Photosynthetic Characterization of the Plant Dicranopteris dichotoma Bernh. in a Rare Earth Elements Mine

In order to investigate the distribution of rare earth elements （REEs） in the natural hyperaccumulator fern Dicranopteris dichotoma Bernh. and to characterize this plant photosynthetically, concentrations of REEs in D. dichotoma from mines mining heavy and light REEs （HREEs and LREEs, respectively）, as well as in D. dichotoma from an area in which no mining occurred, in southern Jiangxi Province were determined using inductively coupled plasma-mass spectrometry. The REE concentrations in the lamina of D. dichotoma were in the order LREEs mine 〉 HREEs mine 〉 non-mining area. The maximum REE content in the lamina of D. dichotoma from the LREE mine was approximately 2 648 mg/kg dry weight. The photosynthetic activity of D. dichotoma from areas of HREE and LREE mines was improved by the presence of high concentrations of REEs in the lamina compared with D. dichotoma from the non-mining area. However, this enhancement varied according to the concentrations of the REEs, as well as their type. In addition, 77K fluorescence, electron transport rate, and chlorophyll-protein complex studies showed that the enhancement of the photosynthetic activity of D. dichotoma from HREE mines was mainly due to an increase in the chlorophyll-protein complex of the reaction center of photosystem （PS） Ⅰ, whereas the enhancement observed in D. dichotoma from LREE mines was due to an increase in the internal antennae chlorophyll-protein complex of PS Ⅱ and greater light energy distribution to the light-harvesting chlorophyll-protein complex of PS Ⅱ.     

芒萁多糖提取及抗菌活性初步研究

采用4种方法提取芒萁多糖,其中综合法提取率为5.2%;可溶性多糖经DEAE-纤维素52柱层析进一步纯化,得到1种中性多糖和1种酸性多糖,各占78%和22%。利用纸片法进行抑菌实验结果表明,芒萁多糖显示了不同程度抑制细菌和真菌的活性。     

天然植物铁芒萁体内稀土元素的分布及其叶绿素镧的结构表征

Ｌａ、Ｃｅ、Ｎｄ、Ｔｂ、Ｄｙ 等稀土元素在铁芒萁（ Ｄｉｃｒａｎｏｐｔｅｒｉｓｄｉｃｈｏｔｏｍａ Ｕｎｄｅｒｗ） 体内的分布规律是叶＞ 根＞ 茎, 而Ｐｒ、Ｓｍ 、Ｅｕ、Ｇｄ、Ｈｏ 和Ｙ等稀土元素在铁芒萁体内的分布规律是根＞ 叶＞ 茎。轻、中稀土元素容易被吸收和积累,并表现出选择性吸收。铁芒萁叶绿素中结合有较多的稀土元素,且主要是轻稀土元素,其中Ｌａ 含量最高,占５６ ．０８％ ,其次是Ｃｅ,占１９ ．４０％ 。利用荧光Ｘ射线吸收精细结构（ＦＸＡＦＳ）光谱表征出,在铁芒萁体内Ｌａ 是与两个卟啉环配位的,推断叶绿素镧为双层结构     

不同环境条件下芒萁群落生物量动态规律的研究

一、引言芒萁(Dicranopteris dichotoma)广泛分布于长江以南亚热带地区。常生长于疏林下或山坡,具有湿润亚热带、热带气候和强酸性土相结合的生态环境,是水热条件较好的酸性土指示植物之一。它的地下茎在土层中交织形成     

茶园土壤类型对铁观音茶叶稀土元素分布和组成的影响

为探明铁观音茶的质量安全状况,追溯隐患来源,对福建安溪县不同土壤茶园的铁观音茶叶进行稀土元素的分布、组成、迁移和富集能力进行研究。结果表明,安溪县红壤、黄红壤、黄壤茶园稀土组成均以镧、铈、钕、钇为主,但具体组成特征各异。3种类型土壤茶园铁观音茶叶片、叶柄稀土元素组成均以钇、镧、铈、钕4种元素为主,且含量均以第3叶第2叶第1叶叶柄。同种土壤类型茶园铁观音茶树不同部位叶片的稀土元素组成特征类似,但叶与叶柄对稀土元素的吸收能力不同。土壤类型对茶叶稀土元素的累积有显著影响,黄红壤茶园的茶叶稀土元素含量要显著低于红壤、黄壤茶园的(P0.05)。土壤与茶叶中稀土元素组成的相关系数为0.886～0.985,P 0.001,表明二者稀土元素组成密切相关。因此,铁观音茶叶中稀土元素累积、分布与茶园土壤类型有显著相关性。     

