茎瘤对长喙田菁在铅锌尾矿环境适应中的意义II 茎瘤对长喙田菁固氮和积累重金属的影响

探讨茎瘤对长喙田菁(Sesbania rostrata)在铅锌矿尾矿、客土和纯土环境中结瘤、固氮和积累重金属的影响。结果表明：保留茎瘤使长喙田菁全株植物氮含量和单株植物氮积累量分别比去除茎瘤处理提高了12.4%～34.0%和43.3%～131.4%,且环境愈恶劣,这种作用愈为显著。同时,保留茎瘤处理显著抑制了长喙田菁根瘤的生长,同样表现出环境愈恶劣,抑制作用愈显著的趋势。因此,在尾矿环境胁迫下,长喙田菁更趋向于选择茎瘤作为固氮途径。由此可见,茎瘤对生长在铅锌尾矿环境中的长喙田菁获得氮素及支持其生长有着特别     

茎瘤对长喙田菁在铅锌尾矿环境适应中的意义I. 茎瘤对长喙田菁生长发育的影响

 通过设置保留茎瘤和去除茎瘤处理,研究长喙田菁(Sesbania rostrata)在铅锌尾矿、客土和纯土环境中的生长发育情况。结果表明:保留茎瘤使长喙田菁的株高、地上部生物量、地下部生物量、全株生物量和叶绿素含量分别比去除茎瘤处理提高了2.4%～4.8%、27.4%～67.9%、28.5%～99.3%、27.6%～72.3%和17.0%～23.4%,这种作用在纯尾矿处理组最为显著,客土处理组次之,即环境愈恶劣,茎瘤这种作用愈显著,证明了茎瘤对长喙田菁适应铅锌尾矿环境有积极的贡献。     

茎瘤对长喙田菁在铅锌尾矿环境适应中的意义Ⅰ.茎瘤对长喙田菁生长发育的影响

通过设置保留茎瘤和去除茎瘤处理 ,研究长喙田菁 (Sesbaniarostrata)在铅锌尾矿、客土和纯土环境中的生长发育情况。结果表明 :保留茎瘤使长喙田菁的株高、地上部生物量、地下部生物量、全株生物量和叶绿素含量分别比去除茎瘤处理提高了 2 4 %～ 4 8%、2 7 4 %～ 6 7 9%、2 8 5 %～ 99 3%、2 7 6 %～ 72 3%和 17 0 %～ 2 3 4 %,这种作用在纯尾矿处理组最为显著 ,客土处理组次之 ,即环境愈恶劣 ,茎瘤这种作用愈显著 ,证明了茎瘤对长喙田菁适应铅锌尾矿环境有积极的贡献。     

营养杯对长喙田菁在铅锌尾矿上的生长、固氮和重金属积累的影响

设置移栽时营养杯的有无及其大小作试验,研究长喙田菁在乐昌铅锌矿强酸化尾矿上的生长、固氮和积累重金属情况。结果表明,强酸性(pH<3)是限制植物定植的主要因素,在pH=5-7情况下,长喙田菁能在该尾矿库中定植、生长和固氮,表现出良好的适应性。未带营养杯移栽的长喙田菁在尾矿上生长84d,其株高117cm、茎基部直径1.35cm、单株生物量(干物质)20.2g、单位面积生物量(干物质)2828kghm-2、氮素积累量40kghm-2;带营养杯移栽的上述各指标分别达到140-144cm、1.59-1.68cm、36.6-38.8g、5124-5432kghm-2和77-107kghm-2,均显著高于未带营养杯处理的。长喙田菁根部铅、锌、铜、镉含量均最高,其次为茎,叶中最低;长喙田菁的4种重金属积累量为锌(186-221mgkg-1)>铅(96-145mgkg-1)>铜(17-30mgkg-1)>镉(3-4mgkg-1)。带营养杯移栽能有效提高长喙田菁的产量和氮积累量,且明显降低其体内的重金属含量。试验证明长喙田菁是较理想的铅锌矿尾矿废弃地植被重建的先锋植物。     

