水稻根际酶活性对土壤重金属污染的响应

为了解水稻根际土壤酶活性的变化及其与根际重金属有效性的关系,选取酸性矿山废水污灌形成的多重金属污染水稻土,采用根际袋模拟水稻根际环境,研究水稻根际土壤脲酶、磷酸酶、蔗糖酶、过氧化氢酶活性的变化特征及其与土壤有效态Cd、Pb、Cu和Zn含量的关系。结果表明,根际土壤pH和脲酶活性均低于非根际土壤,根际土壤微生物量碳和磷酸酶活性均高于非根际土壤。根际土壤有效态Cd和Zn含量低于非根际土壤,有效态Pb 和Cu含量高于非根际土壤。土壤pH与有效态Pb和有效态Zn均呈显著负相关,有效态Cd、有效态Pb 和有效态Cu含量与微生物量碳均呈显著正相关,有效态Cd、有效态Pb、有效态Cu和有效态Zn含量与土壤脲酶活性呈显著负相关,有效态Cd、有效态Pb 和有效态Cu含量与蔗糖酶活性呈显著正相关。可见,在多重金属污染土壤,土壤酶活性受不同重金属有效态含量影响;该结果可为水稻重金属污染治理研究提供理论依据。     

生物炭对设施栽培土壤重金属Cd形态变化的影响

设施土壤重金属Cd污染问题备受关注,为阐明生物炭对设施栽培土壤重金属Cd污染的修复效果,试验设置B0(0 t/公顷)、B10(10t/公顷)和B20(20t/公顷)3个生物炭水平,研究生物炭增施对土壤Cd形态、含量以及生物有效性的影响。结果表明：生物炭施用显著增加设施土壤pH值和有机质含量,改变了土壤Cd的形态分布,氧化态、有机态和残渣态含量增加,交换态Cd含量降低。随着生物炭施用量的增加,土壤固定Cd的速率会增加。与对照相比,B10降低土壤交换态Cd 45-62％,而B20可降低66-89％。另外,试验还表明,生物炭对Cd污染较轻的设施大棚土壤有效态Cd的固定效果要好于Cd污染严重的设施大棚。因此,生物炭可以通过改变设施土壤Cd形态,降低土壤重金属有效性,但对受Cd污染严重的设施土壤的修复效果不好。     

酸碱度调节剂对稻田土壤中有效态镉的影响研究

为弄清不同酸碱度调节剂对稻田土壤中有效态Cd的动态影响差异,采用室内培养试验,通过对1、5、10、20 mg/kg外源Cd浓度污染麻砂泥土壤添加4种酸碱度调节剂处理,探讨在第15天和45天其对Cd的有效性影响。结果表明:与不施加酸碱度调节剂的对照对比,添加SH1.5、SH3、GG1.5和GG3调节剂可在一定程度增加土壤pH,从而降低土壤中Cd的有效态含量。4种外源Cd浓度污染土壤中,用TCLP和CaCl_2提取的有效态镉含量与土壤pH均成负相关关系。培养过程中,TCLP提取态和CaCl_2交换态Cd含量分别下降17.41%~48.02%、30.95%~87.89%,同时SH3修复效果表现突出。研究结果可为Cd超标稻田的安全生产及阻控提供科学指导。     

