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1.
In Calicut populations of P. hydrodromous, the ovary is not refractory during September—November of the prebreeding season; it is inhibited from developing apparently by a gonad-inhibiting hormone(s) contained in the eyestalks. The prevalent tendency in Paratelphusa during the prebreeding season is to reproduce, and not to moult. The precocious ovarian growth induced by eyestalk removal during this season is biochemically impoverished, possibly due to uneven oocyte development, which in turn may be caused by the unpreparedness of a section of the population of oocytes for vitellogenesis. The ovary appears to have to pass through a period of oogonial proliferation under the influence of the moult-precipitating hormones during the moulting season, and subsequently through a period of oocyte differentiation during the prebreeding season, for normal vitellogenesis during the breeding season.  相似文献   

2.
Summary

In adult males of the freshwater crab Paratelphusa hydrodromous, judging from testicular activity, November-May is the reproductively inactive season and June/July through October the active season. The reproductively active period also represents the mating season of this species. In males over one year old, moulting is an annual event scheduled during June/July and the individual remains in intermoult from July/August to May. This intermoult comprises two phases: (1) the reproductive phase (July/August through October) when the physiological emphasis is more on reproduction and much less on somatic growth (as evidenced by the ability to regenerate autotomized walking limb), (2) the somatic phase (February/March through May) when the emphasis is more on somatic growth and much less on reproduction. Thus there exists an antagonism between reproduction and somatic grown in male P. hydrodromous as already established in the female. Experimental studies suggest that the testicular inactive phase of P. hydrodromous is caused by a possible increase of titre of the gonad-inhibiting hormone (GIH) along with a decrease in titres of the gonad-stimulating hormone (GSH) and androgenic hormone (AH).  相似文献   

3.
锯缘青蟹卵黄发生期卵母细胞和卵泡细胞之间的结构变化   总被引:24,自引:0,他引:24  
通过电镜研究了锯缘青蟹二次卵巢发育过程中卵黄发生期(分为初期和后期)卵母细胞表面的结构和胞质的变化。卵黄发生初期分为:内源性卵黄发生阶段和有卵泡细胞直接参与的外源性卵黄合成阶段,前者特征为:在卵母细胞中充满了内质网泡,在泡内有不同程度的卵黄物质合成,此时在卵母细胞的表面区域,可见很多卵泡细胞向卵母细胞表面迁移,并包围卵母细胞。后者其特征是在卵母细胞的表面,有大量的胞饮小泡出现在卵膜的内面,随着两细胞表面膜的逐步融合和胞饮作用加强最后形成链锁状结构,胞质中靠近卵质周围有卵黄体的积极合成和大更换 脂肪滴积累,在此阶段的后期,卵泡细胞质已基本吸收完毕,卵泡细胞膜和卵母细胞膜融合,某些界面已无膜结构。卵黄发生后期在亲蟹孵出幼体后的第11d至第27d基本结束,此期也主要以外源性卵黄发生为主,在卵母细胞的周围,卵泡细胞迅速扩大,其间分布着大量的大小不同的囊泡和线粒体,在接近卵母细胞表面,还常可见大量的脂肪滴存在。卵泡细胞与卵母细胞间其膜结构完全消失,从而可使滤泡大片细胞质直接融入卵母细胞中,以后随着卵黄发生的进一步发展,卵母细胞与卵泡细胞的交界面逐步形成一个网状的膜结构屏障,同时在卵巢中可见正在降解的卵母细胞,在卵黄发生近结束以后,在卵母细胞的表面,逐步形成两层卵膜,这时的卵母细胞质中几乎充满了卵黄体和脂肪滴。  相似文献   

4.
5.
在35、30、25℃3种温度下观察了蚤状(Daphniapulex)的生长和生殖。其生长随年龄的增加而逐渐减慢,寿命因温度升高而缩短。在25℃条件下,蚤状寿命、产仔数和产仔率明显高于其他组,其平均寿命为65.5天,累计产仔总数为401.6个,产仔率为21.22。  相似文献   

