The pollination of zygogynum (winteraceae) by a moth, sabatinca (micropterigidae): an ancient association?

The primitive and vesselless angiosperm Zygogynum (Winteraceae), which is restricted to New Caledonia, is pollinated by a moth, Sabatinca (Micropterigidae). Fossil records of both the moth and the plant families extend to the Early Cretaceous. Adult Sabatinca have grinding mandibles and usually feed on the spores of ferns and on pollen. The insects use the flowers as mating sites and eat the pollen which is immersed in a dense pollenkitt. This mode of pollination in which flowers serve as mating and feeding stations with floral odors acting as cues may have been common in the early evolution of flowering plants.     

Terrestrial soft-bodied protists and other microorganisms in triassic amber

Protozoa, cyanobacteria, sheathed algae, sheathed fungi, germinating pollen or spores, and fungal spores have been found in amber 220 to 230 million years old. Many of these microorganisms can be assigned to present-day groups. This discovery of terrestrial, soft-bodied protists that can be referred to modern groups indicates that morphological evolution is very gradual in many protists and that both structural and probably functional stasis extend back at least to the Upper Triassic period.     

Haploid plants from pollen grains

A method is presented by which hundreds of haploid plants of various species of Nicotiana can be raised from pollen grains. Stamens should be excised when pollen grains have been individualized, but are still uninucleate and free of starch. When grown in vitro on a relatively simple medium, some pollen grains proliferate into embryo-liké, structures which develop in stages similar to those of zygotic embryos. The plantlets mature and flower profusely, but do not set seed.     

Maternal behavior in wolf spiders: the role of abdominal hairs

Newly emerged, juvenile wolf spiders do not settle on clothed or shaved areas of their mother's abdomen until after a period of days. Spiny, knobbed hairs, peculiar to adult female lycosids, apparently provide the stimulus and means for attachment by the inner layer of spiderlings. Innervated long, smooth hairs are mechanoreceptors which probably serve in other aspects of brood care.     

Flowers and fungi use scents to mimic each other

Some flowering plants mimic the scent and appearance of mushroom fruiting bodies. Fungi may also mimic flowers. In addition, infection of plants by certain fungi can direct the plant to develop nonfunctional floral-like structures that nonetheless primarily serve the reproductive advantage of the fungus. These various mimicries may serve to attract insects that in turn spread fungal spores or plant pollen, thus facilitating sexual reproduction of the cryptic organism.     

Palynological Investigation of a Core from the Biscay Abyssal Plain

An investigation of Quaternary, Tertiary, Mesozoic, and Paleozoic pollen and spores found in sediments of the Biscay Abyssal Plain provides data leading to the interpretation of the provenance of the lutite in which reworked plant microfossils occur. Owing to the difficulty of distinguish(Ag between Quaternary and reworked Tertiary pollen grains belonging to extant genera, caution is necessary in interpreting the pollen record in terms of Quaternary climatic changes.     

Strange floral attractors: pollinator attraction and the evolution of plant sexual systems

Individual plants of hummingbird-pollinated Besleria triflora display two flower morphs: staminate flowers, which have shortened styles and do not produce fruit, and hermaphrodite flowers. Experiments with B. triflora indicate that pollinator attraction can drive the evolution of a dimorphic plant sexual system. In field-manipulated plants, visitation increased at large floral displays; however, pollen receipt increased only when staminate flowers were used to enlarge the display. Laboratory experiments showed that staminate flowers do not remove pollen from visiting pollinators, effectively concentrating outcross pollen onto stigmas of fertile flowers. A dimorphic sexual system is favored because the morphology of staminate flowers enhances their role in pollinator attraction.     

小麦未熟胚离体培养的研究──再生植株后代花粉粒育性观察

试验以ＩＥ８５１５－２８（７７（２）春品种的胚培后代）１４个早熟株系的ＩＥ５代植株为材料，观察植株后代花粉粒育性．结果表明．小麦未熟胚离体培养后所产生的后代，结实均表现正常，但在成熟花粉粒育性观察中发现空瘪、小型以及多萌发孔等畸形花粉粒．而且不同株系各种异常花粉粒所占比例不同．说明胚培无性系后代遗传基础受到深刻影响，包括小孢子形成和发育的全过程．     

Disruption of the terrestrial plant ecosystem at the cretaceous-tertiary boundary, Western interior

The palynologically defined Cretaceous-Tertiary boundary in the western interior of North America occurs at the top of an iridium-rich clay layer. The boundary is characterized by the abrupt disappearance of certain pollen species, immediately followed by a pronounced, geologically brief change in the ratio of fern spores to angiosperm pollen. The occurrence of these changes at two widely separated sites implies continentwide disruption of the terrestrial ecosystem, probably caused by a major catastrophic event at the end of the period.     

