光照强度和温度对营养生长的巨藻雌、雄配子体光合放氧的影响

利用氧电极法测定了光照强度和温度对巨藻(Macrocystis pyrifera)雌雄配子体光合放氧的影响。结果表明,巨藻配子体营养生长的最适光强为1 500~2 000 lx,最适温度为18~20℃。雌雄配子体最高放氧速率分别为1 699.4 nmol/(min.g)和1 497.3 nmol/(min.g)。     

An Undercover Angiosperm from the Jurassic of China

<正>Searching for early angiosperms is a riveting activity in botany because it helps to resolve the phylogenetic relationships among seed plants and among angiosperms themselves.One of the challenges for this job is what the target fossils look like.Most possibly early angiosperms may elude our scrutiny with gymnospermous appearances.This possibility becomes a reality in a Jurassic plant,Solaranthus gen.nov,which bears a peltaspermalean appearance and enclosed ovules.According to knowledge available hitherto,the latter feature makes it an angiosperm.However,such a feature is more likely to be eclipsed by its gymnospermous appearance.The early age and unexpected character assemblage of Solaranthus urge for a fresh look on the assumed-simple relationship between angiosperms and gymnosperms.Its resemblance to the order Peltaspermales favors the Mostly Male Theory.     

Gender of large river deltas and parasitizing rivers

Deltas are the most dynamic part of large rivers and the characteristics of deltas reflect the basic nature of morphodynamics,ecology and anthropogenic influence.The authors investigated many deltas of...     

中国对虾雄对虾交配能力和精荚再生的研究

于1987年对中国对虾雄对虾交配能力进行实验观察;于19941995两年进行补充实验。结果证明,在实验室条件下,保持雄对虾的相对数量而且有充足雌对虾供交尾选择的情况下,中国对虾雄对虾在一个交配季节中的自然交配能力可达到3—4次;交配后生成新的精荚并再次发生交配的平均时间约为3d,但部分雄对虾交配次日即可生成新的精荚并再次发生交配行为;雌雄性比5：1和2：1对雄对虾在整个交配季节中的累计平均交配率没有明显影响。但在交配盛期,雌雄5：1实验组的累计交配率为2．6次,而21两个实验组的累计交配率只有1．13和1．43次,说明较多可供选择的雌对虾的存在,对雄对虾在一定时期内的交配能力和精荚再生可能有诱导作用。     

中华绒螯蟹(Eriocheir sinensis)雄性生殖系统发育过程中生化成分的季节变化

采用生化方法测定了中华绒螯蟹雄性生殖系统及肝胰腺各组织中甘油三酯、胆固醇、蛋白质、葡萄糖和糖原含量的季节变化。结果表明，全年胆固醇含量在肝胰腺、血淋巴和精巢中均有2个高峰，分别在6月和12月、7月和12月、9月和次年1月，且第二峰值均明显高于第一峰值；肝胰腺葡萄糖含量最高值出现在6月，之后逐渐下降，而血淋巴和精巢则在7月，之后亦逐渐下降；肝胰腺和血淋巴出现糖原峰值的时间和葡萄糖相似，但精巢在9月，而副性腺在8月时已达到较高含量，最高值出现在次年1月；蛋白质的变化与上述3种物质基本相似，但血淋巴出现峰值的时间要早于肝胰腺。上述各生化成分变化的先后顺序和连续性表明，肝胰腺内上述物质在进入性腺快速发育期前，经血淋巴向精巢和副性腺转移，精巢对胆固醇和葡萄糖的积累要早于副性腺，这些物质的变化与生殖周期存在明显的相关性。肝胰腺中甘油三酯始终处于积累状态，而精巢和副性腺在前期对甘油三酯的积累极少，直至后期才略有上升，表明甘油三酯并非性腺发育所必需。     

Sex dependent sexual reproduction strategies in a cyclic parthenogen—A case study from intermittent urban pond

The fitness of animals inhabiting highly unpredictable intermittent ponds depends on the effectiveness of the production of their resting stages. Daphnia living in such an environment produce sexual eggs as well as the males needed to fertilize them. We hypothesize that the strategy of permanent male presence should coexist with the synchronization of the production of males with that of sexual eggs. To test this hypothesis, we collected plankton samples from a model urban pond, two times a week, throughout the growing season. We analyzed in detail a number of environmental factors and the population dynamics of two Daphnia populations. The percentage of ephippial females and males periodically reached c.a. 50 % of the population. Depending on the moment of the growing season, this proportion was primarily influenced by population crowding, the richness of invertebrate predators in the habitat, extreme high temperatures and the occurrence of the autumnal photoperiod. Our results confirm the hypothesis that Daphnia produce simultaneously long-living males and males synchronized with receptive females. Additionally, we have shown that the number of resting eggs deposited by temporally-isolated populations varied significantly; thus the fitness of a particular genotype depends on the season and on the particular timing of its activation.     

裙带菜雄配子体营养生长过程中的营养吸收

于１９９７年在香港科技大学,采用ＬＡＣＨＡＴ自动离子分析仪对裙带菜雄配子体（１９９２年６月自青岛分离的野生品系）进行营养分析,结果表明,在恢复营养供给后的１小时内,雄配子体对ＮＨ４－Ｎ、ＰＯ４－Ｐ和ＮＯ３－Ｎ三种营养盐的吸收速率依次为２２．７１μｇ／（ｇ．ｈ）、１４．８６μｇ／（ｇ．ｈ）和８．０８μｇ／（ｇ．ｈ）,吸收速度的排列顺序不随培养时间的延长而变化;雄配子体对氨氮的吸收速度远高于对硝酸氮的