6.
In vitro somatic embryogenesis and regeneration of somatic embryos to whole plants through micropropagules was successfully demonstrated from pigmented uniseriate filamentous callus of Kappaphycus alvarezii (Doty) Doty in axenic cultures. More than 80% of the explants cultured on 1.5% (w/v) agar‐solidified Provasoli enriched seawater (PES) medium showed callus development. The callus induction rate was consistently higher for laboratory‐adapted plants. The excised callus grew well in subcultures and maintained its growth for prolonged periods if transferred to fresh medium in regular intervals. Some subcultured calli (<10%) did undergo transformation and produced densely pigmented spherical or oval‐shaped micropropagules (1–5 mm in diameter) that subsequently developed into young plantlets in liquid PES medium. The micropropagule production was further improved through somatic embryogenesis by a novel method of culturing thin slices of pigmented callus with naphthaleneacetic acid (NAA) or a mixture of NAA and 6‐benzylaminopurine. Transfer of embryogenic callus along with tiny somatic embryos to liquid medium and swirling on orbital shaker facilitated rapid growth and morphogenesis of somatic embryos into micropropagules that grew into whole plants in subsequent cultivation in the sea. The daily growth rate of one tissue cultured plant was monitored for seven generations in field and found to be as high as 1.5–1.8 times over farmed plants. The prolific somatic embryogenesis together with high germination potential of somatic embryos observed in this study offers a promising tool for rapid and mass clonal production of seed stock of Kappaphycus for commercial farming.  相似文献   

7.
中华绒螯蟹微卫星标记与生长性状相关性的初步分析   总被引:4,自引:0,他引:4  
研究采用30个微卫星标记分析同池养殖的长江水系中华绒螯蟹群体,以筛选生长性状(体重、体长和体宽)相关的分子标记。结果表明,位点ESIN33、ESC29和ESC57与体重、体宽和体高呈极显著相关(P<0.01);位点ESC65与体高、体宽呈极显著相关(P<0.01),与体重呈显著相关(P<0.05)。不同基因型间的多重比较表明,ESIN33位点的AC基因型、ESC29位点的DD基因型、ESC65位点的BB基因型的平均体重、体宽和体高均高于其他基因型,且差异显著,是生长性状的优势基因型。研究结果可为中华绒螯蟹的分子标记辅助选育提供参考。  相似文献   

8.
中华绒螯蟹(Eriocheir sinensis)精子顶体反应的研究   总被引:11,自引:6,他引:11  
分别用卵水、海水、caCl_2或NaCl水溶液对中华绒螯蟹成熟精子进行人工诱导顶体反应,结果表明:精子的生理性成熟、同种卵或Ca~(++)的存在、碱性环境以及与一定的固体接触均为精子顶体反应触发的重要条件。3月份精子诱导率最高。 电镜观察证明,中华绒螯蟹精子的顶体反应可分四个阶段:(1)辐射臂收缩;(2)顶体囊外翻;(3)顶体管前伸;(4)片层结构脱落。  相似文献   

9.
本文报道了中华绒螯蟹越冬后肝胰脏、肌肉和生殖腺维生素C的含量及变化。肝胰脏为中华绒螯蟹储存维生素C的器官;越冬后的雌性中华绒螯蟹,其肌肉和生殖腺的维生素C高于雄性;正常活动雌性或雄性,其肝胰脏、肌肉和生殖腺的维生素C含量均高于死亡的个体的维生素C含量;产卵且抱卵孵化的雌体,其肝脏维生素C的含量高于那些不产卵的雌体,维生素C含量的降低是越冬时或越冬后中华绒螯蟹死亡的主要原因之一。  相似文献   

10.
提高木薯循环培养的次生体胚再生植株频率研究   总被引:3,自引:1,他引:3  
用木薯成熟体胚子叶作外植体诱导次生体胚,接种7d或15d后分别在诱导培养基或成熟培养基中加入AgNO3,可明显提高植株再生频率。前者可使体胚再生植株频率由对照的40.5%提高到58.1%;后者可使植株再生频率由对照的36.1%提高到61.3%。用ABA进行上述处理,效果更加显著。诱导期处理,可使植株再生频率由对照的40.5%提高到72.6%;成熟期处理,植株再生频率由对照的36.1%提高到81.3%。若诱导7d后,将2,4-D浓度由4.0mgL-1降至2.0mgL-1,并加AgNO3,继续诱导15d,转到附加0.25mgL-1ABA的成熟培养基中培养至30d,能极显著地促进体胚的发育和成熟,使植株再生频率达到一个相当高的水平,最高达95%,平均每个外植体产生的植株数达39.6个,分别相当于对照的2.38倍和2.46倍。  相似文献   

