能发育的

Studies were made on the development and viability of eggs of the pig Ascaris under natural conditions in Peking.

实验证明，在北京地区的自然坏境中猪蛔虫卵从4月至10月都能进行发育，5月至9月间能发育成侵袭性幼虫期卵。

At the same time,there were not marked difference in the numbers of biastomere and mitotic index of control group and all treatment groups, suggesting that 2 -celt embryos were not only most sensitive to exogenous H2O2 but also rasiest to occur to development block.

但是经H2O2处理之后，度过2-细胞期发育阻滞的胚胎能在以后的发育中发生补偿性生长，其胚细胞数和分裂指数都和体外正常发育的胚胎没有差异。

Vg could be detected in haemolmph of the water—fed female at 48h after eclosion, too.

用10％的蜂蜜和清水分别饲喂两组成虫(简称"蜜组"和"水组")，以研究成虫期的营养对Vg发生和卵巢发育的影响，结果显示，成虫期营养对于Vg的启动合成并不起关键的决定性作用，两组成虫均可以在羽化的48小时检测到Vg，且水组中的血淋巴水平并不低于蜜组对照，但绝大多数水组个体的卵巢发育停留在卵黄沉积的某一时期，此时在血淋巴中也检测不到，只有约20％的饲水个体卵巢可以发育成熟，出少量卵；用高剂量的ZR515于羽化当日点滴处理饲水个体，可以使所有接受处理的饲水个体的卵巢发育成熟，但是产卵〓依旧低于对照组的，不能恢复正常；这说明成虫期营养对卵巢中全体卵母细胞的成熟是必需的，其作用的产生是通过内分泌系统途径实现的。

Cultured in MS medium with different concentration of calcium, explants of Luffa Cylindrica, which could not generate root in usual medium, generated roots with enhanced rates and amounts according to the concentration of supplemented calcium. Moreover, some explants show transformed root from either shoot or flower bud.

在正常Ca2+浓度下，仅激素处理不能生根的丝瓜外植体，处以不同Ca2+浓度处理时，随Ca2+浓度升高，外植体生根数明显加快并增多，且有少量植株叶腋处异化生根，在一定程度上改变了腋芽的发育方向，这说明Ca2+改变了卷须芽或花芽的发育方向，使其发育为根。

These observations show that reprogramming is easier in interspecific embryos reconstructed with ES cells than that reconstructed with somatic cells, and that ES cells have the higher ability to direct the reconstructed embryo development normally than fibroblast cells. Oocytes were reconstructed with outbreeding Kunming albino mouse ES cells and enucleated rabbit oocytes, and the effects of the passages of ES cells and 6-DMAP on the development of interspecific reconstructed oocytes were analyzed. The interspecific reconstructed ES-rabbit oocytes were activated either by combined two set electric pulses and 6-DMAP or by two set electr

以上结果显示，6－DMAP能增加胚胎干细胞异种重构卵的卵裂率，对重构卵囊胚的发育率影响不大；高培养代数和低培养代数的胚胎干细胞用于异种核移植不影响异种重构卵的卵裂率和囊胚发育率；用胚胎干细胞作为供核细胞；比体细胞作为供核细胞所构建的异种重构胚更容易进行重编程，并且胚胎于细胞指导异种克隆胚胎正常发育的能力强于体细胞。

The spore germination and gametophyte development of 21 ferns are studied. It indicates that :① the development period of prothallium and young sporophyte of the same species is different due to seeding time of spores;② the optimal temperatures of spores germination and gametophyte development of 21 ferns are about 15 -24 ℃;③ the rate of spore germination of rare ferns is much lower than the ferns which occur large populations in nature;④ the treatment with GA 3 can accelerate the germination of the spores;⑤ the prothallium changes from large to small, green to yellow when young sporophyte comes out. The prothalliums of all 21 ferns die away after the appear of the 3rd leaf of sporophytes;⑥ shapes of the 1st and 2nd leaves of the young sporophyte are different from those emerged later;⑦ spores cultured in dark can not germinate;⑧ a prothallium can develop only one young sporophyte though it has many archegoniums, and the spore propagation with leaf mould substrate is an economical method.

