970 resultados para Disney characters.


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通过野外采集和观察,标本鉴定和实验研究,从植物形态学,叶柄和根状茎的解剖,叶表皮的显微观察,和孢子形态的扫描电镜观察等方面进行研究与分析,对中国瓦韦属(除薄叶组)进行了分类学修订研究。 1. 形态性状分析 研究了国内外重要标本馆的大量瓦韦属植物标本,通过对一些重要的形态性状的观察和分析,判定其变异规律及分类学意义。根状茎上的鳞片和孢子囊上的隔丝的形状和网眼结构是瓦韦属属下分类和种的划分的最主要的形态学性状。其它特征如孢子囊群着生的位置、中脉的颜色、根状茎直立或横走等在种内也具有一定的稳定性,可以帮助种的划分和鉴定。因此,在对瓦韦属植物进行分类时要结合几个相关性状而不是单一的性状进行分类。 2. 叶柄和根状茎的解剖 对瓦韦属(除薄叶组)49 个种的叶柄和根状茎进行解剖观察,发现叶柄中维管束的条数一般为1--7 条不等,排成一字形、三角形或半圆形。两根粗的维管束排列在腹面,较细的维管束排列在背面。叶柄中没有厚壁组织,但是在叶柄和根状茎的连接部位叶足处有厚壁组织的存在。根状茎横切面观察显示除了维管束外还有厚壁组织的存在,在常绿种内厚壁组织较多,落叶类型中厚壁组织较少。 3. 叶表皮形态 观察了瓦韦属51 个种的叶表皮形态和结构,发现该性状对于属下划分具有一定的系统学意义,也有助于疑难物种的鉴别。瓦韦属植物的叶表皮细胞形状通常为多边形、不规则;垂周壁式样为波状和浅波状;气孔器类型比较复杂,在所观察的类群中,气孔器都分布在下表皮上,极细胞型Polocytic type,共环极细胞型Copolocytic type ,腋下细胞型Axillocytic type ,聚腋下细胞型Coaxillocytic 是最常见的类型,不规则型Anomocytic type ,不规则四细胞型Anomotetracytic type,不等细胞型Anisocytic type,辐射状细胞型Actinocytic type 和双环不等四细胞型Amphicycloanisocytic type 也存在于瓦韦属的叶表皮中。属下同一个组的叶表皮特征近似,不同的组具有一定的差别。 4. 孢子形态 在扫描电镜下对瓦韦属50 个种的孢子形态进行了观察。瓦韦属的孢子两侧对称,极面观为椭圆形,赤道面观为肾形、豆形或半圆形。孢子的表面纹饰可以分为6 类,分别是光滑、颗粒状、瘤状、皱状、波状以及疣状的纹饰。瓦韦属的孢子周壁较薄,纹饰由外壁组成。孢子形态具有重要的系统学意义,可以为属下分类提供可靠的证据,对形态近似的物种的划分也有重要参考价值。 通过对大量标本的研究,以及模式标本的考证,结合野外居群观察,综合分析有关分类学资料,主要依据比较稳定的微观性状,对瓦韦属植物进行了新的分类学修订。结果承认中国瓦韦属(除薄叶组)有37 种,可以分为5 个组,有3 个名称被首次处理为异名,另有2 个种暂时存疑。

