水位调节对三峡水库消落带植被群落特征的影响

水位运行或调节模式是影响水库消落带植被组成与结构的关键因素,三峡水库独特的水位调节形成了具有明显不同出露-淹没特征的梯度性消落带.为了解水位调节对三峡库区消落带植物群落特征的影响,选择在三峡水库高水位运行5年后,在库区腹地3个受人为干扰较小且近自然状态的消落带,开展了不同高程(150 m、160 m和170 m)梯度的消落带植被物种组成、盖度、生物量、生物多样性和优势物种的比较研究.结果显示:消落带植被共有51种植物,多年生和一年生植物分别为25种和26种;随着高程增加,总物种数量越来越高,3个高程分别为8种、22种和45种分布;150 m高程盖度和生物量明显低于160 m和170 m两个高程,而后两者均没有显著差异;不同水位高程优势种明显不同,以白酒草为主的一年生植物多分布在消落带170 m高程,以狗牙根和马唐为主的多年生和一年生植物分布在消落带的160 m高程,以狗牙根为主的多年生植物分布在150 m高程;生物多样性指数随着高程的增加而变大,其中Shannon-Wiener多样性指数在150 m、160 m和170 m高程分别为0.877±0.298、2.137±0.186和3.097±0.407.综上表明,水位调节导致三峡水库消落带植被在30 m高程(145-175 m)范围内形成了不同组成与结构的群落,优势物种间差异可能是消落带植物对三峡水库水位调节模式的一种适应性策略体现;150 m高程出露时间相对较短,其土壤沉积物淤积严重,表层土壤种子库萌发受影响,物种数量、生物多样性、植被盖度和生物量明显低于其他高程,自然恢复能力较差.     

水深梯度对黑藻生长的影响

采用盆栽试验方法,将黑藻(Hydrilla verticillata)顶枝种植在水下0.5、1.0、1.5、2.0、2.5、3.0、3.5、4.0 m处塑料盆内,研究水深对黑藻生长的影响。结果表明,水深能够明显影响黑藻的存活,当水深>2.5 m时,由于光照不足,黑藻生长受到了明显抑制,水深3.0、3.5、4.0 m处黑藻分别于试验第57、33、21天死亡。水深改变了黑藻植株形态。水深对黑藻株高的影响极显著(P<0.01)。试验80 d时,不同水深处黑藻的茎节数、节间距、分枝数均差异显著(P<0.05)。试验80 d时,水深0.5～2.0 m处,黑藻株高和茎节数随水深增加而逐渐增加,当水深>2.0 m时,随水深增加开始减少。试验80 d时,水深0.5～2.5 m处,黑藻节间距随水深增加而不断延长。同一生长时间黑藻分枝数随水深增加而递减。各水深梯度处黑藻生物量呈先升高后降低的趋势,水深0.5～1.5 m处黑藻生物量随深度增加呈上升趋势,水深1.5 m处生物量最大,水深2.0、2.5 m处生物量迅速降低,不同水深梯度间黑藻生物量差异极显著(P<0.01)。该试验条件下,黑藻的光补偿水深在水体平均透明度(1.0 m)...     

等高固氮植物篱中套种桑树的桑叶产量及生物产量

对套种在等高固氮植物篱中的桑树（植物篱桑）和地埂桑全年的桑叶产量和生物产量、树势、桑叶营养成分等进行了研究,结果表明,植物篱桑各季的桑叶产量和单叶面积分别比地埂桑高114．3％－180．6％、7．8％－56．6％;全年株总片叶量、株冬条重、株枝叶总量分别比地埂桑高157．0％、294．3％、186．6％;单叶重除晚秋桑比地埂桑高4．1％外,其它各季高27．6％－66．5％;植物篱桑的树势极显著优于地埂桑,其有效条数、平均有效条长、平均粗和平均每m条着叶的数分别比地埂桑高84．8％、29．5％、39．0％、15．5％;植物篱桑下的土壤有机质和全氮含量高于地埂桑;二者桑叶的营养成分高低则相差不大。表5参16。     

