How does rice learn to avoid water? A serious rice lover tells you the real reason why the taste of northern and southern rice is different

How does rice grown in water breathe?

Rice can grow in water because there are many gaps between its roots, stems and leaves, which are called air cavities. These air cavities connect the various parts of rice (leaves, stems and roots), making the whole plant like a straw inserted in the water. Oxygen can reach the roots at the bottom of the water through these air cavities, allowing rice to grow in water.

However, this does not mean that rice is not afraid of flooding. When a flood breaks out and the water level exceeds the leaves, the entire plant will be submerged in water and the rice will not be able to breathe. Therefore, when serious waterlogging occurs, drainage must be carried out in time to ensure the normal growth of rice.

Why is rice grown on a large scale in the South?

The rice planting area in China has been relatively stable, basically maintaining at around 450 million mu, with little change. The rice planting area accounts for about one-third of the total cultivated land in my country. In terms of geographical distribution, the rice planting area in the south is relatively large, while that in the north is relatively small, which is also the so-called "rice in the south and noodles in the north" phenomenon. In addition, the influence of the natural geographical environment has also led to other regional differences, such as "ships in the south and horses in the north", "tea in the south and wine in the north", "oranges in the south and citrons in the north", and "sweet in the south and salty in the north".

The main reason why the rice planting area in the south is larger is that the land and climate conditions are more suitable for the growth and development of rice. The climate in the south is warm and humid, with abundant rainfall, and the temperature and humidity are very favorable for the growth of rice.

In addition, the eating habits of southern residents are also one of the reasons why the rice planting area in the region is large. Southerners like to eat rice, so rice planting is closely related to the lives of southerners.

Why is Northeastern rice so delicious?

"Three meals a day, rice is the food", rice, as the staple food, plays a pivotal role in our daily life. In the process of enjoying rice for many years, people have found that Northeast rice is always more delicious than southern rice. There are several reasons for this:

First of all, the black soil in Northeast China provides rice with unique advantages. The black soil is famous for its deep soil layer, which can reach a depth of 40 to 80 centimeters. This fertile soil provides rich nutrients for rice, making the rice quality better.

Secondly, the climate conditions in Northeast China are very suitable for rice growth. The suitable temperature range for rice growth is 21 to 25 degrees Celsius. The weather conditions in Northeast China happen to meet this requirement. The temperature with a large temperature difference between morning and evening is more suitable for rice growth, and it is also conducive to controlling the temperature difference within the ideal range of 21 to 25 degrees Celsius. In addition, the long sunshine hours in Northeast China provide sufficient sunshine for rice. This temperature condition is very conducive to the growth of rice.

Furthermore, the starch structure of rice varies depending on the growing environment. There is a fundamental difference in starch structure between Northeastern rice and southern rice. One of the factors that affect the taste of rice is the content of amylose. When the amylose content in rice is high, the rice tastes sticky; when the amylose content is low, the rice tastes hard and lacks elasticity. The amylose content of Northeastern rice is generally between 20% and 25%, while the amylose content of southern rice is between 15% and 18%. Therefore, when tasting rice, some rice tastes sticky and elastic, while others taste hard.

In addition, the taste of early rice is not as good as that of mid-season and late rice because the filling period is too short. The filling period of early rice is in a relatively hot stage in the south, and this high temperature environment may shorten the filling period of early rice. In rice cultivation, this situation is called "high temperature forced ripening". This means that the short filling period of early rice is due to the influence of high temperature. Under high temperature, the filling speed is accelerated, and the organic matter formed by photosynthesis accumulates quickly and irregularly inside the husk, resulting in a more chaotic arrangement of starch molecules. Due to the fast filling speed, the taste of rice is affected. In contrast, the filling period temperature of mid-late rice is relatively low, and the filling speed is relatively slow. In this way, the starch molecules are arranged in an orderly and compact manner in the grains, which is similar to the filling of Northeast japonica rice. Therefore, the taste of mid-late rice is generally better than that of early rice.

Produced by: Popular Science in China to Benefit Farmers

Scientific Advisor: Tang Zhong, Professor and Doctoral Supervisor, College of Agricultural Engineering, Jiangsu University

Co-ordinators: Liao Danfeng, Zheng Fengmao, Wang Changhai, Zhang Ruijie

Planning: Wu Yuetong

Editor: Lu Jingwen (internship)