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通过无融合生殖方式固定水稻杂种优势是水稻育种中极具诱惑力的研究内容之一。自从1979年以来,我国水稻无融合生殖充种研究主要集中在筛选和鉴定水稻多胚苗材料。根据前人的研究结果,具有无融合生殖特性的植物大多数为多倍体。本试验以多胚苗水稻APIV及其衍生系为研究材料,在二倍体[APIV_((2))]、同源三倍体[APIV_((3))]和同源四倍体[APIV_((4))]水平,对其多个世代中的特征特性,其中包括形态学特征,遗传学和胚胎学特性进行了研究,旨在探讨在多倍性水平筛选水稻无融合生殖种质的可能性,获得如下主要研究结果: 1.在二倍体APIV_((2))的多个世代中,只发现单胚苗、双胚苗和三胚苗植株,多胚苗频率比较低(4.67~5.14%),多胚苗性状的表达在一定程度上受到环境因素的影响,并且,多胚苗植株的成活率比较低(11.70~17.39%),大部分多胚苗植株在三叶期之前死亡,这很可能与其胚乳的营养供应有关。根据APIV_((2))的多胚苗性状在多个自交世代和杂交世代中的表达特点,多胚苗性状不是显性性状,也不是隐性性状,而是一种比较特殊的数量性状。 2.胚胎学的研究结果表明,在APIV_((2))的2857个子房的胚囊中没有观察到与不定胚生殖有关的特异生殖现象;APIV_((2))在发生受精之前的胚囊构型包括正常蓼型胚囊(76.5%)、退化型胚囊(16.0%)和变异型胚囊(7.5%),在变异型胚囊中包括双卵卵器胚囊(86.7%)和三卵卵器胚囊(13.3%);APIV_((2))的双受精与前人在正常二倍体水稻中所观察到的结果大致相符;在不同季节的颖花和同一季节同一稻穗的不同颖花内多卵和多胚苗频率存在着明显差异。 3.在同源四倍体水稻的诱导中对种芽进行预处理,促使其胚芽鞘明显伸长后再进行诱导处理是诱导成功的关键技术。在同源四倍体APIV_((4))的同一稻穗中强势颖花的多卵频率要明显地高于弱势颖花的多卵频率。在APIV_((4))去雄后的颖花中意外地观察到了单胚和双胚现象。同源四倍体水稻APIV_((4))的有性生殖能力明显变弱,在花药内正常花粉粒少而败育花粉粒多;在受精前正常胚囊数少而退化胚囊数比较多(36.0%);花粉管进入胚囊的时间比较晚;双受精频率低而单受精频率高。 4.异倍性水稻间具有一定的可交配性,但其结实率比较低(0.20~-1.64%),通过常规杂交方法所获得的同源三倍体成活植株的频率更低(0.07%)。在湖南湘潭的秋季条件下同源三倍体水稻植株雄性完全败育,但有部分稻穗能结实(0.59%~7.71%),由此可获得饱满种子和不饱满种子。 5.通过子房培养可以获得异倍性水稻间杂种植株。在APIV_((4))/APIV_((2))杂交组合的子房培养中出现了一株双胚苗;同源三倍体成活植株的获得率仍然比较低(0.78%),但比通过常规杂交法首先获得种子,进而获得同源三倍体成活植株的效率要倍出11.14倍。根据试验结果,提出了6个问题进行讨论。认为在杂交后代中有可能筛选到多胚苗发生频率更高的单株;多胚苗性状是比较复杂的数量性状;同源四倍体水稻的有性生殖能力明显变弱;通过合理配组和复重授粉可以提高异倍性水稻间的杂并结实率;通过子房培养可以明显提高获得同源三倍体成活植株的效率;在多倍体水稻中筛选无融合生殖种质在比二倍体水稻中筛选可能更容易成功。

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Psednos rossi new species (Teleostei: Liparidae) is described from two specimens collected in the North Atlantic Ocean off Cape Hatteras, North Carolina, at depths of 500–674 m. Psednos rossi belongs to the P. christinae group, which includes six other species and is characterized by 46–47 vertebrae and the absence of a coronal pore. Psednos rossi differs from those six species by having characters unique within the genus: straight spine, body not humpbacked at the occiput, and a very large mouth with a vertical oral cleft. Other distinguishing characters include a notched pectoral fin with 15–16 rays, eye 17–19% SL, and color in life orange-rose. With P. rossi, the genus Psednos as currently known includes 26 described and five undescribed species of small meso- or bathypelagic liparids from the Atlantic, Pacific, and Indian Oceans.

