对虾对东北苏打盐碱湖泊的适应性研究

碱度、pH对凡纳滨对虾幼虾的急性中毒实验和盐碱湖泊幼虾生存能力试验结果表明,碱度对幼虾的24h半数有效浓度(EC50)为2.73mmol/L,24h、48h、96h半数致死浓度(LC50)分别为12.40mmol/L、11.24mmol/L及10.49mmol/L,长期生存的安全浓度(SC)为2.77mmol/L。当碱度为5.37~14.66mmol/L时,pH对幼虾的24h、48h、72h、96h半数致死值(LpH50)分别为9.26~8.98、9.14~8.86、9.10~8.80及9.00~8.80,长期生存的安全值(SpH)为8.42~8.14。幼虾在碱度为18.68~38.78mmol/L、含盐量1.57~3.50g/L、pH8.5~9.5的苏打盐碱湖泊可存活4.8~9.2h。凡纳滨对虾幼虾对水环境碱度和pH的适应性,以及对东北地区苏打盐碱湖泊水环境的综合适应性均低于淡水鱼类。     

重金属铜、镉对蝌蚪毒性的研究

试验研究铜、镉对蝌蚪的急性毒性和联合毒性结果表明,Cu~(2 )对蝌蚪24h、48h、96h的半致死浓度LC_(50)分别为0.201mgg/kg、0.138mg/kg和0.118mg/kg,Cd~(2 )对蝌蚪24h、48h和96h的LC_(50)分别为32.1mg/kg、23.3mg/kg和18.9mg/kg。Cu~(2 )和Cd~(2 )共存对蝌蚪24h、48h和96h联合毒性的相加指数AI分别为1.03、1.2和1.20,均为协同作用。     

叠氮化钠诱变对离体蝴蝶兰类原球茎生理的影响

以2、4、6和8mmol/L的叠氮化钠浸泡6h处理蝴蝶兰类原球茎后进行组织培养,测定了处理组和对照的蝴蝶兰类原球茎中脯氨酸、丙二醛和可溶性糖含量以及超氧化物歧化酶和过氧化氢酶的活力。结果表明,经叠氮化钠处理的类原球茎中的超氧化物歧化酶活力、脯氨酸和丙二醛含量均有上升,而过氧化氢酶活力与可溶性糖含量均有下降,并呈现浓度梯度效应。叠氮化钠诱变的半致死剂量介于4～8mmol/L之间,其中4mmol/L的叠氮化钠对蝴蝶兰类原球茎生理损伤较小,因此认为4mmol/L的叠氮化钠是诱变蝴蝶兰类原球茎较为合理的浓度。     

土壤脱水过程中NaCl胁迫对羊草水分利用效率的影响

通过室内模拟实验研究了土壤脱水过程中NaCl胁迫对羊草生长和水分利用的影响。结果表明,在土壤脱水过程中,羊草株高、根长、干物质积累量、相对生长率(RGR)和蒸散量随盐度增加显著降低。羊草生长的临界土壤溶液NaCl浓度为253mmol/L,临界土壤含盐量为0.60%。在低盐处理(NaCl25～225mmol/L,总盐0.17～0.53%)时,增加盐度,水分利用效率(WUEET)、钾钠吸收选择性和运输选择性有显著提高;而在高盐(NaCl275～325mmol/L,0.63～0.73%)条件下,随盐度的增加,水分利用效率(WUEET)、钾钠吸收选择性和运输选择性降低。     

高抗重金属盐的微紫青霉菌(Penicillium janthinellum)菌株GXCR的遗传转化

我们曾分离到一株高抗多种重金属盐的微紫青霉菌(Penicillium janthinellum)菌株GXCR。本研究在该菌株中建立了基于携带苯菌灵抗性基因(Benr)的质粒pCPXBN-1、聚乙二醇(PEG)介导的原生质体转化体系。原生质体的产量和再生的最佳条件是酶解液中的酶浓度在0.6%~0.8%(纤维素酶∶蜗牛酶=1∶1)、孢子萌发后培养24 h的菌体和0.05 mol/L二硫苏半糖醇(DTT)预处理。最佳转化组合条件为3×108原生质体/mL,50μg质粒DNA组合条件下,40%PEG4000,山梨糖醇(sorbitol)-三(羟甲基)氨基甲烷盐酸盐(Tris-HCl)-氯化钙(CaCl2)缓冲液(STC)[1 mol/L sorbitol,50 mmol/L Tris-HCl(pH 7.0),50 mmol/L CaCl2],室温转化20 min。在此条件下的转化效率为0.3个转化子/μg DNA。     