氮肥和水分条件对长喙田菁生长、结瘤和固氮的影响

 盆栽试验研究了长喙田菁(Sesbania rostrata) 茎瘤固氮根瘤菌（Azorhizobium caulinodans）共生体系在不同水分和无机氮肥条件下的生长、结瘤和氮积累。水分处理为: 不浸水、浅浸水(土壤水分为田间持水量)和深浸水, 氮肥处理分别为每千克土施加无机氮肥10 mg、20 mg和40 mg。结果表明,水分条件对共生体系有较大影响, 浸水环境虽然抑制了根瘤的形成, 却促进了茎瘤的结瘤作用和长喙田菁根系的生长, 田间持水量状态下共生体系能获得最大的生物量和氮累积量; 无机氮肥对共生体系的影响受水分供应的影响较大,实验氮肥施用浓度范围内,长喙田菁的结瘤作用对复合态氮无负敏感反应,明显有别于一般根瘤体系的复合态氮反应。     

长喙田菁-Azorhizobium caulinodans共生固氮体系在华南地区的生长、结瘤、固氮和种子生产

研究了长喙田菁－Ａｚｏｒｈｉｚｏｂｉｕｍｃａｕｌｉｎｏｄａｎｓ共生固氮体系在华南地区的生长、结瘤、固氮和种子生产．结果表明,长喙田菁－Ａ．ｃａｕｌｉｎｏｄａｎｓ共生固氮体系在华南地区生长正常,并具旺盛的茎根瘤结瘤作用．经６５天的生长,其在湛江地区的单位面积生物量（干物质）和单位面积Ｎ产量分别为２８７５２和６８１ｋｇ·ｈｍ－２,远优于普通田菁的１６５２０和３５２ｋｇ·ｈｍ－２;茎瘤菌Ａ．ｃａｕｌｉｎｏｄａｎｓ品系ＡＲ１１１和ＡＲ５６在华南地区混合接种效果良好,植株茎瘤结瘤率达到１００％,平均单株茎瘤个数为１８２个,单株茎瘤鲜重约为１．２ｇ,茎瘤生物量在茎根瘤总生物量中所占比重为７０％,而其根瘤生物量略高于普通田菁;长喙田菁在华南地区能够正常开花结实,在栽植密度为４×１０４株·ｈｍ－２的条件下,其种子产量达３２００ｋｇ·ｈｍ－２．     

多花黑麦草在酸化铅锌尾矿上的定植和生长

铅锌矿尾矿上设置长喙田菁压青和不压青处理,在此基础上研究多花黑麦草的萌发、生长和重金属积累情况.结果表明,种植长喙田菁改善了尾矿理化性状,尤其是提高了有机质、全N、有效态磷和K的含量.尾矿的强酸性环境(pH<3)是影响黑麦草在其上定植的主要因素.施用石灰可暂时改善尾矿酸度,但实验结束时尾矿酸度几乎完全恢复原状.因此,施用石灰可能只对种子发芽产生作用.大多数情况下多花黑麦草能在尾矿上萌发、生长和定植,并产生较大的生物量(DM1.4～3.2t·km^-2),表现出对酸性尾矿环境的一定的适应性.与未栽培长喙田菁的对照相比,栽培长喙田菁处理以及栽培长喙田菁并压青处理分别使多花黑麦草的生物量提高了4.8%～39.5%和7.7%～139.5%,其中压青处理又比不压青处理提高了2.7%～75.8%.“长喙田菁多花黑麦草”植被系列是一个成功的铅锌矿尾矿废弃地复垦的先锋阶段.     

田菁茎瘤固氮根瘤菌对小麦叶组织的促生作用研究

利用GFP标记的田菁茎瘤固氮根瘤菌(Azorhizobium caulinodans ORS 571)侵染露白24h的小麦种子,分别在侵染后0、6、12、24、48、72和96h采样,利用实时荧光定量PCR方法检测小麦体内6条与促生作用相关miRNAs(miR156、miR159、miR160、miR167、miR168和miR403)的表达模式,检测其中3条miRNAs(miR159、miR167和miR168)的靶基因表达模式;以接菌8d的小麦样品做切片,利用激光共聚焦显微镜检测小麦叶部田菁茎瘤固氮根瘤菌的分布,并测定小麦的生理指标。结果显示:(1)田菁茎瘤固氮根瘤菌侵染小麦后能够在叶片边缘部位定殖。(2)小麦叶片中与促生作用相关的6条miRNAs出现了不同程度变化,在12~24h到达其峰值,随后逐渐下降,其中miR159在峰值时的表达量为初始表达量的2.88倍。(3)3条miRNAs的靶基因表达模式与相应miRNA表达模式相对应,但并不严格。(4)生理指标测定结果显示,接种田菁茎瘤固氮根瘤菌对小麦叶片产生明显的促生作用,其中叶鲜重在96h的变化与对照差异极显著。研究表明,接种的田菁茎瘤固氮根瘤菌能够到达小麦叶组织,对小麦叶片的生长产生明显的促生作用,其中miRNAs在促生过程中发挥重要作用。     

