What is a Plant?

What is a plant?

 

Plants are actually more similar to us human beings than you may think. 

How? 

Well let me show you. We have blood that flows through their veins carrying blood and oxygen to vital parts of our body. A plant has veins through which flows sap which like blood carries nutrients. Plants like us humans also have the ability to breathe and their lives are controlled by hormones and believe it or not rudimentary nervous system. Plants also have the ability to reproduce themselves.

Human blood is almost identical to chlorophyll which is a green pigment present in all green plants, which is responsible for the absorption of light to provide energy for photosynthesis. The difference between blood and chlorophyll is that blood contains iron and chlorophyll contains magnesium, as stated in this medical paper

If you want even more evidence you can compare the DNA of the human to the DNA of the banana and you will be surprised to know of that over 60% of human DNA is identical to the DNA of a banana. You can read the article from the Journal of Biological Databases and Curation. 

So now that I have shown you how similar we are to plants let’s have a look at the parts of a plant.

Roots

There are two main types of routes for plants.

Branching roots also known as adventitious roots

Whenever you take a plant out of its pot or dig up a plant these are the large ones you can see. Branching roots are there to anchor it to the ground and they usually spread out over a wide area.

Tap roots

You normally find these on plants such as carrots parsnips. Tap roots are used by plants up for storing starches that will be used as fuel by the plant when flowering the following season.

Root Structure of Plants. Source

You may be surprised to know that none of these roots take in water, the uptake of water by plants is done by microscopic root hairs concentrated round the very tips of the main roots. Along with water these root hairs are also responsible for the take-up of dissolved nutrients by the plant. Think of it this way plants can’t really take in solid food instead they suck up a sort of mineral soup almost like a vacuum caused by the water evaporating from its leaves above. Look at it this way in one way out the other.

Root hair, water intake diagram. Source

Water flow with a plant diagram. Source

How water evaporates through plant leaves. Source

Stems

Stems are considered the skeleton of a plant, they make sure that a plant doesn’t fall over, that it can hold its leaves flowers and even fruit up to the best possible position for the plant.

In longer living plants such as trees, stems adapt and form almost solid structures (wood), which provide them with an even stronger framework which is vital as they are big and have a lot of weight to carry.

Stems are like the veins of the plant and they contain a special tissue called xylem that transports water and dissolved minerals all around the plant and up phloem up which takes starches and other things the plant has many pictured to where it’s needed.

Cross section of a plant stem. Source

Leaves

Think of these as the powerplant of a plant using solar panels. This is where photosynthesis takes place with the use of that green pigment chlorophyll using the sun’s energy transforming it into chemical energy using carbon dioxide from the air and water from the soil and other nutrients into starches. The starch is then used by the plant to build more plant parts.

Some plants actually store starch in underground reservoirs such as carrots and potatoes. As a result of photosynthesis plants breathe out oxygen which is vital for the planet and our survival.

Flowers and seeds

Flowers are quite simply the reproductive part of a plant, flowers come in a variety of shapes and sizes. How does it work? well quite simply, male pollen from one flower is transferred to another of the same species so that the female part of the flower is fertilised. This will then produce a fruit or a pod which will eventually ripen and shed to produce the next generation. An example of this is an Apple falling from a tree onto the floor, the seeds have every chance of growing into new apple tree.

Every flower is made up of several different parts. You have the petals, think of these like waving flags calling pollinating insects “come here land on me” Next you have the stamen and this is the male reproductive part flower it consists of stem called the filament and a two-lobed pollen loaded anther on top. Next you have the pistil this is the female reproductive part of the flower; the pistil is centrally located and usually has swollen base which contains the ovary; a stem arising from the ovary; and a pollen receptive tip called the stigma.

It’s in the ovary that seeds form and will ultimately be either a fruit or seed pod. So just like when young birds leave the nest so too must seeds otherwise the parent plant would be competing for vital nutrients, water, and light against its offspring. Because of this, seeds have developed various ways of travelling.

Seed dispersal

Wind dispersal

Seeds are simply blown about land in all kinds of places. To increase the chance of the seeds landing in locations that can support seed growth, these plants have to produce lots of seeds. For example dandelions and maple trees.

Animal dispersal (including humans)-

One method of animal dispersion is birds, they eat fleshy fruit that contain seeds such as raspberries, then they often fly away from the parent plant and drop the seeds in their droppings.

Some seeds have hooks and Barbara catch onto animal fur, feathers, or even human clothing. For example burdock.

Water dispersal

An example of this is quite simply coconuts, if all of the tree land in the ocean and get carried away by the ocean current to a new location. Waterlilies and mangrove trees do the same.

Explosion dispersal

Some plants have seedpods that will dry out, and once dry will simply pop sending seeds in all directions. Pea and bean plants do this.

Fire/heat dispersal

There are some species of pines that require heat before their cones open and release seeds.

It’s important to know that most flowers have both male and female parts however there are some plants such as courgettes that have separate male flowers and separate female flowers on the same plant these are called monoecious plants.

Plants like hollies have male and female flowers on separate plants, these are called dioecious plants.

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