醋酸-醋酸铵缓冲体系中草酸对高岭石的溶解特征

采用间歇法模拟研究醋酸-醋酸铵缓冲体系中草酸对高岭石的溶解特征,以了解低分子量有机酸溶解高岭石时,其质子和配体的相对贡献.试验表明:反应液中Al、Si浓度随草酸浓度提高、反应液pH降低及反应时间的推移而增加,当草酸浓度为10 mmol/L,反应液pH为3.5,反应1 656 h后A1、Si的浓度达到最高,分别为2.27和1.86 mmol/L;且配体(RL)促进速率随着反应液酸度的增强而升高;低浓度草酸(1 mmol/L)时,增幅随pH的降低而大幅增加,高浓度草酸(≥5 mmol/L)时,随着酸度的升高,增幅大幅减弱;相对于质子对高岭石的溶解作用,本试验浓度及酸度范围内,配体对高岭石溶解的贡献是主要的.     

苏打碱土盐分水平冲洗模拟研究

通过模拟实验对苏打碱土盐分水平冲洗的效果进行了研究,分析了磷石膏对盐分冲洗效果的影响,探讨了应用水量与盐分冲洗总量和盐分冲洗效率的关系,并对一次性冲洗和少量多次性冲洗两种方案的盐分冲洗效果进行了比较.结果表明:水平冲洗能够有效排出土壤盐分,显著降低土壤盐度和碱度;3次冲洗后,1 L,2 L,3 L,4L,5 L应用水量分别使对照处理的土壤盐度从3.39 dS/m降低到了1.83,1.73,1.39,1.26,1.13 dS/m,使土壤碱度从98.27(mmolc/L)1/2下降到了15.33,19.14,17.96,15.73,15.04(mmolc/L)1/2;与对照相比,磷石膏使土壤盐度略有提高,但显著降低了土壤碱度;盐分冲洗总量随应用水量的增加而提高;盐分冲洗效率与应用水量间呈幂函数递减关系;在应用水量相同情况下,一次性冲洗和少量多次性冲洗两种方法的碱土改良效果无显著差异.     

GR24及氮磷供应对丹参-AM真菌共生体养分吸收及功能物质形成的影响

【目的】探究了外源GR24 (人工合成独脚金内脂结构类似物)、磷水平和氮源对丹参–丛枝菌根(AM)真菌共生体氮素吸收及丹参酮类物质积累的影响，为丹参高质量生产提供参考。【方法】同位素示踪试验采用三室系统进行，试验设置3个磷水平[0μmol/L (P0)、35μmol/L (P35)、700μmol/L (P700)]和3个¹⁵N标记氮源(硝酸钾、硫酸铵、尿素，¹⁵N标记浓度均为4 mmol/L)，分析丹参菌根中¹⁵N丰度。GR24试验采用砂培方法进行，设置3种总氮浓度为4 mmol/L的氮源：硝酸钾、硫酸铵、尿素；设置3个AM真菌处理：不接种AM真菌(NM)、接种AM真菌(AM)、接种AM真菌+0.1 mmol/L GR24 (AM+GR24)，分析植株氮、磷积累量、氮磷比及丹参酮类物质的积累。【结果】同位素示踪试验结果显示，磷供应水平和氮源共同影响着丹参菌根对氮的吸收运转。硝酸钾处理下，磷供应水平对丹参菌根的¹⁵N丰度无显著影响；硫酸铵处理下，提高磷的供应水平显著降低丹参菌根的¹⁵     