感耦等离子体发射光谱法研究土壤—铁芒萁系统中稀土元素的分布、累积和迁移特征

用感耦等离子体发射光谱法（ICP－AES）测定了东西赣南地区非稀土矿区和4处不同稀土矿区内,土壤－铁芒萁系统中La、Ce、Pr、Nd、Sm、Gd、Dy、Yb和Y的含量,并对其在土壤剖面层及铁芒萁植物体内的分布、迁移特征进行了研究,结果表明,土训层的底土层含量最高,但表土层铈相对富集、稀土元素总量（∑REE）在铁芒萁植物体内的分布规律是叶＞根＞茎＞叶柄,单一稀土的分布规律各异,La、Ce、Pr、Nd的分布规律表现为：叶＞根＞茎＞叶柄;Sm和Gd在不同采样点表现为叶＞根＞茎＞叶柄或根＞叶＞茎＞叶柄;Dy、Yb和Y均有3种不同的分布模式：叶＞根＞茎＞叶柄、根＞叶＞茎＞叶柄及根＞茎＞叶＞叶柄,稀土元素在铁芒萁体内的迁移过程中,发生了明显的分馏作用,茎、叶柄、叶中的重稀土相对贫乏。     

稀土元素在药用植物细胞和组织培养中的应用

介绍了稀土元素对药用植物细胞、组织的生长及次生代谢产物合成的作用,探讨了稀土的作用机理.大量的实验证明,稀土在药用植物细胞和组织培养中具有广泛的应用前景.     

感耦等离子体发射光谱法研究土壤-铁芒萁系统中稀土元素的分布、累积和迁移特征

用感耦等离子体发射光谱法(ICP-AES)测定了江西赣南地区非稀土矿区和处不同稀土矿区内,土壤-铁芒萁系统中La、Ce、Pr、Nd、Sm、Gy、Db、Yb和Y的含量,并对其在土壤剖面层及铁芒萁植物体内的分布、迁移特征进行了研究.结果表明,土壤剖面层的底土层含量最高,但表土层铈相对富集.稀土元素总量(∑REE)在铁芒萁植物体内的分布规律是叶＞根＞茎＞叶柄,单一稀土元素的分布规律各异,La、Ce、Pr、Nd的分布规律表现为:叶＞根＞茎＞叶柄;Sm和Gd在不同采样点表现为叶＞根＞茎＞叶柄或根＞叶＞茎＞叶柄;Dy、Yb和Y均有3种不同的分布模式:叶＞根＞茎＞叶柄、根＞叶＞茎＞叶柄及根＞茎＞叶＞叶柄.稀土元素在铁芒萁体内的迁移过程中,发生了明显的分馏作用,茎、叶柄、叶中的重稀土相对贫乏.     

DL-α-白氨酸与稀土硝酸盐固体配合物的合成及性质

用白氨酸分别和三种稀土硝酸盐在有机溶剂中首次合成了三种相应的1:2型固体配合物,经化学分析和元素分析确定了其组成为RE(Leu)_2(NO_3)_3·2H_2O(RE=Ce,Nd,Sm;Leu=DL-α-Leucine)。并通过X—粉晶衍射、红外光谱、TG—DTG和电导等对其性质进行了讨论。     

Inorganic and Organic Nitrogen Acquisition by a Fern Dicranopteris dichotoma in a Subtropical Forest in South China

The fern Dicranopteris dichotoma is an important pioneer species of the understory in Masson pine (Pinus massoniana) forests growing on acidic soils in the subtropical and tropical China. To improve our understanding of the role of D. dichotoma in nitrogen (N) uptake of these forests, a short-term ¹⁵N experiment was conducted at mountain ridge (MR, with low N level) and mountain foot (MF, with high N level). We injected ¹⁵N tracers as ¹⁵NH₄, ¹⁵NO₃ or ¹⁵N-glycine into the soil surrounding each plant at both MR and MF sites. Three hours after tracer injection, the fern D. dichotoma took up ¹⁵NH₄ ⁺ significantly faster at MF than at MR, but it showed significantly slower uptake of ¹⁵NO₃ ⁻ at MF than at MR. Consequently, ¹⁵NO₃ ⁻ made greater contribution to the total N uptake (50% to the total N uptake) at MR than at MF, but ¹⁵N-glycine only contributed around 11% at both sites. Twenty-four hours after tracer injection, D. dichotoma preferred ¹⁵NH₄ ⁺ (63%) at MR, whereas it preferred ¹⁵NO₃ ⁻ (47%) at MF. We concluded that the D. dichotoma responds distinctly in its uptake pattern for three available N species over temporal and spatial scales, but mainly relies on inorganic N species in the subtropical forest. This suggests that the fern employs different strategies to acquire available N which depends on N levels and time.     

