小麦花粉培养中蔗糖浓度外源激素对启动细胞分裂的作用

以4个小麦品种为材料，对培养基中的蔗糖浓度、外源激素等对离体花粉中小孢子细胞分裂启动的诱导效果进行了研究．结果发现3％的蔗糖浓度适用于小麦花粉培养，而较高蔗糖浓度（9％）不利于花粉培养；蔗糖浓度高于9％时则不能启动花粉粒的脱分化及雄核发育．实验表明，外源激素的存在是花粉脱分化并进入雄核发育的必要条件，2，4－D在诱导花粉粒转向孢子体发育的过程中起主要作用．     

光周期条件对罗氏沼虾幼体存活率及体长生长率的影响

用４Ｌ：２０Ｄ、８Ｌ；１６Ｄ；１２Ｌ；１２Ｄ和２４Ｌ：０Ｄ四种光周期条件培养罗氏沼虾骚状幼体，观察其存活率和生长、发育情况。研究结果表明，随着光照时间的延长，特别是在连续照明的条件下，与最短的光照条件相比，幼体的存活率及体长生长率分别提高１５７．７％和２．２％ｄ，而育成Ｐ１的时间却相应缩短了１０ｄ。     

胡萝卜愈伤组织的诱导及细胞悬浮培养研究

分别以胡萝卜子叶、下胚轴和直根形成层为外植体诱导出愈伤组织,并建立细胞悬浮系.实验结果表明:胡萝卜下胚轴是诱导愈伤组织和进行细胞悬浮培养的理想外植体;诱导松散型愈伤组织的最佳激素浓度配比是1.0mg/L2,4 D+0.5mg/LKT;细胞悬浮培养细胞最佳起始密度为1.125×104个/mL～2.325×104个/50mL时,7d～9d为对数生长期;继代培养4代～5代时,可得到稳定的悬浮细胞系.     

MOMENT-METHOD ESTIMATION BASED ON CENSORED SAMPLE

In reliability theory and survival analysis, the problem of point estimation based on the censored sample has been discussed in many literatures. However, most of them are focused on MLE, BLUE etc; little work has been done on the moment-method estimation in censoring case. To make the method of moment estimation systematic and unifiable, in this paper, the moment-method estimators(abbr. MEs) and modified momentmethod estimators(abbr. MMEs) of the parameters based on type Ⅰ and type Ⅱ censored samples are put forward involving mean residual lifetime. The strong consistency and other properties are proved. To be worth mentioning, in the exponential distribution,the proposed moment-method estimators are exactly MLEs. By a simulation study, in the view point of bias and mean square of error, we show that the MEs and MMEs are better than MLEs and the “pseudo complete sample” technique introduced in Whitten et al.(1988). And the superiority of the MEs is especially conspicuous, when the sample is heavily censored.     

Not every drought is bad: quantifying reproductive effort in the harlequin frog Atelopus laetissimus (Anura: Bufonidae)

Atelopus laetissimus is an endemic and threatened harlequin frog from the high mountain forests of Sierra Nevada de Santa Marta, Colombia. Knowledge of its reproductive biology is essential for understanding the intraspecific interactions that can help the conservation of Atelopus species. We quantified the energy, measured in body weight, invested by males and females of A. laetissimus for reproduction, and how this energetic investment is related to the survival of individuals and rainfall conditions in habitats during two years (2014 and 2015). Our results show plasticity in terms of reproductive phenology linked to rainfall with short- and long-duration breeding strategies. The first year of this study, 2014, had a precipitation level in accordance with the annual averages at the area. During this time frogs exhibit a short breeding period. Contrary to 2014, 2015 was a year with little precipitation, below the annual averages, which probably facilitated the females’ quick spawning in the creeks and a consequent reduction in the duration of amplexus and low breeding efforts by males. This, in turn, was related to a long breeding period that favors the survival and reproduction of males during the entire year. In 2014 we found a decrease of 25% to 30% body weight of potentially reproductive males, which may be attributed to a prolonged duration of amplectant events.     

