Corn, potatoes, and sweet potatoes are the three staple foods we take for granted in our lives.

In fact, their hometown is far away in America. They were introduced to China during the Ming and Qing Dynasties and gradually became popular and became an indispensable food on the Chinese table.

So, what are the advantages of these three major crops from the Americas?

What impact has it had on China’s population growth?

Let botanist Shi Jun analyze it carefully for us.

Literature, History and Military Pictures Zhang Yang In 1368 AD, Zhu Yuanzhang established his capital in Nanjing and began the rule of the Ming Dynasty.

In the following 500 years, despite experiencing wars and dynasty changes, China maintained a state of great unification during this period.

China's population has grown rapidly, especially during the Qianlong period of the Qing Dynasty. It has grown by leaps and bounds. From 143 million people in the sixth year of Qianlong's reign to more than 200 million or 300 million people, it only took a few decades.

The Ming and Qing Dynasties were a period of very frequent and severe natural disasters in Chinese history, which was obviously not a good thing for ancient agriculture, which almost relied on the sky for food.

So what was the reason for the rapid population growth during this period?

Many historical scholars believe that the introduction and widespread planting of various New World crops in the late Ming and early Qing Dynasties was an important driving force.

To clarify this issue, we still need to clarify the time when potatoes, sweet potatoes and corn were introduced, as well as the special abilities they possess.

Corn, the Super Food with Flaws There is no doubt that, as the food that nourished American civilization, corn has an irreplaceable position in the food circle.

Compared with wheat and rice, corn has stronger environmental adaptability and good yield.

Corn is suitable for planting in relatively arid mountainous areas. In addition to their well-developed root system, what is more important is the special photosynthesis pathway that supports them - the C4 pathway.

Generally speaking, when plants perform photosynthesis, they use the carbon dioxide that enters the stomata of their leaves.

However, the concentration of carbon dioxide in the air is limited after all, which greatly limits the efficiency of photosynthesis.

C4 plants like corn have a clever trick, which is to first concentrate carbon dioxide and then perform photosynthesis.

The carbon dioxide entering the corn mesophyll cells combines with phosphoenolpyruvate (PEP) to produce oxaloacetate with 4 carbon atoms (hence the name of the C4 pathway), which is then converted into malic acid or aspartic acid; subsequently,

These special acids are concentrated and sent to the leaf sheath, where they are decomposed into carbon dioxide and pyruvate.

In this way, the carbon dioxide concentration in the leaf sheath cells increases, and the photosynthetic efficiency naturally increases.

Not only that, C4 plants also have amazing water use efficiency.

C4 plants require only 230 to 250 ml of water to produce 1 gram of dry matter, while C3 plants consume two to three times the amount of water.

Because of this, corn has become an important food crop in arid areas with medium and high altitudes.

In addition to being a good seed, corn is rich in nutrients that the human body needs.

The carbohydrates contained in fresh corn account for 74% of the dry matter, and there are also 9.4% protein.

Because of its rich nutrition, corn was already used as a staple food by the Mayans in America as early as 8,000 years ago.

However, compared with rice and wheat, corn has an inherent disadvantage-the nicotinic acid contained in corn kernels cannot be released without treatment with an alkaline solution.

People who rely on corn for food can suffer from pellagra due to a lack of niacin, a special vitamin.

Fortunately, the Chinese diet is quite rich in food composition, which naturally solves this problem.

Sweet Potato, the Strength of Natural Genetically Modified Crops Although the status of sweet potato has not been as high as that of corn in South America, sweet potato is also a food crop that has its own halo.

Sweet potatoes are a naturally genetically modified crop that occurred about 1 million years ago.

Yes, this is not done by us humans, but an arrangement of nature.

In fact, the roots of the ancestors of sweet potatoes were not strong, more like the adenophora and platycodon we see today.

However, just 1 million years ago, a sweet potato was invaded by a bacteria called Agrobacterium tumefaciens. It survived tenaciously and acquired special genes, allowing future generations to embark on the path of "putting on weight"

.

In today's laboratories, Agrobacterium tumefaciens is the most commonly used tool among scientists.