Note: Comparison of three laboratory methods to evaluate the pathogenicity and virulence of tenPseudomonas syringae pv.syringae strains on apple, pear, cherry and peach trees

The pathogenicity and virulence of ten GreekPseudomonas syringae pv.syringae strains from different hosts (citrus, pear, apple, peach and cherry) were evaluated using three different laboratory methods, which produced results in good agreement. All ten strains were virulent on apple, pear, cherry and peach trees. The extent of tissue colonized varied considerably among strains and cultivars. On excised shoots and twigs of apple and pear, strains BPI 176, BPI 203, PI 2 and PI 14 were the most virulent and strains BPI 689, BPI 992, BPI 4, BPI 20, PI 18 and PI 19 were the least virulent. On excised shoots and twigs of peach and cherry, strains BPI 176, BPI 203, PI 2, PI 14, PI 18 and PI 19 were the most virulent and strains BPI 4 and BPI 20 were the least virulent. Moderate virulence was evinced by strains BPI 689 and BPI 992. These pathogenicity assays are proposed as rapid and reproducible screening systems to evaluate the susceptibility of apple, pear, cherry and peach cultivars to this bacterial pathogen.     

黄瓜离体器官再生植株研究进展

概述了黄瓜离体器官再生植株的途径,从离体器官(子叶、下胚轴、真叶、叶柄、幼胚、根等)获得原生质体、胚状体,然后形成植株和离体器官(子叶、真叶、茎尖)直接分化出芽或花的研究。     

海洋贝类配子及胚胎的低温冷冻保存

综述了海产贝类配子及胚胎的低温冷冻保存技术的发展现状,对目前的文献进行了汇总和分析,讨论了冷冻保存的降温程序、抗冻剂配方以及评价保存效果的指标等方面的问题,并对目前在海产贝类配子和胚胎的低温冷冻研究方面存在的问题和解决的途径进行了探讨。     

软籽石榴胚离体培养和快繁技术探讨

正确的处理条件以及适宜的植物激素配比在软籽石榴胚培养和快繁技术上起关键性作用。本研究以软籽石榴胚组织为材料,研究确定最适宜软籽石榴发育的胚处理条件、增殖培养基、生根培养基,为软籽石榴的优质高产提供理论依据。通过对比低温(4℃)下不同处理时间(0, 4d,8d, 16 d)和两种不同处理方式(保留种皮,去除部分种皮)、不同植物激素处理、不同炼苗基质对软籽石榴胚培养和快繁的影响,得出结论:石榴果实在4℃下保存4 d,除去部分种皮有利于胚萌发;软籽石榴组培苗最适增殖培养基为MS+0.5 mg/L NAA+0.5 mg/L GA3 +0.5 mg/L 6-BA,试管苗株高3.8 cm、增殖系数达到4.8,其中植物激素对增殖的影响程度6-BA>NAA>GA3;最佳生根培养基为1/4MS+0.1 mg/LIBA+0.1 mg/L PP333,生根率为85%;最佳炼苗基质为泥土,苗成活率达到90%以上且苗长得快而茁壮。该研究通过胚培养技术筛选适宜软籽石榴快速繁育的培养条件,有望为软籽石榴的快速繁殖和培养优良性状的新品种提供依据。     

油菜小孢子培养技术及其在遗传育种中的应用研究概况

小孢子培养作为一种辅助育种手段越来越受到育种家的重视,并应用于各个领域。由于影响小孢子成胚和成苗的因素较多,低诱导频率及成苗率严重限制了该技术在育种中的应用。为了全面了解小孢子胚状体发生能力及影响再生体系的各项因素,掌握该技术的研究动态和发展方向,本文总结了近年来国内外影响小孢子培养的主要因素：供体植株基因型、供体植株生长条件及生理状态、小孢子发育时期、培养基组成、培养条件,以及在双单倍体育种、诱变育种、转基因育种等领域中的应用。     

不同因素对水稻离体根吸收四价硒影响

研究结果显示,pH对水稻离体根吸收4价硒(Se)有显著影响,这与不同pH下4价Se的存在形式有关。进一步研究表明,低温抑制4价Se吸收和一定浓度的NaCl促进4价Se吸收,可能在于低温和NaCl影响到根内代谢而间接影响4价Se吸收,而P抑制4价Se吸收可能与二者拥有共同吸附位点有关。     

