妊娠期牦牛肉阜间区子宫腺的形态计量学分析

运用形态计量学方法对31头牦牛肉阜间区子宫腺的相关组织学数据进行了测定,并进行统计分析。研究发现,除了妊娠151~180 d,牦牛肉阜间区子宫腺上皮高度随着妊娠时间的增长极显著降低(P0.01);妊娠期子宫腺管周长和面积非常明显增大(P0.01);不同妊娠阶段之间体积密度差异极显著(P0.01),先增加后下降,而表面密度无显著差异(P0.05);除了妊娠151~180 d,扭曲腺管和管状腺管的比例随着妊娠时间的增长分别非常显著地增大或减小(P0.01);分泌腺管的比例在妊娠期间有明显变化(P0.05),牦牛肉阜间区还存在嵌套腺管。结果显示,妊娠期牦牛肉阜间区子宫腺形态结构有明显的变化,子宫腺变的更大、更长,形状更加扭曲。     

Pollination dynamics in a Douglas-fir seed orchard as revealed by pedigree reconstruction

• ? Pollination dynamics was studied in a Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) seed orchard using 8 nuclear microsatellite markers and pedigree reconstruction.
• ? The seed orchard consisted of 49 parents (clones). Cone-crop management included bloom delay and supplemental mass pollination (SMP) using 12 internal and 4 external pollen donors.
• ? A random sample of 801 bulk seeds was genotyped for both haploid megagametophyte and corresponding diploid embryo.
• ? Using the parental population’s multilocus genotypes, full pedigree reconstruction generated all the information needed to estimate the maternal, paternal, and parental reproductive success, selfing, pollen contamination, and pollination success of the 4 external pollen donors.
• ? Maternal, paternal, and parental reproductive success varied with 80% of gametes being produced by 23, 45, and 37% of the orchard’s parents, respectively, resulting in a drastically reduced effective population size as compared to the census number (14 vs. 53).
• ? Selfing, pollen contamination, and aggregate SMP success (internal and external) were estimated to be 15.2, 10.4, and 15.0%, respectively.
• ? Full pedigree reconstruction was effective in unraveling the orchard’s pollination dynamics and both female and male reproductive success.

     

利用ACGM分子标记研究10个毛竹不同栽培变种的遗传多样性

应用40对ACGM引物扩增10个毛竹不同栽培变种及其2个近缘种材料,结果有35对引物可以在至少1个材料中得到特异性PCR产物,其中27对引物在12个供试材料中表现出多态性,占引物总数的67.5%.8对引物在供试材料间没有多态性位点,进一步对无多态性位点的扩增序列研究表明,相同引物扩增出的序列间差异性很小.从拷贝数来看,在水稻中表现为单拷贝的基因,有些在竹子中表现为多拷贝的特性;有些在部分供试材料中为单拷贝,而在另一些供试材料中表现为多拷贝.聚类结果表明:在10个毛竹不同栽培变种中,绿槽毛竹和黄槽毛竹的亲缘关系最近;圣音毛竹与其他不同栽培变种的毛竹亲缘关系最远.     

Sap flow measurement by a single thermal dissipation probe: exploring the transient regime

? In thermal dissipation method the stationary regime is used to estimate sap flow density from the temperature difference between a heating probe and a non-heating one.

? A new approach, based on the non-stationary regime of a single heating probe, is investigated on an olive tree branch. Probe temperature is monitored for different flow densities and for heating and cooling modes. Measurement sequences of 10 min using 5 s time steps are made just after the heating is switched on or off.

? Results show that temperature variation has a quasi-exponential phase whose duration decreases for increasing flow densities. Thermal indices using temperature of the probe measured at initial, final, and intermediate times t _i were developed. Relationships between sap flow density and thermal indices were found to be linear for t_i = 10 s?60 s with better coefficients of determination in cooling mode (R ² = 0.94–0.96) than in heating (R ² = 0.83–0.93). Validation tests confirmed the robustness of the single probe method with lowest error obtained for t _i = 20 s.