Structural differences between light and heavy rare earth elment binding chlorophylls in naturally grown fern Dicranopteris linearis

Chloroplasts and chlorophylls were isolated from the leaves of Dicranopteris linearis, a natural perennial fern sampled at rare earth element (REE) mining areas in the South-Jiangxi region (southern China). The inductively coupled plasma-mass spectrometry (ICP-MS) results indicated that REEs were present in the chloroplasts and chlorophylls of D. linearis. The in vivo coordination environment of light REE (lanthanum) or heavy REE (yttrium) ions in D. linearis chlorophyll-a was determind by the extended X-ray absorption fine structure (EXAFS). Results revealed that there were eight nitrogen atoms in the first coordination shell of the lanthanum atom, whereas there were four nitrogen atoms in the first coordination shell of yttrium. It was postulated that the lanthanum-chlorophyll-a complex might have a double-layer sandwichlike structure, but yttrium-binding chlorophyll-a might be in a single-layer form. Because the content of REE-binding chlorophylls in D. linearis chlorophylls was very low, it is impossible to obtain structural characteristics of REE-binding chlorophylls by direct analysis of the Fourier transform infrared (FTIR) and ultraviolet (UV)-visible spectra of D. linearis chlorophylls. In order to acquire more structural information of REE-binding chlorophyll-a in D. linearis, lanthanum—and yttrium-chlorophyll-a complexes were in vitro synthesized in acetone solution. Element analyses and EXAFS results indicated that REE ions (lanthanum or yttrium) of REE-chlorophyll-a possessed the same coordination environment whether in vivo or in vitro. The FTIR spectra of the REE-chlorophyll-a complexes indicated that REEs were bound to the porphyrin rings of chlorophylls. UV-visible results showed that the intensity ratios of Soret to the Q-band of REE-chlorophyll-a complexes were higher than those of standard chlorophyll-a and pheophytin-a indicating that REE-chlorophyll-a might have a much stronger ability to absorb the ultraviolet light. The MCD spectrum in the Soret band region of lanthanum-chlorophyll-a showed a special peak, but yttrium-chlorophyll-a did not have this special peak, corresponding well to their double-layer and single-layer structure, respectively. Structural differences between lanthanum—and yttrium-chlorophyll-a might result from the difference in ion radius between yttrium and lanthanum. These data might be useful for understanding of both the properties of REE-chlorophyll-a complexes and the physiological roles of REEs in the hyperaccumulator D. linearis.     

Uptake of Trace Metals and Rare Earth Elements from Hornblende by a Soil Bacterium

Analysis of trace elements released from hornblende between pH 6.5 and 7.5 in the presence of Arthrobacter sp. shows that Fe, Ni, V, Mn, and, to a lesser extent, Co are preferentially released into solution relative to bacteria-free experiments. This enhanced release into solution could be due to contributions from the slightly lowered pH, the presence of low molecular weight organic acids (LMWOAs), or the presence of a catecholate siderophore in experiments with bacteria. The best explanation for enhanced metal release is siderophore complexation at the mineral surface followed by release to solution. However,the relative rates of metal release to solution in these experiments do not strictly follow the trend predicted by the relative ordering of metal hydrolysis, which might be predicted for siderophore-promoted dissolution. For some of these metals, release to solution is fast initially in biotic experiments, but concentrations in solution reach a steady state value or decrease with time as the bacteria cell numbers increase exponentially. Lack of enhanced release to solution for some metals and decreases in release rate with time for others may be explained by uptake into bacteria. Many of the metals predicted to strongly complex with siderophore (including Al, Ti, Fe, Cu) are heavily taken up into cellular material. The relative ordering of organic ligand-element complexation may therefore partially explain the relative ordering of uptake of trace metals and rare earth elements into cell material. Fractionation of heavy rare earth elements taken up into cellular material is also very strong, and increases from Ho to Lu. Strong fractionation in uptake of some elements by bacteria may create biological signatures either in the mineral substrate or in any mineral precipitates associated with the cellular material.     