芽胞杆菌属(Bacillus sp.)10株细菌混合制剂对4种作物出苗及苗期生长的影响

以10株具有促生及抑制病害的芽胞杆菌属菌株(Bacillus sp．)的培养物，按不同比例配制成5个混合剂型细菌制剂．A、B、C、D剂型播种时接种不结球小白菜30d后，株高、叶片数、根长和干重分别增加7．8％、6．2％、9．4％和13．8％，除C处理的株高与对照差异不显著外，其余均达显著水平．接种A和B剂型显著提高豌豆出苗率，出苗9d时两菌剂处理的地上和地下部干重分别平均提高92．3％和183．3％，并发现5株供试菌株对引起豌豆病害病原菌有明显的抑菌作用．以A、B、E三个剂型菌悬液培养水稻种子4d时，各处理的平均芽长提高33．3％，根长提高16．0％，培养25d时株高、根数和地上部干重平均分别提高16．0％、9．5％和22．7％，均达显著水平．B剂型的培养物培养小麦27d时发现对株高、叶片数和植株干重的影响都不显著，但对根数和根重有显著的促进作用．综合分析认为，A菌剂最有利于供试作物出苗和苗期生长，其次为B剂型．表5参17     

大气CO_2浓度和气温升高对谷子生长及产量的影响

研究大气CO_2浓度和气温升高对谷子的影响,有助于人们了解未来气候变化背景下谷子(Setaria italica)生产的变化,以提前采取必要的应对措施。采用控制系统来模拟气温升高2℃和CO_2浓度增加200μmol·mol-1的未来气候情景,研究气候变化对谷子光合及产量的影响。试验设对照(与室外气温、CO_2浓度一致,CK)、增温2℃(C0T1)、CO_2浓度增加200μmol·mol-1(C1T0)和增温2℃+CO_2浓度增加200μmol·mol-1(C1T1)4个处理,对谷子灌浆期的光合作用及成熟期形态指标、生物量和产量进行测定。结果表明,与对照相比,气温升高(C0T1)后,谷子叶片净光合速率无明显变化,气孔导度和蒸腾速率上升,水分利用率下降;大气CO_2浓度升高(C1T0)谷子叶片净光合速率升高,气孔导度和蒸腾速率下降,水分利用率提高;大气CO_2浓度和气温同时升高(C1T1)后,谷子净光合速率提高,气孔导度和蒸腾速率升高,水分利用率下降。与对照相比,气温升高(C0T1)显著增加谷子的株高、穗长、茎直径、叶质量、茎质量、穗质量、地上部分生物量和产量,分别增加了62.29%、63.51%、59.87%、73%、77%、70%、72.3%和76.6%;大气CO_2浓度升高(C1T0)显著增加谷子的株高、穗长、茎直径、节数、叶质量、茎质量、穗质量和地上部分生物量,比对照分别增加35.18%、32.75%、25.80%、21.54%、21.5%、70.8%、19.4%和32.3%;升温和升CO_2复合处理(C1T1)条件下,谷子株高、穗长、茎直径、叶质量、茎质量、穗质量、地上部分生物量和产量升高,与对照相比分别增加58.24%、42.69%、131.89%、34.8%、80%、77.6%和92.6%。未来气候变化对谷子生长发育将以正效应为主。     

盐胁迫下外源硅对硅突变体与野生型水稻种子萌发的影响(Effects of Silicon on the Germination of Si Mutant Rice and Wild Rice Seeds under Salt Stress)

为深入了解盐胁迫下外源硅(Si)对水稻种子萌发的作用,采用溶液培养法研究了外源Si对盐胁迫下野生型和硅突变体水稻(不能正常吸收Si)种子萌发各指标的影响.结果表明,随着NaCl浓度的提高(0～150mmol·L-1),两种水稻的芽长、发芽势、发芽率均不断降低.在150mmol·L-1NaCl胁迫下,野生型和硅突变体水稻的芽长分别为0.33cm和0.55cm,仅为对照的8.0%和11.1%;发芽率仅为对照的29.7%和53.7%;发芽势则分别降低至0%和2%.外源Si可以提高盐胁迫下两种水稻的发芽指标,且对硅突变体水稻的影响显著大于野生型水稻.2mmol·L-1Si浸种+2mmol·L-1Si处理可使野生型水稻芽长、芽重和发芽率分别比对照增加127.27%、169.23%和55.17%,发芽势则由对照时的0%提高至23.33%;硅突变体水稻芽长、芽重和发芽率分别比对照增加307.27%、285.71%和80.29%,发芽势则由对照时的2%提高至82.22%.     