Haversian bone-mimicking bioceramic scaffolds enhancing MSC-macrophage osteo-imunomodulation

The interaction between immune cells and bone forming cells plays a vital role in maintaining the homeostasis of the skeletal system, and is regulated by the three-dimensional structure of tissues. Whether the construction of biomaterials can activate or reproduce this spatial “cross-talk” between immune cells and bone forming cells in bone natural formation process is a prerequisite for successful fracture healing and bone regeneration. Herein, a bone marrow mesenchymal stem cells (MSCs)/macrophages-laden Haversian bone-mimicking bioceramic scaffold was successfully prepared through the biomimetic design of biomaterials and 3D printing technology. MSCs and macrophages were respectively distributed in the cancellous bone and Haversian canals of the scaffold to simulate the three-dimensional structure regulation of the cell spatial distribution and multiple intercellular interaction in natural bone tissue, and worked in concert to modulate the scaffold material-mediated osteo-immune microenvironment. The in vitro study revealed that the pro-inflammatory response of macrophages was more significantly inhibited when distributed with MSCs in the scaffolds at a cell ratio of 0.5:1 for co-culture, in comparison with multicellular culture at other ratios and unicellular culture. Meanwhile, MSCs exhibited the relatively high osteogenic potential, most likely via the activation of certain key signaling pathways mediated by macrophages-derived paracrine signaling mediators (OSM, BMP-2, and WNT10b). This work not only establishes a bionic platform for the regulation of multicellular osteo-immune response and regeneration but also offers a promising tissue-engineered biomimetic scaffold with improved immunomodulatory function for promoting bone tissue regeneration.     

稻纵卷叶螟人工饲料的研究

 以稻纵卷叶螟为研究对象,按不同配方配制了6种人工饲料分别用来饲养稻纵卷叶螟,以筛选出适合饲养稻纵卷叶螟的人工饲料。结果表明,在温度为24~26 ℃,相对湿度大于80%,光照条件大于14 h的条件下,其中饲料D、E、F饲养稻纵卷叶螟二龄幼虫只能完成二龄发育,少数幼虫存活到三龄或三龄以上;饲料C饲养稻纵卷叶螟二龄幼虫也只能完成三龄发育;而饲料A和B饲养的稻纵卷叶螟二龄幼虫能完成整个世代发育,存活率分别为26.17%和36.40%,接近对照组新鲜水稻叶饲养的存活率36.67%,且蛹质量和新鲜水稻叶饲养的幼虫没有显著差异,但与对照相比,幼虫历期延长4~6 d、化蛹率下降8%~9%、羽化率下降11%~12%。     

饲料中添加虾青素对斑节对虾生长和免疫指标的影响

 虾青素以不同质量分数(0,10,20,40,80,160 mg·kg^-1)添加到斑节对虾 Penaeus monodon 的饲料中投喂30 d,研究虾青素对斑节对虾［初始体质量（1.32±0.03 ）g］生长、存活和免疫指标的影响。结果显示：虾青素可提高斑节对虾的存活率,但无明显规律性;而增质量率和特定生长率,实验组和对照组间差异显著(P<0.05);就终末均质量而言,实验组与对照组差异显著(P<0.05),但实验组之间无显著差异(P>0.05);虾青素可提高斑节对虾酚氧化酶（PO）的活力,除10 mg·kg^-1和20 mg·kg^-1 组外,其余实验组与对照组差异显著(p<0.05),但对碱性磷酸酶(ALP)、过氧化物酶(POD)、超氧化物岐化酶(SOD)的活力无显著影响。以增重率、特定生长率和酚氧化酶（PO）活力为参考指标,虾青素适宜添加量为40～80 mg·kg^-1。     

抗松针褐斑病湿地松组培苗生根条件的优化

以抗松针褐斑病湿地松组培苗为研究材料,对影响组培苗不定根发生的条件进行优化。结果表明:在含4.0 mg/L IBA和0.07 mg/L NAA的WPM培养基中添加0.4 mg/L多效唑对湿地松组培苗不定根的形成和再生植株的成活率有促进作用;湿地松组培苗不定根原基形成后,出瓶移至装有蛭石的穴盘中,有利于不定根的表达,且根茎连接非常好,植株成活率高达85%;基因型对苗的成活率有决定性的影响,不同家系及同一家系不同无性系间移栽成活率差异较大。     

论仿拟在新闻语体中的生存机制

当今的新闻传播中,仿拟辞格的应用频率极高。通过对仿拟辞格的特点和新闻传播过程特点的考察发现:仿拟作为一种修辞行为,其造词和修辞的两大功能恰好满足了新闻传播时效性和可读性的两大需求;满足了从传播者的编码到接受者的解码这一认知过程中的各种心理需求。正是以上两方面的因素,构成了仿拟辞格在新闻语体中重要的生存机制。