混合盐碱对紫花苜蓿苗期根系特征的影响

为研究紫花苜蓿根系对混合盐碱胁迫的响应,探索紫花苜蓿对混合盐碱的适应特点,为紫花苜蓿在盐碱地的栽培实践提供理论依据。本试验以"甘农三号"紫花苜蓿为试验材料,采用两种中性盐NaCl和Na2SO4及两种碱性盐NaHCO3和Na2CO3,按不同比例混合成为A(NaCl∶Na2SO4=1∶1)、B(NaCl∶NaHCO3=1∶1)、C(NaCl∶Na2SO4∶NaHCO3∶Na2CO3=1∶1∶1∶1)、D(Na2SO4∶Na2CO3=1∶1)、E(NaHCO3∶Na2CO3=1∶1)5种混合盐,分别以25 mmol.L 1、50 mmol.L 1、100 mmol.L 1、150 mmol.L 14种盐浓度,模拟出20种盐度和碱度各不相同的混合盐碱条件对紫花苜蓿幼苗进行处理,测定了根系总长度、根系平均直径、根表面积、根尖数等指标,以了解紫花苜蓿根系在混合盐碱胁迫下的生长特性。结果表明,盐浓度为影响紫花苜蓿根系生长的主要因素。混合盐碱对根尖数的影响表现出明显的负效应,对根系平均直径的影响并不明显。随着混合盐浓度的升高,根系总长度、根表面积呈现先增大后减小的趋势。A、B处理的根长分别在盐浓度为25 mmol.L 1和50 mmol.L 1时达到最大值,分别比对照(0 mmol.L 1)增加50.7%和37.9%,而且差异均达到显著水平(P<0.05);在盐浓度达到150 mmol.L 1时,A、B、C、D、E的根系总长度分别比对照减少26.6%、37.7%、51.6%、37.0%和55.7%,差异显著。A、C、D组处理下仅在25 mmol.L 1时,根表面积显著增加,分别比对照增加21.1%、43.4%和12.7%;在浓度为150 mmol.L 1时,E处理下根表面积显著减小,比对照减少49.6%。表明低浓度混合盐碱对紫花苜蓿根系的生长影响不显著或具有一定的促进作用,高浓度胁迫下抑制根系的生长;在高盐浓度下随着碱性盐比例的增加,对紫花苜蓿根系生长的抑制作用越明显。     

外源Ca2+对NaCl胁迫下西葫芦生长特征及光合、生理特性的影响

以西葫芦品种阿兰一代为试验材料,研究外源Ca2+对NaCl胁迫下西葫芦植株生长特征及光合、生理特性的影响.结果表明,较低浓度(5 mmol/L)Ca2+处理对NaCl胁迫的缓解作用不明显;当Ca2+浓度增加到10 mmol/L时,显著改善了NaCl胁迫下西葫芦植株的生长状况,使株高增高、叶面积增大,该条件下,西葫芦叶片丙二醛(MDA)和脯氨酸(Pro)含量维持在较低水平,说明植株受到的胁迫较小;10 mmol/LCa2+处理叶片的过氧化氢酶(CAT)和过氧化物酶(POD)活性最高,分别比CK增加20.6％和52.2％,叶绿素a、b含量较高;10～20 mmol/L Ca2+处理的光合速率(Pn)、气孔导度(Gs)和蒸腾速率(Tr)均高于CK和30 mmol/L处理,而胞间CO2浓度(Ci)显著低于CK和30 mmol/L处理;当Ca2+处理浓度超过20 mmol/L时对NaCl胁迫的缓解作用下降;当Ca2+浓度达到30 mmol/L时,各指标与CK间的差异不显著.综合分析认为,10 mmol/L的Ca2+处理浓度对NaCl胁迫的缓解效果最为显著.     

Soil-profile distribution of primary and secondary plant-available nutrients under conventional and no tillage

Nutrient distributions under no tillage (NT) compared with conventional disk-and-bed tillage (CT) management in the warm, humid region of the southeastern USA need to be assessed so that future placement, quantity, and type of fertilizers can be altered, if necessary, to efficiently match crop demands. We determined soil-profile distributions of pH, N, P, S, K, Ca, Mg, Na, Zn, Fe, Mn, and Cu to a depth of 0.9 m at the end of 8.5 years of continuous CT and NT management on a Weswood silty clay loam (fine, mixed, thermic Fluventic Ustochrept) in southcentral Texas. Most dramatic changes occurred within the 0–0.05 m depth, where soil under NT had lower pH, Fe, and Cu than under CT, but greater P, K, Zn, and Mn. Greater P and K under NT than under CT also occurred below the till-zone (0.15–0.3 m). At a depth of 0–0.3 m, soil under NT contained greater amounts of extractable P, K, Zn, Fe, Mn, and Cu than under CT. Nitrogen fertilization had little effect on nutrient distributions, except resulting in greater extractable K at 0–0.05 m and greater nitrate at 0–0.15 m. Few changes in soil-profile distributions were observed for extractable S, Ca, Mg, and Na. Long-term continuous use of NT on this fine-textured, high-fertility (except for N) soil had no apparent adverse effects on nutrient distributions relative to CT, but enhanced conservation and availability of P, K, Zn, Fe, Mn, and Cu near the soil surface where crop roots proliferate.     