毛萼田菁茎瘤豆血红蛋白含量与固氮活性的关系

在个体瘤发育的不同阶段和植株生长的不同时期,以及在不同的光照条件下,分别测定茎瘤的固氨活性和豆血红蛋白含量。结果表明,毛萼田菁茎瘤的固氨活性和豆血红蛋白含量呈正相关,豆血红蛋白在茎瘤的共生固氮中起着重要的作用。     

多花黑麦草在酸化铅锌尾矿上的定植和生长

铅锌矿尾矿上设置长喙田菁压青和不压青处理,在此基础上研究多花黑麦草的萌发、生长和重金属积累情况．结果表明,种植长喙田菁改善了尾矿理化性状,尤其是提高了有机质、全N、有效态磷和K的含量．尾矿的强酸性环境(pH<3)是影响黑麦草在其上定植的主要因素．施用石灰可暂时改善尾矿酸度,但实验结束时尾矿酸度几乎完全恢复原状．因此,施用石灰可能只对种子发芽产生作用．大多数情况下多花黑麦草能在尾矿上萌发、生长和定植,并产生较大的生物量(DM1．4～3．2t·km^-2),表现出对酸性尾矿环境的一定的适应性．与未栽培长喙田菁的对照相比,栽培长喙田菁处理以及栽培长喙田菁并压青处理分别使多花黑麦草的生物量提高了4．8％～39．5％和7．7％～139．5％,其中压青处理又比不压青处理提高了2．7％～75．8％．“长喙田菁-多花黑麦草”植被系列是一个成功的铅锌矿尾矿废弃地复垦的先锋阶段     

Heavy metal localisation in mycorrhizas ofEpipactis atrorubens (Hoffm.) Besser (Orchidaceae) from zinc mine tailings

Summary The metal distribution within mycorrhizal and nonmycorrhizal roots ofEpipactis atrorubens collected from zinc mine tailings and an area rich in heavy metal ores (both located in southern Poland) was investigated. The tailings, consisting of postflotation material, were characterised by high levels of toxic elements such as Zn, Pb, and Cd, while soil outside the tailings was also strongly enriched in heavy metals. Atomic absorption spectrometry and proton-induced X-ray emission analysis revealed that heavy metals were mostly accumulated within orchid roots. Elemental maps from proton-induced X-ray emission showed that plant root epidermis and fungal coils which had developed within cortical cells of roots collected from the zinc mine tailings were the main places of Zn and Pb accumulation, associated with increased concentrations of Fe, Cd, Ti, Mn, Si, Ca, and S. The mean content of Pb and Zn in the coils was 4 to 5 times higher than in the root epidermis. In mycorrhizal roots from the tailings a statistically significant decrease in Pb and Zn content towards the inside of the root was observed. The mean content of Pb in coils from roots of plants growing outside the tailings was about 1% of the concentration in root coils from the tailings. Coils selected from orchid roots originating from a site outside the tailings contained comparatively high concentrations of Zn, Cd, and Cu, which was probably due to the high content of these elements in the soil. The results presented suggest a biofiltering effect against heavy metals by orchid mycorrhizal fungi.     

