甲壳动物生殖量和环境关系Ⅲ.其他甲壳类

本文是《甲壳动物生殖量与环境关系》系列文章的第三篇,也是最末篇,专述其他甲壳动物,包括鳃足类、介形类、蔓足类、涟虫类、等足类、端足类、糠虾类、磷虾类,以及十足类(含樱虾类、真虾类、海螯虾类、龙虾类,及寄居蟹类、蟹类)和口足类的生殖量和环境关系。本文内容也分为“生殖量变化”和“生殖量和环境关系”二大部分。这样,可与前二篇作对比研究,从而找出其异同点。并为探索生殖量变化机制及规律,打下理论基础。     

淡水枝角类的生殖

淡水枝角类是一类富有经济意义的小型浮游甲壳动物,它是淡水养殖角类(鲤、鲢、鳙、鲩等)鱼苗的重要饵料。因此,它们的产量可以直接影响这些经济鱼类的生长繁殖,而影响它们产量的主要因素是生殖量和生殖率。如果生殖量高,生殖率快。产量必然增高,这是很明显的。所以研究枝角类的生殖对渔业增产具有实     

圆唇散白蚁补充生殖蚁发育过程中的卵黄蛋白原基因的表达及卵子发生

【目的】研究圆唇散白蚁Reticulitermes labralis(Hsia)补充生殖蚁分化及发育过程中卵黄蛋白原(Vitellogenin,Vg)基因的表达、卵母细胞的发育以及子代品级分化。【方法】通过使用实时定量PCR(Real-time quantitative polymerase chain reaction)技术测定补充生殖蚁从分化到产卵的过程中Vg基因相对表达量的动态变化;采用组织染色的方法进行卵母细胞发育阶段的观察;对子代的数量及分化进行统计分析。【结果】补充生殖蚁发育过程中,Vg基因表达呈现先升高后降低的动态变化模式。在补充生殖蚁分化后的第10天开始形成具卵黄的卵母细胞,在20 d时具卵黄卵母细胞的数量达到最高值。第1个月至第3个月,补充生殖蚁的产卵数逐渐增加,分别为(2.45±1.43)、(7.68±2.53)和(12.10±7.09)粒。第3个月,巢内开始出现幼蚁,数量为(5.15±2.41)头;第10个月,巢群内有工蚁、前兵蚁和兵蚁的分化,分别为(17.03±2.28)、(1.45±0.31)和(0.79±0.18)头。【结论】在新建巢群中,若蚁的分化在工蚁和兵蚁分化之后。圆唇散白蚁若蚁在巢群需要的时候,可以在很短时间内转化为补充生殖蚁;Vg基因的表达水平与卵母细胞的卵黄形成相关,Vg基因表达量的增加启动了卵母细胞的卵黄摄取过程。虽然单个补充生殖蚁产卵量不如单个原始生殖蚁的多,但是在一个巢内补充生殖蚁总的产卵数目要远远超过原始生殖蚁,因为补充生殖蚁的数量比原始生殖蚁的数量多。因此补充生殖蚁对巢群稳定和发展具有重要作用。     

黑胸散白蚁工蚁与工蚁型补充生殖蚁体内抗氧化酶和解毒酶的活性及基因表达变化

【目的】社会性白蚁的工蚁可以转化成补充生殖蚁参与生殖,提高自身适合度。本研究旨在探究工蚁转变成补充生殖蚁后,与氧化应激抗衰老相关的抗氧化酶和解毒酶活性的变化,为揭示生殖蚁的繁殖和抗衰老机制提供参考。【方法】利用生化方法分别测定黑胸散白蚁Reticulitermes chinensis工蚁、工蚁型补充生殖蚁和原始生殖蚁体内的2种抗氧化酶过氧化氢酶(catalase, CAT)和超氧化物歧化酶(superoxide dismutase, SOD)与4种解毒酶酸性磷酸酶(acid phosphatase, ACP)、碱性磷酸酶(alkaline phosphatase, AKP)、羧酸酯酶(carboxylesterase, CarE)和细胞色素P450(cytochrome P450, CYP450)的酶活性;同时利用qRT-PCR检测这些酶对应的基因RsCAT, RsSOD, RsACP, RsCYP450和RsCarE的表达量。【结果】与雌性工蚁相比,黑胸散白蚁工蚁型补充生殖蚁体内的CAT, SOD, ACP, AKP和CarE活性显著上升,分别达到雌性工蚁的5.82, 1.41, 1.39, 2.27和2.70倍,CYP450活性在两品级间没有显著差异;RsCAT, RsSOD, RsACP, RsCarE和RsCYP450的表达量也显著增加。补充生殖蚁体内CAT和ACP活性显著高于原始生殖蚁的,而SOD和AKP活性在两品级间没有显著差异;雌雄补充生殖蚁RsCAT的相对表达量分别是原始生殖蚁的5.68和3.60倍,RsACP的相对表达量分别是原始生殖蚁的81.12和46.72倍。【结论】黑胸散白蚁工蚁由非生殖品级转化为生殖品级以后,体内抗氧化酶和解毒酶的酶活力和基因表达水平显著升高,从一定程度上揭示了生殖品级的抗衰老机制。     