沼液浸种对水稻种子萌发及幼苗生长的影响

为探讨沼液对水稻早期萌发和幼苗生长的影响,以不同浓度沼液对日本晴水稻(Oryza sativa)种子浸种24 h后催芽,分析其种子萌发及幼苗生长情况.结果表明,2％沼液浸种可增加水稻幼苗根数和芽生物量,但降低了幼苗根生物量,该浓度沼液浸种对种子萌发率、萌发速率、幼苗芽长、茎粗及总根长没有显著影响(P＞0.05).更高浓度的沼液浸种对水稻种子萌发和幼苗生长均产生抑制作用.沼液浸种对根生物量的影响大于芽生物量,从而导致各浓度沼液处理组芽/根生物量比值均大于对照.对呼吸速率的分析结果进一步佐证了沼液处理对萌发后期水稻种子具有不利影响.建议水稻早期生产中慎用沼液.     

低磷胁迫下云南稻形态性状的氮肥反应

采用盆栽试验每份材料栽2桶,每盆装4 kg低磷酸性红壤(速效磷2.53 mg·kg-1、速效氮156.7 mg·kg-1和pH=6.03),设置不施氮肥(速效氮156.7 mg·kg-1)和施氮肥(速效氮490.0 mg·kg-1)两种处理对539份云南稻核心种质17个形态性状及其相对指标,研究低磷胁迫下云南稻形态性状的氮肥效应结果表明:总体上低磷胁迫下云南稻核心种质籼稻氮效反应明显比粳稻敏感;按氮反应相对指标将云南稻种17形态性状划分为氮反应的强敏感、中敏感、弱敏感和不敏感型四种类型;揭示了低磷胁迫下云南稻种氮高效鉴定指标以相对穗干质量和相对总干质量为主,相对穗长、秆干质量、地上干质量、根干质量和茎蘖数可作为参考指标,其中穗干质量为氮反应的强敏感型,总干质量、地上干质量、秆干质量和茎蘖数属中敏感型,根干质量属弱敏感型和穗长属不敏感型.另外,低磷胁迫下云南稻种8个对氮反应敏感相对性状无论是在539份云南稻核心种质及其籼粳亚种间,还是在五个稻作区间总趋势是一致的;既证实了该文提出的低磷胁迫下8个氮反应敏感指标性状是十分可靠的,又揭示了低磷胁迫下5大稻作区氮反应的生态差异和土攘类型多样性是云南成为亚洲栽培稻籼粳分化中心之一的驱动力.     

青岛东风盐场中极端嗜盐古细菌的特性

从青岛东风盐场分离到3株嗜盐古细菌（编号：ZDA－1,ZDA－2和ZDA－5）,细胞为多形态杆状（0．7～15μm×2．0～50μm）,最适生长NaCl浓度为3．4mol／L,含有甘油二醚脂,类胡萝卜素色素和极性脂TGD－2（三糖基二醚脂）,x（C＋C）分别为63．7％,62．7％,和64．3％,据此,这3株菌可归入嗜盐小盒苗属（Hchoarcula）;但它们不水解淀粉,明胶不液化,不水解酪蛋白等生理生化特性不同于该属中现已正式承认的两个种,因此,本工作分离的3株菌可能是嗜盐小盒菌属一个新种.     