11.
认识鱼类的生活史特征及其对生态环境变化的响应,是鱼类物种保护与资源合理利用的基础。于2009年5月至2010年4月研究了黄山地区徽水河中宽鳍鱲(Zacco platypus)的年龄、生长和繁殖。共采集标本352尾,雌雄性比为0.49∶1,与1∶1差异显著。以鳞片为年龄鉴定材料,雌、雄个体的最大寿命均为3龄;年轮主要形成于3月份。全长和体重呈幂函数关系,两性间无显著性差异,关系式表达为W=6×10–6L3.10;全长和鳞径呈线性关系,且两性间差异显著,关系式分别表达为L♀=29.58R+38.84和L♂=33.17R+34.99;2龄个体的退算全长在雌、雄两性间无显著性差异。繁殖时间为4—7月份;2龄时达50%初次性成熟,其个体全长为98.22(雌)和105.69 mm(雄);绝对繁殖力为(758±362)卵粒,相对繁殖力为(77.38±22.15)卵粒/g。同已有的少量研究资料相比较,徽水河宽鳍鱲的年龄结构较北京地区种群的相对简单,个体生长较同为黄山地区的浦溪河种群相对快速,这种生活史特征差异可能是生态环境空间异质性的作用结果,但有关宽鳍鱲各生活史特征之间的权衡及其对生态环境的响应还有待于进一步研究。  相似文献   

12.
Laboratory studies were used to examine how variation in the density of spore settlement influences gametophyte growth, reproduction, and subsequent sporophyte production in the kelps Pterygophora californica Ruprecht and Macrocystis pyrifera (L.) C. Ag. In still (non-aerated) cultures, egg maturation in both species was delayed when spores were seeded at densities 300 · mm?2. Although the density at which this inhibition was first observed was similar for both species, the age at which their eggs matured was not. P. californica females reached sexual maturity an average of 4 days (or ~ 30%) sooner than did M, pyrifera. As observed previously in field experiments, per capita sporophyte production was negatively density dependent for both species when seeded at spore densities of 10 · mm?2. Total sporophyte production (i.e. number · cm?2) for both species, however, was greatest at intermediate densities of spore settlement (~ 50 spores · mm?2). In contrast, total sporophyte production by P. californica steadily increased with increasing spore density in aerated cultures; highest sporophyte density was observed on slides seeded at a density of 1000 spores · mm?2. Preliminary experiments with P. californica involving manipulation of aeration and nutrients indicate that inhibition of gametophyte growth and reproduction at higher densities of spore settlement in non-aerated cultures was probably caused by nutrient limitation.  相似文献   

13.
Abstract Frankliniella bispinosa was reared at five constant temperatures using pollen of Typha domingensis as food. At 15°C, 37.5 days are required for completing the life cycle and the adult females survived for about 30 days. The immature stage and the female longevity were significantly reduced when temperature increased and they were only 9.2 and 3.9 days, respectively, at 35°C. The maximal number of eggs (123.2/female) were laid at 25°C, as compared with 29.5, 42.1, 11.6 eggs per female, respectively, at 15°C, 20°C and 30°C. F. bispinosa occurs on Bidens pilosa flowers all the year round in south Florida. However, the population is more abundant from mid-March to early April.  相似文献   

14.
SUMMARY

The scale studies indicate that the annulus is a reliable year mark. A linear relationship exists between anterior scale radius and body length so that back-calculations of length were possible. Males and females had a similar growth rate. The growth rate is similar to that found by Mulder (1973) for L. capensis in the Vaal River. Fish under 35 centimetres in length had a sex ratio of 1:1, but in larger fish, only 16 per cent were males. Males reach sexual maturity at a length of 15 to 25 centimetres and females at a length of 20 to 25 centimetres. The spawning season extends from September to March with a peak in November. Fecundity increased with an increase in length from 12 664 for a fish of 22.8 centimetres to 106 286 for a fish of 34.8 centimetres.

The results are basically similar to those found by Mulder (1973) in the Vaal River except for fecundity and length at sexual maturity.  相似文献   

15.
王仁忠 《植物研究》2000,20(4):450-457
植物种群营养生长和生殖生长的关系是植物生殖生态学研究的重要内容之一,自本世纪70年代,国外已有大量报道,但国内的研究报道很少。本文在种群水平上研究了人工油松种群一年生雌性枝条和雄性枝条在枝长、直径、叶数、叶生物量、枝生物量及新生枝条在大小孢子球生物量、雌雄枝条长度和生物量等方面的差异,结果表明,一年生枝条除在西方向上雌雄枝条直径差异显著和在东、西方向上雌雄枝条生物量差异显著外,其它处理条件下雌雄枝条在长度、直径、叶数、叶生物量和枝生物量等方面差异均不显著;而对新生枝条的取样分析表明同方向上雌雄枝条在大小孢子球生物量、雌雄枝条长度、雌雄枝条生物量等方面差异均显著或极显著。无论是一年生枝条,还是新生枝条,在东、西、南、北四个方向上其各项指标差异显著或极显著。  相似文献   