污灌区盐渍化土壤重金属Cd的形态分析及其影响因素

以受盐渍化及重金属Cd污染的天津污灌区土壤作为研究对象,探讨盐渍化土壤重金属的形态分布及其影响因素。研究的盐分种类主要为NaCl和Na_2SO_4,盐度7个[添加质量分数依次为0%(CK)、0.2%、0.4%、0.6%、1%、2%和5%],采用Tessier连续提取法测定土壤前3种重金属的形态(可交换态、碳酸盐结合态、铁锰氧化态),得出重金属的形态分布规律。结果表明:在添加NaCl盐度条件下,土壤中Cd碳酸盐结合态可交换态铁锰氧化态,可交换态含量与盐度、重金属总量、pH值和有机质均呈显著相关。在添加Na_2SO_4盐度条件下,土壤中Cd铁锰氧化态可交换态碳酸盐结合态,可交换态、碳酸盐结合态与pH值和有机质均呈极显著相关,铁锰氧化态与pH值呈显著负相关。盐度与Cd各形态也有不同程度的相关性。在添加NaCl盐度条件下,pH值对可交换态含量有重要影响;有机质对碳酸盐结合态含量有重要影响;Cd含量对铁锰氧化态含量有重要影响。在添加Na_2SO_4盐度条件下,有机质对可交换态含量有重要影响;pH值、有机质对碳酸盐结合态含量有重要影响;CEC对铁锰氧化态含量有重要影响。得出的Cd形态分布规律以及土壤各理化性质对Cd形态含量的影响分析对土壤重金属的污染防治和生态风险评价提供了基本的理论依据。     

晚粳稻籽粒中As、Cd、Cr、Ni、Pb等重金属含量的基因型与环境效应及其稳定性

选择籽粒Cd、Cr、As、Ni和Pb等重金属含量差异较大的12个晚粳稻基因型，种植于浙江省晚粳稻主产区嘉兴、湖州、杭州、宁波、绍兴等市的6个试点，研究籽粒中5种重金属含量的基因型与环境变异及其稳定性、籽粒和土壤有效态（DTPA提取态）Cd、Cr、As、Ni和Pb等重金属含量之间及与Fe、Zn含量之间的关系，以及土壤pH对籽粒重金属积累的影响。结果表明，环境、基因型及其互作效应对籽粒重金属含量的效应均达极显著水平，表明筛选和选育籽粒重金属含量低的品种以及通过农艺措施减少籽粒重金属含量是可能的。同时，籽粒中这5种重金属含量的稳定性因环境、基因型而有较大差异，且亦因重金属种类而异。因此，为降低籽粒重金属含量，应针对特定重金属污染的环境进行基因型选择，并同时考虑基因型籽粒重金属含量的稳定性。土壤pH不仅影响土壤重金属有效性及水稻籽粒中重金属积累量，还影响籽粒重金属积累的基因型与环境互作效应（即积累稳定性）。此外，土壤中一些重金属常发生复合污染，如Cd和Cr、As或Ni，Cr和As，Pb和As间表现为协同消长，Cd含量较高的稻米往往As和Pb含量也高，Cr和Ni含量以及As和Pb含量之间也呈正相关。     

土壤盐分对酶活性和镉形态的影响

为了研究水稻在盐分和镉(Cd)污染作用下的生理变化以及土壤酶活性和镉形态变化,利用盆栽试验在不同盐分处理的重金属Cd污染盐碱土上种植水稻,对酶活性（土壤、植物）及Cd形态转化进行研究。结果表明：在同一Cd污染水平下,盐分从0.3%增加到0.5%时,脲酶和碱性磷酸酶活性提高了2.1%~19.5%和3.8%~64.3%。当盐分含量高于0.5%时,水稻幼苗萎鄢。植物体内过氧化氢酶活性和丙二醛含量随着盐分和Cd含量升高而提高。盐分处理也导致Cd不同形态之间的转换,并改变Cd的形态分布,盐分含量越高交换态和还原态比例升高,说明Cd 污染盐碱土上,土壤和水稻酶活性受到多种因素影响。盐分和Cd污染对土壤和植物的影响呈现协同效应。     

桑树修复农田镉和铅的土壤微环境特征分析

在江西某矿区周边重金属污染农田上栽植桑树,栽植三年后,分析桑园土壤中重金属含量、重金属各形态含量分布、土壤微生物分布、土壤酶活。分析结果表明,栽植桑树3年后,农田土壤Cd和Pb的修复指数达到96.87%和81.93%,含量分别为12.31mg/kg和595.44mg/kg。且重金属Cd和Pb均主要是富集在桑树根部。桑树不同部位中的Cd和Pb含量分布都表现为夏季含量最高,其次为春季,随后为秋季,最低为冬季。土壤中的Cd和Pb均存在金属可交换态、碳酸盐结合态、金属残渣态、Fe-Mn氧化物结合态、有机质结合态,分别以可交换态Cd和残渣态Pb作为主要形态分布。同时土壤中Pb和Cd各化学形态含量与土壤中微生物群落分布、土壤理化特征以及酶活性具有显著相关性。研究结果表明桑树修复矿区重金属过程中土壤微环境同步变化和改善,桑树栽植三年后,该矿区土壤环境质量达到三级标准。     