? Single probe method seems to be a promising technique to measure tree sap flow. Its application could be considered under cooling mode using t _i = 20 s and relatively short measurement sequences e.g. 5–10 min.

     

Bursaphelenchus tusciae in Tunisia associated with Hylurgus ligniperda

Bursaphelenchus tusciae is reported for the first time in Tunisia and North Africa, associated with the insect Hylurgus ligniperda Fabricius (Coleoptera: Curculionidae: Scolytinae). Nematode identification was based on restriction fragment length polymorphism analysis and sequencing of the internal transcribed spacer (ITS) regions of ribosomal DNA. Phylogenetic analysis revealed that Tunisian B. tusciae clusters together with two other B. tusciae isolates forming a separate group close to B. hildegardae and B. eggersi. As H. ligniperda is among maritime pine scolytids pests in Tunisia and is widely distributed in North Africa, this study is an important contribution to the knowledge of Bursaphelenchus species associated with bark beetles of pine forests in Tunisia and North Africa.     

Root-zone temperature affects the phytoextraction of iron in contaminated soil

The effect of root temperatures on the uptake and content of iron (Fe) in different organs of potato plants was studied. Four different plastic covers were used (T1: transparent polyethylene; T2: white polyethylene; T3: white and black coextruded polyethylene), using plants without plastic covers as control (T0). The results of this study indicate that in treatments with the highest root temperature (T2 and T3), chelate-reductase activity significantly increased, that could enhance the uptake and subsequent accumulation of Fe in the different organs analyzed of the potato plant. In addition, the roots and particularly the tubers proved to be the main organs of Fe bioaccumulation in treatments T0, T2, T3, and T4. On the contrary, in the T1 treatment, the bioaccumulation of Fe was detected in the shoot (stems and leaves). Finally, the foliar bioindicators of Fe analyzed, chl a and b, carotenes, peroxidase activity and catalase activity reflected the foliar status of Fe.     

Applications of biotechnology for forest regeneration

The Forest Biotechnology Centre is an interdisciplinary research group dedicated to the development and application of advanced technology for the enhancement of forest regeneration. The Centre carries out contracts on behalf of clients in forest-related industries and government agencies. In addition, there are a number of long-term, in-house projects aimed at the development of proprietary technologies in genetics and propagation, and seedling production and establishment. Technical capabilities include: tissue culture, molecular genetics, pathology and microbial inoculants, and ecophysiology. These techniques are also being used to improve nursery culture regimes, disease assessment, planting regimes, and new product development for a variety of conifer species. Additional programs relate population genetics to adaptive traits, and develop clonal testing within elite families from tree-breeding programs.     

A Near-Isogenic Fusarium oxysporum f. sp. lycopersici Strain with a Novel Combination of Avirulence Characteristics

ABSTRACT A novel Fusarium oxysporum f. sp. lycopersici strain (F1-27) was obtained from protoplast fusions between race 1 Fol004 (putative avirulence genotype A1a2a3) and race 2 Fol007 (a1A2A3). Bioassays using different tomato cultivars revealed new virulence characteristics for F1-27 that were mitotically stable. The corresponding avirulence genotype for F1-27 was assigned a1A2a3. Despite their distinction in avirulence genotype, molecular analysis revealed that parent Fol007 and F1-27 were near-isogenic strains. The electrophoretic karyotype of F1-27 was identical to that observed for Fol007. Foxy-amplified fragment length polymorphism (AFLP) marker analysis showed that all Fol007-specific bands were present in F1-27. In addition, 11 new F1-27-specific Foxy insertions were identified. Segregation of both virulence and these new Foxy-AFLP markers was observed in a backcross between F1-27 and its parent Fol007. One marker was found to cosegregate with the a3 allele. The nature of the genetic change in this strain is discussed.