16.
本文提出一种用香蒲 (Typhadomingensis)花粉饲养花蓟马 (F .bispinosa)的方法 ,恒温饲养表明 ,在1 5℃时 ,该蓟马的世代历期长达 3 7 5d ,雌成虫平均寿命为 3 0d ;在 2 0℃和 2 5℃恒温下 ,世代历期分别为1 8 9和 1 3 8d ,雌成虫寿命分别为 2 9 0和 2 3 3d。平均产卵量在 2 5℃时达到最高 (1 2 3 2头 雌 ) ,而在其他几种恒温下产卵量显著减少。在佛罗里达南部 ,终年可见该蓟马在鬼针三叶草 (BidenspilosaL .)花上发生 ,而种群高峰期在三月中旬到四月初 ,平均每朵花中蓟马成虫数最高时可达 48 7头。  相似文献   

17.
Pericarps generally are thought of as structures having determinate growth, serving as a protective covering for the developing gonimoblast. In laboratory culture, the pericarps of Champia parvula (C. Agardh) Harvey, Lomentaria baileyana (Harvey) Farlow and Lomentaria sp. exhibited indeterminate growth. These tissues could be excised and grown as separate female plants. The new plants were indistinguishable from the parent tissue, were fertile, and produced viable carpospores.  相似文献   

18.
神经内分泌因子调控鱼类生殖和生长的相互作用   总被引:17,自引:0,他引:17  
脊椎动物的生长与生殖活动有着密切的联系并相互作用。许多调节生长和代谢活动的内分泌因子对青春期或者性腺的发育产生影响。同样,调节生殖活动的许多激素亦同时对生长和代谢产生影响。近年来,我们和其他学者对鱼类生长和生殖的神经内分泌调节的相互作用进行了研究,主要的进展是:①在促进性腺的激素影响生长方面,发现促性腺激素释放激素(GnRH)和多巴胺都能和脑垂体生长激素细胞的特异性受体结合而刺激生长激素释放,并能  相似文献   

19.
中华绒螯蟹染色体的研究   总被引:16,自引:1,他引:16  
中华绒螯蟹(Eriocheir sinensis H.Milne Edwards)属甲壳纲(Crustacea)、软甲亚纲(Malacostraca)、十足目(Decapoda)、方蟹科(Grapsidae),俗称河蟹,是我国重要的经济蟹类,其形态解剖、生态习性及生理等方面的研究已有报道(Panning,1939;Koch,1952;堵南山,1954,1957,1958;Bauchau,1960;Leersnyder,1966,1967;Dbainaut et al.,1976;Chevigue,1976;Leeranyder et al.,1977,1978;Pequenx et al.,1982;Chapelle et al.,1982;谈奇坤等,1984.),但至今未见有关细胞遗传学方  相似文献   

20.
The chlorophyte Ulva is perceived as a simple and uniform algal form, with little functional differentiation within a thallus. We compared morphology, pigmentation, photosynthesis, growth, reproduction, and UV‐B sensitivity between different thallus regions of Ulva pertusa Kjellman. Thallus thickness and cell size were significantly greater, whereas cell number was less in the basal region than in other regions. Photosynthetic pigment contents were lowest in the basal region and increased toward the marginal region. Photosynthetic capacity and photosynthetic efficiency normalized to fresh weight, area, volume, and cell number showed a progressive increase from the basal to marginal parts; however, on a chl basis those values were equal regardless of thallus part. Values of light saturation point were not statistically different between regions. Growth rates increased from marginal to basal and to middle parts of the thallus, whereas sporulation was highest in marginal (100%) followed by middle (30%) and basal parts (0%). Daily observation over 9 days showed that 56% of the basal cells divided once and did not produce spores, whereas every marginal cell went through its first division and 89% of the primary daughter cells also divided, resulting in 100% sporulation. A 7‐day treatment with PAR and PAR + UV‐A caused a significant decrease in the effective quantum yield of all thallus regions, followed by a recovery toward the initial values, whereas PAR + UV‐A + UV‐B irradiation led to greater photoinhibition and less recovery. Marked differences in the UV‐B sensitivity were observed, with marginal parts being more sensitive and basal parts most resistant.  相似文献   

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