NaCl胁迫对甜高粱发芽期生理生化特性的影响

为筛选耐盐甜高粱材料,探讨NaCl胁迫对甜高粱发芽期生理生化特性的影响,研究了0、70、140、210 mmol.L-1NaCl胁迫对吉甜3、BJK156、甜132、凯勒、威利、考利、吉甜2、戴尔等8个甜高粱材料发芽率、发芽势、发芽指数、活力指数、芽长、根长、芽鲜质量、根鲜质量等8个指标盐害系数的影响,利用系统聚类分类法对甜高粱耐盐性进行聚类可分为3类：耐盐性最强的是甜132,耐盐性中等的是BJK156,耐盐性较敏感的是考利、吉甜3、吉甜2、戴尔、凯勒、威利。进一步研究了盐胁迫对甜高粱芽苗中丙二醛、可溶性蛋白含量及过氧化物酶（POD）、过氧化氢酶（CAT）、超氧化物歧化酶（SOD）活性的影响。结果得出：随着盐胁迫的加重丙二醛含量逐渐增加,可溶性蛋白含量逐渐减少。NaCl胁迫不同程度地提高了8个甜高粱材料POD、CAT、SOD活性,受3种NaCl质量浓度胁迫后8个甜高粱材料POD、CAT、SOD活性的变化趋势不同,这可能是它们耐盐差异的生理原因之一。另外,在3种NaCl浓度胁迫后甜132中的丙二醛增加量在8个材料中都是最低的,这与系统聚类分析得出甜132耐盐性最强的结论相吻合。研究认为丙二醛含量的变化可以作为筛选发芽期耐盐甜高粱品种的一个指标。     

九寨沟自然保护区4种水深梯度下芦苇分株地上生物量的分配与生长

芦苇是世界自然遗产--九寨沟自然保护区的一种重要的湿地植物.本文对该地区芦苇海4个不同水深梯度下芦苇的无性系地上分株的生物量分配、生长与繁殖策略进行了比较研究.结果表明,在47 cm (水在土层表面上)水深环境中,芦苇单株的平均生物量(4.2 g)最大.在-15 cm (水在土层表面下15 cm)的生境中,叶生物量百分比(叶生物量占单株总生物量的百分比, 46.1%)最大.芦苇地上分株高度、地上分株有分枝的单株百分比(茎上有分枝的分株占样地总分株的百分数)也存在明显的差别.茎的生物量分配百分比和生长速率随水深的增加而增加.在滩地生境中,开花率、花序的生物量百分比明显大于水较深的生境.分株株高与分株生物量、茎生物量与叶生物量都表现出较明显的幂指数异速生长规律.在-15 cm水深的生境中,叶生物量的生长快于茎的增长;在其他水深梯度的生境中,则是茎生物量的增加快于叶生物量的增加.     

Effects of clonal integration on the growth and physiology of Phalaris arundinacea under simulated herbivory北大核心CSCD

In order to investigate the effects of clonal integration on the adaptation of clonal plants to the environmental stress of homogeneous herbivory, we conducted a greenhouse experiment to investigate the ecophysiological response characteristics of Phalaris arundinacea collected from the riparian zone of the Poyang Lake wetland and Le'an River in Jiangxi Province and the effect of clonal integration on this dominant plant under two-months of simulated cyclical homogenous herbivory. Simulated herbivory strength was set at four different levels: no leaf removal (control) and 25%, 50%, and 75% leaf removal. We implemented two methods of clonal integration including no integration, in which the rhizome connection was severed, and integration, in which the rhizome connection was intact. We found that simulated herbivory significantly decreased the number of leaves, total shoot length, number of ramets, and biomass of P. arundinacea (P < 5%), regardless of whether the rhizomes were intact or severed. Ramets with severed rhizome connections (RRC) generally had higher growth indices than those with intact rhizome connections (RIC). Severing rhizomes did not significantly affect the chlorophyll content of P. arundinacea, while RRC under simulated herbivory intensities of 25% and 50% leaf removal had higher chlorophyll a (Chl a), chlorophyll b (Chl b), and total chlorophyll (Chlt) contents than RIC did, and simulated herbivory increased the chlorophyll contents of all ramets. RRC net photosynthesis rate (Pn), stomatal conductance (Gs), intercellular CO2 concentration (Ci), and transpiration rate (Tr) were all higher in RRC than they were in RIC under simulated herbivory intensities of 50% and 75% leaf removal; however, the opposite relationship was observed under a simulated herbivory intensity of 25% leaf removal. Further, simulated herbivory limited the photosynthetic index of P. arundinacea. These effects resulted in an inadequate accumulation of nutrients in the plant. Phalaris arundinacea can adapt to simulated herbivory treatments in terms of growth, but clonal integration cannot improve the growth of P. arundinacea under a homogeneous herbivory treatment. © 2018 Science Press. All rights reserved.     