铅锌尾矿上自然定居植物

在凡口1#铅锌尾矿库内共有10种植物自然定居,这些植物主要生长在尾矿库的边缘区域.植物在尾矿上的生长、分布明显受到表层尾矿某些物理性质如稳定状况、含水量等的影响,尾矿中的营养物质含量与植物的生长高度以及群落盖度有一定的关系.杜虹花(Callicarpa pedunculata)体内的Pb、Zn、Cu和Cd含量大小顺序为叶>根>茎,而盐肤木(Rhuschinensis)和美丽胡枝子(Lespedeza     

Cadmium and copper uptake and accumulation by Sesbania rostrata seedling, a N-fixing annual plant: implications for the mechanism of heavy metal tolerance

Sesbania rostrata,an annual tropical legume,has been found to be tolerant to heavy metals,with an unknown mechanism.It is a promising candidate species for revegetation at mine tailings.In this study,sequential extractions with five buffers and strong acids were used to extract various chemical forms of cadmium and copper in S.rostrata,with or without Cd or Cu treatments,so that the mechanisms of tolerance and detoxification could be inferred.Both metals had low transition rates from roots to the aboveground of S.rostrata.The transition ratio of Cd (4.00%) was higher than that of Cu (1.46%).The proportion of NaCl extracted Cd (mostly in proteinbinding forms) increased drastically in Cd treated plants from being undetectable in untreated plants.This suggests that Cd induced biochemical processes producing proteinlike phytochelatins that served as a major mechanism for the high Cd tolerance of S.rostrata.The case for Cu was quite different,indicating that the mechanism for metal tolerance in S.rostrata is metal-specific.The proportion of water-insoluble Cu (e.g.oxalate and phosphate) in roots increased significantly with Cu treatment,which partially explains the tolerance of S.rostrata to Cu.However,how S.rostrata copes with the high biotic activity of inorganic salts of Cu,which increased in all parts of the plant under Cu stress,is a question for future studies.Sesbania rostrata is among the very few N-fixing plants tolerant to heavy metals.This study provides evidence for the detoxification mechanism of metals in Sesbania rostrata.     

Mobility and Translocation of Heavy Metals from Mine Tailings in Three Plant Species after Amendment with Compost and Biosurfactant

An experiment was performed to determine the effects of mine tailings alone mixed with compost or with compost plus crude biosurfactant on the accumulation of heavy metals (Pb, Zn, Cu, Cr, Cd, and Ni) in Acacia retinodes, Nicotiana glauca, and Echinochloa polystachya. The plants were grown in soil, mine tailings, and mine tailings containing compost over a period of seven and five months for shrubs or grass, respectively. The plants Acacia retinodes and Nicotiana glauca grown in mine tailings containing compost showed increases in dry biomass (from 62 to 79%) compared with plants in only tailings. Heavy metals accumulated in the roots and leaves showed high translocation rates of Cr in N. glauca, Cd in A. retinodes, and Ni in E. polystachya. Concentrations of heavy metals in the three plants irrigated with crude biosurfactant were not significantly different from those irrigated with water. Zn and Cd fractions within mine tailings containing compost were bound to carbonate, Pb was bound to residues, and Cu was bound to Fe-oxides. Cd had the highest mobility factor followed in order by Zn, Pb, and Cu. The elevated concentrations of Pb in roots and the low translocation rate for N. glauca and A. retinodes indicate that they are suitable for phytostabilizing Pb and Zn.     

5种栎树幼苗对铅锌尾矿砂的耐性与植被恢复前景

通过盆栽试验,评价栎属植物在铅锌尾矿中的生长响应及植被恢复前景.分析比较了覆瓦栎、猩红栎、樱皮栎、舒玛栎和白栎5种栎树幼苗在铅锌矿砂中生长30个月后的生物量、根系形态及其对营养元素和重金属的吸收及转移特征.结果表明: 5种栎树在矿砂中均能生长,其中,猩红栎和白栎的生物量较对照有下降趋势,其他3种栎树的生长与对照相比无显著差异;栎树根系生物量均较对照有不同程度增加(猩红栎除外),且仅猩红栎侧根形态学参数较对照有所减少.重金属胁迫下,栎树根系和茎中营养元素浓度较对照无显著变化.5种栎树体内重金属浓度均较低,且其生物富集系数和转移系数均小于1.但樱皮栎叶片和茎中Cd浓度分别为22.4和15.1 mg·kg^-1,转移系数为2.3,显著高于其他4种栎树.除猩红栎以外,其他参试栎树均可作为有潜力的污染土壤修复树种.其中舒玛栎的耐性较高、生物富集系数和转移系数较低,是适合在尾矿区造林和生态修复的优选树种.