伊犁河谷14种野生观赏植物种子活力及休眠破除研究

研究伊犁河谷14种野生观赏植物种子特性,探究其种子保存方法及休眠破除的最佳方案。结果表明,1)低温干藏和超低温干藏处理后,所有种子的活力均有不同程度的下降;2)顶冰花、喜盐鸢尾的种子休眠破除均对赤霉素响应不敏感;马兰、天仙子、菥蓂、团扇荠、花葵、锦葵和欧夏至草在0.1mmol/L赤霉素处理时萌发率最高,而酸模、毒芹、白芷和夏枯草在1mmol/L赤霉素处理下萌发率最高;3)低温干藏和超低温干藏后,顶冰花、白喉乌头、喜盐鸢尾种子休眠对其不响应;低温干藏后,马兰、酸模、花葵、团扇荠、天仙子种子萌发率较高,而超低温干藏后,菥蓂、锦葵、毒芹、白芷、欧夏至草和夏枯草种子萌发率较高。     

Can camels disperse seeds of the invasive tree Prosopis juliflora?

Endozoochory has been recognised as the most important dispersal mechanism in invasive Prosopis species, because their sugary, tasty pods attract animals and because some of their seeds remain intact after passing through some animals' digestive systems. In this study, we evaluated the role of the camel (Camelus dromedarius) as a potential disperser of the seeds of invasive tree Prosopis juliflora. Four camels of similar weight (ca. 400 kg) and age (ca. 2 years) were each fed with 70 fruits (1000 seeds approximately) of P. juliflora, which were retrieved from the camels' dung at 24‐h intervals for 4 days. The seeds retrieved were tested for germination and viability, along with seeds not eaten by the camels, with and without pericarp. Less than 3% of the seeds eaten were retrieved from the camels' dung. Most of the seeds (74%) were retrieved between 24 and 72 h after ingestion. The passage through the camel gut significantly accelerated and increased seed germination of P. juliflora in comparison with uneaten seeds covered with pericarp (48–75% and 15% respectively). While gut passage liberated P. juliflora seeds from the pericarp, increasing and accelerating their germination, the viability of seeds which had not germinated after germination trials were decreased (ca. ~20%) relative to uneaten seeds that had also not germinated. Our results show that, despite the low recorded seed recovery, camels can potentially disperse seeds of P. juliflora, which is in line with field observation showing P. juliflora expansion along the camels' routes in Gebel Elba National Park, south‐east Egypt.     

Seed longevity and seedling emergence rate of Urochloa decumbens as influenced by sowing depth in a Cerrado soil

Urochloa decumbens (Signal grass) is an African grass species that is widely used in Brazil for pasture formation, and it has a high potential for invading natural areas. This study evaluated the longevity of U. decumbens seeds in the soil seed bank and the emergence rates of seedlings from different depths. In the greenhouse (natural light; ~25°C), seeds were sown at depths of 0, 1, 2 or 3 cm, in trays filled with sterile soil, to assess seedling emergence. Seeds sowed on the soil surface began to germinate 3 days after sowing. Seeds sowed at depths of 2 and 3 cm germinated 5 days after sowing. No seedlings emerged after 15 days. The seedling emergence rate was 74 ± 7% with no significant difference between sowing depths. In the field, seed longevity was evaluated by burying 60 replicates of 100 seeds at a soil depth of 2–3 cm, in a Cerrado area in the IBGE Ecological Reserve, Brasília. From September 2016 to April 2017, five samples were retrieved monthly to assess seed viability. In September, the viability was 68%, declining to 3% in October; by February, viable seeds were no longer recorded. As U. decumbens flowers in several episodes throughout the year, a soil survey may result in a misleading interpretation of the formation of a permanent soil seed bank.     