福建赤红壤旱地与红壤旱地水分特性的比较

释放80%的有效水时赤红壤旱地的t值（当释放的土壤有效水占有效水库容的比率为80%时的土壤水吸力值）较小,表明赤红壤旱地持水性较红壤旱地更差,植物更容易受到干旱的协迫。赤红壤旱地贮水库容比红壤旱地小,赤红壤旱地的比水容量达到10-2数量级（难效水）在-10kPa~-30kPa就开始出现,而红壤旱地出现在-30kPa以下,表明赤红壤旱地的失水速度快,保水供水性能弱于红壤旱地。最后,讨论了影响旱地土壤水分性质的因素。     

保水剂对番茄生长及水分利用效率的影响

在砂与木屑复合基质中加入不同用量的保水剂,测定基质物理性状,并进行不同水分处理条件下番茄盆栽试验,以研究保水剂对番茄生长及水分利用效率的影响。结果表明:在每1 L基质分别加入1、2、4、8 g保水剂时,与对照(未加保水剂)相比,基质持水量分别增加16.35%、34.00%、61.29%和135.16%,容重分别降低3.61%、5.37%、9.42%和14.64%;在水分耗竭试验中,番茄萎蔫天数分别延长13.92%、22.79%、31.65%和45.5%,干物质量分别增加7.90%、21.60%、57.08%、179.50%,株高、叶片数、茎粗、鲜质量也都随保水剂用量的增加而明显增加;在基质相对水分质量分数分别为55%、70%、85%及100%4种处理下的番茄水分胁迫试验中,每1 L基质施用2 g保水剂时,与对照(未加保水剂)相比,水分利用效率分别提高29.93%、28.06%、14.36%、7.42%,株高、生物量也随水分胁迫程度加重而明显提高。     

基于复合节间组分关系的结缕草克隆植株形态可塑性特征分析

结缕草Zoysia japonica克隆植株的基本形态学单元是复合节间。分析复合节间组分关系,可以进一步揭示其形态可塑性的细微特征和资源传输与分配的差异,同时也可以为形态可塑性成因提供合理的生理生态学解释。本文对温室内、外两种环境条件下生长的结缕草克隆植株的复合节间组分进行测定和分析,结果表明：温室内、外植株主匍匐茎的长度和生物量的波动比一级分枝大,缩短节间长度比伸长节间长度稳定,但缩短节间生物量较伸长节间生物量变化幅度大。伸长、缩短节间长度、生物量分别与复合节序数呈二次函数关系。伸长、缩短节间生物量和分株生物量在一个生长季的生长方程亦均呈二次函数关系。主匍匐茎根数量、生物量随复合节数递增基本呈递增趋势。在两种环境下,A分株根数、生物量均大于B分株根数、生物量（在结缕草匍匐茎上,着生于每个复合节的基端和梢端缩短节间上的分株分别称为A、B分株）,且差异明显。温室内植株,在分株发育形成后,伸长、缩短节间的长度、生物量分别与匍匐茎根、A分株根数、B分株根数、生物量间相关性显著,温室外的相关性格局较复杂,且总体显著性低于温室内。结缕草克隆植株基本形态结构单元的复合节上的各个组成部分之间存在的密切相关关系,是导致结缕草克隆植物形成形态可塑性的细微特征格局的主要原因。     

Individual and combined effects of Ca/Mg ratio and water on trait expression in Mimulus guttatus

