水曲柳DNA浓度及滴加时间对杨树花粉管通道法结实率的影响

[目的]对适宜的水曲柳DNA浓度及滴加时间进行初步探索,获得具有水曲柳优势性状的杨树植株。[方法]通过花粉管通道法,将携带水曲柳基因组的DNA导入杨树。人工授粉后一定时间在花柱基部进行横切,把不同浓度DNA溶液滴加到子房切口端,10 d后统计结实率。[结果]在同一时间点,随着水曲柳DNA浓度的增加,结实率呈现逐渐降低趋势;随着授粉与滴加DNA时间的延长,同一浓度下呈现出结实率先降低后升高趋势。当水曲柳DNA溶液滴加时间控制在人工授粉后6 h左右,DNA浓度为50μg/ml时是在杨树上运用花粉管通道法转化水曲柳基因最适宜的条件,结实率可达17%。[结论]滴加时间与外源DNA不同梯度水平对转化结实率有很大影响。     

核桃不同品种花粉生活力及其贮藏条件研究

[目的]测定核桃不同品种花粉的生活力,并研究其贮藏条件。[方法]采用固体培养基和液体培养基测定维纳、元丰、香玲、丰辉和当地核桃5个品种的花粉生活力,并对贮藏条件进行考察。[结果]固体培养基测定的花粉生活力普遍高于液体培养基0.98%~2.51%。5个品种均在2.5%蔗糖溶液中萌发率高;花粉最适宜的贮藏条件为-20℃、遮光。核桃不同品种的花粉生活力存在显著差异(P0.05);在同一培养基上,维纳花粉生活力最高为12.3%,其次是丰辉、元丰、香玲,当地核桃最低为3.9%。[结论]花粉生活力的测定以固体培养基较适合。同一培养基上,维纳花粉生活力最高。     

万载龙牙百合花粉生活力测定及贮藏方法研究

[目的]筛选出适宜龙牙百合花粉生活力的测定及贮藏的方法.[方法]试验采用醋酸洋红等4种常用的花粉活力测定方法,对龙牙百合花粉生活力进行测定;同时对保持花粉生活力的贮藏方法进行研究.[结果]试验表明,以醋酸洋红法测定龙牙百合花粉生活力效果最好,能较清晰地观察到花粉染色状况;在所研究的11种花粉贮藏方法中,-20℃干燥法和-67℃干燥1～3h均较有利于保持百合花粉活力.[结论]研究可为龙牙百合花粉生活力的测定及花粉贮藏育种提供实用可行的方法.     

3种核桃花粉生活力的比较研究

花粉具有生命力是确保核桃(Juglans regia L.)杂交育种成功的重要条件之一。然而,不同品种的核桃雄花序开花时间不同,而且大多会比雌花蕊需要授粉的时间要早一些。由于花期不同,用不同的花粉进行授粉有时需要保存雄花粉。为了明确不同核桃品种花粉保存的时间及保存方法,选用了西林3号、西洛3号和香玲3个核桃品种的花粉进行试验,把它们分别放在室温和4℃冰箱冷藏,用MTT染色法测定其活力随时间的变化情况。结果表明,不同核桃品种花粉生活力存在差异;放在冰箱里的核桃花粉的生活力保存时间较长,可以达到10 d左右,而放在室温下的只能保存6 d左右。     

中华槭花粉活力探究

以中华槭为研究对象,研究了中华槭花粉离体培养萌发最佳测定时间,中华槭花粉活力快速测定的方法,蔗糖、硼酸、氯化钙浓度以及不同贮藏温度(室温、4℃、-20℃)对中华槭花粉活力的影响。试验结果表明:中华槭花粉离体培养16h后,再进行其花粉活力的测定较为适宜;用离体培养萌发法测定的花粉活力,最接近于中华槭花粉的真实活力。适于中华槭花粉萌发的蔗糖、硼酸、氯化钙浓度分别为:100g/L、50mg/L、50mg/L。中华槭花粉在4℃下可以存活60d,在-20℃下可以保存120d,在室温下仅可以存活7d。     

不同品种蓖麻花粉生活力特性的研究

以中北3号、金长城5号、汾蓖1号、秀蓖1号四个蓖麻品种为材料,研究蓖麻花粉萌发能力与温度、贮藏湿度及采集时间的相关性,结果表明：最适宜蓖麻花粉萌发的温度为30～35℃,花粉萌发率达到75.12％～80.24％;一天中蓖麻花粉萌发能力最强的时间为8：00～14：00时,花粉萌发率达到81.35％～90.18％;蓖麻花粉收集、贮藏的最适温度为45％～55％,花粉萌发率在84.03％～88.01％.     

Are Primary Cultures of Trout (<Emphasis Type="Italic">Oncorhynchus mykiss</Emphasis>) Ventricular Cardiomyocytes Metabolically Viable?