Assessing the effectiveness of conservation measures: Resolving the “wicked” problem of the Steller sea lion

“Wicked” problems are those that are complex and that change when solutions are applied. Many conflicts in conservation fall into this category. The study approached the problem of how to constrain the apparent wickedness of a problem in the conservation management of a species by using simple empirical indicators to carry out iterative assessment of the risk to a population and to document how this risk evolves in relation to the addition of new data and the implementation of management actions. Effects of high levels of uncertainty within data and also concerning population structure were examined through stochastic simulation and by exploration of scenarios. Historical trends in the example used, the Steller sea lion, showed rapid declines in abundance in some regions during the 1980s. The current total population is 130,000-150,000 Steller sea lions through Alaska and British Columbia and this number has been stable since about 1990 in spite of regional differences in population dynamics. Regional differences in the sequence of changes in the number of pups and non-pups, suggested that an internal re-distribution of juveniles could have happened between 1980 and 1990. Current productivity also appears close to the long-term mean. Stochastic population projection using various scenarios showed that, based upon this history, the risk of extinction for the population has declined and is below reasonable thresholds for considering the population to be endangered. The trends in risk suggest that management actions taken since 1990 have probably been effective. Consequently, the conservation management objectives for the Steller sea lion are probably being met. The approach provides a mechanism, based upon experience and scenario analysis, for exploring future policy options and may help to constrain the debate amongst stakeholders about the cost-benefit trade-offs associated with different options.     

“绿色革命”以来大气CO2浓度升高对C3作物营养品质的影响

自20世纪60年代"绿色革命"以来,育种技术和农耕技术的发展促进了农作物产量的大幅提升,然而作物的营养品质出现下降趋势。在相似的遗传背景下,大气CO_2浓度升高会使单位体积农作物产品的营养元素含量下降,因此"绿色革命"至今,农作物产品的营养元素下降可能受大气CO_2浓度升高影响。通过植物生长箱模拟"绿色革命"初期和目前的大气CO_2浓度水平(310μmol/mol和400μmol/mol),针对主要C_3作物水稻、小麦和大豆,研究"绿色革命"以来大气CO_2浓度升高对其籽粒的C、N、Fe、Zn元素含量的影响,结果表明:CO_2浓度升高对3种作物籽粒的C元素含量几乎没有影响,变化幅度在±1.5%之间;籽粒的N、Fe、Zn元素含量普遍呈现下降趋势,但均未达到显著水平。     

Potential of wild species for genetic enhancement of some semi-arid food crops

Discovery and incorporation of genes from wild species provide means to sustain crop improvement, particularly when levels of resistance in the cultigens are low and virulent strains of pests and pathogens overcome the host plant resistance. The extent of utilization and the potential of the wild genepool for genetic enhancement were reviewed in five important food crops viz. sorghum, pearl millet, chickpea, pigeonpea and groundnut grown in the semi-arid tropics. Introgression from compatible wild germplasm in the primary gene pool resulted in transfer of new cytoplasmic male sterility systems in pearl millet and pigeonpea, development of high protein, cleistogamous flower and dwarf pigeonpea lines and foliar disease resistant groundnut cultivars. Utilization of wild species in secondary and tertiary gene pools has been generally limited due to sterility, restricted recombination or cross incompatibility. Nevertheless, these species are extremely important as they contain high levels of resistance to several important biotic and abiotic stresses. Several of them, like those belonging to the Parasorghum section and the rhizomatous Arachis species are sources of multiple resistances and hold great promise to sustain crop productivity.     