Low Ca/Mg ratios (a defining component of serpentine soils) and low water environmental conditions often co-occur in nature and are thought to exert strong selection pressures on natural populations. However, few studies test the individual and combined effects of these environmental factors. We investigated the effects of low Ca/Mg ratio and low water availability on plant leaf, stem, stolon, and floral traits of Mimulus guttatus, a bodenvag species, i.e., a species that occurs in serpentine and non-serpentine areas. We quantified genetic variation and genetic variation for plasticity for these leaf, stem, stolon, and floral traits at three hierarchical levels: field-habitat type, population, and family, and we evaluated the relative importance of local adaptation and plasticity. We chose two populations and 10 families per population from four distinct field "habitat types" in northern California: high Ca/Mg ratio (non-serpentine) and season-long water availability, high Ca/Mg ratio and seasonally drying, low Ca/Mg ratio (serpentine) and season-long water availability, and low Ca/Mg ratio and seasonally drying. Seedlings were planted into greenhouse treatments that mimicked the four field conditions. We only detected genetic variation for stem diameter and length of longest leaf at the field-habitat level, but we detected genetic variation at the family level for nearly all traits. Soil chemistry and water availability had strong phenotypic effects, alone and in combination. Our hypothesis of an association between responses to low water levels and low Ca/Mg ratio was upheld for length of longest leaf, stem diameter, corolla width, and total number of reproductive units, whereas for other traits, responses to Ca/Mg ratio and low water were clearly independent. Our results suggest that traits may evolve independently from Ca/Mg ratios and water availability and that our focal traits were not simple alternative measures of vigor. We found genetic variation for plasticity both at the field-habitat type and family levels for half of the traits studied. Phenotypic plasticity and genetic variation for plasticity appear to be more important than local adaptation in the success of these M. guttatus populations found across a heterogeneous landscape in northern California. Phenotypic plasticity is an important mechanism maintaining the broad ecological breadth of native populations of M. guttatus.     

Modeling the buoyant flow of heated water discharged from surface and submerged side outfalls in shallow and deep water with a cross flow

In this study, a three-dimensional model was used to numerically study the buoyant flow, along with its mixing characteristics, of heated water discharged from the surface and submerged side outfalls in shallow and deep water with a cross flow. Hydraulic experimental data were used to evaluate the applicability of the model. The simulation results agree well with the experimental results, particularly, the jet trajectories, the dimensions of the recirculating zone, and the distribution of the dimensionless excess temperature. The level of accuracy of the simulation results of the present study is nearly identical to that of the results conducted by McGuirk and Rodi (1978). If the heated water is discharged into shallow water where the momentum flux ratio and the discharge densimetric Froude number are high, the submerged discharge method is better than the surface discharge method in terms of the scale of the recirculating zone and the minimum dilution. In deep water, where the momentum flux ratio and discharge densimetric Froude number are low, however, the submerged discharge method had few advantages. In shallow water, the discharge jet is deflected by the ambient cross flow, while forcing the ambient flow to bend towards the far bank for the full depth. For a submerged discharge in shallow water, the recirculating zone is the largest in the lowest layer but becomes smaller in the upper layer. As the water depth increases, the ambient flow goes over the jet and diminishes the blocking effect, thereby decreasing the bending of the jet.     