Mdivi-1, mitochondrial fission inhibitor,impairs developmental competence and mitochondrial function of embryos and cells in pigs

Mitochondria are highly dynamic organelles that undergo constant fusion/fission as well as activities orchestrated by large dynamin-related GTPases. These dynamic mitochondrial processes influence mitochondrial morphology, size and function. Therefore, this study was conducted to evaluate the effects of mitochondrial fission inhibitor, mdivi-1, on developmental competence and mitochondrial function of porcine embryos and primary cells. Presumptive porcine embryos were cultured in PZM-3 medium supplemented with mdivi-1 (0, 10 and 50 μM) for 6 days. Porcine fibroblast cells were cultured in growth medium with mdivi-1 (0 and 50 μM) for 2 days. Our results showed that the rate of blastocyst production and cell growth in the mdivi-1 (50 μM) treated group was lower than that of the control group (P < 0.05). Moreover, loss of mitochondrial membrane potential in the mdivi-1 (50 μM) treated group was increased relative to the control group (P < 0.05). Subsequent evaluation revealed that the intracellular levels of reactive oxygen species (ROS) and the apoptotic index were increased by mdivi-1 (50 μM) treatment (P < 0.05). Finally, the expression of mitochondrial fission-related protein (Drp 1) was lower in the embryos and cells in the mdivi-1-treated group than the control group. Taken together, these results indicate that mdivi-1 treatment may inhibit developmental competence and mitochondrial function in porcine embryos and primary cells.     

四种鸢尾属植物种子休眠和萌发研究

燕子花(Iris laeviga ta)、玉蝉花(Iris ensa ta)、溪荪(Iris sanguinea)、黄菖蒲(Iris pseudacorus)是鸢尾科4种喜水湿植物。经萌发实验证明,除溪荪种子没有休眠外,其它3种种子都有休眠。经去除种皮、低温沙藏、赤霉素处理和胚培养4种处理,证明燕子花、玉蝉花、黄菖蒲中抑制种子萌发的主要因素是胚乳。不同种打破休眠的有效方法不同,其中50 mg/L GA3处理可提高黄菖蒲种子的发芽率,达到84.4%,而低温沙藏30 d可使玉蝉花种子的发芽率达到94.4%,低温沙藏90 d则可提高燕子花的发芽率达到87.8%。     

PCR法进行胚胎性别鉴定的研究进展

通过胚胎性别鉴定,可控制家畜后代性别比例,获得巨大经济效益。早期胚胎性别鉴定的方法有,核型分析法,H-Y抗原法,X-连接酶检测法和PCR扩增法等。PCR法因其简单、快速、准确等优点,成为目前比较理想的胚胎性别鉴定方法。笔者对性别决定基因、PCR法胚胎性别鉴定的几个关键环节进行了综述,并对其前景进行了展望。     

Spawning, early development and first feeding in the gobiid fish Priolepis nocturna

The reproductive behavior, embryonic development and early larvae of Priolepis nocturna are described. Three pairs of P. nocturna began spawning 41 days after acquisition and maintained a 5–10 day spawning cycle lasting beyond several months. Spawning was initiated by the female who signaled her readiness to spawn by displaying to the male. Egg clutch size averaged 1578 ± 51.23 eggs and ranged from 268 to 3121. Egg length averaged 0.82 ± 0.01 mm total length (TL) and ranged from 0.75 to 0.90 mm. Egg width averaged 0.51 ± 0.51 mm total width (TW) and ranged from 0.49 to 0.52 mm. Fertilized eggs were ovoid in shape and attached to the ceiling of provided shelters via adhesive filaments at the proximal end. Hatching rates averaged 97.3 ± 0.51% and ranged from 91.9 to 99.8%. Larvae measuring 1.89 ± 0.04 mm TL hatched 121 ± 0.5 h post fertilization and did not rotate position prior to hatching. Skeletal elements of the chondrocranium were simplistic and dominated by the hyoid, hyomandibulosymplectic cartilage, ethmoid and Meckel's cartilage in first feeding larvae. No elements were added to the cranial architecture by 5 days post hatch (DPH) when larvae measured 2.05 ± 0.04 mm TL. First feeding larvae consumed only dinoflagellates and tintinnids suggesting that feeding was constrained by a poorly developed feeding mechanism. Embryology and larval development are described to 5 DPH.