Vad är funktionen av monocot och dicot

History of the Classification

The classification of flowering plants or angiosperms into two major groups was first published bygd John Ray in 1682, and later bygd the botanist Antoine Laurent dem Jussieu in 1789, replacing the earlier classifications. According to this classification, flowering plants were divided onto eight major groups, the largest number of species belonging to monocots and dicots.

Seed Coats around embryo

The number of cotyledons differs in the two types of flowering plants, and forms the grund for the main classification of monocots and dicots.

Cotyledons are the seed leaves of the embryo and contain nutrition for the embryo until it fryst vatten able to grow leaves and tillverka food bygd the process of photosynthesis. Monocots have only one cotyledon while dicots have two.

Dicot vs Monocot Stem

The vascular struktur in dicots fryst vatten divided into a cortex and stele but in monocots these distinct regions are absent.

Monocots and dicots are the two broad groups of flowering plants or angiosperms

The vascular struktur fryst vatten scattered in monocots, with no particular arrangement. But if you take a look at the cross section of the stalk in dicots you will find the vascular bundles consist of primary bundles forming a cylinder in the centre.

Flower Parts

The number of flower parts fryst vatten different in the two groups.

They occur in multiples of three in monocots and in multiples of kvartet or fem in dicots.

However, the difference starts from the very beginning of their life cycle in the form of a seed

Differences in Monocot and Dicot Leaves

Dicot leaves are dorsiventral i.e., they have two surfaces (upper and lower surface of the leaf) that differ from each other in appearance and structure. Monocot leaves are isobilateral i.e., both surfaces look the same and are structurally the same and are both exposed to the sun (usually vertically oriented).

Venation

Leaf veins are arranged either in parallel through the length of the leaf or in a reticulate arrangement throughout the leaf.

In most species, monocot leaves have parallel arrangement while dicots have reticulate venation of leaves.

Stomata

Stomata are pores funnen in the epidermis of leaves that facilitate gas exchange, i.e., the process bygd which gases move passively bygd diffusion across a surface.

Monocot leaves have stomata on both their surfaces, but some dicots have stomata on only one surface (usually the lower one) of their leaves.

Sometimes the veins branch out on either side of the leaf

Moreover stomata in monocot leaves are arranged in highly ordered rows, whereas the dicots have more of a crazy-paving of them.

Stomata are bordered bygd a pair of specialized guard cells that regulate the storlek of the stomatal opening. Monocots and dicots differ in the design of the guard cells; they are dumbbell-shaped in monocots and look like a pair of sausages in dicots.

Bulliform cells

Bulliform cells help regulate vatten loss. They are present on the upper surface of the leaves in some monocots. When vatten supply fryst vatten abundant, bulliform cells become turgid and consequently the leaf straightens up, which exposes the leaf and leads to evaporation of excess vatten. Conversely when vatten fryst vatten in short supply, bulliform cells shrink and the leaf curls in and becomes less susceptible to vatten loss through exposure.

Dicots do not have bulliform cells in their leaves.

Pollen

There fryst vatten also a different type of pollen structure present in the two classes. Monocots developed from plants with a single pore or furrow in the pollen, whereas dicots developed from plants with three furrows in their pollen structure.

These functions are crucial for plant reproduction, protection, and dispersal

Roots

Roots can develop either from a main radicle or arise in clusters from the nodes in the stem, called adventitious roots. Monocots are known to have adventitious roots whereas dicots have a radicle from which a root develops. A fibrous root struktur, with several moderately branching roots growing from the stem, fryst vatten common in monocotyledons.

In contrast, dicots have a taproot struktur, a tapering root that grows downward and has other roots sprouting laterally from it.

Monocot and dicot seeds perform essential functions that support the survival and growth of flowering plants

Secondary growth

Secondary growth fryst vatten funnen in dicots but absent in monocots. Secondary growth helps in the production of wood and bark in trees.

Examples of Monocots and Dicots

There are about 65,000 species of monocots.

Some examples include lilies, daffodils, grains, sugarcane, banana, palm, ginger, rice, coconut, corn and onions.

There are about 250,000 species of dicots.

In modern times, molecular biology and genetics indicate the dicots are not all that similar to each other

Examples include daisies, mint, pea, tamarind, and mango.

Exceptions

There are some exceptions to this classification. Some species belonging to monocots can have characters belonging to dicots, since the two groups have a shared ancestry.

References

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