岩溶区铁锰结核胁迫下土壤重金属元素形态分析

内容摘要:采用连续提取法对岩溶区铁锰结核胁迫下的土壤重金属元素的形态进行了分析,并用原子吸收分光光度法对重金属元素的含量进行了测定。结果表明,土壤A、B层Cd、Cr、Cu、Pb、Zn以残渣态所占比例最高,Mn以铁锰氧化态所占比例最高;土壤A、B层生物可利用态所占比例以Cd最高,其它元素所占比例甚低,Cd成为本区的主要污染因素,Mn元素的潜在可利用态所占比例最高,也应加以注意其影响。     

长期污水灌溉条件下土壤重金属形态及生物活性的研究

摘 要: 通过野外调查和实验分析,对孝义市污灌区土壤中Ni、Cr、Pb、Cu、Zn、Cd 6种重金属的含量、形态分布和生物活性进行了研究。结果表明,孝义市污灌区土壤中重金属都未超过国家二级标准,但Ni、Cr、Pb比当地背景值都有所增加。土壤中重金属各形态的分布存在很大差异。Ni、Cr、Zn主要以残渣态的形式存在。Pb主要以残渣态和铁猛氧化态存在。Cu主要以残渣态和有机结合态的形式存在。Cd在残留态中比例最小,碳酸盐结合态和交换态含量比例很高。与对照相比,污灌降低了重金属残留态所占比例,改变了土壤中重金属存在形态,提高了重金属的生物有效性和迁移能力。污灌区土壤中重金属活性系数的大小顺序为：Cd＞Pb＞ Cu ＞Cr ＞Zn ＞Ni;迁移系数的大小顺序是：Pb ＞Cd＞ Cu ＞Cr ＞Zn＞Ni,土壤中Cd 、Pb的生物活性最高, 生态污染风险最大,应引起足够重视。     

不同钝化剂对恩施Cd污染土壤的钝化效果研究

为解决恩施高山蔬菜土壤重金属镉(Cd)污染问题,采用盆栽试验,研究施加不同钝化剂（生物炭、羟基磷灰石、石灰粉、粉煤灰、混合有机钝化剂）对试验土壤中Cd的钝化效果及小白菜产量、品质及Cd含量的影响。结果表明,除石灰粉处理对小白菜生长抑制外,其他处理对小白菜鲜重、株高均有促进作用,且粉煤灰处理增加小白菜鲜重达109.72%。羟基磷灰石、石灰粉和混合钝化剂等3种处理分别提升土壤pH 25.18%、36.61%和28.21%。各处理对土壤脲酶、纤维素酶、蔗糖酶活性无显著性影响;生物炭、混合钝化剂处理显著提高磷酸酶活性达52.85%和69.82%,而石灰粉处理显著抑制了磷酸酶活性。5种钝化剂处理均降低了小白菜重金属Cd的含量,其中生物炭、羟基磷灰石、石灰粉、混合钝化剂均达到抑制吸收显著效果,且石灰粉最优,降低了73.80%。各处理对小白菜品质无显著性影响。生物炭和混合钝化剂处理分别降低了土壤中总Cd含量27.21%、46.98%;石灰粉和混合钝化剂处理降低了土壤中离子交换态Cd43.67%、47.35%。5种钝化剂的施用均能降低小白菜的Cd含量,其中混合钝化剂处理在不影响小白菜产量和品质的同时,增强了土壤酶活性,降低了土壤中总Cd及有效Cd（离子态、水溶态）比例。     

Location of a high-lysine gene and the DDT-resistance gene on barley chromosome 7