Enhanced establishment and growth of giant cardon cactus in an eroded field in the Sonoran Desert using native legume trees as nurse plants aided by plant growth-promoting microorganisms and compost

To evaluate the feasibility of long-term desert reforestation technology of mixed vegetation, cardon cactus (Pachycereus pringlei) seedlings from indoor and outdoor nurseries were planted in the field adjacent to one seedling of potential legume nurse trees: mesquite amargo (Prosopis articulata), yellow palo verde (Parkinsonia microphylla), and blue palo verde (Parkinsonia florida). Some of the planting holes were also supplemented with common dairy compost. Additionally, the combinations of legume tree–cactus were inoculated with either a consortium of desert arbuscular mycorrhizal (AM) fungi, plant growth promoting bacteria (PGPB; the diazotroph Azospirillum brasilense Cd, and the phosphate solubilizer Paenibacillus sp.), or a mixture of all. The field experiments were evaluated periodically during 30 months for survival and growth. Cardons reared in an outdoor screen house survived better in the field than those reared in a controlled growth chamber and hardened later outdoors. Association with any legume nurse tree increased survival and enhanced growth of untreated cardons. For cardons growing alone, application of either compost, AM fungi, and all the treatments combined increased survival. For these plants, no treatment affected plant growth during the first 3 months after transplanting. Later, all treatments, except for AM fungi, enhanced plant growth. However, only 2 years after transplanting the enhanced growth effect of AM fungi was also significant. In the presence of the legume nurse trees, transient positive effects on cardon growth were recorded. General evaluation after 30 months of cultivation showed that the treatments positively affected cardon growth when growing alone or in combination only with mesquite amargo but not with the other two legume trees. This study proposes that young legume trees have the capacity to enhance survival and growth of cardon cactus, depending on the legume cactus combination. Additional treatments such as compost or PGPB can either amplify the effect or else attenuate it.     

Karyotypic and genome size variation in Cajanus cajan (L.) Millsp. (pigeonpea) and some wild relatives

Detailed karyotypes and 4C DNA amounts have been studied in five cultivars of Cajanus cajan and 20 species belonging to Cajanus, Rhynchosia, Dunbaria, Flemingia and Paracalyx. C. cajan shows intraspecific variability and its karyotype is most similar to that of C. cajanifolius (sect. Cajanus) in the morphology and number of satellite chromosomes and the lack of any correlation between chromosome size within the complement and asymmetry. Karyotypes of C. lineatus and C. sericeus belonging to sect. Atylia are similar with respect to maximum r-index and the ratio of longest and shortest chromosomes in their respective complements. C. acutifolius (sect. Frutocosa) is distinct in having a very low ratio (1.44) between the longest and the shortest chromosomes, while in C. albicans, C. goensis, C. scarabaeoides (sect. Cantharospermum) there is no chromosome pair with r-index >2.0. C. mollis and C. volubilis (sect. Volubilis) show similarity with regard to ratio between the longest and the shortest chromosomes and a distinct chromosome pair with an arm ratio of 2.7 and C. platycarpus is distinct (sect. Rhynchosoides) in having the smallest ratio (1.36) between the longest and the shortest chromosomes. 4C DNA amounts in Cajanus and Rhynchosia vary between 3.28 pg to 11.69 pg and 4.92 pg to 11.13 pg respectively, while in Dunbaria, Flemingia and Paracalyx these vary between 4.70 and 7:06 pg. In the genus Cajanus karyotypic features and 4C DNA amounts agree with the sectional classification and bring out a close relationship between C. cajan and C. cajanifolius. This is supported by studies based on seed protein patterns, isozyme analysis, trypsin and chymotrypsin inhibitor patterns, RFLP and RAPD data and crossability relationships. A clear relation between DNA amount and abnormalities effecting the extent of pairing and recombination in interspecific hybrids shows the importance of this study in developing future breeding programme involving C. cajan and its wild relatives that are of potential value.     

Faculty positions:Center for Agricultural Resources Research,Chinese Academy of Sciences

正The Center for Agricultural Resources Research(CARR),the Institute of Genetics and Developmental Biology(IGDB),Chinese Academy of Sciences,invites applicants for several research group leader positions.CARR is one of the research organizations in Chinese Academy of Sciences(CAS).We seek nominations and applications     

Effect of some fungicide seed treatments on the survival of Bradyrhizobium japonicum and on the nodulation and yield of soybean [Glycine max. (L) Merr.]