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A developmental series of larval and pelagic juvenile pygmy rockfish (Sebastes wilsoni) from central California is illustrated and described. Sebastes wilsoni is a non- commercially, but ecologically, important rockfish, and the ability to differentiate its young stages will aid researchers in population abundance studies. Pigment patterns, meristic characters, morphometric measurements, and head spination were recorded from specimens that ranged from 8.1 to 34.4 mm in standard length. Larvae were identified initially by meristic characters and the absence of ventral and lateral midline pigment. Pelagic juveniles developed a prominent pigment pattern of three body bars that did not extend to the ventral surface. Species identification was confirmed subsequently by using mitochondrial sequence data of four representative specimens of various sizes. As determined from the examination of otoliths, the growth rate of larval and pelagic juvenile pygmy rockfish was 0.28 mm/day, which is relatively slow in comparison to the growth rate of other species of Sebastes. These data will aid researchers in determining species abundance.

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Independent molecular markers based on mitochondrial and nuclear DNA were developed to provide positive identification of istiophorid and xiphiid billfishes (marlins, spearfishes, sailfish, and swordfish). Both classes of markers were based on amplification of short segments (<1.7 kb) of DNA by the polymerase chain reaction and subsequent digestion with informative restriction endonucleases. Candidate markers were evaluated for their ability to discriminate among the different species and the level of intraspecific variation they exhibited. The selected markers require no more than two restriction digestions to allow unambiguous identification, although it was not possible to distinguish between white marlin and striped marlin with any of the genetic characters screened in our study. Individuals collected from throughout each species’ range were surveyed with the selected markers demonstrating low levels of intraspecific character variation within species. The resulting keys provide two independent means for the forensic identification of fillets and for specific identification of early life history stages.

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Intergeneric hybridization between the epinepheline serranids Cephalopholis fulva and Paranthias furcifer in waters off Bermuda was investigated by using morphological and molecular characters. Putative hybrids, as well as members of each presumed parent species, were analyzed for 44 morphological characters and screened for genetic variation at 16 nuclear allozyme loci, two nuclear (n)DNA loci, and three mitochondrial (mt)DNA gene regions. Four of 16 allozyme loci, creatine kinase (CK-B*), fumarase (FH*), isocitrate dehydrogenase (ICDH-S*), and lactate dehydrogenase (LDH-B*), were unique in C. fulva and P. furcifer. Restriction fragments of two nuclear DNA intron regions, an actin gene intron and the second intron in the S7 ribosomal protein gene, also exhibited consistent differences between the two presumed parent species. Restriction fragments of three mtDNA regions—ND4, ATPase 6, and 12S/16S ribosomal RNA—were analyzed to identify maternal parentage of putative hybrids. Both morphological data and nuclear genetic data were found to be consistent with the hypothesis that the putative hybrids were the result of interbreeding between C. fulva and P. furcifer. Mean values of 38 morphological characters were different between presumed parent species, and putative hybrids were intermediate to presumed parent species for 33 of these characters. A principal component analysis of the morphological and meristic data was also consistent with hybridization between C. fulva and P. furcifer. Thirteen of 15 putative hybrids were heterozygous at all diagnostic nuclear loci, consistent with F1 hybrids. Two putative hybrids were identified as post-F1 hybrids based on homozygosity at one nuclear locus each. Mitochondrial DNA analysis showed that the maternal parent of all putative hybrid individuals was C. fulva. A survey of nuclear and mitochondrial loci of 57 C. fulva and 37 P. furcifer from Bermuda revealed no evidence of introgression between the parent species mediated by hybridization.

