请双击下面的英文字幕来播放视频。
翻译人员: Jiasi Hao
校对人员: Harper Chang
00:06
Centuries ago, the Inca developed
ingenuous suits of armor
0
6971
4060
几个世纪前,
印加人发明了一种独特的盔甲,
00:11
that could flex
with the blows of sharp spears and maces,
1
11031
4840
这种盔甲能够随着锋利长矛
和狼牙棒的打击而弯曲,
00:15
protecting warriors
from even the fiercest physical attacks.
2
15871
4406
从而保护士兵免受于
哪怕是最猛烈的物理攻击。
00:20
These hardy structures
were made not from iron or steel,
3
20277
4280
这些坚固的结构
并不是由铁或钢制成的,
00:24
but rather something unexpectedly soft:
cotton.
4
24557
4208
而是由一个极其柔软的材料制成:
棉花。
00:28
These thickly woven,
layered quilts of cotton
5
28765
3211
这些厚厚编织、层层堆叠的棉花
00:31
could distribute the energy from a blow
across a large surface area,
6
31976
4229
能够将击打的力量
分散在一块较大的表面积,
00:36
shielding warriors
without restricting their mobility.
7
36205
4274
因此在保护士兵的同时,
也不会局限他们的活动能力。
00:40
These seemingly contradictory features—
8
40479
2511
这些看似相互矛盾的特性——
00:42
strength and flexibility,
softness and durability—
9
42990
3825
强硬度和灵活性、
柔软度和耐用性,
00:46
have their roots in the intricate biology
of the nearly invisible cotton fiber.
10
46815
5810
来源于复杂生物学中
肉眼几乎无法看见的棉纤维。
00:52
These fibers begin life
deep within a cotton flower,
11
52625
3950
这些纤维的生命始于
棉花花朵表面的种籽。
00:56
on the surface of a seed.
12
56575
1990
00:58
As many as 16,000 fibers
will festoon a single seed,
13
58565
4592
一个种子中能被
多达 16,000 根的纤维充斥,
01:03
bulging from the seed’s surface
like miniature water balloons.
14
63157
4373
宛如迷你水气球,
从种子表面向外膨胀。
01:07
Each cotton fiber,
no matter how large it grows,
15
67530
3220
不论长成多大个,
每根棉纤维
01:10
is made of just one cell.
16
70750
2435
01:13
That cell has multiple layers
of cell wall.
17
73185
3790
这种细胞有好几层细胞壁。
01:16
After a few days,
the sides of the first layer,
18
76975
3140
几天后,第一层细胞壁,
亦称为初生细胞壁,
01:20
called the primary cell wall,
19
80115
2130
01:22
stiffen, pushing cell growth
in one direction
20
82245
3360
变硬,向一个方向推动细胞生长,
01:25
and causing the fiber to elongate.
21
85605
2970
从而使纤维被拉长。
01:28
The fiber elongates
quickly for about 16 days.
22
88575
3770
在 16 天左右的时间,
纤维被快速拉长。
01:32
Then it begins the next stage:
strengthening the cell wall.
23
92345
4165
其后,它便进入下一个生长阶段:
强化细胞壁。
01:36
It does this by making more
of the carbohydrate cellulose.
24
96510
4255
这是通过产生更多的
碳水化合物纤维素来完成的。
01:40
Cellulose will make up
34% of the cell wall at this stage
25
100765
4270
在这一阶段,该纤维素
占细胞壁构成成分的 34%,
且占比仍旧快速上升。
01:45
and swiftly increases.
26
105035
2075
这一生长促使
对现有细胞壁纹理的抵触,
01:47
This new growth
also reinforces the cell wall
27
107110
3140
01:50
by going against the grain
of the existing wall.
28
110250
3420
因此也强化了细胞壁。
01:53
The strengthened wall is more rigid,
restricting further growth.
29
113670
4379
被强化的细胞壁变得更加坚硬,
会限制其进一步生长。
这意味着如果纤维素过早
改变细胞壁结构,
01:58
That means if the fiber
remodels its walls too early,
30
118049
3505
棉花纤维就会很短,
02:01
it will be short,
31
121554
1030
02:02
and ultimately make rough, weak fabrics.
32
122584
3320
最终只能产出粗糙且易破的布料。
02:05
But if cell wall strengthening
begins too late,
33
125904
2846
但如果细胞壁强化阶段开始得过晚,
02:08
the wall won’t be sturdy enough—
34
128750
2170
那层细胞壁就会不够坚固,
02:10
producing fibers that are too weak
to hold fabrics together well.
35
130920
4180
生成的纤维会过为柔弱,
难以很好地将布料合成。
理想的生长条件是:
02:15
In ideal growing conditions—
36
135100
1996
适宜的温度、水、肥料、
害虫防治,还有光线。
02:17
with the right temperature, water,
fertilizer, pest control, and light—
37
137096
6796
02:23
a cotton fiber can grow
up to 3.6 centimeters long
38
143892
4580
这样,一根棉纤维
可以生长至长 3.6 厘米,
02:28
with only a 25 micrometer width.