Summary The high-lysine gene in Risø mutant 1508 conditions an increased lysine content in the endosperm via a changed protein composition, a decreased seed size, and several other characters of the seed. The designation lys3a, lys3b, and lys3c, is proposed for the allelic high-lysine genes in three Risø mutants, nos 1508, 18, and 19. Linkage studies with translocations locate the lys3 locus in the centromere region of chromosome 7. A linkage study involving the loci lys3 and ddt (resistance to DDT) together with the marker loci fs (fragile stem), s (short rachilla hairs), and r (smooth awn) show that the order of the five loci on chromosome 7 from the long to the short chromosome arm is r, s, fs, lys3, ddt. The distance from locus r to locus ddt is about 100 centimorgans.     

Simultaneous Determination of Four Phenolic Acids in Radix Salviae Miltiorrhizae Formula Granules by QAMS

[Objectives]This study aimed to establish a QAMS(quantitative analysis of multi-components by single-marker)method for simultaneous determination of four phenol...     

Pollen and pollination experiments. III. The viability of apple and pear pollen as affected by irradiation and storage

Summary Apple and pear pollen was irradiated with doses of 0, 50, 100, 250 and 500 krad (gamma rays) and stored at 4°C and 0–10% r.h. From the in-vitro germination percentages an average LD 50 dose of about 220 krad was estimated. For both irradiated and untreated pollen a close and corresponding lineair relationship existed between germination percentage and pollen tube growth.Irradiated pollen was much more sensitive to dry storage conditions than untreated pollen, resulting in less germination and more bursting. Apparently, irradiation caused the pollen cell membrane to lose its flexibility faster than normal. Rehydration of dry-stored, irradiated pollen in water-saturated air restored germination percentages up to their initial levels. The importance of this procedure in germination trials is stressed.     

Evolution under domestication involving disturbance of genic balance

Summary An hypothesis is developed that the rapid change from wild plants into domesticated crops principally involves the selection of alleles with non-functional gene products which leads to reduced control of the highly integrated metabolism and morphogenesis previously accumulated by lengthy natural selection. Such disturbance of the genome produces altered physiological and morphological development which, although deleterious in nature, serves mankind better and has been selected.     

Genetic variation for disease and nematode resistances and forage quality in perennial diploid and tetraploid lucerne populations (Medicago sativa L.)

Summary Twenty-five lucerne populations of the Medicago sativa complex, which were either diploid or tetraploid and wild or cultivated, were analysed for their resistance to four different fungal diseases and to stem nematode. Forage quality, including stem digestibility and saponin content, was also tested.Populations varied in susceptibility to the diseases caused by Colletotrichum trifolii, Verticillium albo-atrum, Sclerotinia trifoliorum and Pseudopezizza medicaginis, and to the nematode Ditylenchus dipsaci. Except for Sclerotinia rot, sativa and falcata subspecies differed in susceptibility, but this grouping of populations did not account for the full range of variation among them. However, the resistance to P. medicaginis was much lower in the sativa than in the falcata populations.Populations also varied significantly in stem fiber content and digestibility. Stem digestibility was negatively correlated to forage yield. Wild sativa and falcata populations had lower fiber content and higher digestibility than cultivated sativa populations. The medicagenic acid was the sapogenin responsible for the anti-nutritional effect of the lucerne measured by the yellow mealworm larvae Tenebrio molitor. The medicagenic acid content was lowest for the pure sativa populations, highest for the pure falcata populations, and intermediate for the French sativa varieties that have some traits originating from falcata germplasm. Some populations could be used in breeding programs to improve disease and nematode resistance, and forage quality.     

Review of Effects of Active Components of Gastrodiae Rhizoma on Central Nervous System

In order to explore the pharmacological effects of active components of Gastrodiae Rhizoma on the central nervous system,through consulting related literatures,...     

Effects of Pb on Rhizosphere Soil Enzyme Activity and Chemical Constituents of Achyranthes bidentata Blume

[Objectives]The purpose of this study was to investigate the effects of Pb on rhizosphere soil enzyme activity and chemical constituents of Achyranthes bidentat...     

