阔叶猕猴桃抗生素敏感性及遗传转化的研究

以阔叶猕猴桃(Actinidia latifolia)叶片为外植体,研究了各种抗生素对形态分化和器官形成的影响,并以叶盘为受体,通过根癌农杆菌介导法获得了抗性愈伤组织和抗性芽,组织化学染色表明gus基因已在植物组织中表达。研究结果表明,对不定芽分化来说,头孢霉素(Cef)效果明显好于羧苄青霉素(Carb)。Cef浓度为300mg.L-1时效果最好,再生频率达100%,平均再生芽数达最大为9.76个芽/外植体。生根过程中高浓度的Cef(≥200mg.L-1)明显抑制生根,而Carb对生根没有显著影响。在卡那霉素(Kan)和Carb组合处理中,Carb对生根没有显著影响,但Kan明显抑制生根。随着Kan浓度的升高,生根率和平均根数迅速减少,当浓度升高到50mg.L-1时,生根完全被抑制。因此,农杆菌介导的阔叶猕猴桃遗传转化中愈伤组织和不定芽诱导过程宜选用300mg.L-1Cef来抑制农杆菌生长,Kan筛选的临界浓度为20mg.L-1。在抗性芽生根过程中Kan浓度应该控制在50mg.L-1以内,并改用Carb作为杀菌剂,生根效果会更好。该研究确定了农杆菌介导的阔叶猕猴桃叶片遗传转化中使用抗生素的种类和用量,为通过基因工程对阔叶猕猴桃进行遗传改良奠定了基础。     

火龙果茎段愈伤组织诱导及再生体系的建立

为了进一步改良火龙果品种,提高产量,以红皮红肉型火龙果紫红龙幼嫩茎段为试材,通过不同植物生长调节剂及浓度配比筛选出适宜火龙果愈伤组织诱导、不定芽再生及生根成苗的培养基,以建立稳定、快速、高效的火龙果再生体系.结果表明:高浓度的TDZ有利于茎段愈伤组织的形成,但不利于不定芽的再生,纵接比横接更利于愈伤组织和丛生芽的诱导,TDZ、2,4-D和NAA 3种生长调节剂通过正交试验筛选的愈伤组织和丛生芽诱导的最适培养基为:MS +2,4-D 1.0 mg·L-1 +TDZ0.4 mg·L-1+ NAA 0.5 mg· L-,愈伤组织诱导率为89.1％,丛生芽诱导率高达94.0％;生根诱导最适培养基为MS+ CCC 0.5 mg· L-1+6-BA 3.0 mg· L-1+ AC 200 mg· L-1,生根率达到97％,平均根数7.0条每株,平均根长达10.3 cm.     

雪樱子组织培养及植株再生体系的研究

以雪樱子无菌苗叶片及茎段为外植体,研究了不同激素及不同浓度激素配比的培养基对雪樱子愈伤组织的诱导、不定芽分化及其生根的影响。结果表明,愈伤组织诱导以及芽分化最适培养基为MS+6-BA 2.0 mg/L+ IAA 0.2 mg/L,出愈率为87.5%,分化率为65.0%;生根最适培养基为MS+ IAA 0.2 mg/L。     

江南牡丹茎段愈伤组织诱导与植株再生

为探讨不同培养基、不同植物生长调节剂对江南牡丹茎段愈伤组织诱导及植株再生的影响,本研究以江南牡丹凤丹幼嫩茎段为材料,通过愈伤组织途径建立了植株再生体系。结果表明:改良MS培养基为牡丹茎段愈伤组织诱导的最佳培养基,愈伤组织最高诱导率为93.3%,最佳的培养基组合为改良MS+2,4-D0.2mg·L-1+6-BA2.0 mg·L-1+NAA0.3 mg·L-1。在愈伤组织分化过程中,加入KT0.2mg·L-1效果最好,有机物也能促进愈伤组织分化,其中加入水解酪蛋白300 mg·L-1效果最佳。牡丹茎段愈伤组织分化培养基为改良MS+KT0.2 mg·L-1+6-BA0.3 mg·L-1+NAA0.1 mg·L-1,分化率为37.8%,牡丹愈伤组织不定芽在1/2MS+IBA0.2 mg·L-1条件下能够诱导生根,诱导率为最高的13.3%。本研究结果将为进一步开展江南牡丹的高效再生体系和转基因育种等研究提供技术支持和理论依据。     

