Fig. 34-2 is a schematic diagram showing different organs of the mature plant of Welsh onion.

(1) Roots: The radicle sprouted from the seeds of Chinese onion grows into primary roots, and when the cotyledons of the seedlings are straight, adventitious roots grow. When the seedlings have the first true leaf (1 leaf), branched roots occur on the adventitious roots, and many adventitious roots gradually grow with the growth of the plants, and branched roots occur one after another to form fibrous roots.

The main roots of mature plants (plants with about 30 leaves) are distributed 35 ~ 40 cm below the soil surface, and the transverse diameter is 65 ~ 84 cm, which is shallow root system.

(2) Stems: During the vegetative growth period, the stems of green onions are shortened into a disk, which is called a stem disk, and new leaves and adventitious roots constantly appear on it.

After vernalization, the terminal buds of plants are transformed into flower buds, which are stretched out to form flower stems (or flower beds and flower beds).

After the seeds mature, the flower stems die.

The lateral buds of non-tillering Welsh onion germinate on the stem plate after the first flowering, and new tillering plants can be seen at the end of flowering.

The flower stems are stout and have strong photosynthesis, which is the main source of photosynthetic products of seeds.

(3) Leaves: The green onion cotyledons are unearthed in the shape of needles and noses, and the tips of cotyledons remain in the seed coat to absorb endosperm nutrients.

Because the inflexion point of the tortuous cotyledon-the rear part of the cotyledon knee (near the root end) grows faster, the cotyledon finally leaves the endosperm and straightens out, and becomes an autotrophic cotyledon seedling. Later, the first true leaf comes out of the leaf sheath at the lower part of the cotyledon knee, and when the second true leaf appears, the cotyledon dies.

The leaves of scallion are divided into two parts: leaf body and leaf sheath.

The leaf body is green and tubular, and the upper part of the leaf sheath is green, which gradually fades down to white.

In the process of growth, annular nested leaves are constantly occurring on the stem disk, and the leaf sheaths are nested to grow into rod-shaped pseudostems, also known as scallion.

Leaf sheaths are fleshy because of storing nutrients and water, so scallion is the main feeding part of green onions.

The length and thickness of pseudostems vary with varieties, and the thickness depends on the number of layers of fleshy leaf sheaths and the thickness of each layer.

There are only 7 layers of fleshy leaf sheaths on the pseudostems of Zhangqiu scallion, and each layer is thin, so the scallion is thin.

The fleshy leaf sheaths of Laixuan 1 and Longyao chicken leg onion pseudostems have 8 ~ 9 layers, and each layer is thicker, so the scallion is thicker.

With the growth of green onion, the functional leaves on the outer layer gradually aged and dried up, and were replaced by the functional leaves on the inner layer, but each plant always kept 5 ~ 7 functional leaves.

Excellent varieties and good cultivation techniques will make the plants have more functional leaves, larger photosynthetic area and more photosynthetic products, so the yield is high and the quality is good.

There is a leaf hole at the junction of the leaf body and leaf sheath of Chinese onion.

The leaf body of the new leaf grows out of the leaf hole of the previous adjacent leaf, and the leaf sheath is wrapped in the leaf sheath of the previous adjacent leaf to grow.

The morphological characteristics of leaf holes in adult plants are related to the cultivation classification and false stem characteristics of Welsh onion.

Spread the leaf sheath, and the apex angle of the leaf sheath varies with the variety type of green onion.

The vertex angle of the leaf outlet hole type of the adult Chinese onion is less than about 60 degrees,

Onion-white scallion, such as Zhangqiu scallion, is called type C for short; The top angle is between 60 and 90, and the short onion type and the chicken leg onion type, such as Tianjin Wuyeqi and Longyao chicken leg onion, are called DJ type for short; The apex angle is between120 ~180, such as Japanese onion and Japanese onion, which is called Z-shaped for short.

The distance between the leaf outlet holes of adjacent leaves of type C is longer, 3 ~ 4 cm, and the included angle is less than 90 (the top left figure of Figure 34-3).

The scallion is slender, the outer leaf sheath is cracked from top to bottom, the leaves of mature scallion are easy to hang freely, and the compactness of pseudostems is poor.

DJ-shaped adjacent leaves have a short distance of 2 ~ 3 cm, and the included angle is less than 90 (the top row of Figure 34-3).

The scallion is thick and short, and the outer leaf sheath is also cracked from top to bottom, but the leaves of mature scallion are not easy to hang freely and the pseudostems are tight.

The outlet holes of Z-shaped adjacent leaves are not intersecting, but are nearly parallel (the top row of right in Figure 34-3).

The scallion is slender, the outer leaf sheath is basically not cracked, the leaves of mature scallion are not easy to hang freely, and the pseudostems are tight.