Photosynthetic rate

[QuarkQuarkQuark2001]

Increase in light intensity speed up the rate of photosynthesis.

Does increase in light intensity also speed up the rate of respiration?

I think so, but my teacher never talked about it.

[Bryn]

No it doesn't, otherwise they'd be no oxygen for us to breath

 

It may increase it as an indirect result if the sunlight increases the temperature of the plant but the increase would be insignificant compared to the increase in rate of photosynthesis.

[QuarkQuarkQuark2001]

But don't they need more kinetic energy for photosynthsis when increased in light intensity, such as conducting water and some other movement, then they need more oxygen for the respiration part, right?

[QuarkQuarkQuark2001]

anyone help me ?

[Glider]

Plant respiration will speed up as photosynthesis speed up. The faster the rate of photosynthesis, the greater the need for CO2 (and H2O) to provide the building blocks for the sugars the plant is creating.

 

You can see this in some oxygenating aquatic plants. When you shine light on them, they start to release bubbles of oxygen. When you turn the light off, the bubbles stop. If you turn the intensity of the light up, the rate of bubbles increases, up to a point.

[QuarkQuarkQuark2001]

Plant respiration will speed up as photosynthesis speed up. The faster the rate of photosynthesis' date=' the greater the need for CO2 (and H2O) to provide the building blocks for the sugars the plant is creating.

 

You can see this in some oxygenating aquatic plants. When you shine light on them, they start to release bubbles of oxygen. When you turn the light off, the bubbles stop. If you turn the intensity of the light up, the rate of bubbles increases, up to a point.[/quote']

 

Your thought is my idea! I think they need more energy for photosynthesis, so they burn their carbonhydrates, right?

However, the graph in some book are not like our thought.

The line respresent the rate of respiration does not change, it is horizontal all the time. Then I suspected my thought.

[aommaster]

Well, light intensity affects the rate of photosynthesis only because there is more light available for hte plant to use. It doesn't have an effect on the energy there. Think of it like this:

 

There is a sheep in a farm. Let's say that this sheep is your plant. IF you provide it with food (which is the light that you are giving to the plant) then it will eat. The more food you give it, the more it ill grow and get fatter.

 

The light is something called a limiting factor because, as the light increases, the photosynthesis that plant does increases. The more light, the more photosynthesis.

 

Is that what you are looking for?

[QuarkQuarkQuark2001]

Well' date=' light intensity affects the rate of photosynthesis only because there is more light available for hte plant to use. It doesn't have an effect on the energy there. Think of it like this:

 

There is a sheep in a farm. Let's say that this sheep is your plant. IF you provide it with food (which is the light that you are giving to the plant) then it will eat. The more food you give it, the more it ill grow and get fatter.

 

The light is something called a limiting factor because, as the light increases, the photosynthesis that plant does increases. The more light, the more photosynthesis.

 

Is that what you are looking for?[/quote']

 

My doubt is why increase the light intensity does no effect on the rate of respiration.

Please help me again!

[aommaster]

Respiration and photosynthesis are completely two different process. Respiration has absolutely nothing to do with light, and that is why light doesn't affect it. As for photosynthesis, it cannot happen without light, so, obviously, the more light you put in, the faster it becomes, to a certain point, look back at the example i gave with the sheep. Now think about a wolf, put as much grass as you want, and yet nothing happens, because the wolf does not eat the grass. The wolf is your resiration process

[QuarkQuarkQuark2001]

Respiration and photosynthesis are completely two different process. Respiration has absolutely nothing to do with light, and that is why light doesn't affect it. As for photosynthesis, it cannot happen without light, so, obviously, the more light you put in, the faster it becomes, to a certain point, look back at the example i gave with the sheep. Now think about a wolf, put as much grass as you want, and yet nothing happens, because the wolf does not eat the grass. The wolf is your resiration process

I think there is a small change in the rate of respiration, so when scientist plot graph, they omit the change.

[aommaster]

Yup! whatever the change is, it may be slightly changed for many reasons (which i don't know of )