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本论文对草地群落地上/地下生物量构成、根冠比特征及其影响因子以及土壤呼吸测定方法比较等的国内外研究进展和主要成果进行了综述,在此基础之上对地处我国北方农牧交错带中段的内蒙古多伦县境内的18种草地群落(包括天然草地和人工草地群落)进行了相关内容的研究工作。 在2002年生长季期间,对这18个植物群落中选取的16个进行了群落学调查,测定了其地上、地下生物量,同时测定了土壤含水量、土壤容重、土壤全氮含量和土壤有机质含量。分别分析了地上、地下生物量以及根冠比(root to shoot ratio)与这些立地因子间的相关关系。同期,从18个群落中选定10个代表性群落测定其土壤呼吸速率,测定方法选用了动态红外气体分析法 (Infra red gas analysis, abbreviated as IRGA)和碱液吸收法(Alkali absorption, abbreviated as AA)。对这两种方法的测定结果进行了比较分析,同时分析了不同群落间土壤呼吸变化与土壤水分和养分状况等的相关关系。主要结论如下: ①16种植物群落的地上和地下生物量差异明显,地上生物量变化范围在80~500 g•m-2之间;相比之下,地下生物量的变化范围要大得多,16个群落中地下生物量最小的为猪毛菜群落,最大的为拂子茅群落,分别为533 g•m-2和2590 g•m-2。群落的根冠比在1.5~11.21之间,平均根冠比为 5.69。 ②土壤含水量对地上和地下生物量有着重要的影响,土壤含水量高的样地(羊草样地)较含水量低(小米蒿样地)的样地地上生物量高,反之亦然。但含水量与地下生物量之间的这种关系却不明显,即土壤含水量高的样地其地下生物量并不一定比含水量低的样地地下生物量高;根冠比与土壤含水量之间基本上呈负相关。土壤全氮含量和有机质含量与地上、地下生物量也存在着一定的正相关关系,而土壤容重却与生物量存有负相关关系;根冠比与土壤全氮、有机质和容重的关系正好与此相反,即根冠比与全氮和有机质含量呈负相关,与容重为正相关。 ③10种植物群落土壤呼吸的昼夜变化比较明显,均为单峰型曲线,主要受土壤温度的驱动,但同时也受到当日降水情况和云量、风速等气象因子的较大影响。因此,影响到这些群落土壤呼吸日动态的一致性,使得规律性并不明显。 ④用碱液吸收法和动态密闭气室法测定的10个群落的土壤呼吸速率变化范围分别为394~894mg C•m-2•d-1和313~2043 mg C•m-2•d-1,其中碱液吸收法测定结果平均为动态气室法的67.5%,明显低于动态密闭气室法。 ⑤两种测定方法具有很好的相关性,R2为0.8739。本研究中发现,在土壤呼吸速率低的情况下,两种方法的测定结果十分接近,甚至碱液吸收法的测定结果稍大于动态密闭气室法;而在土壤呼吸速率较高的情况下,动态密闭气室法测定结果则显著高于碱液吸收法。上述结果与国内外同类研究的结果高度一致,从而为校正我们以往采用碱液吸收法在该区域的测定结果提供了可靠依据。 ⑥各个群落间的土壤呼吸变化与立地土壤水分和土壤养分之间存有一定的相关关系,但并不显著,可能与这些群落土壤呼吸测定不是在同一天进行有关。

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The metric and meristic characters of Drepane punctata from Versova Fish Landing Centre of Bombay have been studied. The meristic characters showed considerable variations. The number of dorsal fin rays were relatively stable characters. Statistical interpretation of metric data indicated that there is a direct relationship between the preanal, predorsal in relation to total length and eye-diameter in relation to head length.

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Upeneus moluccensis were collected from the catches of bottom fish trawl of "M. V. Saraswati" off Veraval coast in the area lat. 20 degree 26 N and long. 70 degree 35 E. The fish were analysed for length-weight relationship and morphometric characters. The fishes were found to vary from 116 to 161 mm in length and 20.0 to 50.0 g in weight. The exponent value and correlation coefficient for length-weight relationship was found to be 2.73 and 0.991 respectively.

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The different morphometric characters of Therapon jarbua showed a linear relationship and uniformity in the various biometric measurements whereas the length-weight relationship showed a curvilinear graph. The studies also indicate that there is no significant difference, in the morphometric characters and length-weight relationship between the males and females. Ponderal index values for males and females was found to fluctuate between 1.3 to 1.5 for most of their life times with the peaks and crests appearing at different lengths for males and females.

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Morphometrics of 14 metric and 6 meristic characters of Trypauchen vagina of Bombay coast is presented. Number of spines and rays of dorsal, anal and pectoral fins differ with earlier studies. Sexual dimorphism in the length of caudal and anal fins was observed. Length weight relationship of males and females have been worked out to be W = 0.00000 687L super(2.8440) and W = 0.00000 2747L super(3.0274) respectively. The fish is a prolific breeder and peak breeding activity occurs in December. The growth rate was found to be 15.20 mm/month.