预处理和激素对草莓花药离体培养的影响

花药培养是进行植物脱毒和获取单倍体的有效方法。为提高草莓花药培养的再生效率,采用低温和黑暗的方式对草莓花药进行预处理,以不同种类和浓度的激素诱导诱导愈伤组织形成、不定芽形成与增殖。结果表明,培养前低温处理可促进愈伤组织形成,以4℃低温处理72h的效果最好。但花药黑暗预处理对愈伤组织形成没有作用。较高浓度的2,4-D(MS+1.0mg·L-16-BA+2.0mg·L-12,4-D)最适合诱导且促进花药愈伤组织形成,有助于下一步分化培养。而NAA对不定芽分化起着重要作用,诱导成功率达到10%以上,其中以MS+1.0mg·L-16-BA+0.2mg·L-1NAA诱导效果最好。在添加NAA的基础上再加入KT也能提高不定芽分化率。不定芽增殖过程不宜添加过高浓度的细胞分裂素和生长素,以MS+0.7mg·L-16-BA+0.1mg·L-1NAA诱导增殖效率最高,激素浓度过高时易出现玻璃化,现象,形成畸形苗。本研究建立了高效的草莓花药培养再生体系,为获得无病毒草莓苗和单倍体提供了条件。     

红颜草莓花瓣离体再生体系的建立试验初报

为了建立红颜草莓花瓣离体再生体系,以红颜草莓未开放的花蕾为试验材料,设置不同的TDZ浓度,对红颜草莓愈伤组织及不定芽进行诱导。结果表明:用5%NaClO消毒5 min,置于MS+2.4 mg·L-1 TDZ+0.1 mg·L-1IBA的培养基上不定芽诱导率达到32%,诱导效果最佳。     

东方百合“甜梦”花器官组织培养再生植株研究

研究东方百合"甜梦"品种花器官的组织培养,为"甜梦"百合种球生产产业化提供技术支持。以"甜梦"花器官为外植体诱导愈伤组织,以MS添加不同浓度6-BA为愈伤组织分化培养基,MS添加不同浓度6-BA及NAA配比为诱导叶片产生不定芽的培养基,MS添加不同浓度糖为结鳞茎培养基,进行组织培养。结果表明:花器官不同部位诱导愈伤组织从易到难为:子房花柱花药花托;愈伤组织分化以MS+6-BA 3.0 mg/L培养基较适宜;无菌叶片诱导不定芽以MS+6-BA 2.0 mg/L+NAA 0.1 mg/L培养基为好;添加60 g/L糖的培养基利于不定芽结鳞茎生根;带鳞茎组培苗可直接移栽于大田菜园土。通过"甜梦"花器官的培养,得到可用于生产的组培苗,该技术可应用于"甜梦"百合种苗工厂化生产。     

铁炮百合的胚性愈伤组织诱导和植株再生

以铁炮百合(又称麝香百合)杂种系品种‘White heaven’的组培苗叶片为外植体,研究了不同种类和浓度的激素对愈伤组织诱导和植株再生的影响,并通过叶片位置、接种方式以及光暗等不同处理进一步优化胚性愈伤组织的诱导。结果表明:以组培苗基部叶片为外植体,采用叶片近轴面向上的接种方式,在MS+1.0mg.L-12,4-D+0.1mg.L-16-BA的培养基上暗培养可诱导出胚性愈伤组织,诱导率可达65.74%;经石蜡切片鉴定可观测到球形胚和心形胚。最佳分化和生根培养基分别为MS+0.1mg.L-1NAA和1/2MS+0.5mg.L-1IBA,分化率达81.48%,生根率达91.67%。结果还显示2,4-D在百合胚性愈伤组织的诱导中起到了关键作用。     

安祖花愈伤组织诱导及其分化的正交试验设计

用正交设计法研究了不同激素处理及不同外植体对安祖花愈伤组织诱导及分化的影响。结果表明,在本试验设计中,外植体是诱导安祖花愈伤组织的主要因素;以茎段为外植体诱导愈伤组织的最佳培养基为MS+1.0mg/L NAA+2.0mg/L 6-BA;愈伤组织不定芽诱导的主要因素是6-BA;不定芽诱导分化的最佳培养基为1/2MS+0.5mg/L 2,4-D+1.0mg/L 6-BA。     

