Why are the leaves of green onions hollow

Back to the landlord, first of all, I'm not a biology major. But I often like to read popular science books and magazines, so I can talk about it roughly.

An important criterion of biological evolution is that evolution proceeds in the most streamlined direction while satisfying the needs of biological survival.

1 leg, difficulty maintaining balance at rest and in motion. If humans walk upright, if they only have one leg, they will become extinct long ago under the harsh natural conditions.

In order to ensure the stability of uprightness, we need 3 fulcrums that are not in the same straight line, but if a person has 3 legs, then it is too wasteful, because as an upright walking animal, the space for the transverse profile is limited, if there is a leg in the middle. Where do other things grow?

Then we can use the previous thing to achieve an effect close to the 3 fulcrums - the soles of the feet.

As long as the ball of one foot is completely grounded, you can have at least 3 fulcrums – plantar + heel + plantar heel of the other foot – to maintain balance, regardless of whether the other foot is on tiptoe or flat, without having to use most of the upper limb to maintain balance as you would if you were standing upright on one foot.

In this way, 2 legs can ensure the stability of the person's limbs when standing still and moving, and there is a faster movement speed than 1 leg, so as to avoid danger as soon as possible.

Why do people have two legs?

<> the leaves and stems of green onions are hollow and burning. The leaves of green onions are composed of leaf bodies and leaf sheaths, the leaf body is long conical, hollow, green or dark green, the leaf sheath of a single skin limb is generally cylindrical, the leaf sheath of multiple layers and the 4-6 young leaves that have not yet been unsheathed are wrapped inside, and the hunger key forms a club-like pseudostem.

Summary. Excessive soil moisture. Green onions are native to Central Asia, West Asia and other places, and are resistant to drought and excessive humidity.

Especially in the slow growth stage of high temperature, drought will not cause death, and excessive soil moisture often causes waterlogging and death of plants, which is the saying "green onions do not die and drown". This year, the summer and autumn rains are more frequent, although the rainfall is not large, but the soil has been in a moist state, causing waterlogging, suffocating the root system, and the aboveground part of the leaf yellowing. 2.

The air humidity is too high. There is a layer of wax on the surface of green onion leaves, which has the effect of protecting water dispersion and loss, and the transpiration effect is small. This year's summer and autumn have more cloudy and rainy days, and the air humidity is high, which inhibits transpiration.

As a result, the absorption of the root system is reduced, and the nutrients brought to the leaves by absorbing water - nitrogen, phosphorus, potassium, calcium, magnesium, sulfur, zinc and other fertilizer elements - are also greatly reduced. Long-term lack of fertilizer elements can also cause yellowing of leaves. 3.

The disease is severe. Due to years of continuous cropping, soil-borne diseases are serious, resulting in a large number of soft rot, blight, root rot and downy mildew. In addition, excessive soil moisture exacerbates the damage of diseases, which can cause dry and yellow leaves.

Measures to prevent dried green onions from yellow leaves:

Excessive soil moisture. Green onions are native to Central Asia, West Asia and other places, and are resistant to drought and excessive humidity. Especially in the slow growth stage of high temperature, drought will not cause death, and excessive soil moisture often causes waterlogging and death of plants, which is the saying "green onions do not die and drown".

This year, the summer and autumn rains are more frequent, although the rainfall is not large, but the soil has been in a moist state, causing waterlogging, suffocating the root system, and the aboveground part of the leaf yellowing. 2.The air humidity is too high.

There is a layer of wax on the surface of green onion leaves, which has the effect of protecting water dispersion and loss, and the transpiration effect is small. This year's summer and autumn have more cloudy and rainy days, and the air humidity is high, which inhibits transpiration. As a result, the absorption of the root system is reduced, and the nutrients brought to the leaves by absorbing water - nitrogen, phosphorus, potassium, calcium, magnesium, sulfur, zinc and other fertilizer elements - are also greatly reduced.

Long-term lack of fertilizer elements can also cause yellowing of leaves. 3.The disease is severe.

Due to years of continuous cropping, soil-borne diseases are serious, resulting in a large number of soft rot, blight, root rot and downy mildew. In addition, excessive soil moisture exacerbates the damage of diseases, which can cause dry and yellow leaves. Measures to prevent dried green onions from yellow leaves:

Pest and disease green onion blight is a very common disease, which often occurs simultaneously with downy mildew, purple spot disease, thrips, spotted submarine fly and other insect pests, which can be said to be as simple as a human cold; When the disease is severe in the later stage of downy mildew, it will cause the green onion leaves to gradually turn yellow and dry up;

Part of Shandong green onions hollow, perhaps because of the variety, Shandong green onions are white and long, some green onions grow too long and too thick, the green onion heart is not wrapped, in addition, Shandong green onions are stored for too long, there will also be hollow phenomenon.

This is related to its evolution and adaptability, the onion has a thick waxy layer on the skin, and the whole leaf is observed under the microscope, the epidermis has fewer pores, and a hollow air cavity is formed in the middle of the leaf for gas exchange.

Have a great day