深州蜜桃黑斑病（Alternaria alternata）的研究Ⅱ．侵染规律和发病诱因

桃树健康和枯死组织普遍带有链格孢，枯死组织带菌率更高。病菌侵染果实主要在盛花期至盛花后约４０ｄ这段时期，侵染高峰在花萎期（４月下旬）。空中孢子捕捉试验证明，当气温稳定在２０℃以上时（５月中旬以后），雨后空中孢子迅速增长，此期空中孢子量与侵染高峰有密切关系。密植树、幼树发病较轻、树下部发病较轻，６月中旬以后套袋对黑斑病发病率无明显影响。     

低能Ar+注入对玉米花粉萌发及Ca2+浓度分布的影响

To investigate the effect of low energy ion implantation on maize pollen germination and cytosolic Ca2+ distribution during pollen germination process, the argon ion (Ar+) with energy of 30 keV, dose of 0.78 ×1015-13×1015 ion/cm2 was implanted into maize pollen by irradiation, and the germination of pollen and cytosolic Ca2+ distribution during pollen germination process of the Ar+ implanted pollen were studied. The results showed that when been irradiated with Ar+ with dose of 5.2×1015 ion/cm2, the germination rate of maize pollen increased remarkably, while implantation of ions with dose exceeding 5.2×1015 ion/cm2 sharply decreased the germination rate of maize pollen. Meanwhile, tracing of esterified Ca2+ fluorescence probe fluo-3 AM for intact pollen showed that variation of cytosolic Ca2+ concentration was consistent with the change of pollen fertility. The dynamics of cytosolic Ca2+ concentration caused by low energy ion implantation may be concluded as the initial effects of pollen germination.     

禾长蠕孢菌孢子及粗毒素对稗草防御酶系活性的影响

[目的]探讨禾长蠕孢菌(HGE)孢子及其代谢产物粗毒素对稗草主要防御酶系活性的影响。[方法]在室内条件下测定了HGE孢子及其粗毒素对稗草防御酶系[苯丙氨酸解氨酸(PAL)、过氧化物酶(POD)、超氧化物歧化酶(SOD)]活性的影响。[结果]HGE孢子、粗毒素及二者混合处理稗草后,不同程度地影响了稗草PAL、POD的活性,对SOD活性无明显影响,并且孢子和毒素对稗草防御酶系的影响具有相似性。[结论]病原真菌孢子和毒素对寄主的作用具有一定的相似性,基于病原菌致病过程的复杂性,毒素可以替代病原菌研究其部分致病性作用机理。     

Evidence for a pollination-drop mechanism in paleozoic pteridosperms

A noncellular substance containing pollen and spores has been discovered protruding from the micropyle of a seed fern ovule of Middle Pennsylvanian age. This provides direct evidence that pollination-drop mechanisms comparable to those of many extant gymnosperms characterize some Paleozoic pteridosperms.     

Palynological and iridium anomalies at cretaceous-tertiary boundary, South-central Saskatchewan

The Cretaceous-Tertiary boundary in south-central Saskatchewan is marked by coincident anomalies in abundance of iridium and fern spores at the extinction level of a suite of Cretaceous pollen taxa. Evidence of disruption of the terrestrial flora includes the fern-spore abundance anomaly and local extinction of as much as 30 percent of angiosperm species. The reorganized earliest Tertiary flora is made up largely of surviving species that assumed new roles of dominance. Persistence of climatically sensitive taxa across the boundary indicates that if paleoclimate was altered by the terminal Cretaceous event, it returned quickly to the pre-event condition.     

牡山羊草细胞质雄性不育小麦败育的生物学特性和细胞学研究

为明确牡山羊草细胞质雄性不育小麦的染色体组成及雄性败育特点,采用分子标记技术和酸性聚丙烯酰胺凝胶电泳技术对牡山羊草细胞质雄性不育小麦是否含有1BL/1RS易位染色体进行了鉴定。另外,为揭示牡山羊草细胞质雄性不育小麦败育发生的时期和败育的细胞学机理,以牡山羊草细胞质雄性不育小麦(Ju87B1-706A)和其同型保持系(706B)为供试材料,采用I2-K染色、醋酸洋红染色、DAPI染色和石蜡切片法对其花药形态特征及小孢子形成和发育过程进行细胞学观察。结果表明:Ju87B1-706A具有黑麦1RS的特异扩增条带(1 500bp),但缺少1BS的特异扩增条带(220bp),与其在A-PAGE结果的ω区与黑麦特异蛋白谱带的结果相对应,从而说明牡山羊草细胞质雄性不育小麦Ju87B1-706A为1BL/1RS雄性不育小麦类型;I2-K染色说明Ju87B1-706A的败育类型为典败和染败;Ju87B1-706A能正常进行减数分裂形成小孢子,到单核晚期时能形成正常的核但细胞皱缩,二核期细胞形态不规则能形成正常的精核但有些营养核不清晰,三核期精核呈圆形不能形成梭形的精核并发生部分空胞化;其单核晚期花药中绒毡层的延迟解离以及二核期三核期细胞团侵入药室造成小孢子败育,从而推测单核晚期是其雄性不育发生的关键时期,可能与绒毡层异常有关。     

