玉米花粉电动采集器的研制

研制的玉米花粉电动采集器由变压器、整流滤波电路、轴流风机、蓄电池与采粉器组合而成。玉米花粉电动采集器是利用轴流风机高速旋转产生负压从而加速了玉米花粉飘落与收集。电动采集器每充电一次 ,可连续使用 8h,在相同时间内采集花粉的数量比手工作业高 3倍。     

室内条件下离体玉米花粉生活力保持时间的研究

通过用室内水培法采集花粉并在室内条件下保存一定时间，尔后用于田间授粉的方法，研究了花粉在室内条件下生活力保持时间。结果表明，豫北地区室内条件下，离体花粉生活力可保持全天不明显降低，即上午8点散落的花粉在下午6点30分仍具有正常授粉能力。     

Origin of the sudbury complex by meteoritic impact: neodymium isotopic evidence

Samarium-neodymium isotopic data on whole rocks and minerals of the Sudbury Complex in Canada gave an igneous crystallization age of 1840 +/- 21 x 10(6) years. The initial epsilon neodymium values for 15 whole rocks are similar to those for average upper continental crust, falling on the crustal trend of neodymium isotopic evolution as defined by shales. The rare earth element concentration patterns of Sudbury rocks are also similar to upper crustal averages. These data suggest that the Sudbury Complex formed from melts generated in the upper crust and are consistent with a meteoritic impact.     

Geotropism in corn roots: evidence for its mediation by differential Acid efflux

The elongation zone in intact growing corn roots secretes acid leading to a reduced pH along the surface of the root and in the adjacent medium. This can be detected by placing the root on an agar medium containing the pH indicator dye bromocresol purple. When the root is treated with a growth inhibitory concentration of the hormone indole-3-acetic acid, the acid efflux is reversed and growth is greatly retarded. When the root is mounted vertically, acid secretion is uniform along the elongation zone, and the root grows straight downward. When the root is placed horizontally, there is enhanced acid efflux along the upper surface of the elongation zone and reduced acid efflux along the lower surface. An increased rate of elongation of the upper cells relative to the lower cells then results in downward curvature of the root. The correlation between acid efflux patterns and growth patterns indicates that proton efflux is important in the control of root growth.     

Winteraceous pollen in the lower cretaceous of Israel: early evidence of a magnolialean angiosperm family

Pollen of the primitive angiosperm family Winteraceae has been discovered in the Aptian-Albian of Israel, extending the fossil record of this phylogenetically important family of flowering plants from the uppermost Upper Cretaceous back some 40 million years to the upper Lower Cretaceous. This appears to represent the earliest known record of a magnolialean angiosperm family and is convincing evidence for the existence in the Early Cretaceous of an extant family of angiosperms.     

利用滑石粉作为甜玉米花粉增量剂的贮藏 技术分析及应用

[目的]利用滑石粉作为增量剂稀释甜玉米花粉,对比离体花粉在不同稀释比例、不同温度和不同贮藏时间条件下的储藏效果,为提高玉米育种和制种产量及降低减产风险提供参考依据.[方法]以金卡HM608甜玉米的父本花粉为试验材料,用滑石粉作为玉米花粉的增量剂,共设3个(按质量分数)增量剂填充处理(10%、30%、100%),4个时间处理(1、3、5和7 d),5个温度处理(-5、5、10、15和25℃),以不添加增量剂的花粉作为对照,结合田间测定法及氯化三苯基四氮唑(2,3,5-triphenyltetrazolium chloride,TTC)染色法,探讨在不同增量剂比例、不同处理温度及处理时间下离体甜玉米花粉的TIC染色率和田间结实率.[结果]当处理温度为-5、5和10℃时,贮藏1 d的花粉田间结实率在82.26%以上;贮藏5 d后,无增量剂花粉的T TC染色率及田间结实率显著下降,平均为25.24%和13.68%;添加10%和30%增量剂的花粉,贮藏5 d仍然有61.22%以上的田间结实率;当增量剂比例在100%且贮藏为5 d时,田间平均结实率为7.19%,当处理温度为15和25℃时,田间结实率为0,反映出增量剂比例和温度过高均不利于花粉的保存,增量剂越多或持续时间越长对花粉活力伤害越大.不同增量剂填充处理的花粉活性及田间结实率均随着处理温度上升和贮藏时间延长而降低.[结论]保存温度在-5~10℃,添加10%和30%滑石粉作为甜玉米花粉增量剂能有效延长花粉生活力,该贮藏技术操作简单易行,对于指导授粉工作、减少制种风险、提高制种产量具有现实意义.     

Origin of whales in epicontinental remnant seas: new evidence from the early eocene of pakistan

Pakicetus inachus from the early Eocene of Pakistan is the oldest and most primitive cetacean known. The dentition of Pakicetus resembles that of carnivorous mesonychid land mammals as well as middle Eocene cetaceans. The otic region of the cranium lacks characteristic specializations of whales necessary for efficient directional hearing under water. Pakicetus occurs with a land-mammal fauna in fluvial sediments bordering epicontinental Eocene remnants of the eastern Tethys seaway. Discovery of Pakicetus strengthens earlier inferences that whales originated from terrestrial carnivorous mammals and suggests that whales made a gradual transition from land to sea in the early Eocene, spending progressively more time feeding on planktivorous fishes in shallow, highly productive seas and embayments associated with tectonic closure of eastern Tethys.     