39
148472
3610
宽仅为 25 微米。
细长且高品质的纤维
相较于短且质量较次的纤维,
02:32
Long, fine fibers
can wrap around one another
40
152082
2988
02:35
better than shorter,
less fine fibers,
41
155070
2730
能更好地缠绕彼此。
02:37
which means those long, fine fibers
make stronger threads
42
157800
3940
这表示那些细长且高品质的
纤维能够制造出更坚韧的棉线,
02:41
that hang together better as fabric.
43
161740
2539
编织成更好的面料。
02:44
Cotton with these qualities
has diverse uses—
44
164279
2871
因为棉花的特性,
它们被广泛使用,
02:47
from soft textiles
to the U.S. dollar bill,
45
167150
2940
从柔软的纺织品到美元纸钞——
内含 75% 的棉成分。
02:50
which is 75% cotton.
46
170090
3053
在下一个棉花纤维
成长的关键阶段,
02:53
The next crucial stage
of the cotton fiber’s growth
47
173143
2915
大量纤维素在次生细胞壁内
02:56
begins as it thickens
its secondary cell wall
48
176058
3290
02:59
by depositing large quantities
of cellulose into the secondary layer.
49
179348
4689
堆积并从而强化细胞壁。
纤维素的重量占比上升,
超过纤维净重的 90% 。
03:04
Cellulose goes on to make up
over 90% of the fiber’s weight.
50
184037
4470
03:08
The more cellulose that gets deposited,
51
188507
2148
越多纤维素堆积,
03:10
the denser that secondary layer becomes—
52
190655
2623
次生细胞壁
就变得更紧实——
03:13
and this determines
the strength of the final fiber.
53
193278
3060
这决定了最终棉花纤维的强度。
03:16
This stage is essential
for developing long-lasting material
54
196338
3734
对于后阶段是否能产出
经久耐用的材料,比如 T 恤,
这一生长阶段至关重要。
03:20
for the likes of, say, a t-shirt.
55
200072
2546
03:22
The garment’s capacity
to withstand years of washing and wear
56
202618
3930
一件成衣经受多年穿洗的能力
03:26
is largely determined by the density
of that secondary cell wall.
57
206548
4410
很大程度上
取决于次生细胞壁的密度。
03:30
On the other hand,
58
210958
1037
从另一方面来说,
03:31
its softness is strongly influenced
by the length of the fiber,
59
211995
3805
成衣的柔软性
主要受到棉纤维长度的影响,
03:35
established with the remodeling
of the primary wall layer.
60
215800
4630
而纤维长度是由
初生细胞壁重塑的。
03:40
Finally, after about 50 days,
the fiber is fully grown.
61
220430
4141
终于,在大约 50 天后,
纤维生长完毕。
03:44
The living matter
within the cell dies off,
62
224571
2599
细胞死亡,
03:47
leaving behind only the cellulose.
63
227170
3220
只留下纤维素。
03:50
The dried cotton seed pod, or boll,
that surrounds the fibers cracks open,
64
230390
5317
包裹纤维的干燥的
棉籽荚,也叫棉铃裂开了,
03:55
unveiling a burst of several thousand
fiber cells in a fluffy mass.
65
235707
5468
露出一簇簇柔软蓬松的纤维细胞。
04:01
The thread-like fibers we see—
thinner than a human hair—
66
241175
3940
我们看到的丝状纤维——
比人类毛发还要细——
04:05
are the remains of those dense,
dried out walls of cellulose.
67
245115
4704
是那些紧实干燥的
纤维素壁(原细胞壁)的残留物。
04:09
Tens of thousands of these fibers
spun into yarn
68
249819
3280
数以万计的这些纤维被纺织成纱线,
随后继续加工生产为各种东西,
从面料织物,到咖啡过滤器、尿布,
04:13
will go on to make everything from fabric,
to coffee filters, diapers,
69
253099
4436
04:17
and fishing nets.
70
257535
1575
还有渔网。
04:19
And with the help of modern science,
71
259110
2045
利用现代科学的帮助,
04:21
cotton might soon be softer, stronger,
and more resilient than ever
72
261155
4937
调整营养、气候和基因等学科因素,
科研人员正在研究如何优化棉花生长。
04:26
as researchers investigate
how to optimize its growth
73
266092
3430
04:29
based on nutrients, weather conditions,
and genetics.
74
269522
3733
棉花可能在不久将来
变得更柔软、更坚硬,以及更有韧性。
New videos
关于本网站
这个网站将向你介绍对学习英语有用的YouTube视频。你将看到来自世界各地的一流教师教授的英语课程。双击每个视频页面上显示的英文字幕,即可从那里播放视频。字幕会随着视频的播放而同步滚动。如果你有任何意见或要求,请使用此联系表与我们联系。