摘 要：以腐叶土为培养基质，对 21 种蕨类植物进行了孢子萌发和原叶体发育的研究，结果表明：①不同时期播种的同种蕨类的孢子，发育出原叶体和幼孢子体所历经的时间长短不同；②孢子萌发和配子体生长发育的适宜温度约为 15 ～ 24 ℃；③稀有蕨类的孢子萌发率低，而在野外能形成较大种群的蕨类的孢子萌发率高；④用 GA 3 处理孢子可以促进萌发；⑤当原叶体上长出幼孢子体时，原叶体由大变小，由绿变黄， 21 种蕨类的原叶体都在幼孢子体上长出第 3 片叶时消失；⑥幼孢子体上长出的第 1 、 2 片叶在形态上与以后长出的叶不同；⑦孢子萌发需要光；⑧ 1 片原叶体尽管有多个颈卵器，但仅发育出 1 株幼孢子体；⑨利用腐叶土进行蕨类孢子繁殖是一种经济实用的繁殖方法。

Past study re-sults had indicated that MMC in the apomictic type could at most develop to te-trad stage.We observed that the sexual embryo sac of"Pingyi Tiancha"coulddevelop into 4-nuclei embry sac.

前人只观察到无融合生殖类型的大孢子母细胞至多能发育到四分体时期，而我们观察到平邑甜茶的有性胚囊能发育到四核胚囊。

Megaspore development and abortion of"Pingyi Tiancha"Compar-ing with regular developing megaspore of normal M.baccata,the megasporemother cellof"Pingyi Tiancha"could form mono-nucleus embryo sacby perhaps irregular meiosis,then most of sexual MES depauperatedand degenerated,finally aborted,or only a few further developed.Of asexualembryo sac,one or more large cells at the chalazal end of nucellus developed in-to one to more asexual embryo sac initials.After the competition between sexu-al embryo sacand asexual embryosac,most ovules only had one asexual embryo sac matured.

平邑甜茶大孢子的发育和败育与正常发育的山定子大孢子对比，平邑甜茶大孢子母细胞经减数分裂能形成单核胚囊，之后多数有性胚囊萎缩、退化而败育，只有极少数进一步发育；而无性胚囊则从胚珠合点端1个或多个较大的珠心细脆形成并首先发育为一个或多个无性胚囊原始体；经过有性胚囊和无性胚囊以及无性胚囊和无性胚囊之间的竞争，多数胚珠只有一个无性胚囊成熟。

During somitogenesis, zebrafish FoxD3 is known of maintaining the somitic expression of myf5, and subsequently regulates myogenesis. FoxD5, another gene of the FoxD family, is also expressed in forming somites of the anterior PSM. However, the regulatory function of FoxD5 in somitogenesis is not clear.

虽然已知斑马鱼中FoxD3在体节发育时，能维持myf5在体节的表现并藉此参与於肌肉的发育；但FoxD转录因子家族中的另一员，FoxD5，在体节发育时也会表现在presomitic mesoderm前端生成中的体节处，而这个FoxD转录因子是否在体节发育的过程中扮演调控的角色目前仍不清楚。

During the last three decades, several models have been proposed to explain the formation of somites, including the clock and wavefront model, the reaction-diffusion type model, clock and induction model, clock and trail model etc. Although some of them are satisfactory in the different aspects of somitogenesis, no one can explain the formation and regulation of somites perfectly.

近三十年来，研究者们就体节的发生和发育提出了多种解释模型，这包括时钟波阵面模型，反应扩散模型，时钟诱导模型，时钟痕迹模型等，虽然这些模型能从不同角度不同程度来解释动物体节发生和发育的不同现象，但无一能够解释体节发生和发育的全部。

In the United States, chronic alcoholism and hepatitis C are the most common ones.

在美国，慢性酒精中毒，肝炎是最常见的。

If you have any questions, you can contact me anytime.

如果有任何问题，你可以随时联系我。