绿潮藻类暴发对天鹅湖水体和沉积物磷含量的影响

在荣成天鹅湖藻类暴发区域采集新鲜沉积物和丝状硬毛藻（Chaetomorpha spp.）,进行室内模拟试验,监测了生长过程中硬毛藻的生物量、磷富集量以及不同处理水体总磷（TP）和可溶性磷（SRP）质量浓度的变化,并分析了藻类生长对沉积物中各形态磷含量的影响。结果表明,当水体磷含量较高时,硬毛藻生长较快,相对生长速率高达14.88%,之后随着水体磷浓度的下降,生长速率逐渐减小。不同处理间硬毛藻的生物量相差很大,高磷含量处理显著高于低磷处理,最大差值可达26.50 g。随着藻类的生长,水体TP和SRP含量明显降低,其中高磷含量处理的TP质量浓度由0.93 mg·L-1降至0.01 mg·L-1,低磷含量处理水体SRP质量浓度均降至0.006 mg·L-1以下。当水体磷含量降至一定水平,沉积物中磷可向水体释放,其中可还原态磷和铁铝结合态磷的降幅分别为23.98%和12.61%。在高磷含量处理组,藻体中磷的富集量显著升高,且当水体磷含量相同的条件下,有沉积物处理的富集量显著高于无沉积物处理。相关分析表明,藻体生物量与水体TP和SRP的相关性较好,其中高磷含量处理组生物量与水体TP、SRP呈高度负相关,而相对生长速率与之呈显著正相关。结果说明,水体及沉积物中磷均可作为硬毛藻生长的营养来源;另一方面,藻类生长可明显降低水体磷含量,并促进沉积物中磷的释放。     

3种水生植物对锰污染水体修复作用的研究

通过静态水培试验,研究了3种水生植物水葫芦（Eichhornia crassipes（Mart.）Solms）、水浮莲（Pistia stratiotes L.）、水花生（Atlernanthera philoxeroides）在55、155mg L-1锰（Mn）质量浓度下的生物量、Mn质量分数、富集系数、转运系数,以及对2种Mn质量浓度水体的修复作用。结果表明,水浮莲的鲜质量、干质量、相对生长率、Mn质量分数、富集系数随着取样时间的延长而显著增加（P〈0.05）。2种Mn质量浓度下,水葫芦与水浮莲的鲜质量与相对生长率显著高于水花生。植物茎叶的Mn质量分数依次为水浮莲〉水葫芦〉水花生（P〈0.05）,其中155mg L-1Mn处理水浮莲与水葫芦茎叶Mn质量分数均高于10000mg kg-1,分别为12431.05mg kg-1、11238.28mg kg-1。3种植物茎叶、根的富集指数均显著大于1,且茎叶的富集系数依次为水浮莲〉水葫芦〉水花生（P〈0.05）,根富集指数依次为水浮莲≈水葫芦〉水花生（P〈0.05）。在10,21d这2个取样时期,水浮莲的转运系数要高于其它植物,其中在155mg L-1处理下,水浮莲的转运系数要高于1,分别为1.04、1.01。种植3种水生植物后,2种Mn处理水体的Mn质量浓度随着取样时间的延长而降低。水葫芦、水浮莲、水花生收获时,55mg L-1Mn处理的水体Mn质量浓度分别降低了31.84%、31.44%、18.47%;155mg L-1Mn处理则降低了12.02%、18.53%、7.57%。可见,水浮莲符合超积累植物对Mn质量分数、富集系数、转运系数的要求,其在Mn污染水体修复方面有很好的应用前景。     

Morphology, growth and carbohydrate storage of the plant Typha angustifolia at different water depths

Morphological characteristics, growth and carbohydrate storage dynamics of Typha angustifolia in relation to water depth were investigated. The study was based on observations carried out in two stands, namely Akigase and Teganuma, for two growth seasons. The latter stand was about two times deeper than the former. Teganuma stands exhibited significantly higher number of thick shoots compared to those of Akigase. Conversely, the difference in shoot heights between the two stands was insignificant. The same was true for rhizome lengths. Rhizome diameters were significantly bigger for Teganuma compared to Akigase. Furthermore, both the above and belowground biomass were significantly higher for Teganuma compared to those of Akigase. Teganuma stands allocated 55% of the total biomass to the aboveground parts, while Akigase stands allocated 60%. Similarly, Teganuma exhibited significantly higher stocks of total non-structural carbohydrates (TNC) compared to Akigase. The higher number of thick shoots and the relatively bigger rhizome diameters in Teganuma are seemingly important tolerance strategies in maintaining effective aeration into the rhizosphere, by reducing internal resistance. In addition, the higher TNC stocks and biomass help not only to enhance survival under anoxia for longer durations, they also provide firm substrate anchorage in the deeper Teganuma stands.