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Populations of three species of ribbonfishes (Trichiurus lepturus, Lepturacanthus savala, Euplerogrammus muticus) off the Bombay coast were studied for meristic and morphometric characters. All meristic characters except pectoral fin ray count, showed interspecific as well as intraspecific variations. Regression studies for various characters showed a linear relationship and high degree of correlation to the total and head lengths. Variations between the sexes were found insignificant. A comparison of the mean ratios of body parts of samples from Bombay and Mandapam showed significant variations for L. savala and E. muticus.

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Studies on genetic improvement of penaeid prawns for the character higher tail weight using methods of selective breeding were undertaken. Prior to the actual breeding experiments it was necessary to find out the quantum of available variability in the character tail weight amongst the natural populations of Penaeus merguiensis from the Indian waters. Thirteen morphometric variables were measured and various statistical analyses were carried out. The tail weight showed almost double values of coefficient of variation in the females than the males (C.V. 20.37 and 11.08 respectively). The combination of the characters viz. sixth segment length (SSL), sixth segment depth (SSD) and posterior abdominal circumference (PAC) gave the highest R super(2) values. These variables were easy to measure and gave maximum variation in the character tail weight without sacrificing the breeders in the brood stock. The quantitative character tail weight was influenced by both genetic and environmental factors was statistically ascertained by applying 2-Factor analysis.

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Thirteen morphometric and seven meristic characters, length-weight relationship and food and feeding habits of Otolithoides biauritus of Bombay coast (Maharashtra, India) were studied. Compared morphometric characters revealed positive allometric growth and high correlation ("r" ranging 0.898 - 0.996) between each other. Meristic characters were observed to be B sub(vii), D sub(1) 8-10, D sub(2) 27-31, P 17-20, V 5-7 and 7-10. Number of gill rackers on the first left gill arch ranged from 15 to 19. Length-weight relationship for both sexes together worked out to be W = 0.026, L super(2.646). The species is a predator, feeding mainly on motile Acetes, small fish and Loligo in order of preference.