小果野蕉（Musa acuminate Colla）花粉母细胞减数分裂过程 异常的细胞学观察

香蕉是重要的热带水果,由于雄性不育、单性结实等原因导致其杂交育种困难。小果野蕉（Musa acuminate Colla）是现代香蕉栽培种的祖先之一,在理论研究和应用中有非常重要的地位。前期研究发现小果野蕉存在部分可育 花粉,但导致花粉活力下降的原因未知。为了探求导致小果野蕉花粉活力降低的细胞学原因,本研究通过亚历山大红 染色法对小果野蕉花粉活力进行检测,通过卡宝品红染色对小果野蕉花粉母细胞减数分裂阶段和小孢子发育阶段进行 观察。结果表明：小果野蕉花粉活力为 84.33%;小孢子发育阶段未见明显异常;正常四分体比例为 81.3%;花粉母细 胞减数分裂过程终变期、中期Ⅰ、后期Ⅰ、中期Ⅱ、后期Ⅱ均存在异常,比例分别为 8.8%、8.5%、7.6%、10.6%、12.1%。 因此,可能是部分花粉母细胞减数分裂异常导致小果野蕉花粉活力的降低。     

斜带石斑鱼肝细胞分离及原代培养方法的建立

本研究以斜带石斑鱼肝细胞为实验对象,在不同培养条件下进行原代培养,旨在探讨稳定可靠的斜带石斑鱼肝细胞分离及原代培养方法。采用组织块分离法和胰蛋白酶(含EDTA)消化法分离肝细胞,并通过密度梯度离心法分离纯化肝细胞,细胞悬液于DMEM/F-12、M199和L-15培养液中培养;细胞活力及数量采用血球计数板计数,并通过MTT法测定细胞增殖率;同时,测定不同时间培养上清液中乳酸脱氢酶(LDH)活性、白蛋白(ALB)和尿素氮(BUN)的含量,以分析肝细胞生长状态。结果表明,组织块方法不适于斜带石斑鱼肝细胞的培养,未见细胞从组织块中迁出,而胰蛋白酶消化法获得良好稳定的培养效果,细胞产量达到1.6×108个/g肝重,活细胞数达到95%;L-15培养基细胞生长明显优于DMEM/F-12和M199培养基;启动原代培养的48~72 h阶段肝细胞生长代谢旺盛,培养上清液中LDH活性显著降低,ALB和BUN含量显著升高。结果显示,0.25%的胰蛋白酶常温消化法适合斜带石斑鱼肝细胞的分离,斜带石斑鱼肝细胞原代培养的最适培养基为L-15培养基,肝细胞在启动原代培养的48~72 h生长代谢旺盛。     

玉蝉花花粉生活力检测和超低温保存研究

[目的]研究花粉超低温保存方法,对于解决植物杂交育种花期不遇问题以及实现种质资源的保存等都具有重要的现实意义。[方法]以鸢尾属植物观赏价值很高的耐寒种玉蝉花为研究对象,对其花粉悬滴法活力检测离体培养基筛选和超低温保存方法进行研究。[结果]玉蝉花花粉活力检测较适合的液体萌发培养基配方为蔗糖150 g/L+H_3BO_3200 mg/L+CaCl_2150 mg/L+Fe_2(SO_4)350 mg/L+KNO350 mg/L+MgSO_4·7H_2O 100 mg/L;超低温保存要采集活力较高的初花期花粉,较适宜含水量为15.0%~20.0%,超低温保存后选用自来水水冲化冻,花粉萌发率由保存前的56.04%提升到保存后的60.53%;玉蝉花花药也可作为超低温保存材料,保存后采用自来水水冲化冻其花粉萌发率为54.11%。[结论]保存后的花粉活力符合花粉使用活力要求,可用于指导实践。     

酸枣花器官结构、花粉形态及生活力比较研究

为了给酸枣花器官研究、花粉生活力的快速测定提供理论依据,笔者测定了不同的酸枣类型花器官结构、花粉形态及花粉萌发率和生活力的差异。结果表明：（1）不同的酸枣类型花序花朵数、花冠直径、蜜盘直径、雄蕊长度等方面都有不同程度的差异。花序花朵数一般在2~9个;单花雄蕊个数为5个;蜜盘颜色一般有淡黄色和黄绿色2种。（2）酸枣花粉比较小,通常在18.86~26.19 μm,以近球形为主,萌发孔以三孔沟居多。（3）不同的酸枣类型花粉的萌发率存在显著差异,其中酸枣4的萌发率最高,为32.54%;TTC法和I-KI法测定的花粉生活力显著高于离体培养法,测定值误差较大,故离体培养法更适合酸枣花粉生活力的测定。     