水稻(威优49)幼苗根系K~+(~(86)Rb~+)吸收的调节

杂交稻威优49幼苗根系的K~+(~(86)Rb~+)吸收速率受到根含钾量的直接反馈调节,而与地上部的含钾量无显著相关性。随着根部含钾量的增加,K~+(~(86)Rb~+)净吸收的速率减小。净吸收速率的改变主要是由于内流速率的变化,而受外流速率变化的影响不大。根系上运K~+(~(86)Rb~+)滞后于吸收约1.5h。但上运一旦开始后,运输速率便不受根和地上部含钾量变化的影响。这表明杂交稻威优49幼苗根系K~+(~(86)Rb~+)吸收速率的改变主要受根部液泡含钾量的调节,而向上运输则决定于细胞质的K~+(~(86)Rb~+)状态。     

Kisspeptin在女性生殖内分泌和辅助生殖技术中的研究进展

近年来研究显示,kisspeptin在大脑的性别分化、性激素正负反馈调节、青春期始动以及机体能量信号转导等生理过程中起到重要作用,表明kisspeptin可能是女性生殖功能成熟及调控的一个关键性信号因子。除下丘脑分泌的kisspeptin之外,生殖器官局部表达的kisspeptin在机体正常生殖过程中的作用也不断得到证实。研究表明,很多生殖内分泌疾病,如单纯性促性腺激素分泌不足的性腺机能减退症(isolated hypogonadotropic hypogonadism, IHH)、多囊卵巢综合征(polycystic ovary syndrome, PCOS)、卵巢早衰(premature ovarian failure, POF)、病理性高泌乳素血症等,都与kisspeptin的异常表达有关。通过给予外源性kisspeptin可解决辅助生殖技术应用中的一些问题。本文主要就kisspeptin在女性生殖内分泌尤其是在辅助生殖领域研究中所取得的进展进行论述。     

丛枝菌根真菌对烟草钾素吸收的研究

在盆栽条件下研究了接种AM真菌Glomus mosseae对烤烟K素吸收的影响。结果表明,施钾量与AM真菌对烤烟K累积量与分配有明显的影响,对烤烟不同时期生长、不同叶位含钾量影响显著(P<0．01)。菌根菌与施钾量二者组合对烤烟烟叶含钾量的提高作用在生长中、后期最为显著,接种AM真菌对烤烟整株烟叶含钾量的影响,主要是提高了上、中、下位叶的含钾量,进而提高了整株烟叶的含钾量;接种AM真菌提高了钾在叶中的分配比例。降低了K在茎中的分配比例,比较而言,在0．75～1．125g·kg^-1施钾(K2O)水平,AM真菌对烤烟K的累积与分配及含钾量的作用效果最佳。     

温度及pH对隆线溞生长和生殖的影响

研究了隆线溞(Daphnia carinata)在不同温度(15、20、25、30℃)和pH(6、7、8、9、10)影响下的内禀增长率(rm)、周限增长率(λ)、平均世代周期(T)、净生殖率(R0)、平均寿命、第一怀卵日、平均生殖间隔期和总生殖量.结果表明,温度对隆线溞的生命参数有显著影响,30℃组的内禀增长率(rm)...     

