What are the differences between the appearance and internal structure of monocots and dicots?

Angiosperms are divided into two categories: monocots and dicots, and there are differences in the number of cotyledons, the number of petals, and vegetative organs, and the most important difference is the number of cotyledons.

Number of cotyledons. The embryo of monocot seeds has one leaf, such as corn, wheat, rice, etc.; The embryo of dicot seeds has two ** leaves, such as beans, peanuts, broad beans, soybeans, etc.

The number of petals. The former is usually 3 and the latter is 5 or 4.

vegetative organs. Dicotyledons have well-developed taproots, vascular bundles in the stems are arranged in a ring, and the leaf veins are mostly reticulated; Monocots have well-developed fibrous roots, the taproot is underdeveloped, the vascular bundles in the stem are often scattered, and the leaf veins are mostly parallel or arcing.

The above distinction is not absolute, and there are some exceptions. For example, monocotyledons are also found in the water lily family in dicots, and liliaceae in monocots also have 4 cardinal flower types.

Problem solving process] is the same point as the characteristics of the whole angiosperm.

Monocots:

Seeds: 1**leaf.

Leaf veins: parallel veins.

Roots: Generally, the taproot is underdeveloped, and the fibrous root system is formed by most adventitious roots.

Flowers: The number of flowers is usually 3, and the calyx and corolla are very similar.

Dicotyledons:

Seeds: 2** leaves.

Leaf veins: reticular veins.

Roots: Generally, the taproot is well developed, so it is mostly a straight root system.

Flowers: Plants usually have a flower base of 5 or 4, and the morphology of the calyx and corolla is also very different.

Seedless plants include ferns, bryophytes, bathing plants.

Dicotyledons have two **leaves.

3. It can be used in a low-temperature, dry environment, and pay attention to ventilation, if possible, nitrogen, helium, and other rare gases can be introduced to reduce the concentration of oxygen and reduce aerobic respiration.

The leaves of monocots are generally linear veins, and dicotyledons are reticulated; Monocots are generally short, and dicotyledons are some very tall.

In monocots, from the perspective of leaves, the leaf veins are parallel; while dicots are reticulated veins; From the point of view of seeds, monocot seeds have only one **leaf, and dicots have two** leaves.

Dicotyledons:

The outermost layer is peridermal, vascular bundles.

It is an infinite external toughness type. From the outside to the inside is the phloem, xylem, cambium.

The outermost layer of monocots is the epidermis, and the vascular bundles are radial.

Dicotyledons have no pith in their roots and pith in their stems. Monocots have pith in their roots and no pith in their stems.

1.Dicotyledons:

Their leaves have reticular veins; Monocots:

The blades are parallel or arc-shaped.

2.Dicotyledons generally have a well-developed taproot, so they mostly have straight roots; Monocots, on the other hand, generally have underdeveloped taproots, and fibrous roots are formed by most adventitious roots.

3.Dicotyledons usually have a flower base of 5 or 4, calyxes.

and the shape of the corolla is also very different; Monocots, on the other hand, usually have a flower base of 3, and the calyx and corolla are very similar.

4.The branch ends of dicots are not closed, so there are free branch terminals; In monocots, the branch ends are closed, so there are no free branch endings.

5.The embryo of a dicot seed usually has two leaves, while the embryo of a monocot seed has only one leaf.

6.Vascular bundles in dicot stems.

Arranged in a ring, that is, arranged in a circle, and there is a cambium layer, which can produce secondary xylem and secondary phloem, which belongs to infinite vascular bundles (open vascular bundles), so the stems of dicots can continue to thicken; Whereas, the vascular bundles in the stems of monocots are scattered and not arranged in loops. If it is arranged in a circle, it is arranged in two or more circles, and there is no cambium, so it cannot produce secondary xylem and secondary phloem, and it is a finite vascular bundle (closed vascular bundle), so the stem of monocots cannot be arbitrarily thickened.

7.The stomata on the leaves of dicots are arranged irregularly, and most of them are scattered, such as geraniums.

cotton, etc.; The stomata on the leaves of monocots are arranged in a relatively regular manner, mostly arranged in rows, such as corn.

8.The pollen of dicots has 3 germination pores, such as rape; Pollen from monocots often has a single germination pore, such as corn.

Dicotyledons complex.

The epidermal monolayer cell composition generally does not contain chloroplasts, has well-developed bai vacuoles, contains zhi anthocyanidins, and contains stratum corneum DAO

There are multiple layers of cells in the cortex, mainly parenchyma cells.

Vascular gymnosperms mainly have tracheidal ethriform cells that constitute vascular tissue.

Monocotyledonous epidermis.

The arrangement is relatively neat.

Several layers of thick-walled cells under the epidermis of the basic tissue make up the mechanical tissue.

Dicotyledonous plants and monocots.

Primary structure of the stem.

Difference: (bai1).Epidermis:

a.Dicotyledonous phytophytos: The cells are mostly rectangular or square-shaped, and there is no obvious distinction between long cells and short cells; b.

Monocots: composed of long and short cells, the former keratinized and the latter plugged and silicified; （2）.Differentiation of cortex and medulla:

a.Dicotyledons: with a pronounced differentiation of the cortex and the pith, which is composed of thick-horned tissue (sometimes with chloroplasts) and parenchyma; b.

Monocots: no obvious cortex and pith distinction, collectively referred to as basic tissues, composed of thick-walled and parenchyma tissues, sometimes with anabolic tissues; (3) Arrangement of vascular bundles: a

Dicotyledons: with obvious vascular columns, composed of vascular bundles, pith, and medullary rays, and the vascular bundles are arranged in a round, which is a wireless vascular bundle; b.Monocots:

Vascular bundles are scattered in the basic tissues or arranged in two wheels, and are limited vascular bundles.