地中海仙客来花粉生活力研究

为进行种内繁殖及种间杂交,利用TTC染色法对4种不同类型的地中海仙客来花粉活力进行测定,同时利用I₂-KI染色法和花粉萌发法对H型花粉活力进行了测定。结果表明：TTC染色法是测定地中海仙客来花粉生活力的最佳方法。不同类型地中海仙客来在花粉活力及持续期上均存在明显差异;开花后第2~3天是采集花粉的最佳时期;H型及B型花粉开花后第5天,L型第7天,X型第12天花粉生活力仍在40%以上,可利用此花粉进行授粉。本研究为地中海仙客来杂交授粉提供了重要依据。     

Fucoxanthin and Its Metabolite Fucoxanthinol in Cancer Prevention and Treatment

Fucoxanthin is a carotenoid present in the chloroplasts of brown seaweeds. When ingested, it is metabolized mainly to fucoxanthinol by digestive enzymes of the gastrointestinal tract. These compounds have been shown to have many beneficial health effects, including anti-mutagenic, anti-diabetic, anti-obesity, anti-inflammatory and anti-neoplastic actions. In every cancer tested, modulatory actions of fucoxanthinol on viability, cell-cycle arrest, apoptosis and members of the NF-κB pathway were more pronounced than that of fucoxanthin. Anti-proliferative and cancer preventing influences of fucoxanthin and fucoxanthinol are mediated through different signalling pathways, including the caspases, Bcl-2 proteins, MAPK, PI3K/Akt, JAK/STAT, AP-1, GADD45, and several other molecules that are involved in cell cycle arrest, apoptosis, anti-angiogenesis or inhibition of metastasis. In this review, we address the mechanisms of action of fucoxanthin and fucoxanthinol according to different types of cancers. Current findings suggest that these compounds could be effective for treatment and/or prevention of cancer development and aggressiveness.     

Modelling human impacts on the Tasmanian wedge-tailed eagle (Aquila audax fleayi)

The wedge-tailed eagle is Australia’s largest bird of prey and one of the largest eagles in the world. Aquila audax fleayi is an endemic Tasmanian subspecies isolated for 10,000 years from the nominate subspecies on the Australian mainland. The Tasmanian wedge-tailed eagle is classified nationally and at a State level as endangered due to its small number of breeding pairs, low breeding success and high rate of mortality from unnatural causes. The subspecies experiences mortality throughout its range from shooting, poisoning, trapping, road accidents, electrocutions and collisions with wind turbines, aircraft, fences and overhead wires, which we term ‘un-natural mortality’. A portion of the subspecies’ range is managed for timber production, which can lead to disturbance of nest sites and the loss of nest trees. We use a model of the eagle population from the Bass District in northeast Tasmania to explore the relative importance of different sources of mortality and nesting habitat loss, and the potential for mitigating impacts associated with unnatural mortality, disturbance, nesting habitat loss and human access to forests. We create a habitat map including suitable nest sites and link it to a dynamic landscape population model based on life history traits and disturbance responses. Using the program RAMAS-Landscape, we model alternative forest management scenarios, ranging from no timber harvesting and a natural wildfire regime, to scenarios prescribing native forest harvesting and regeneration and different levels of conversion of native forest to plantation under the same natural wildfire regime. The results indicate that the Tasmanian wedge-tailed eagle is sensitive to unnatural mortality, plantation establishment and native forest harvesting. The predicted decline over the next 160 years (65%) will most likely be driven largely by loss of current and potential future nest sites associated with harvesting activities, exacerbated by unnatural mortality in the wider landscape. Interventions that minimise unnatural mortality, reduce nest disturbance, and retain breeding habitat and nest sites may improve the prospects for the subspecies in the Bass District. If nest disturbance and unnatural mortality continue at the rates modelled here, the species appears to face a high risk of declining substantially in the region.