There are a variety of plants. Seed production is crucial to the existence of plants. Botanists divide the plant kingdom into groups according to the characteristics found in various plant species.
Gymnosperms are those plants that grow seeds but do not produce fruits. E.g. Cycas, Pinus, Cedrus. Parthenocarpic plants produce fruit but have no seeds, e.g., Banana, Pineapple.
Plants are classified into two main groups depending on the way they reproduce:
- Seed-producing plants (flowering plants as well as cone plants).
- Plants that produce spores (such as ferns and mosses, liverworts, and the green algae).
The world of plants includes cone-bearing as well as fruit-bearing plants. The two types of plants differ in designs for seeds, leaf types, and pollination methods. Their cones and needle-like leaves can identify Cone-bearing plants, and fruit-bearing plants are identified through their flowers and fruits. Cone-bearing species are also known as gymnosperms. Fruit-bearing plants are known as angiosperms.
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Seed Formation in Plants – Fertilization
Seed plants have unique structures (flowers also known as cones) that allow male and female cells to mate via a process known as fertilization. After fertilization occurs, a tiny plant called the embryo is created inside the plant. The seed is a shield for the embryo from harm and provides food. Seeds are scattered away from the plant, and when the conditions are favorable, the embryo begins to germinate and transforms into a brand new plant.
There are two main categories of seeds:
- Gymnosperms – plants that have cones.
- Angiosperms – plants that have flowers.
Gymnosperms
These seeds do not contain fruit or flowers; their seeds are stored in cones. Male cones create pollen that is then carried to female cones by the wind. Once the female gametes are fertilized by male gametes using pollen, female cones begin to produce seeds. The seeds of a gymnosperm are exposed to the surroundings. They are then blown away out of the plant via animals or wind.
Gymnosperm Characteristics
The term “gymnosperm” refers to “naked seeds,” which means that the seeds aren’t enclosed in fruit but rather exposed or on the scales of cones like the pine cone. The leaf structures of gymnosperms, as well as angiosperms, are different. Gymnosperms are cone bearers. They produce needle-like leaves that have a thick coating of wax. Cone-bearers grow as woody evergreens like pines, spruces, and firs, and they have no leaves to shed.
The majority of gymnosperms can be described as tree-like. There are several species of gymnosperms, like Kahikatea ( Dacrycarpus dacrydioides white pine), matai ( Prumnopitys taxifolia black pine), Totara ( Podocarpus totara), and the rimu ( Dacrydium cupressinum the red pine) and the kauri ( Agathis australis).
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Angiosperms
Angiosperms grow flowers that are specific structures that reproduce. They are composed of male parts that produce pollen and female parts that contain Ovules. Certain plants have male and female parts within various flowering plants. Pollen is transported from a male to a female through wind or animals (a process known as pollination) and releases male gametes, fertilizing female gametes within the Ovules. Ovules form into seeds, from which new plants are born. In most angiosperms, a part of the flower grows into a fruit, which shields the seeds in the ovules. Fruit can be soft as oranges or hard as nuts.
Angiosperm Characteristics
Angiosperm seeds are housed in fruits and have flowers. Male flowers are typically small, whereas female flowers are more prominent. After these flowering plants are pollinated, the flower as well as its reproductive parts die and then fall off, and the plant grows fruits or seeds enclosed. The flowers of flowering plants usually feature flat leaves with veins. They are deciduous plants, meaning that the leaves change color during the fall and then fall off the tree. The trees produce new leaves every spring. Certain flowering plants keep their leaves, like live oak and the rhododendron.
Variations in Pollination
Pollination patterns differ between fruits-bearing as well as cone-bearing plant species. Gymnosperms that produce cones are pollinated by winds, while fruit-bearing plants are typically pollinated by bees as well as other insects that transfer pollen from the plant. Female cones of cone bearers may take a long time to mature, and flowering plants develop quicker than cone bearers. This implies that the flower-bearing angiosperms will be capable of producing more seeds. That’s why flower-bearers constitute the most significant portion of the plants.
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Different Types of Gymnosperms
Gymnosperms can be described as any plant with a vascular system that reproduces via the exposed seed. Although most flowering plants, called angiosperms, contain seeds enclosed in an ovary or fruit, gymnosperms (“naked seeds”) are not covered with cover for their seeds.
Gymnosperms are classified into four categories –
- Ginkgo
- Cycads
- Conifers
- Gnetophytes.
Conifers comprise the largest gymnosperm phyla that include spruce, fir pine, cedar, as well as a redwood tree. Cycads consist of plants that bear cones; however, they also produce palm-shaped leaves. Cycads thrive in subtropical and tropical regions. Ginkgo is one of the plants native and native to China, while gnetophytes comprise plant species that develop deep taproots, as well as cones that are above ground.
Ginkgo
Also known as the maidenhair plant, Ginkgo Biloba is the last remaining species belonging to the Ginkgophyta plant division. While they can only be found naturally in China, they have been cultivated worldwide. They sport fan-shaped green leaves that turn yellow in colder temperatures. Male trees produce tiny cones which produce pollen. After pollination and fertilization, the females have seeds that emit an unpleasant smell.
Cycads
The oldest plants date back to the Jurassic period; cycads can be mostly found in subtropical and tropical climates. Cycads have big trunks with thick, slender leaves. They share a visual resemblance to tree ferns and palms.
Conifers
In all parts of the globe, Conifers are mostly woody plants, with the trees comprising the majority of conifers. They have both female and male cones, which pollinate and propagate.
Conifers are:
- Pines
- Spruce
- Junipers
- Cedars
- Firs
- Redwoods
- Yews
- Cypresses
- Larches
- Kauris
Gnetophytes
The plant classification is quite broad, comprising about 70 species. All contain vessel elements that transport water inside the plants. Examples of gnetophytes with no flowers include Ephedra, Gentium, and Welwitschia.
Other Non-Flowering Plants
Contrary to Gymnosperms, other flowering plants reproduce with spores and do not have seeds. Spores are small living cells that quit the plant from which they were born and are fertilized and pollinated far away from the organism they came from. Some more well-known non-flowering plants include ferns, liverworts, and mosses.
Ferns
The most common species are vascular plants that possess an erect stem, leaf, and root. They are found in the forest, but they are also planted to enhance the soil’s quality or improve air quality. Ferns are extensively used as ornamental plants in landscaping, as well as in homes, and some even eat the plants. They release spores that develop into a photosynthesis structure known as the prothallus. The underside of the prothallus is home to organs that produce sperm as well as eggs that permit the ferns to self-fertilize, after which the sporophyte grows into a plant.
Mosses
With over 12,000 species of mosses, they are widespread and are found in moist places with very little light.
Club Mosses
Tropic mountains form the central location for club mosses. They are evergreen mosses with needle-like leaves and in clusters.
Psilotales
Also called Whisk Ferns, the Psilotales are a small collection of plants, including Psilotum and Tmesipteris, which are considered to be from the Devonian period.
Horsetails
Equisetum is the sole Genus belonging to this plant that is not flowering that’s not extinct. With tiny leaves on their stems, they are between 7 inches to 26 feet in height, based on the species.
Liverworts
The tiny plants look like moles; however, they have flattened stems or bodies and can grow on rocks or the ground. Some are even found in water pools. There are more than 8,500 species found worldwide, mostly in areas of high humidity, but there are exceptions that live in dry climates.
Hornworts
Hornworts are found in all kinds of places in damp areas, from the back of trees to fields and gardens. They are tiny and short and can be considered to be weeds. They were previously a component of the category as liverworts and mosses.
