These hardy structures were made not from iron or steel, but rather something unexpectedly soft: Cotton.

這些結實的結構並不是用鐵或鋼製成，而是一種出乎意料軟的材料：棉。

These thickly woven, layered quilts of cotton could distribute the energy from a blow across a large surface area, shielding warriors without restricting their mobility.

這些編織得很厚實、 多層襯墊的棉材料能把來自攻擊的能量分散到很大的表面面積上，在保護戰士的同時， 不會限制他們的行動力。

These seemingly contradictory features, strength and flexibility, softness and durability, have their roots in the intricate biology of the nearly invisible cotton fiber.

這些看似很矛盾的特徵——力量和靈活度，柔軟和耐受度——源於幾乎不可見棉纖維的複雜生物學特性。

These fibers begin life deep within a cotton flower, on the surface of a seed.

這些纖維的生命始於棉花內部深處，種子的表面。

As many as 16,000 fibers will festoon a single seed, bulging from the seed's surface like miniature water balloons.

單一顆種子上就纏繞了一萬六千條纖維，纖維從種子表面凸起，好像迷你的水氣球。

Each cotton fiber, no matter how large it grows, is made of just one cell.

每一根棉纖維，不論長得多大，都只由一個細胞構成。

That cell has multiple layers of cell wall.

該細胞具有多層細胞壁。

After a few days, the sides of the first layer, called the primary cell wall, stiffen, pushing cell growth in one direction and causing the fiber to elongate.

幾天之後，第一層的邊，即「初生細胞壁」硬化，迫使細胞朝向一個方向生長，造成纖維增長。

The fiber elongates quickly for about 16 days.

纖維會快速增長十六天左右。

Then it begins the next stage: strengthening the cell wall.

接著進入下一階段：強化細胞壁。

It does this by making more of the carbohydrate cellulose.

通過製造更多碳水化合纖維素來做到這一點。

Cellulose will make up 34 percent of the cell wall at this stage and swiftly increases.

在這個階段，纖維素會構成 34% 的細胞壁，並快速增加。

This new growth also reinforces the cell wall by going against the grain of the existing wall.

這種新的生長也會強化細胞壁，因為它的生長方向和既有的細胞壁紋路不同。

The strengthened wall is more rigid, restricting further growth.

強化的細胞壁比較堅固， 限制了進一步的生長。

That means if the fiber remodels its walls too early, it will be short, and ultimately make rough, weak fabrics.

這表示若過早重塑細胞壁， 纖維長度就會很短，最終就會製成粗糙、脆弱的織物。

But if cell wall strengthening begins too late, the wall won't be sturdy enough, producing fibers that are too weak to hold fabrics together well.

但如果細胞壁的強化太晚才開始，細胞壁就不夠堅固，產生出來的纖維會太脆弱， 無法給織物良好的支撐力。

In ideal growing conditions with the right temperature, water, fertilizer, pest control, and light, a cotton fiber can grow up to 3.6 centimeters long with only a 25 micrometer width.

最理想的生長條件為適宜的溫度、水、肥料、害蟲控制及光線，棉纖維可以長到 3.6 公分長，寬度只有 25 微米。

Long, fine fibers can wrap around one another better than shorter, less fine fibers, which means those long, fine fibers make stronger threads that hang together better as fabric.

比起短而較粗的纖維，長而細的纖維可以彼此包覆，即這些細長的纖維能製成強度更好的線，做成織物時結合得更好。

Cotton with these qualities has diverse uses, from soft textiles to the U.S. dollar bill, which is 75 percent cotton.

具有這些特性的棉用途很多，從軟性紡織品到美金鈔票，美金鈔票有 75% 是棉。

The next crucial stage of the cotton fiber's growth begins as it thickens its secondary cell wall by depositing large quantities of cellulose into the secondary layer.

棉纖維生長的下一個關鍵階段始於大量纖維素進入到第二層，導致次生細胞壁開始增厚時。

Cellulose goes on to make up over 90 percent of the fiber's weight.

此時纖維素繼續增加到占棉纖 90% 的重量。

The more cellulose that gets deposited, the denser that secondary layer becomes.

纖維素累積得越多，第二層就會變得更密實。

And this determines the strength of the final fiber.

這就會決定最終纖維的強度。

This stage is essential for developing long-lasting material for the likes of, say, a t-shirt.

若要開發出持久耐用的材料， 譬如製成 T 恤，這個階段至關重要。

The garment's capacity to withstand years of washing and wear is largely determined by the density of that secondary cell wall.

衣服對經年累月的清洗和穿著的耐受程度，主要取決於次生細胞壁的密度。

On the other hand, its softness is strongly influenced by the length of the fiber, established with the remodeling of the primary wall layer.

另一方面，衣服的柔軟度則主要是受到纖維長度的影響，而長度的建立是要靠重塑初生細胞壁層。

Finally, after about 50 days, the fiber is fully grown.

最後，在大約五十天後， 纖維完全長成了。

The living matter within the cell dies off, leaving behind only the cellulose.

細胞內部的活質都死光了，剩下的就只有纖維素。

The dried cotton seed pod, or boll, that surrounds the fibers cracks open, unveiling a burst of several thousand fiber cells in a fluffy mass.

包裹著纖維的乾燥棉種子莢，或棉鈴，會裂開，綻開數千個纖維細胞，成為一個蓬鬆的毛茸塊。

The thread-like fibers we see—thinner than a human hair—are the remains of those dense, dried out walls of cellulose.

我們看到像線一樣的纖維——比人類頭髮還細——是那些密實乾燥的纖維素細胞壁所剩下來的部分。

Tens of thousands of these fibers spun into yarn will go on to make everything from fabric, to coffee filters, diapers, and fishing nets.

數萬條這種纖維會被紡成紗，接著便可以製作各種東西， 從織物到咖啡濾紙、尿布，以及漁網。

And with the help of modern science, cotton might soon be softer, stronger, and more resilient than ever as researchers investigate how to optimize its growth based on nutrients, weather conditions, and genetics.

在現代科學的協助下，棉可能很快就會變得比過去更軟、更堅固，且更有彈性，因為研究者正在根據營養物、 氣候條件，以及遺傳學，探究如何將棉的生成做到最佳化。

The cotton from your favorite t-shirt likely begin its life in America, China or India.

你最喜歡的 T 恤裡面的棉可能來自於美國、中國或印度。

How did they get from there to your bag?

他們是怎麼從這些地方來到你的購物袋裡呢？

Find out in this video.

看看這支影片來得到答案吧！