Question about photosynthesis

Fred Duran · 03-13-2009, 07:10 PM

Does anybody know whether or not ultraviolet light has an adverse effect (or any effect at all) on photosynthesis? If, for example, a mega-thick cloud rolled over someplace and blocked out the sunlight (the light and the UV and everything), would all the plantlife in that area die?

I'm not planning world domination, by the way, I'm doing research for a story. Wikipedia is being an asshole and the articles I can find on the subject are twenty feet over my head. A simple yes or no would be amazing.

Thanks!

Fred

DemolitionSamurai · 03-13-2009, 07:17 PM

Plants usually have pigments that protect them from UV light since it causes damage to them, just like in us.

edit: Here's something short and pretty easy:
http://www2.mcdaniel.edu/Biology/bot.../l2inature.htm

Fred Duran · 03-13-2009, 07:28 PM

Thank you very much sir.

Fred

Biofungus · 03-13-2009, 10:14 PM

Wait, what does UV light have to do with a mega-cloud blocking light? And for the record, yes, if the cloud stayed in that same area long enough, it could kill the plant life. (First they would go into winter 'withdrawal', then eventually it would die if it couldn't get light after awhile.

Fred Duran · 03-13-2009, 10:37 PM

Quote:

Originally Posted by Biofungus

Wait, what does UV light have to do with a mega-cloud blocking light?

Actually . . . I can't really remember.
The whole idea sort of came to me in one of those 5am moments of eureka where you're still half asleep, so a few parts of it still don't make too much sense (the armless psychology teacher being one of them).

Quote:

Originally Posted by Biofungus

And for the record, yes, if the cloud stayed in that same area long enough, it could kill the plant life. (First they would go into winter 'withdrawal', then eventually it would die if it couldn't get light after awhile.

That's what I was thinking . . . sort of. 5am eureka. Yep.

Thanks kind sir

Fred

J. Alexopoulos · 03-14-2009, 12:26 AM

Maybe off topic?

I remember an interesting experiment from high school, that displays the effect of no sunlight vividly:

Fold a strip of aluminum foil over a segment of a leaf (of some potted plant). Leave it for a week, and then remove the strip of foil. I remember that the rest of the leaf was still green, while the part that had been beneath the strip had lost much of its colour.

Nitecrawlah2 · 03-14-2009, 12:40 AM

Good luck with the Weather Dominator or whatever the fuck you're up to Fred!

Fred Duran · 03-14-2009, 03:39 AM

Quote:

Originally Posted by J. Alexopoulos

Maybe off topic?

I remember an interesting experiment from high school, that displays the effect of no sunlight vividly:

Fold a strip of aluminum foil over a segment of a leaf (of some potted plant). Leave it for a week, and then remove the strip of foil. I remember that the rest of the leaf was still green, while the part that had been beneath the strip had lost much of its colour.

Turn the foil into a mega-huge cloud, and that's exactly the effect that I'm looking for. Good stuff.

Quote:

Originally Posted by Nitecrawlah2

Good luck with the Weather Dominator or whatever the fuck you're up to Fred!

Haha . . . Weather Dominator. Madness . . .

. . . and thanks

Biofungus · 03-14-2009, 03:21 PM

Quote:

Originally Posted by Nitecrawlah2

Good luck with the Weather Dominator or whatever the fuck you're up to Fred!

Yeah, Fred's working for COBRA nowadays

Newt · 03-14-2009, 04:04 PM

As said, if all light were blocked out by a cloud UV would not be high on the plants' list of current issues. However:

UV degrades proteins, including photosystems I and II. All photosynthesizing plants expend considerable energy repairing these systems as part of normal operation, but plants in areas with higher-than-normal UV exposure, as deserts and high mountains, often have special adaptations. Many such plants have very thick waxy cuticles or hairs to filter UV as well as limit water loss, while some turn or fold the leaves during mid-day to reduce surface area exposed to radiation. Sudden increase in UV levels will overwhelm plants' defenses and lead, depending on level, to reduced photosyntheitic capacity and increased energy expenditure due to photosystem damage, or to more fundamental damage to cellular structures and genetic material. Plants are less susceptible to cancers than are animals, but sufficient genetic damage is still lethal.

UV is dangerous stuff. We use it in bacterial chambers and aquaria as a sterilizer- more effective than bleach!

Fred Duran · 03-14-2009, 04:24 PM

Interesting stuff. But isn't UV super powerful, so, for example, you can still get a bitchin' sunburn on a cloudy day? Like if there was a cloud that blocked out the kind of light that the plants used for photosynthesis could the UV still get through? And if it could still get through, with the plants only getting the UV instead of the UV and the "good" sunlight, would they wither and whatnot that much faster?

