Difference Between Angiosperms and Gymnosperms

To understand this more clearly let us first take a look at the reproduction cycle of plants through sexual reproduction.

What is Sexual Reproduction?

Sexual reproduction is the process of the male and the female reproductive parts of the plant coming together to form the seeds which then give rise to new plants. We all know about sexual reproduction briefly and also further know that there the pollen grains and the stigma. Sexual reproduction is mainly carried out in the flowers.

The petals and the sepals protect the internal reproductive organs from any damage, and the stem and the receptacle keep the plant at an elevated level to differentiate it from the rest of the plant. The stamen is the male part of the plant which is divided into two parts, the anther which produces the pollen, and the filament which supports the anther; the male gametes. The female reproductive organ includes the stigma, the style and the ovary inside which we find the ovules. A stigma is a sticky part of the female reproductive system that attaches the pollen to it as it is carried on by several means. The style is a stick-like structure that supports the stigma and consists of pollen tubes that carry the pollen grains to the ovaries. Inside the ovary, the ovules produce the female gametes.

Pollination is the process where the male part of the plant matures up and begins producing the pollen and the same pollen interacts with the stigma. Pollination can be carried out by either wind and water or insects and birds. However, the pollination through wind and water is carried out best in plants that have the stamen outside the plant and the stigma of the female plant hangs lowly like in upturned flowers. Pollen grains carried by wind and water are generally soft and smooth and very small in size, and the petals of the flowers with which they pollinate are also dull in colour. While on the other hand, the pollinators carry large and rough pollen grains with the petals of the plant being bright and huge. The stigma of such flowers is inside the petal hidden away from any damage and so is the stamen.

After the pollination follows the fertilization stage. The fertilization stage then leads to the formation of seeds and with time the plant, if it is a fruit-bearing plant, matures and turns into a fruit. The pollen grain, when comes into contact with the stigma of the female reproductive system (of the same species), from where the pollen grain travels to the ovaries of the female plant through the pollen tube and enters the ovary through a tiny opening called the micropyle and then fertilizes the flower.

What are Angiosperms and Gymnosperms? What is their Role in the Plants?

The main classification of the plants is mainly done by the fact of whether they are angiosperms or if they are gymnosperms. Their diversity and their age gap are one of the major ways to differentiate between the two. Angiosperms are plants that grow flowers with the seeds protected within the flowers. Plants whose seeds are not protected by either the flower or fruit or not protected at all are known as the gymnosperms.

They do not have a particular role in plants except for differentiating the plant types. It is an excellent way to categorize plants into primary categories. The angiosperms and the gymnosperms are both plants that are derived through seeds which entails that they come through the process of sexual reproduction in plants like we have talked about earlier in the article. And they both have a reduced gametophyte stage, which is the sexual stage or the life cycle of plants.

Difference Between Angiosperms and Gymnosperms in Tabular Form

Properties	Gymnosperms	Angiosperms
Meaning	Plants that produce seeds without the help of a flower.	Plants that produce seeds with the help of flowers.
Pollination	Through wind only.	Wind and water and other pollinators.
Fertilization	Double fertilization cannot take place.	Double fertilization is possible.
Fruits	Do not make fruits.	Make fruits.
Flowers	Absent.	Present.
Ovules	The ovules are unprotected and naked.	Ovules are covered by the ovary and are thus protected.
Companion cells	Companion cells are not present.	Companion cells are present.
Type	Usually consists of the trees.	Plants, herbs, shrubs or trees all may come under this category.
Vessels	Xylem vessels are not present.	Xylem vessels are present.
Endosperm	Endosperms are haploid.	Endosperms triploid.
Archegonia	Archegonia is present in the gymnosperms.	Archegonia is absent in the angiosperms.
Sexuality	Strobili are unisexual.	Flowers are usually bisexual.

