It’s ''In The Air''
by Jolene Adams, past ARS president
This article was published in The Criterion, Winter 2020 issue.
Why do we need to know about the air? After all – our roses don’t have noses – they can’t “smell” the air around them! What do they do with air anyway?
Well, we are certainly glad you asked. No, plants don’t have noses but they DO utilize natural processes to move essential gases around – gases found in our “air”. They release oxygen at times, and they release carbon dioxide at other times – just like us. In fact, plants are responsible for this thick blanket of “air” we have wrapped around our planet. And they continue to keep the oxygen level just right for animal life on earth.
The atmosphere surrounding Earth is full of air! The air in our atmosphere is made of molecules of different gases. The most common gases are nitrogen (78%) and oxygen (about 21%) and less than 1% is argon, carbon dioxide, and other gases — as well as varying amounts of water vapor. Plants need gases from the air to do photosynthesis. Animals need to breathe air to get the oxygen they need for their own biological processes. For both plants and animals, no air means they die.
Ultimately, the gases in the atmosphere are used to help the organism make “food”. And the organism then allows gases produced in the process of making that food to escape back into the atmosphere. We breathe out and in, plants “breathe” out and in – but we don’t call it that.
Plants “respire”. During photosynthesis, the chlorophyll in the plant uses water from the soil and carbon dioxide from the atmosphere plus sunlight to make sugars and oxygen. (No rays of light or chloroplasts are harmed in this process.) Some of the sugar produced during photosynthesis is used by the plant for its life processes (such as growing and reproducing); the excess is converted mainly to starch and stored in various plant parts which can be eaten by animals. Excess oxygen is released back into the atmosphere.
At the same time – the plant is using the sugars and some of the oxygen for its own life processes – like making amino acids and complex carbohydrates, various enzymes and hormones, and leftovers like carbon dioxide. The carbon dioxide must be released – and that is called Respiration.
Occurs in the presence of light (and chlorophyll in plant cells)
Requires energy (light) to make sugar (glucose)
Complex substances (sugar) are formed from simpler ones.
Carbon dioxide and water are the raw materials.
Oxygen is given out.
Occurs at all times in cells
Releases energy from sugar
Complex substances (sugar) are broken down into simpler ones.
Carbon dioxide and water are the waste products.
Oxygen is taken in.
Respiration goes on all the time, day and night. But photosynthesis only happens in the presence of sunlight (or its equivalent).
Give and Take
Photosynthesis and respiration both release gas molecules. And the cycles are opposite! In photosynthesis, carbon dioxide goes in and oxygen comes out. In respiration, oxygen goes in and carbon dioxide comes out. Together, these gaseous releases help balance out our atmosphere.
Plants Eat Animals!
OMG!!! But they do ... you just aren’t noticing. Ever wondered why you don’t find a lot of dead birds lying all over the place? I mean – there are a lot of birds out there. And they live and die. So who is recycling the leftovers? Whatever is left after scavenging is complete is slowly consumed by these minute creatures. And they are decomposers. There are bazillions of microscopic plant-like “thingies” in the soil. They find dead tissues from plants and animals and slowly digest them. If they happen to have chloroplasts in their cell structure – they are listed over on the side of the plant kingdom. If there are no chloroplasts, they are on the other team – animal kingdom.
These are necessary functions performed by almost invisible living creatures. They get around, they do their job, they excrete and also release gas molecules. Gases again ... like, they exhale (kinda). More likely the gas molecules just pass through the cell membrane and enter whatever atmosphere they find.
And In The Soil Too
The story just gets better as we go along. There is air in the soil! Yes, and the roots of plants are very happy about that. Roots have needs too – they aren’t just storage containers for excess foods (well, some of them actually are), they have life processes that need oxygen in order to keep on going. And carbon dioxide. So – how does the air get to them?
Plant parts respire – remember? Even roots ... just a bit. Also, air gets incorporated in the soil when it is disturbed by cultivation, or by worms and other animals tunneling through it, by larger animals digging in it, sharp hooves cutting into it, all kinds of ways. And those little plant-like guys are also down there letting go with a few molecules here and a few molecules there.
Loose, friable soil has a lot of air in it. The air is “stuck” in the pore spaces between the soil particles (you remember the lecture about soil, right?). Water and the gas molecules are in the pore spaces, the roots reach out and the little root hairs attract the gas molecules. The gas is absorbed into the plant (that happens to water molecules too).
Plants have been here longer than we have – they know how to get what they need for their vital processes. Keep this in mind – your roses release oxygen into the atmosphere, and also release carbon dioxide – sometimes into the soil as well as into the atmosphere.
A Lesson To Be Learned
All in all, we should be taking care of our world. We all need a healthy atmosphere and plants keep the air balanced out for us.
So – plant more roses!