研究哺乳动物受精作用的历史与背景

在F、R、Lillie(1919)写的一本小书叫《受精的问题》(Proplems of Fertilization)中,他说:“人类生存的主要动机是解决饥饿问题与爱情问题。这就是说,个体保存与种族延续是每个生物的主要目的”。他又说到William Harvey(1651)认为怀孕(conception)是由于雄性与雌性的生殖液的混合。在《生殖生理学》的第二版中,Marshall(1922)也提到Harvey研究过鸡的发育。因此,我们可以认为,关于生殖生理与受精问题,首先用科     

高三生物学教学纲要(5)

1)生殖是生物产生新个体的过程 两大类生殖方式对后代的遗传影响不同(有性生殖与无性生殖;简述各种微生物、植物和动物的主要生殖方式)。     

Is energy supply the trigger for reproductive activity in male edible dormice (<Emphasis Type="Italic">Glis glis</Emphasis>)?

In edible dormice (Glis glis) reproduction is synchronised with the intermittent masting of the European beech (Fagus sylvatica). In years of mast failure dormouse males seem to anticipate future low food availability and fail to develop functional testes. We hypothesised that the availability of high-quality food is linked to male reproductive capacity, because of high male energetic demands during gonad maturation. We therefore evaluated the relationship between beech seed production and male reproductivity in the field between 1993 and 2005. In order to know whether the energy content of the food as such triggers sexual capacity, we supplemented high-quality food in the field for 3 years and investigated reproductive output, reproductive capacity, and body mass changes. Results revealed that male reproductive capacity was positively linked with beech seed production. Body mass changes of reference males during the high reproductive year further revealed high energetic demands of male reproduction, which were counter balanced in food-supplemented males. However, in contrast to our assumptions, artificial food supply during a year of mast failure failed to evoke high reproductivity in edible dormice. The availability of high-quality food can therefore be ruled out from being the primary trigger for sexual activity in male edible dormice.     

Processing of environmental stimuli and primate reproduction

The prosimian primates have much in common with the non-primate mammals in that reproduction is strictly limited by the physical environment. This determines the onset of the ovarian cycle which in turn synchronizes reproductive behaviour with ovulation. In simian species (monkeys and apes), however, the reproductive cycle does not directly depend on such environmental factors as temperature, rainfall or day length. Indirectly, of course, such factors exert an influence in so far as they dictate the nature of the habitat which in the long term has shaped social organization and in the short term determines the availability of food. It is through these factors, social organization and food availability, that the physical environment determines the timing of reproduction. The seasonal onset of reproductive cycles is principally related to the changing nature of mother-infact interactions, which in annual breeders is influenced by the availability of food. This availability depends in part on climatic conditions, but also on social status: high rank determines priority of access to food, so that dominant females resume cycling after giving birth earlier than do females of low rank. Another way in which social status operates to enhance the reproductive success of animals that achieve high rank is by the suppression of sexual behaviour in subordinate males and inhibition of fertility in low-ranking females. Of importance in this context has been the emancipation of reproductive behaviour (proceptivity/receptivity) from strict gonadal control. The degree to which this emancipation from both the external, physical environment and the internal, gonadal environment has been made possible is related to the growth of the neocortex and its domination of the limbic brain.     

玻璃温室与田间栽培小麦幼穗分化的比较

以河南省大面积种植的弱春性品种"郑麦9023"及半冬性品种"周麦18"为材料,开展了玻璃温室和田间栽培条件下小麦幼穗分化进程的比较研究。结果表明,在小麦全生育期,玻璃温室内平均温度高于田间环境,小麦幼穗分化所需时间极显著低于田间环境(P < 0.01)。温度和0 ℃以上积温升高,小麦幼穗分化进程加快。与田间种植小麦相比,玻璃温室内小麦幼穗分化缩短的时期主要集中在分化前期(出苗-伸长期、单棱期、二棱期)。玻璃温室内小麦幼穗分化持续时间和总积温均随播期推迟而降低,幼穗分化各阶段出现时间亦随播期的推迟而后延。小麦幼穗分化进程存在品种间差异,其中"郑麦9023"幼穗分化持续时间小于"周麦18",各阶段出现的时间亦早于"周麦18"。温度对幼穗分化各时期的影响存在品种间差异。温度升高对"郑麦9023"幼穗分化中期(二棱期、护颖分化期、小花分化期)影响较大,对"周麦18"幼穗分化前期和后期(单棱期、二棱期、药隔分化期)影响较大。积温对"郑麦9023"护颖分化期和"周麦18"药隔分化期、二棱期影响较大。     

