有性生殖的

Meiosis is the most important reproduce and favoured by organisms. The key events of meiosis identified are pairing, synapsis, genetic recombination, segregation.

李丽减数分裂是生物体重要的有性生殖方式，它提供来自母本和父本的基因信息，产生具有生物多样性的子代，使其能够适应环境的变化而不断进化。

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。

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。

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。