This questions got me...

D

Dudeyhed

Conformer
Registered Senior Member
sorry, but this is a homework question.

I've done a prac titled 'Plant responses to stimulation' and we just tested the plants response to light.

I've found out that the plant will grow towards the light source because an auxin (or many auxins... not sure) move to the side, in a higher concentration, getting the least light and so there is uneven growth in the plant stem so that the plant bends.

now, the question I'm stuck on is this:
'Explain the internal hormonal change that enabled the response (The plant bending)?'

I dunno what I'm supposed to write, coz in the last question 'How did the plant achive the response?' I've already disscussed auxins... which I though were the hormones...

is there something I'm missing?
 
oh I should know this

Sorry, Dudeyhead, I know I should know this, I remember learning about it. Since I don't work on plants, I promptly forgot.
Besides auxin induced uneven growth, I have no idea what hormonal change it could be refering to.
 
Oh well,
I'm going to have to hand it in tomorrow so I there's no point in getting an answer (I'll just make something up :p), but if someone can answer it, it would be good for all to see. :D

Thank you for considering the question wrmgrl :)
 
Im just guessing (I last covered this when I was 17, 4 years ago) but I think there are photoreceptors that release the hormone (an auxin) which either inhibits or stimulates growth. I can't remeber which one, but if you know just say it is released in the light or dark accordingly.

Auxins make seedless grapes, perhaps it's the inhibitor?
 
Auxins make seedless grapes, perhaps it's the inhibitor?
Click to expand...
Are you sure about this? I was under the impression that seedless fruit was due to selective breeding of a tetraploid plant with a diploid one. The resulting triploid plants are infertile, and thus have no seeds. Perhaps grapes are different, but this was the explanation given by my genetics instructor on the subject of seedless bananas and watermelons.
 
Originally posted by Idle Mind
Are you sure about this? I was under the impression that seedless fruit was due to selective breeding of a tetraploid plant with a diploid one. The resulting triploid plants are infertile, and thus have no seeds. Perhaps grapes are different, but this was the explanation given by my genetics instructor on the subject of seedless bananas and watermelons.
Click to expand...

both methods are used for different types of fruit.
 
Originally posted by Dudeyhed

'Explain the internal hormonal change that enabled the response (The plant bending)?'

'How did the plant achive the response?'
Click to expand...

sounds to me as if question one wants you to explain the presence of higher auxin consentration on the light side oft he plant, and question two wants an explination of how the higer consentration is acheived.



you want some fun plant responces to stimuli, a good friend of mine found that when "healing" crystals were placed in proximity to plants, and growth rates were chanrted, something along the lines of an 80% improvment in growth was found :bugeye:. When a "detrimental" stone was placed in proximity, there was a 35% growth reduction off the control. His teacher told him he would fail the class if he did this proposed experiment, and ended up giving him and A! Plants also grow better when exposed to classical music, when they are talked to, when they are prayed for...

Some icelandic flowers bend over the course of an 18 hour day to make sure that they are always facing the sun head on, like a radar dish. An elm tree infected with Dutch Elm disease emites a specific pheremone which prompts the other local trees to pump up their immune systems. Some insect-pollinated flowers capture and pummel their pollinator w/ pollen sacks before releasing them...others get their pollinators drunk for a while, then let them go-via a pollen laden escape hatch at the bottom of the flower.

Plants are amazing.
 
Originally posted by Idle Mind
Are you sure about this? I was under the impression that seedless fruit was due to selective breeding of a tetraploid plant with a diploid one. The resulting triploid plants are infertile, and thus have no seeds. Perhaps grapes are different, but this was the explanation given by my genetics instructor on the subject of seedless bananas and watermelons.
Click to expand...

I've heard of triploid fish being bred (which are sterile), perhaps so that the females do not waste nutrients making eggs when they could be making tasty flesh.

Anyway, I think river-wind is right. I.e. we both are! :)
 
Sounds good to me. I guess you learn something new everyday, to exhaust an old adage.
 
Thanks for all your help guys. It's really appreciated.
I ended up just writing the answer for the previous question buy just rephrasing it. Got a B. Diddn't help that I lost the results... anyway, tomorrows another day and I'm not stressing :D.

river-wind, that sure was fun! :eek: What kind of explanation did your friend come up with for that one?
 
Originally posted by Dudeyhed
Thanks for all your help guys. It's really appreciated.
I ended up just writing the answer for the previous question buy just rephrasing it. Got a B. Diddn't help that I lost the results... anyway, tomorrows another day and I'm not stressing :D.

river-wind, that sure was fun! :eek: What kind of explanation did your friend come up with for that one?
Click to expand...

Well, he's Wiccan, so his explination was "There are many things that we stil don't understand about the world. Ancient cultures and their sciences and medicines are just one of them"

My theories:
1)small amounts of the material which make up the crystals were washing into the plant soil during waterings. he swore he didn't water ontop of the crystals, though. Maybe, similar to how honey uses the crystaline structure of a dust mote to crystalise itself entirely, having a few bits of certain type of crystal help promote root growth via template patterns.
2)that small amounts of the crystal sublimate into the air, which is then absorbed by the plant, again somehow catalising growth reactions or providing template for said growth.
3)that the vibrations of the atoms and the patterns int he crystaline material actually can effect the growth patterns through yet-not-understood pathways.

who knows? cool study, though. I'll have to dig up the copy of the paper he gave me, I saved it somewhere...
 
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