Difference Between Angiosperms and Gymnosperms in Points

• Gymnosperms are the species of the plant kingdom that produce the seeds without the help of the flowers. That is, they do not produce the seeds with the help of the flowers which keep the seeds protected until the flowers swell and become a fruit. The term gymnosperm is derived from the Greek words, ‘gymnos’ which means naked and ‘Sperma’ which means seeds, thus coming together the word means naked seed. The name is given to the type of plants because their seeds are uncovered and usually found at the top of the plant. The seeds often form at the surface of the scales or the leaves and swell up to become cones which are then broken away from the plant through natural or human means and then they form new plants under the likeable circumstances. Angiosperms on the other hand are flowering plants that protect the seeds inside the flower. It is derived from the Greek word, ‘angeion’ which means vessel or a container and we already know that ‘Sperma’ means seeds. Therefore it means that the angiosperms are vessels or containers that protect the seeds in a plant. The petals form a protective covering for the ovary inside which are the ovules where the seeds are generally formed. Once the fertilization process has been completed, the flowers swell and give us the fruits.
• The pollination in the gymnosperms takes place through the wind only. The male and female plants are separate in the gymnosperms thus the pollen grains, which are produced by the mature male plants are carried through the air toward the female plants resulting in the completion of pollination. This must also be noted that the gymnosperms produce heaps of pollen grains to reach the female cones which give them a greater chance of forming the seeds and then giving birth to a new plant once the seed matures and falls off of the plant. It is only through a very heavy gust of wind that these plants can carry the pollen seeds to a faraway place. The other pollinators do not do a favour to the gymnosperms because of their appearance. We know that bees and butterflies and most insects feed on the flowers or the plants that are supposed to have flowers. Thus, in that regard, the angiosperms can be pollinated through wind, water or other pollinators because of their flowers. Also, the fact that angiosperms are usually bisexual, that is they have both the male and female plants in the same body, the pollination is quite easy in them. A tiny shake of the flower because of the wind during the pollination season of the male organ can produce seeds easily in the plants.
• The gymnosperms do not allow double fertilization. But angiosperms have double fertilization. Gymnosperms do not have a flower nor do they have a fruit thus double fertilization is impossible in their case. But when we have fruits we see that the fruits do not have just one seed except for some exceptional fruits such as mangoes. But fruits like apples, bananas, watermelons etc. have multiple seeds. This phenomenon is known as double fertilization. It is the fusion of the egg and the sperm and alongside another sperm also fuses with the polar nuclei and forms the endosperms of the seeds.
• Gymnosperms do not form the fruits once fertilization takes place. However, the angiosperms produce the fruit after the flower has been fertilized with the pollen seed and then the flower swells up and turns into a fruit, and once the fruit is consumed or decomposed and if all the requirement of the given plant is met, it forms a new plant from the seed of the fruit. The fruit is the prime component that helps a plant produce more seeds and then continue the process of reproduction. Gymnosperms undergo a completely different process to make the seeds form a new plant.
• As discussed in the point above, gymnosperms do not make fruits while the angiosperms produce fruits.
• The ovules of the gymnosperms are unprotected and naked. This allows the pollen grains to interact with the female part of the plant directly and without any barriers. The pollens are in a large number as we already know of the theory by Charles Darwin of the survival of the fittest, we know that the fittest pollen grain fertilizes the female ovary and results in the seeds for the new plant. It works much like the human reproductive system, where it is the fastest and the fittest sperm that gets to fertilize the egg. But the ovules in the angiosperms are highly protected by first the ovaries, then the petals of the flower. The ovary is a protective layer that surrounds the ovules and the petals are the final and the colourful protective layer of the flowers which gives it a beautiful look and also attracts the pollinators to the plants. The prettier the plant the more the pollinators.
• The angiosperms have the companion cells but the gymnosperms do not have the companion cells. According to Merriam-Webster, a living nucleated cell that is closely associated in origin, position, and probably function with a cell making up part of a sieve tube of a vascular plant are known as the companion cells of the plant.
• Gymnosperms usually consist of trees.  The gymnosperms are vascular plants in the subkingdom Embyophyta. And we know that there are more trees in the world than there are flowers, thus gymnosperms are more commonly found in the ecosystems. The trees are usually found in the forests in abundance and they do not require a flower for reproduction. The seeds just fall off of the trees and once it gets the appropriate soil, sunlight, water and minerals, the tree grows into a new one. Angiosperms are often the shrubs, herbs, flowers and sometimes trees. They do not have any restrictions as there are trees too that grow flowers and later swell into fruits. The angiosperms belong to the kingdom Plantae. And they can be found anywhere, though usually they are harvested because of the fruits they bear and even if a flower does not bear the fruits, it is used for reproduction and the flowers are sold in the market. It is no secret that flowers have always been in high demand by people because of their odour and their appearance.
• The xylem vessels are not present in the gymnosperms but are present in the angiosperms. The vessel is also known as the trachea is a type of a cell that is found in the xylem, which is known as the water conducting tissues of the plants. The xylem vessel is known to carry the water and the minerals from the soil to the plant until its very tip to the roots and the xylem along with the phloem tubes work towards carrying the food and water to the rest of the plant. While the xylem vessel carries water and mineral, the phloem tube carries the food from the leaves to the upper parts of the plant until the very bottom of the roots. The xylem vessel also provides support to the angiosperms.
• The endosperms of gymnosperms are haploid because it (endosperm) is formed in the plants before the fertilization process. Whereas the endosperms in the angiosperms are triploid, which means three chromosome sets per nucleus.
• Archegonia is present in the gymnosperms while absent in the angiosperms. An archegonium is the female reproductive organ often found in the ferns and mosses and cycads and conifers.

References

• https://www.sciencedirect.com/topics/biochemistry-genetics-and-molecular-biology/angiosperm
• https://www.thoughtco.com/what-are-gymnosperms-4164250