有性生殖

The results showed that the sex ratio of trees was 1 m 2 f, and the natural T. cuspidata tree was able to sexually reproduce for many years. Male trees had fecundity when the diameter at breast height ranged from 1.5 cm to 92 cm, while female trees had fecundity when the DBH from 9.5 cm to 68.1 cm. Male trees typically flowered at the age about 20 years earlier than female trees. The numbers of microstrobili were 3 times more than that of megastrobili, and only 1/10 megastrobili developed into seed. The numbers of strobili and seed were correlated with DBH, crown diameter and height of trees; however, no significant correlations were observed with other site factors. Numbers of strobili decreased from the upper to lower canopy layers, while the quantity of seed decreased from the middle, upper to lower canopy layers. Seed-setting rate increased from the upper to lower canopy layers. Numbers of strobili and seeds in different directions of the canopy were not uniform, but the differences weren't significant.

结果表明：现实东北红豆杉天然种群中，♀♂性比为1：2；天然东北红豆杉有性生殖持续时间长，雄株胸径在1.5~92cm，雌株胸径在9.5~68.1cm保持生殖状态，雄株较雌株早约20年进入花期；天然东北红豆杉小孢子叶球数量平均为大孢子叶球数量的3倍，大孢子叶球转化为果实的数量不足1/10，孢子叶球数量、结实数量与样株的胸径、冠幅、树高显著相关，与其他立地因子相关不显著；孢子叶球数量在冠层间的分布呈现由上至下的递减规律，而结实数量在冠层间沿中、上、下递减，结实率沿冠层自上而下递增；孢子叶球与结实数量在树冠不同朝向上也呈现出一定的特点，但总体上差异不显著。

Stromata surrounded the flag leaf sheathes, white, as long as 47.5-165.0 mm. From its appearance in late April until crash in middle July, no mature sexual structures were either observed in nature or conducted by artificial mating tests.

子座长47.5~165.0mm，白色，包裹其宿主植物的旗叶叶鞘；于4月下旬形成，7月中旬完全崩溃；在自然条件下、人工交配试验中，子座上均未形成有性生殖结构。

Coevolution, freshwater snails, maintenance of sexual reproduction, Red Queen hypothesis, Trematoda, parthenogenesis.

&研究表明，在寄生虫丰富的环境中，有性生殖可以赋予物种进化优势，&约凯拉表示。

However, the growth of rotifer fed on high-density Chlorella pyrenoidosa was inhibited notably, and there was no effect on its fecundity. Sexual reproduction of Brachionus urceus was not promoted by improving the density of diet.

结论］低食物浓度下，轮虫生命周期缩短、繁殖力降低；食物浓度过高，能抑制轮虫生长，但对繁殖力影响不大；提高食物浓度，对壶状臂尾轮虫的有性生殖没有明显的促进作用。

It was investigated that the seasonal dynamics of bud bank, the effects of high sexual reproductive allocation on bud bank and daughter shoots, the changes of bud bank under different parent shoot density, C and N compound of apic ...更多 al rhizome bud response to bud bank seasonal dynamics, the effect of covering treatment during different growing phase on bud bank. The main results and conclusions were as follows:(1) Each bud type has distinct earliest timings to break. B1-1 begins to generate during late May, but B1-2, B2 and B3 occur during late June.

本文分别从羊草地下芽库的季节动态、高有性生殖分配对芽库的影响、不同基株密度条件下芽库及所生成子株的数量变化、根茎顶芽碳氮化合物在克隆生长中的重要作用以及不同阶段遮光处理对芽库数量的影响方面对羊草进行研究，得出的主要结果和结论如下：(1)每种类型芽都有不同的起始产生时间。

Specimens were reared under different temperatures, photoperiods, and densities. Total weights of lacerates were used as an index of investment in asexual reproduction, whereas gonad weights as an index of investment in sexual reproduction.

为了解答这个疑惑，我们以美丽海葵（Aiptasia pulchella Carlgren 1943）为材料，以不同的环境变因：温度、光周期、海葵个体密度为处理，并以碎裂片数目、大小及湿重代表无性生殖的反应与投资，以生殖腺湿重代表有性生殖的投资，探讨海葵的有、无性生殖投资之间是否有补偿作用的现象。

PCD during sexual reproduction in plants is a universal phenomenon in the development of plants. The degeneration of some cells in the procreating apparatus is very important for the sexual reproduction.

PCD是植物发育过程中的一种普遍现象，植物生殖器官中一些细胞的死亡对植物有性生殖具有重要作用。

Among them,light is one of the most important factor influencing the rate of the growth of corals.

在同一环境条件下，海葵的适应性更强，在实验条件下能进行分裂生殖和有性生殖。

Conjugation is a sexual model of reproduction, a feature for ciliates.

接合生殖是纤毛虫特有的一种有性生殖模式。

Delph L F Sexual-differental resource allocation patterns in the subdioecious shrub Iiebe subalpina 10.2307/1938271 Ecology , 1990,4

王仁忠 不同生境条件下羊草种群无性系和有性生殖特征的比较研究应用生态学报， 2001，3

This paper demonstrated the impact on the environment today, an important factor is Education.

本文主要展示了当今影响环境的一个重要因素——教育。

Article 16 The power to interpret these Procedures shall remain with the Ministry of Agriculture and CAA.

第十六条本程序由农业部、国家认证认可监督管理委员会负责解释。