四种抗微管物质诱导毛新杨2n花粉粒的研究

该文揭示了 4种抗微管物质 ,秋水仙碱、戊炔草胺、安磺灵和氟乐灵都有能力诱导毛新杨 2n花粉 .秋水仙碱虽然诱导 2n花粉比率最高 ,但花粉量最少 .另外 3种除草剂 ,诱导 2n花粉效率比用秋水仙碱处理的结果要低 ,但花粉量较大 ,其中 ,用戊炔草胺处理效果最好 .其最佳处理为注射花芽 4次 ,药品浓度 2 0 0 μmol L ,这不仅能使 2n花粉比率达到 84 4 % ,花粉量达到 0 .70mg 序 ,而且注射处理 10个花芽的费用仅为 0 .0 84元 ,远远低于用秋水仙碱处理同样数量花芽的花费 .该文证明了在所采用的这 4种抗微管物质中 ,戊炔草胺是诱导杨树花粉染色体加倍效果最好的药剂     

Bacterial spores: chemical sensitization to heat

Spore heat resistance is largely an inducible property, chemically reversible between a sensitive and resistant state. Therefore, the constitutive assumption and common practices based on it, such as direct testing of spores for heat resistance without prior treatment and the assumption of logarithmic death for spores in general, are no longer appropriate. A new approach is reported to the reduction of heating severity for a given survivor reduction of bacterial spores suspended in complex biological mixtures at their ordinary pH. Heating time advantages amount to severalfold and do not involve antimicrobial additives.     

小豆花粉生活力的初步观察

作者将大纳言、JN0 0 1、JN5、B 1、NL3、B 47等 6个材料新鲜的小豆花粉置于不同温湿环境条件下进行保存 ,利用花粉离体培养技术在显微镜下观察花粉萌发能力 ,以花粉萌发率作为小豆花粉生活力测定的指标 ,从而评价小豆花粉生活力。结果表明 :(1)检测小豆花粉萌发的最佳培养液配方为 0 0 12 0 %硼酸 +2 5%蔗糖 ,最佳处理时间是 1～ 1 5h ;(2 ) 1d中不同时段相同形态的花蕾的花粉萌发率相差不大 ,但花粉萌发率的最高值均出现在 8:0 0～ 10 :0 0 ;(3 )湿度是影响小豆花粉萌发的主要因素 ,低温干燥条件下可以延长花粉的生活力 ,干燥器中取出的花朵吸湿 3 0min后其花粉萌发率会提高。     

西葫芦雄蕊与雄配子体发育的研究

西葫芦（ＣｕｃｕｒｂｉｔａｐｅｐｏＬ．）雄蕊５枚，由（２）＋（２）＋１的三体组成，花丝粗短，各花药具２个花粉囊，呈Ｓ形弯曲。横切面观察，有３０个花粉囊分布其表面。药隔发达；造孢细胞分裂仅２～３次，小孢子母细胞减数分裂基本同步，四分体时胼胝质壁发达。为四面体型排列，胞质分裂为同时型，小孢子大而明显；雄配子体球形，外壁厚具刺，萌发孔多个，具盖状结构，属于２－细胞型。     

珙桐花粉离体萌发及花粉管生长研究

[目的]揭示珙桐濒危的原因和机制,为珙桐花粉保存和杂交育种工作及保护提供参考。[方法]运用方差分析、多重比较等方法对珙桐花粉的萌发和花粉管生长进行了研究。[结果]研究得出,培养基内蔗糖、硼酸、琼脂在一定浓度范围内,对花粉萌发及花粉管生长起促进作用,但超过一定浓度时则起抑制作用;吲哚乙酸对花粉萌发及花粉管生长影响不显著。温度20~25℃时,珙桐花粉萌发和花粉管生长最好;同时,花粉萌发也要求合适的湿度条件,湿度太低花粉萌发率低,湿度太大花粉管易吸水破裂。[结论]珙桐花粉萌发和花粉管的生长因培养基组分和培养条件的的改变而不同,其花粉萌发和花粉管生长不仅需要一个适宜的组分浓度,也需要有一个合适的培养条件。