黑果枸杞高效植株再生与遗传转化体系的建立

为建立高效的黑果枸杞组织培养与遗传转化体系,本研究以黑果枸杞叶片、茎节、茎段为外植体,在含有不同浓度组合的NAA和BAP培养基上进行愈伤组织和不定芽诱导比较;选择黑果枸杞叶片为材料,采用农杆菌介导法,将带有绿色荧光蛋白基因(sGFP)的双元表达载体导入黑果枸杞,探讨侵染时间和抗生素浓度对遗传转化效果的影响。结果表明,黑果枸杞的最适植株再生体系为:以叶片为外植体,MS基本培养基中添加0.5 mg·L^-1NAA和0.3 mg·L^-1BAP,愈伤组织诱导率为88.56%,不定芽诱导率为54.54%,将不定芽置于1/2MS培养基中进行生根诱导,生根率为95%;稳定高效的遗传转化体系为:农杆菌侵染液OD₆₀₀为0.25,共培养3 d,卡那霉素(kanamycin)和羧苄西林(carbenicillin)浓度分别为25和250 mg·L^-1。愈伤组织和不定芽诱导时经卡那霉素和荧光标记双重选拔,愈伤组织阳性率为85.47%,出芽生根后经PCR鉴定,阳性转化率为29%;利用实时荧光定量PCR检测转基因植株,导入的外源sGFP基因均有较高的表达水平。本研究为利用基因工程技术对黑果枸杞进行品种改良提供了技术支撑。     

“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.     

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     

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.     

Collection and preliminary evaluation of native turfgrass accessions in Italy

Despite a raising interest on turfs in Italy, all theavailable varieties of this kind in the Country are of foreign origin, and areoften poorly adapted to the prevailing climatic conditions. This prompted tobegin a collection activity of indigenous turfgrass species, with the ultimategoal of identifying promising materials for future breeding based on localgenetic resources. The collection was carried out in three areas of Italy, viz.the northern Po Plain, the coastal region of Liguria, and the island of Sardiniathat are characterised, respectively, by subcontinental, warm temperate, andtypical Mediterranean climate. Altogether, 141 sites were visited, yielding 226accessions belonging to eight species of potential interest for turfs:Poa pratensis, Poa trivialis,Festuca rubra, Festuca arundinacea,Lolium perenne, Agrostis stolonifera,Agrostis tenuis, and Cynodon dactylon,this last being a warm-season grass. Poa pratensis andCynodon dactylon were mostly collected in northern Italyand Sardinia, respectively, whereas Festuca arundinacea andLolium perenne were rather ubiquitous. The collection sitesranged from 0 to 1040 m asl, but sites over 750 m wereonly visited in the inner part of Sardinia. All the accessions, collected aswhole plants, were transplanted at Lodi, northern Italy, where they are beingevaluated. Their preliminary evaluation for traits of importance for turf use,such as sward colour and overall quality, highlighted the great variation andthe occurrence of interesting accessions in all species. Other characters wererecorded, bearing specific importance in individual species, and in all casespromising accessions were identified. The germplasm of Festucarubra, Festuca arundinacea, and Loliumperenne proved highly infected by endophytic (symbiotic) fungi of thegenus Neotyphodium.     

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.     

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.     

Leaf position and genotype differences for mineral element concentrations in sorghum grown on tropical acid soil 1

Mineral element deficiencies and toxicities are common problems associated with sorghum [Sorghum bicolor (L.) Moench] production on acid soils. To better understand some of the mineral element problems and the analysis of plant tissue of sorghum plants grown on acid soils, four sorghum genotypes were grown on an acid Oxisol at Carimagua, Colombia limed with dolomite at 2 and 6 Mg ha^‐1.

Samples for mineral element analyses were obtained from leaves at different positions on the four genotypes. Concentrations of P and Mg were highest in the flag leaf (Leaf No. 1) and decreased as the position on the plant declined from the top of the plant for plants grown at 2 Mg lime ha^‐1. Similar decreases in P, Mg, K, and Zn concentrations occurred in plants grown with 6 Mg lime ha^‐1. Concentrations of Ca, S, Si, Mn, Fe, Cu, and Al increased as leaf position declined from the flag leaf for plants grown at 2 and 6 Mg lime ha^‐1. The higher lime supply enhanced Ca and reduced Mn and Fe concentrations in leaves. Differences in mineral element concentrations for the four genotypes used were fairly extensive. The elements to show the greatest range among genotypes were Al and Si and the elements to show the least range among genotypes were P, K, and S. Care should be used in collecting leaf samples for plant analysis and genotypic differences for accumulation of mineral elements should be considered in interpretation of results.