogged, semi-drained and drained conditions. Highest relative growth rates (RGR) of 0.097±0.004 g g⁻¹ dw d⁻¹ were reached under waterlogged conditions. This was significantly higher than RGR of plants cultivated semi-drained and drained. Floating Pennywort showed some phenological adaptations to drained soil conditions, including significant differences in the relative amounts of leaf, petiole and shoot biomass, whilst the relative amount of root biomass was not significantly influenced by the water level. Furthermore, Floating Pennywort reached under drained conditions lower relative water contents (RWC) of leaves, petioles and shoots, a significant shorter length of internodes, a significant lower extent of shoot porosity (POR), a lower chlorophyll content and an increased Chl_a:Chl_b ratio. In addition, maximum gas exchange of drained cultivated plants is significantly lower, due to strongly decreased leaf conductance under reduced water availability. Overall, H. ranunculoides showed ability to grow under different water levels, but performed best under waterlogged conditions.     

光强、温度、总氮浓度对黑藻生长的影响

为寻求沉水植物生长的主效环境因子,探求富营养化水体沉水植物的衰亡机理并选择治理富营养化的先锋植物,实验选择长江中下游常见沉水植物种黑藻(Hydrilla verticillata),利用正交试验设计,通过室内静态模拟实验研究三种主要环境因子光照强度、温度、总氮浓度及其互作对黑藻断枝生长的影响。结果表明:光照强度和温度为影响黑藻生长的主效环境因子,并且光强与温度的交互作用对黑藻生长有较为显著的影响,具体表现为黑藻的生长指标(株高、生物量、分枝数)、光合指标(叶绿素a+b浓度、叶绿素a/b、叶绿体总色素含量)和生理活性指标(根活力、可溶性糖含量、MDA含量)的变化均与这两个环境因子及其互作呈显著相关;总氮浓度的变化对黑藻生长影响不大,在2-8 mg/L的总氮浓度下,黑藻均可以正常生长。根据本实验黑藻生长指标、光合色素含量以及生理活性在不同环境因子组合的变化结果可知,黑藻在5320-12000 lx光照强度、20°C-30°C、4-8 mg/L水体总氮浓度的条件下生长良好,故推测黑藻可作为春夏季富营养化水体中恢复和重建沉水植被的先锋工具种。       

Aquatic plants as environmental indicators of ecological condition in New Zealand lakes

Submerged aquatic plants can act as measurable indicators of ecological conditions occurring within a lake, and they need only be monitored once a year or even less. Historically in New Zealand there has been a reliance on water quality sampling for monitoring the health of lakes and these methods can be complex and costly involving multiple site visits and chemical analysis of water samples. As a result, lake monitoring has been irregular, or not done at all. LakeSPI or ‘Lake Submerged Plant Indicators’ is a new management tool that uses aquatic plants to monitor and assess ecological condition in a wide range of lake types. The method generates three indices: a Native Condition Index (extent and diversity of native plants) and an Invasive Condition Index (extent and impact of alien weeds), which are generated from scores allocated to carefully selected vegetation features; and an integrated LakeSPI Index which is largely derived from components of the other two indices and provides an overall indication of lake ecological condition. The LakeSPI method can be used to assess the status of lakes and monitor trends occurring within them, and it is expected that the use of LakeSPI will facilitate regular monitoring and reporting on a much wider range of lakes than has been possible using traditional water quality methods. By utilizing submerged aquatic plants the method focuses on lake littoral margins where there is greatest public interaction and interest.     

Root morphological and structural comparisons of introduced and native aquatic plant species in multiple substrates

Invasions of introduced plants are considered among the greatest threats to biodiversity worldwide. Aquatic habitats suffer invasion more frequently and extensively than do terrestrial habitats. Although the role of roots in plant anchoring and support is important, previous studies have focused much attention on the morphological traits of above-ground parts, with relatively less attention given to the root structures of aquatic plants. In this study, we aimed to compare differences in root morphological and structural traits between introduced and native plants in response to different substrates. We hypothesized that introduced aquatic plants have an advantage over native plants with regard to root trait values and plasticity. A total of six aquatic plants were used: Two invasive and one exotic noninvasive species were paired with their native counterparts according to life form (amphibious emergent, submerged and floating-leaved) and cultivated in substrates of clay, a clay/sand mixture (v:v = 1:1) or sand. Root morphological traits, topological indices and root relative distance plasticity indices were quantified. The results indicated that different substrates have various effects on the root traits of these six aquatic plants; the introduced plants generally exhibited higher plasticity than did their native counterparts of the same life form.