Fig wasps: mechanism of pollen transfer

The fig (Ficus) is absolutely dependent upon pollination by minute agaonid wasps for development of fertile seeds. In some species of the wasp genera Agaon, Allotriozoon, Blastophaga, Ceratosolen, Elisabethiella, Liporrhopalum, and Pleistodontes, the females possess concavities ("corbiculae") to carry pollen. The New World Tetrapus and some Old World Blastophaga lack pollen-carrying structures and may carry pollen dusted over the body or in the digestive tract.     

防治软腐病的魔芋内生细菌的筛选与鉴定

目的了解魔芋被软腐病侵染后内源激素含量的变化。方法采用高效液相色谱法(HPLC)测定换头期前、后中抗软腐病魔芋品种安魔128的内源激素[ 生长素(IAA)、水杨酸(SA)、茉莉酸(JA)、赤霉素(GA₃)和脱落酸(ABA) ]含量变化,并整合RNA-seq测序数据分析激素通路相关基因的表达差异。结果软腐病侵染造成魔芋体内多种内源激素水平发生变化,其中IAA、SA和ABA的含量随着软腐菌侵染而呈先增后减的变化趋势,换头期后其含量虽有所下降,但依然比对照含量高;JA含量随着软腐菌侵染而逐渐增加;GA₃含量虽呈先增后减的变化趋势,但最终含量低于对照。激素通路相关的10个基因的RT-qPCR表达水平验证结果与激素含量变化一致。结论侵染初期激素含量呈增加趋势,表明病原菌入侵激活了激素通路相关基因的表达,但随后其含量下降,推测是由于随着软腐病程度的加深,部分抗性通道被关闭。本研究为解析软腐病侵染致病机制提供了理论基础。     

花粉萌发与花粉管生长的信号调控机制

花粉萌发与花粉管生长是植物生殖过程中的重要生理现象,它关系到植物能否正常完成受精过程.该过程涉及大量的信号通路介导,包括小G蛋白调控、磷酸肌醇信号调控及Ca2+信号通路等.这些信号通路直接或间接影响着花粉萌发与生长过程的各个方面,包括花粉管的极性生长及细胞骨架变化等.综述了不同信号通路对花粉萌发与生长过程的影响,重点关注各个信号分子的作用基础和原理,旨在更深入地展现花粉萌发全过程中信号通路调控下的胞内全景,结合现有试验结果,提供关于花粉萌发与生长的新模式.     

玉米及玉米加工品中的真菌毒素

真菌毒素(Mycotoxin)是由真菌产生的一类次生代谢产物。人畜误食带有毒素的粮食或饲料，就会发生中毒现象或称为真菌中毒症(Mycotoxicoses)。介绍了美国玉米及玉米加工品中常见的黄曲霉毒素(Aflatoxin)和两种镰刀菌毒素(Fusarium toxins)：玉米赤霉烯酮(Zearalenone)及单端孢霉烯族化合物(Tnchothecenes)。重点概述了黄曲霉毒素和镰刀菌毒素在玉米原粮及玉米加工品的不同组分中的分布情况；讨论了真菌毒素的检测和化学分析方法。     

Apatite: Origin of Blue Color

The optical absorption and emission spectra of natural blue apatite are similar enough to spectra of synthetic compounds containing MnO(4)(-3) to conclude that the blue color of natural apatite results from the presence of this ion.     

牛角瓜花粉萌发及花粉管生长研究

运用方差分析、多重比较、正交实验和极差分析方法,对牛角瓜花粉的萌发和花粉管生长进行研究,结果表明,培养基内硼酸、硝酸钙、蔗糖、硫酸镁在一定浓度范围内,对花粉萌发及花粉管生长起促进作用,但浓度过高或过低时,则有抑制作用;钾对花粉萌发及花粉管生长影响不显著;蔗糖和硝酸钙对牛角瓜花粉萌发有显著影响,蔗糖和硫酸镁对牛角瓜花粉管生长有显著影响;牛角瓜最适花粉液体培养基为:15%蔗糖+350mg/L Ca(NO_3)2·4H_2O+60 mg/L H_3BO_3+150 mg/L MgSO_4·7H_2O;在30~35℃温度条件下,牛角瓜花粉块萌发和花粉管生长最好。     

Evolution of pollen morphology

Over evolutionary time, the morphology of angiosperm pollen has evolved toward an increasing number of apertures, among other things. From a neo-Darwinian point of view, this means that (i) some polymorphism for aperture number must exist and (ii) there must be some fitness increase associated with increasing the aperture number. Pollen types with different aperture numbers often occur in the same species. Such is the case in Viola diversifolia. Comparison of pollen with three and four apertures in this species showed that four-apertured grains germinated faster than three-apertured ones but that the four-apertured ones experienced other disadvantages. These results obtained on the gametophyte can be interpreted in terms of strategies of the sporophyte.     

砂梨种质资源花粉量及花粉萌发率的遗传多样性分析

为明确砂梨种质资源花粉的遗传多样性,离体条件下对455份砂梨种质资源的花粉量及花粉萌发率进行检测和分析。结果表明:砂梨不同种质资源的花粉量和花粉萌发率有较大差异,单个花药花粉量变幅为0~41 875粒,花粉萌发率变幅为0~96.11%。砂梨花粉特性的平均变异系数为66.37,平均遗传多样性指数为1.95。不同砂梨种质资源的平均变异系数为国内选育品种(67.12)地方品种(64.58)国外引进(61.08),平均遗传多样性指数为地方品种(1.95)国内选育品种(1.89)国外引进品种(1.81)。不同省(区)地方品种的平均变异系数变幅为53.51~95.90,以广西壮族自治区较高,福建省最低;平均遗传多样性指数在1.55~1.88之间,以湖北省较高,江西省最低。