不同P-Zn配比对小麦幼苗微量元素营养的影响

采用了螯合-缓冲营养液培养方法对小麦进行了苗期培养试验,在3个P水平(0,0.6,3.0 mmol/L)和3个Zn水平(0,3,30 μmol/L)的完全组合下对小麦苗期生长及Zn、Fe、Cu、Mn营养进行了研究,旨在为小麦微肥施用提供理论依据.结果表明,P、Zn的正常供应促进了小麦生长,二者的缺乏与过量均会抑制小麦发育,且这种影响在冠部表现得更为明显.在小麦苗期,Zn与Cu的吸收存在明显的拮抗作用,但供Zn则促进了Zn和Cu的转运,而Mn转运则受到了抑制;过量供Zn时,大量Zn被转运到冠部,同时明显抑制了(Fe+Cu+Mn)的吸收总量;P的供应显著地抑制了Fe的吸收,但P的供应提高了Zn、Cu、Mn的转运率;P、Zn在对Zn与Fe、Cu、Mn间吸收竞争的影响中,Zn本身的影响要比P的影响更为明显,供Zn明显促进了小麦幼苗对Zn的吸收;在小麦幼苗冠部,Zn与Fe的竞争中,供P利于Zn的吸收,缺P则利于Fe的吸收;而Zn与Cu以及Zn与Mn间的竞争中,缺磷时利于Zn的吸收,供磷后则利于Cu和Mn的吸收.总之,小麦幼苗Zn、Fe、Cu、Mn营养中,P、Zn的不同配比会不同程度地改变Zn与Fe、Cu、Mn的协同或拮抗效应.     

Isozyme variation between diploid and tetraploid cytotypes of Glycine tabacina (Labill.) Benth.

Summary Glycine tabacina (Labill.) Benth. is a wild perennial species related to the cultivated soybean, G. max (L.) Merr. It is composed of diploid (2n=40) and tetraploid (2n=80) cytotypes. Currently, to differentiate the cytotypes, plants are grown out in the greenhouse and chromosome counts made on pollen mother cells. It is a laborious and time consuming process. The objective of this study was to determine whether electrophoretic techniques could be utilized to separate the cytotypes. Electrophoretic examination of seven isozyme systems from seed of 67 G. tabacina accessions revealed banding patterns that could be used to differentiate between diploid and tetraploid cytotypes in the species. Among the tetraploid accessions, the number of bands observed were always greater than the diploids. Some tetraploid banding patterns consisted of bands similar to the diploid tabacina and/or additional bands previously identified in other Glycine species. The patterns of isozyme multiplicity and variation in the tetraploid tabacinas suggests more than one mode of origin for the tetraploids.     

Some physiological and photosynthetic characters of rice × sorghum and rice × wheat hybrids

Summary Some photosynthetic characters as-leaf anatomy, leaf photosynthetic rate and CO₂ compensation pointdistinguishing C₃ and C₄ plants and physiological characters as leaf area ratio, nitrogen content, leaf stem ratio and total shoot-to-root and deep root-to-shoot ratios have been studied in rice × sorghum and rice × wheat hybrids. Rice × sorghum 1. has lower values of photosynthetic rate, leaf nitrogen, total root and deep root-to-shoot ratio and CO₂ compensation point as of rice parent where as, rice × sorghym 2. is superior in all these characters. Both hybrids lack kranz anatomy. Though both rice × sorghum hybrids show characters of C₃ rice plant but rice × sorghum 2. has improved drought tolerance and leaf characters in relation to yield. Rice × wheat hybrid have higher assimilatory area and higher total root-to-shoot ratio. Grains of rice × wheat hybrids are identical to rice grain. However, as grains of rice × wheat hybrid does not contain seed coat, it could be exploited as novel rice germplasm after improvement.Abbreviations T CO₂ compensation point - T21 CO₂ compensation point at 21% O₂ - T2 CO₂ compensation point at 2% O₂ - dR/sR deep Root-to-shoot Ratio - LAR Leaf Area Ratio - CER photosynthetic rate - TR/SR Total Root-to-Shoot Ratio