Short day lengths delay reproductive aging

Caloric restriction and hormone treatment delay reproductive senescence in female mammals, but a natural model of decelerated reproductive aging does not presently exist. In addition to describing such a model, this study shows that an abiotic signal (photoperiod) can induce physiological changes that slow senescence. Relative to animals born in April, rodents born in September delay their first reproductive effort by up to 7 mo, at which age reduced fertility is expected. We tested the hypothesis that the shorter day lengths experienced by late-born Siberian hamsters ameliorate the reproductive decline associated with advancing age. Short-day females (10L:14D) achieved puberty at a much later age than long-day animals (14L:10D) and had twice as many ovarian primordial follicles. At 10 mo of age, 86% of females previously maintained in short day lengths produced litters, compared with 58% of their long day counterparts. Changes in pineal gland production of melatonin appear to mediate the effects of day length on reproductive aging; only 30% of pinealectomized females housed in short days produced litters. Exposure to short days induces substantial decreases in voluntary food intake and body mass, reduced ovarian estradiol secretion, and enhanced production of melatonin. One or more of these changes may account for the protective effect of short day lengths on female reproduction. In delaying reproductive senescence, the decrease in day length after the summer solstice is of presumed adaptive significance for offspring born late in the breeding season that first breed at an advanced chronological age.     

Optimal foraging and gut constraints: reconciling two schools of thought

To ecologists, factors such as a forager's encounter rate with prey and its own susceptibility to predation are dominant determinants of foraging. In contrast, digestive physiologists consider foraging to be determined by factors like rates of digestion and absorption of ingested food. We reconcile these views in a model combining encounter rate, external handling, and internal handling of food in the gut. With internal food handling, two food properties become important; energy: external handling time (e/h) and energy: bulk (e/b). We show that internal handling is only one of a suite of rate limiting factors. The gut never reaches full capacity, indicating that spare capacity may be intrinsic to gut structure. Regardless of gut fullness, a food of sufficiently high e/b will always be harvested. Two isolegs in the state space of resource abundances determine diet selectivity. These isolegs, which we call the Mitchell and Pulliam isolegs, divide the state space into regions in which 1) the forager's optimal strategy is opportunism; 2) the forager is always selective on the food with the greater e/h and partially selective on the second food; 3) the forager is always selective on the food with the greater e/h and ignores the second food. The development and analysis of the isolegs thus reconcile the heretofore disparate perspectives of the ecological and the physiological frameworks of foraging.     

Synchronization of weaning time with peak fruit availability in squirrel monkeys (Saimiri collinsi) living in Amazonian Brazil

Many mammals coincide their reproductive activities with factors such as ambient temperature, rainfall, and food availability. In primates that invest immediate food intake into reproduction, the periods of maximum fruit production often coincide with the peak of lactation (to maximize maternal survival) or the occurrence of weaning (to maximize infant survival). This study investigates the relationship between reproductive periods and the availability of ripe fruit in the habitat of a population of wild squirrel monkeys (Saimiri collinsi) in Amazonian Brazil. We combine data from several years (2002–2003; 2011–2015) during which we followed the monkeys and quantified the occurrence of matings, gestations, births, and the number of lactating females. We also collected rainfall and plant phenological data for 24 months. Our results confirm that reproductive events are highly seasonal in S. collinsi. The period of weaning corresponded to the peak in the abundance of ripe fruits consumed by the monkeys. This indicates that the period of infant nutritional independence is optimally timed to coincide with periods of greater food production in this habitat. We suggest that seasonal breeding in these primates does not necessarily reduce maternal energetic stress, but likely improves infant survivorship.     

The influence of temperature and resource level on the fecundity of a predatory planktonic mite,Piona exigua Viets

Summary Piona exigua Viets is a predaceous freshwater mite that can potentially affect the population densities of its cladoceran prey. As part of a study of the effect of Piona exigua on its prey populations we measured the effects of water temperature and prey density on the lifespan, age at first reproduction and per capita egg production of adult female mites. Mites were raised in the laboratory at five prey (Ceriodaphnia, Daphnia) densities (5, 15, 30, 60, 120/l) at 15° C and at four temperatures (10, 15, 18, 22° C) at c. 60 prey/l. In response to increased food level, mites increased the number of eggs laid to reach a maximum at 60 prey/l, the rate at which they were laid increased and the pre-reproductive period was shorter. Low temperatures prolonged the pre-reproductive period. At temperatures above 10° C, food level and temperature had more influence on the timing of reproductive events (growth rate, oviposition rate, age at first reproduction) than on the size of females at first reproduction. When temperatures exceed 10° C and food levels exceed 5 prey/l the major scope for reproductive plasticity in Piona lies in the timing and duration of egg production.     