Several commercial fungicide seed treatments were evaluated for their possible effect on the survival of Bradyrhizobium japonicum on seeds and on the nodulation and yield of soybeans in a greenhouse and a field experiment. quinolate Pro (carbendazim and oxine copper), Vitavax 200FF (carboxin and thiram), and Monceren (pencycuron) had a small effect or no effect on the survival of B. japonicum and on the nodulation and yield of soybeans. They can thus be considered compatible with soybean seed inoculation. Germipro UFB (carbendazim and iprodione), Apron 35J (metalaxyl), and Tachigaren (hymexazol) decreased B. japonicum survival and the nodulation and yield of soybeans and thus cannot be considered compatible with soybean seed inoculation.     

Einfluss der düngungsmethoden auf die entwicklung von zuckerrübenkrankheiten

Während neunjähriger (1994-2002) Untersuchungen in der Versuchsanstalt Ba?cyny (Fahlerde, Fall-Gleyboden, ausgebildet aus leichtem Lehmboden) wurde der Befall mit Krankheiten an der Zuckerrübe in Abhängigkeit von der Düngungsmethode bewertet. Folgende Methoden wurden angewendet: A - Mineraldünger, B - Stalldung und Mineraldünger, C - Stroh-, Gründung und Mineraldünger, D - Kompostdünger und Biopräparate (ökologische Düngung). Auf den Objekten A, B, C wurden bei konstanter Phosphor-Kalium-Düngung die Stickstoffgaben von 0 bis 180 kg.ha^?1 differenziert. Auf dem ökologischen Objekt D ohne Mineraldünger wurden statt Stickstoff die Biopräparate P₅₀₀ und P₅₀₁ verabreicht. Der geringste Befall von Krankheiten wurde an der Zuckerrübe auf jenem Objekt festgestellt, das mit Kompost und den Biopräparaten gedüngt worden war. Im Rahmen der konventionellen Düngungsmethoden wurde allgemein die höchste Intensität der Krankheiten an der mit Stroh, Gründung und Mineraldünger gedüngten Zuckerrübe beobachtet. Ausnahmen von dieser Regel bildete das Vorkommen von echtem Mehltau und Keimlingsfäule. Auf den Objekten A, B, C nahm die Intensität der Krankheiten mit der Steigerung der Stickstoffgabe zu. Auch die auf Objekt D verabreichten Biopräparate stimulierten die Entwicklung der Krankheiten. The effect of various fertilization methods on the diseases of sugar beet was estimated on the basis of nine-year studies (1994-2002) conducted in the Experimental Production Farm in Ba?cyny on loess-based, sedimentary-gley, light-clay soil. The following fertilization methods were applied: A - mineral fertilization, B - mineral and manure fertilization, C - straw, green manure and mineral fertilization, D - ecological compost and biodynamic preparations fertilization. In the objects A, B and C fertilized with phosphorus and potassium, various doses of nitrogen ranging from 0 to 180 kg/ha^?1 were used. In the ecological object D, where mineral fertilization was not used, biodynamic preparations P₅₀₀ and P₅₀₁ were applied instead of nitrogen. The lowest ratio of the diseases of sugar beet was observed in the object fertilized with the compost and biodynamic preparations. In view of the conventional fertilization methods, generally the highest incidence of diseases was noted in the sugar beet fertilized with straw, green manure and mineral fertilizers. The exception was the occurrence of powdery mildew and the black leg. In objects A, B and C the incidence of the diseases increased with the increase in nitrogen doses. The applied biodynamical preparations in the object D stimulated the development of diseases too.     

Prospects for control of Pythium damping-off of lettuce with Trichoderma,Gliocladium and Enterobacter spp.

Summary Damping-off of lettuce (Lactuca sativa) caused by Pythium ultimum was studied in pots containing a non-sterile potting mix in the glasshouse. Fifty P. ultimum sporangia g^-1 compost reduced the plant stand to 15% and shoot dry weight to 18%, but this reduction was totally prevented by applying Trichoderma harzianum at 2×10⁵ viable propagules g^-1 potting mix. Gliocladium virens and Enterobacter cloacae also alleviated the damping-off. E. cloacae did not adversely affect the action of the fungal antagonists. The co-existence of the bacterial and fungal antagonists was revealed on the root surface and inner surface of the testa by scanning electron microscopy, indicating the compatibility of the biocontrol agents.