Quote:

Originally Posted by Biofungus

Yeah, Fred's working for COBRA nowadays

The more questions I ask, the more that seems to be the case

Newt · 03-14-2009, 06:30 PM

UV does penetrate clouds better than does visible light, though it is still partially blocked. So the plants would simply still be facing the normal constant threat of UV radiation while not being exposed to useable radiation. The UV would be a minor factor in comparison to the lack of PAR (photosynthetically active radiation) and the probable lowering of temperature associated with constant cloud cover.

Look up 'nuclear winter' and 'K-T event' for more information on the probable effects of massive clouds on plant life.

Fred Duran · 03-14-2009, 06:41 PM

Will do.

Thanks for all responses!

Cobra Commander will be so proud!

03-13-2009, 07:10 PM	#1
Fred Duran Master Lurker Join Date: Apr 2004 Location: Manhattan Posts: 760	Question about photosynthesis Does anybody know whether or not ultraviolet light has an adverse effect (or any effect at all) on photosynthesis? If, for example, a mega-thick cloud rolled over someplace and blocked out the sunlight (the light and the UV and everything), would all the plantlife in that area die? I'm not planning world domination, by the way, I'm doing research for a story. Wikipedia is being an asshole and the articles I can find on the subject are twenty feet over my head. A simple yes or no would be amazing. Thanks! Fred

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03-13-2009, 07:17 PM	#2
DemolitionSamurai Can derail any thread Join Date: Jul 2003 Location: Portland, ME Posts: 1,932	Plants usually have pigments that protect them from UV light since it causes damage to them, just like in us. edit: Here's something short and pretty easy: http://www2.mcdaniel.edu/Biology/bot.../l2inature.htm

03-13-2009, 07:28 PM	#3
Fred Duran Master Lurker Join Date: Apr 2004 Location: Manhattan Posts: 760	Thank you very much sir. Fred

03-13-2009, 10:14 PM	#4
Biofungus Not for your amusement Join Date: Feb 2002 Location: Nega-Earth Posts: 22,083	Wait, what does UV light have to do with a mega-cloud blocking light? And for the record, yes, if the cloud stayed in that same area long enough, it could kill the plant life. (First they would go into winter 'withdrawal', then eventually it would die if it couldn't get light after awhile.

03-14-2009, 12:26 AM	#6
J. Alexopoulos AKA Beefpipe Join Date: Apr 2007 Location: Whitby, Ontario Posts: 229	Maybe off topic? I remember an interesting experiment from high school, that displays the effect of no sunlight vividly: Fold a strip of aluminum foil over a segment of a leaf (of some potted plant). Leave it for a week, and then remove the strip of foil. I remember that the rest of the leaf was still green, while the part that had been beneath the strip had lost much of its colour.

03-14-2009, 12:40 AM	#7
Nitecrawlah2 Oh come on!! Join Date: Jul 2006 Location: DC Posts: 4,128	Good luck with the Weather Dominator or whatever the fuck you're up to Fred!

03-14-2009, 04:04 PM	#10
Newt Common cold fusion Join Date: Jun 2007 Location: On the mighty Cumberland Posts: 5,136	As said, if all light were blocked out by a cloud UV would not be high on the plants' list of current issues. However: UV degrades proteins, including photosystems I and II. All photosynthesizing plants expend considerable energy repairing these systems as part of normal operation, but plants in areas with higher-than-normal UV exposure, as deserts and high mountains, often have special adaptations. Many such plants have very thick waxy cuticles or hairs to filter UV as well as limit water loss, while some turn or fold the leaves during mid-day to reduce surface area exposed to radiation. Sudden increase in UV levels will overwhelm plants' defenses and lead, depending on level, to reduced photosyntheitic capacity and increased energy expenditure due to photosystem damage, or to more fundamental damage to cellular structures and genetic material. Plants are less susceptible to cancers than are animals, but sufficient genetic damage is still lethal. UV is dangerous stuff. We use it in bacterial chambers and aquaria as a sterilizer- more effective than bleach!

03-14-2009, 06:30 PM	#12
Newt Common cold fusion Join Date: Jun 2007 Location: On the mighty Cumberland Posts: 5,136	UV does penetrate clouds better than does visible light, though it is still partially blocked. So the plants would simply still be facing the normal constant threat of UV radiation while not being exposed to useable radiation. The UV would be a minor factor in comparison to the lack of PAR (photosynthetically active radiation) and the probable lowering of temperature associated with constant cloud cover. Look up 'nuclear winter' and 'K-T event' for more information on the probable effects of massive clouds on plant life.

03-14-2009, 06:41 PM	#13
Fred Duran Master Lurker Join Date: Apr 2004 Location: Manhattan Posts: 760	Will do. Thanks for all responses! Cobra Commander will be so proud!