蚕怎样吐丝
发布网友
发布时间：2022-05-03 00:16
共3个回答
热心网友
时间：2022-06-28 16:17
蚕儿吐丝结茧时，它的头总是时而抬高，时而垂下，并不停地左右摆动着。如果用放大镜仔细观察，蚕儿作茧的丝，是一个个排列得很整齐的“8”字形丝围，每20多个丝圈叫做一个丝列。当茧的一头织好后，它会来个1800大转弯，开始织茧的另一头，因此，家蚕的茧子都是两头稍粗，中间稍细，很像一颗花生。蚕儿每结好一枚茧，需要转换250～500次位置，编织约6万个“8”字形丝围，每个丝围约有0．72厘米长。蚕儿就是这样不停地织呀织的，将自己体内的丝完全抽尽后，才化蛹变娥，接种传代，世世代代为人类造福。
热心网友
时间：2022-06-28 16:18
蚕吐丝结茧可分为4个过程：
（1）熟蚕先将丝吐出，黏结在蔟器上，再吐丝连接周围枝，即结茧网。茧网不具备茧形，只是一些松软凌乱的茧丝层，以作为结茧的支架。
（2）蚕结完茧网后，继续吐出凌乱的丝圈，加厚茧网内层，然后以S形方式吐丝，开始出现茧的轮廓，叫做结茧衣。茧衣的丝纤维细而脆，排列极不规则，丝胶含量也多。
（3）茧衣形成后，茧腔逐渐变小，蚕体前后两端向背方弯曲，成C形，蚕继续吐出茧丝，吐丝方式由S形改变成∞形，这就开始了结茧层的过程。
（4）当蚕由于大量吐丝，体躯大大缩小时，头*摆动速度减慢，而且没有一定的节奏，吐丝开始显得凌乱，形成松散柔软的茧丝层，称为蛹衬。最后，蚕头部向上，尾部向下，吐出最后留存在体内的丝物质，形成一团松软的茧顶，吐丝营茧过程结束。
本条内容来源于：中国农业出版社《中国农业发展报告》
热心网友
时间：2022-06-28 16:18
Silkworms, offspring of moths, proce their highly-desirable, pricey silk, by spewing out thread from tiny holes in their jaws, which they use to spin into their egg-bearing cocoons. This entire proction takes a mere 72 hours, ring which time t
hey proce between 500-1200 silken threads. These miniature, mulberry leaf-munching marvels lay, at minimum, 500 eggs each spring, thereby increasing the number of workers for the proction line.
The ancient Chinese unearthed the silkworm's secret, and were the first to spin the silkworm's threads into cloth. They kept this covert, top-secret operation, from the rest of the world by imposing the death sentence upon those who smuggled the worm or its eggs out of China. Eventually, however, the secret was out, and silkworms are now farmed for their silk, in China, of course, in Japan, in India, in France, in Spain, and in Italy. These countries harness the power of the silkworm through a tedious, labor-intensive, time-consuming process, a process which prominently figures into the price of silk.
Farm workers painstakingly place the 500 plus eggs the grayish-white moth lays, upon strips of paper or cloth, until the following spring, when the incubated eggs hatch, and the tiny, black worms emerge. Once hatched, workers transport the worms to trays brimming with the worm's favorite fodder of finely chopped, white mulberry leaves. After approximately 6 weeks, the satiated worms begin slowly to sway their heads back and forth to signal that show time is at hand.
Once the silkworm completes its cocoon, the farmer snatches his cocoon from him, to prevent the shrunken chrysalis, carefully encased inside, from hatching into a moth in 12 days. The silk farmers ensure that this event does not transpire, and does not kill his moneymaking venture, by exposing the cocoons to heat, thereby executing the chrysalis. Now, the silkworm's labor of love is prepared for the silk proction process.
The process begins by bathing the now-empty cocoons in troughs of warm water, which serves to soften the gum binding the silken filaments together. He now proceeds with the arous task of unraveling several cocoons, and winding the filaments onto a reel that twists 10-12 filaments together into a "single" thread of silk. The end proct is a skein of raw silk, which the farmer profits from by selling to the highest bidder.