Phenotypic plasticity in adult life-history strategies compensates for a poor start in life in Trinidadian guppies (Poecilia reticulata)

Low food availability during early growth and development can have long-term negative consequences for reproductive success. Phenotypic plasticity in adult life-history decisions may help to mitigate these potential costs, yet adult life-history responses to juvenile food conditions remain largely unexplored. I used a food-manipulation experiment with female Trinidadian guppies (Poecilia reticulata) to examine age-related changes in adult life-history responses to early food conditions, whether these responses varied across different adult food conditions, and how these responses affected overall reproductive success. Guppy females reared on low food as juveniles matured at a later age, at a smaller size, and with less energy reserves than females reared on high food as juveniles. In response to this setback, they changed their investment in growth, reproduction, and fat storage throughout the adult stage such that they were able to catch up in body size, increase their reproductive output, and restore their energy reserves to levels comparable to those of females reared on high food as juveniles. The net effect was that adult female guppies did not merely mitigate but surprisingly were able to fully compensate for the potential long-term negative effects of poor juvenile food conditions on reproductive success.     

Reproduction of Japanese quail after microwave irradiation (2.45 GHz CW) during embryogeny

Japanese quail (Coturnix coturnix japonica) embryos were irradiated continuously in ovo with 2.45-GHz continuous wave radiation during the first 12 days of embryogenesis at an incident power of 5 mW/cm2 and a specific absorption rate of 4.03 mW/g. The internal temperature of irradiated and nonirradiated (sham) eggs was 37.5 +/- 0.3 degrees C, which is the optimum temperature for incubating quail eggs. At 35 days after hatching irradiated and sham-irradiated males were paired with irradiated or sham-irradiated females and daily records of reproductive performance were collected through 224 days of age. Progeny were hatched from each of the male-female pairs, and progeny reproductive performance was measured from 35 through 168 days of age. Hatchability was not affected by irradiation during embryogeny. Mortality after hatching, egg production, egg weight, fertility, hatchability of eggs produced, and reproductive performance of the progeny were not affected by irradiation during embryogeny. These observations indicate that irradiation of quail embryos with low-level microwave radiation does not affect the reproductive capacity of the hatchlings or of progeny produced from quail irradiated during incubation.     

Some factors affecting reproduction and sex-ratio of the predacious mite Amblyseius deleoni (Muma and Denmark) (Acari: Phytoseiidae)

Abstract

Several factors were examined to determine their effect on the reproduction and sex ratio in the predacious mite Amblyseius deleoni (Muma and Denmark), in the laboratory. The factors investigated included multiple matings, duration of copulation, capacity of male for mating in excess of females and age of mating females and males. The factors included also, the host plant leaf texture, food deprivation during immature and adult stages, and prey (Tetranychus urticae Koch) density. The results indicated that females of A. deleoni require multiple matings to maximize their reproductive potential, also when copulation was allowed for increasing periods of time, there was a gradual increase in total egg production and oviposition period. A male showed a high reproductive ability for more than 15 days and was able to mate more than once in excess of females. Age of females has an influence on fecundity and sex ratio; old females decreased egg production and produced proportionally more male progeny compared with young females. Similarly, the highest number of eggs deposited per female A. deleoni was reported, when female mated with a young male (0-day old). In addition, males of A. deleoni (at any age) were able to inseminate the females. Results from host plant leaf texture indicated that guava leaf gave the highest reproduction rate, while the fig leaf gave the least female fecundity. Neither the reproductive rate nor the sex ratio of the progeny of females crossed by normal or experimental males had been influenced by the food deprivation during immature stages. A significant lower fecundity was recorded on female's A. deleoni when exposed to different food deprivation programmes during adult stage. The number of eggs laid by the predator female increased with increasing prey density of T. urtice to a maximum of 2.04 eggs deposited per day at a prey density of 30 protonymphs of T. urticae as a prey. As the level of prey density was increased, there was a shift in sex ratio towards an increased proportion of females.