稀土多元复合肥和三种稀土元素的遗传毒性研究

采用蚕豆根尖细胞微核技术,研究市售稀土多元复合肥和稀土元素镧、铈、铒的化合物对蚕豆根尖细胞的遗传毒性和细胞毒性。结果表明,稀土复合肥和三种稀土元素均可诱发微核效应,在一定浓度下可损伤细胞,影响根尖的正常生长,其中稀土复合肥的微核效应表现出明显的剂量-效应关系。稀土复合肥和稀土元素镧、铈、铒的化合物对蚕豆根尖细胞具有一定的遗传毒性作用和细胞毒性作用,在施用稀土微肥和使用稀土制品时应引起重视。 Abstract：This paper presents the study of genetic toxicity and cell toxicity that is give n by rare earth multi-element compound fertilizer and a chemical compound of rar e earth elements-La3＋、Ce4＋、Er3＋ in root tip cells of Vicia faba.The technique used is micronucleus in root tip cells of Vicia faba.The experiment statistical result shows that both the rare earth compound fertilizer and the three kinds of rare earth elements can cause micronucleus ef fect and under certain concentration,they can hurt cells, affect root tip gro wth .The micronucleus effect of the rare earth compound fertilizer shows a clear relation of dosage-effect. The conclusion is that rare earth compound fertilize r and the chemical compound of rare earth elements La3＋、Ce4＋、E r3＋cause certain genetic toxicity and cell toxicity effect to root tip cells of Vicia faba.Therefore a close attention should be paid when the rar e earth multi-fertilizer and other things made by rare earth are used.     

稀土元素在药用植物细胞和组织培养中的应用

介绍了稀土元素对药用植物细胞、组织的生长及次生代谢产物合成的作用,探讨了稀土的作用机理。大量的实验证明,稀土在药用植物细胞和组织培养中具有广泛的应用前景。     

稀土元素对生物机体剂量效应的研究

综述了稀土元素对生物机体的剂量效应,包括稀土对生物体生长发育、内分泌系统、体内分布及其引发的疾病、细胞毒性及抗诱变、抗癌等影响,以期为稀土在生物学领域的进一步应用提供参考.     

稀土元素对生物机体剂量效应机理的研究

综述了稀土元素对生物机体剂量效应的机理,从稀土对细胞质膜、细胞周期及细胞凋亡、CaM水平调节的作用到对蛋白质、DNA的影响等不同层次和水平进行了探讨,以期为稀土在生物学领域的进一步广泛应用奠定理论基础.     

稀土元素对短叶对齿藓生理生化的研究

通过测定分析3个主要生理指标过氧化物酶（POD）活性、丙二醛（MDA）含量和叶绿素含量的变化,研究了短叶对齿藓组培苗在6个不同浓度梯度的轻稀土La³⁺,Ce⁴⁺和重稀土Y³⁺单一元素胁迫下的生理响应和变化。结果如下：（1）短叶对齿藓体内的过氧化物酶（POD）活性和丙二醛（MDA）含量各处理组均低于对照组;Ce⁴⁺元素在3.55×10^-2 mmol·L^-1时显著提高了POD活性,在7.1×10^-2 mmol·L^-1时显著增加了膜脂过氧化产物丙二醛（MDA）含量。表明短叶对齿藓对Ce⁴⁺元素胁迫响应较强;而La³⁺元素各处理浓度间POD的变化较为平缓,胁迫响应较弱;Y³⁺处理居中。（2）较低浓度的La³⁺（1.8×10^-2 mmol·L^-1）和Ce⁴⁺（3.55×10^-2 mmol·L^-1）时显著提高叶绿素a、叶绿素b和总叶绿素含量;3种稀土元素在较高浓度时叶绿素的含量均有明显下降。本研究为进一步探明白云鄂博稀土矿区的苔藓植物生长发育受稀土元素的影响奠定了基础。     

Protective Effect of Rare Earth Against Oxidative Stress Under Ultraviolet-B Radiation

The effects of lanthanum (III) (La(III)) in protecting soybean leaves against oxidative stress induced by ultraviolet-B (UV-B) radiation were investigated. The increase in contents of hydrogen peroxide (H₂O₂) and superoxide () due to UV-B radiation suggested oxidative stress. The increase in the content of malondialdehyde (MDA) and the decrease in the index of unsaturated fatty acid (IUFA) indicated oxidative damage on cell membrane induced by UV-B radiation. La(III) partially reversed UV-B-radiation-induced damage of plant growth. The reduction in the contents of H₂O₂, , and MDA and increase in the content of IUFA, compared with UV-B treatment, also indicated that La(III) alleviated the oxidative damage induced by UV-B radiation. The increase in the activities of superoxide dismutase and peroxidase and the contents of ascorbate, carotinoids, and flavonoids were observed in soybean leaves with La(III) + UV-B treatment, compared with UV-B treatment. Our data suggested that La(III) could protect soybean plants from UV-B-radiation-induced oxidative stress by reacting with reactive oxygen species directly or by improving the defense system of plants.