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为了进一步降低水中营养盐浓度、提高水体透明度,为湖泊生态系统的恢复创造条件,促进湖泊水体生态系统良性循环,以太湖五里湖富营养化水体为研究对象,采用中试规模的人工湿地技术来强化净化富营养化水体。重点研究了不同流态、不同基质、不同植物及植物有无条件下各人工湿地系统对富营养化水体的处理效果。此外,还对生长在人工湿地中的7种湿地植物芦苇(Phragmites communis)、香蒲(Typha angustifolia)、茭白(Zizania caduciflora)、水葱(Scirpus validus.)、菖蒲(Acorus calamus)、鸢尾(Iris pseudacorus)和千屈菜(Lythrum salicaria)的生长、生理生态特性如气体交换、叶绿素荧光、光合色素含量及氮、磷吸收能力进行了研究,旨在探索高等植物在富营养化水体净化过程中的机理和规律,为人工湿地污水净化机理奠定一定的科学和理论基础。主要研究结果如下: 通过对垂直潜流、水平潜流和自由表面流三种类型的人工湿地系统对富营养化水体净化效果的对比研究,我们发现在水力负荷0.64 m d-1,进水污染物浓度化学需氧量(COD) 7.37 mg L-1、氨氮(NH4+-N) 1.63 mg L-1、硝氮(NO3--N )1.41 mg L-1、总氮(TN) 4.82 mg L-1和总磷(TP) 0.15 mg L-1的条件下,三种不同流态的人工湿地对富营养化水体均有一定的净化功能。三种类型的人工湿地对主要污染物COD、NH4+-N、NO3--N、TN和TP的去除效果分别为:垂直潜流40.4%、45.9%、62.9%、51.6%和64.3%;水平潜流39.6%、32.0%、65.3%、52.1%和65.7%;自由表面流16.5%、22.8%、34.2%、19.8%和35.1%。相比之下,垂直潜流、水平潜流对主要的污染物的去除效果明显好于自由表面流人工湿地。除垂直潜流湿地NH4+-N的平均去除率显著大于水平潜流外,两人工湿地在其余指标的去除效果上无显著差异。考虑到土地面积的限制,就太湖五里湖富营养化水体治理而言,垂直潜流和水平潜流较自由表面流更为适合。 以沸石为基质的人工湿地较以砾石为基质的人工湿地对NH4+-N有很好的去除效果,除此之外两种基质类型的人工湿地在其余各污染指标的去除效果方面差异不显著。但随着湿地运行时间的延长,沸石对NH4+-N的吸收能力会逐渐减弱,考虑到湿地构建成本,建议就地取材,以当地较为廉价的砾石为人工湿地基质比较经济适用。 有无植物对有机污染物COD的去除效果影响差异不显著,但对TN和TP去除效果影响差异极显著,有植物的人工湿地对TN的去除率比无植物的分别高出12.5%和13.4%,对TP去除率分别高出16.9%和31.0%。不同植物对人工湿地处理效果的影响差异不显著,可见湿地流态对处理效果的影响大于植物的影响。 各湿地植物叶片的净光合速率(Pn)日变化均为双峰曲线,有光合“午休”现象。其中芦苇、茭白、鸢尾、菖蒲、水葱和千屈菜Pn的下降主要是由气孔导度(gs)的下降造成的,而香蒲则更多的受叶肉光合能力下降的影响。除千屈菜的Pn与gs之间呈显著正相关外,其余植物的Pn与gs之间均呈极显著正相关。气孔行为对湿地植物光合作用碳的固定显示了明显的主导控制作用。 各湿地植物的光补偿点(LCP)差异不显著,其均值都在10µmol m-2 s-1以上,显示了阳生植物的特性。但湿地植物的光饱和点 (LSP)差异极显著,LSP大小依次为香蒲1476.3µmol m-2 s-1>水葱1140.0µmol m-2 s-1>菖蒲753.7µmol m-2 s-1>芦苇751.7µmol m-2 s-1>茭白640.7µmol m-2 s-1>千屈菜567.3µmol m-2 s-1>鸢尾479.0µmol m-2 s-1。7种湿地植物的CO2补偿点差异极显著,CO2补偿点大小依次为水葱47.1µmol mol-1>茭白28.4µmol mol-1>香蒲23.7µmol mol-1>鸢尾16.8µmol mol-1>菖蒲16.7µmol mol-1>千屈菜15.2µmol mol-1>芦苇14.8µmol mol-1。与此相反,湿地植物的CO2饱和点差异不显著。 各湿地植物的Fv/Fm值大小差异也极显著,Fv/Fm值大小依次为千屈菜0.8168>水葱0.8348>香蒲0.8262>菖蒲0.8198>芦苇0.8168>茭白0.8040>鸢尾0.7930。由此可见千屈菜、水葱较芦苇和茭白有较高的PSⅡ效率。7种湿地植物叶片的叶绿素a、叶绿素b和类胡萝卜素含量水平差异极显著,芦苇和茭白叶片的叶绿素和类胡萝卜素含量水平都较高,这在客观上解释了他们为何拥有较强的光合能力。 不同湿地植物的生物量大小差异极显著,平均生物量(干重)变化范围在0.26-6.65 kg m-2之间。除香蒲和水葱的地下部生物量显著大于地上部外,其余植物都是地上部生物量大于地下部,这非常有利于人工湿地生态工程中通过收获植物地上部生物量来达到去除氮、磷污染目的。 不同湿地植物植株氮、磷含量差异极显著。湿地植物对氮吸收总量变化范围为6.09-93.96 g m-2,吸收氮最高是芦苇,最低是菖蒲;对磷吸收总量变化范围为0.51-8.95 g m-2,吸收磷最高是香蒲,最低是菖蒲。经测算,植物吸收的总氮量占人工湿地总氮去除量的0.6-17.1%,总磷量占人工湿地总磷去除量的1.4-40.5%。本次试验中香蒲和芦苇对氮、磷的吸收去除能力比较高,茭白、鸢尾、水葱和千屈菜的吸收去除能力中等,而菖蒲的吸收能力较弱。