The external cause includes unfitting culture conditions, strain aging, unsuitable preservation and infection virus of asexuality propagation.

Asexuality is a fast growing sexual preference.

无性恋是一种正在快速增涨的性倾向。

From 872 clones asexually propagated 3 times from the callus treated with 2% EMS, 7 clones resistant to 3. 5 mmol oxalic acid were screened out, and 5 out of 7 clones were stable in resistance.

经2%EMS处理的愈伤组织扩增3代后，从872块愈伤组织中.筛选到7块抗（耐）3.5mmol草酸的愈伤组织，其中有5块抗性稳定。

Self-fertilization is a risky strategy, which is why sex is so popular among large and complex organisms. 3 There areoccasionally complex animals that reproduce asexually, 4 but this behavior isrelatively rare.

所以说自体繁殖是个很危险的策略，这也是为什么在稍大、稍复杂的种群中，性是如此普遍的原因。3虽然有时一些高等生物也会无性繁殖，4但这种行为是相对罕见的。

For example, plants can sometimes transmit somatic mutations to their descendants asexually or sexually where flower buds develop in somatically mutated parts of plants.

例如，植物有时将体细胞突变通过无性或有性过程传递给后代，而花芽可能由植物的体细胞变异部分发育。

Zizania latifolia Turcz, which originates from China and Southeast Asia, belongs to perennial aquatic vegetables and reproduces asexually.

茭白（Zizania latifolia Turcz）为多年生水生宿根性草本植物，无性繁殖，原产中国和东南亚。

Sugarcane is an asexually reproductive plant, and after continuous cropping for several years, the yield and quality generally decline because of various kinds of pathogens' infecting.

甘蔗系无性繁殖作物，容易因多年连续种植后受到各种病原物的反复侵染，造成产量和品质下降。

They occur naturally when bacteria, plants and insects reproduce asexually, and when mammalian embryos split and go on to develop into identical twins.

在细菌，植物，昆虫中这是自然发生的，当哺乳动物胚胎分裂，继续发育成同卵双胞胎。

now that humans reproduce asexually?"

现在人类可以单性繁殖了？”

Other plants bear unisexual flowers, with only stamens or carpels functional, and others reproduce asexually.

其他植物具单性花，即只有一种功能性雌蕊或雄蕊。

But because many of the crops reproduce asexually producing clones, rather than reproducing through seeds the banking process is far from simple.

但是由于许多作物是无性繁殖的产生的是克隆，而非通过种子繁殖这个种子库的过程远远不那么简单。

These plants can reproduce sexually and asexually.

这些植物既可以有性繁殖，也可以无性繁殖。

Reproducing them asexually allows the researchers to ensure the genes of the different plants don't mix, preserving their genetic identity.

其中大多数品种作为植物保留在室外养殖场，每年通过无性繁殖以确保不同作物的基因不会互串，从而确保其遗传特性。

Asexually propagated crops, such as potato, sweet potato, sugar cane, fruit trees, etc.

无性繁殖作物，如马铃薯、甘薯、甘蔗以及多年生果树等。

But variety has been aged and degenerated severely for long time because of asexually propagation and lack of effective breeding route.

因长期无性繁殖，品种老化和退化严重，但有性世代退化而缺乏有效的育种途径。

When the mosquito bites, it releases the sporozoites, which enter human liver cells through the bloodstream and reproduce asexually.

蚊虫叮咬人的时候就释放出子孢子，它通过血流进入肝细胞，并且进行无性生殖。

An asexually produced reproductive cell, such as a zeospore, found in certain algae.

无性生殖细胞无性生殖细胞，存在于一些藻类植物里。

RESULTS: The product is good at texture and curative effect.

结果: 制成的膜剂质地均匀,疗效确切.

Objective To observe the curative effect of operation for intractable calcaneodynia.

目的观察顽固性跟痛症的手术治疗效果.

Then judge the curative effect according to the curative standard.

根据疗效标准判断疗效.

Edda's home is in Asgard, "a land full of magic and adventure." But Edda, the littlest Valkyrie, doesn't have quite enough to do, until her father flies her "all the way to Earth for the first day of school."

埃达的家在仙宫——“一个充满魔力和冒险的地方”，但小瓦尔基里人埃达却没什么事可做，所以她父亲领她飞到“地球去上学”。