The objectives of this study were to establish a protocol for the isolation of metabolically viable ventricular cardiomyocytes from the rainbow trout and to determine which measures may best reflect viability 24 h after isolation. Cardiomyocytes were isolated by enzymatic digestion and maintained in cell suspension. Viability was assessed using Trypan blue dye exclusion, ATP content, oxygen consumption and lactate dehydrogenase (LDH) leakage into the medium. Viability, assessed by these measures did not significantly change over the time period of this study. ATP content did correlate significantly with oxygen consumption but not with Trypan blue exclusion. We conclude that primary cultured cardiomyocytes remain metabolically viable for at least 24 h after isolation. Also, it appears that ATP content and oxygen consumption most adequately reflect metabolic cell viability. To be confident with a culture, however, a combination of viability measures is necessary when isolating cardiomyocytes from fish.     

刺梨花粉管萌发的荧光显微观察

花粉管作为连接柱头与胚囊的唯一结构,是外源DNA导入的通道。因此,必须首先形成花粉管通道,才能进行外源DNA的导入。本研究利用醋酸洋红染色对刺梨雌蕊、雄蕊进行显微观察,并在人工授粉后的0．5h、1h、3h、6h、10h、12h、14h、16h、18h、20h、24h和30h不同时期取其雌蕊,用苯胺蓝染色后进行荧光显微观察。研究结果初步探明了刺梨人工授粉的最佳时期在花蕾露红期;其花粉管通道从人工授粉后10h左右开始萌发,到18h左右完成萌发,花粉管萌发完成后的2～9h是利用花粉管通道法介导刺梨遗传转化的最佳时期。本研究结果将为花粉管通道法介导刺梨遗传转化技术体系的建立提供基础资料。     

Triage for conserving populations of threatened species: The case of woodland caribou in Alberta

Prioritization of conservation efforts for threatened and endangered species has tended to focus on factors measuring the risk of extirpation rather than the probability of success and cost. Approaches such as triage are advisable when three main conditions are present: insufficient capacity exists to adequately treat all patients, patients are in a critical state and cannot wait until additional capacity becomes available, and patients differ in their likely outcome and/or the amount of treatment they require. The objective of our study was to document the status of woodland caribou (Rangifer tarandus) herds in Alberta, Canada, with respect to these three conditions and to determine whether a triage approach might be warranted. To do this we modeled three types of recovery effort - protection, habitat restoration, and wolf control - and estimated the opportunity cost of recovery for each herd. We also assessed herds with respect to a suite of factors linked to long-term viability. We found that all but three herds will decline to critical levels (<10 animals) within approximately 30 years if current population trends continue. The opportunity cost of protecting all ranges by excluding new development, in terms of the net present value of petroleum and forestry resources, was estimated to be in excess of 100 billion dollars (assuming no substitution of activity outside of the ranges). A habitat restoration program applied to all ranges would cost several hundred million dollars, and a provincial-scale wolf control program would cost tens of millions of dollars. Recovery costs among herds varied by an order of magnitude. Herds also varied substantially in terms of their potential viability. These findings suggest that woodland caribou in Alberta meet the conditions whereby triage should be considered as an appropriate conservation strategy.     

Predicting survival, reproduction and abundance of polar bears under climate change

Polar bear (Ursus maritimus) populations are predicted to be negatively affected by climate warming, but the timeframe and manner in which change to polar bear populations will occur remains unclear. Predictions incorporating climate change effects are necessary for proactive population management, the setting of optimal harvest quotas, and conservation status decisions. Such predictions are difficult to obtain from historic data directly because past and predicted environmental conditions differ substantially. Here, we explore how models can be used to predict polar bear population responses under climate change. We suggest the development of mechanistic models aimed at predicting reproduction and survival as a function of the environment. Such models can often be developed, parameterized, and tested under current environmental conditions. Model predictions for reproduction and survival under future conditions could then be input into demographic projection models to improve abundance predictions under climate change. We illustrate the approach using two examples. First, using an individual-based dynamic energy budget model, we estimate that 3-6% of adult males in Western Hudson Bay would die of starvation before the end of a 120 day summer fasting period but 28-48% would die if climate warming increases the fasting period to 180 days. Expected changes in survival are non-linear (sigmoid) as a function of fasting period length. Second, we use an encounter rate model to predict changes in female mating probability under sea ice area declines and declines in mate-searching efficiency due to habitat fragmentation. The model predicts that mating success will decline non-linearly if searching efficiency declines faster than habitat area, and increase non-linearly otherwise. Specifically for the Lancaster Sound population, we predict that female mating success would decline from 99% to 91% if searching efficiency declined twice as fast as sea ice area, and to 72% if searching efficiency declined four times as fast as area. Sea ice is a complex and dynamic habitat that is rapidly changing. Failure to incorporate climate change effects into population projections can result in flawed conservation assessments and management decisions.