About growing plants with light comming from beneath.....

[albertlee]

Hi all,

 

I know this might not make sense, but can any one explain??

 

we know that plants grow faster and bigger in darker position that in light position, because of etiolation....

 

but my experiment of investigating phototropism in contradiction of geotropism surprised me....

 

I have 3 plants on the shelf of a dark chamber, the distances between each 2 plants are 60 and 30 cm away repectively. just beneath the middle plant, I place a torch, which is situated abit outwards rather than light directly on the middle plant....

 

For days of experiment I saw 1 thing, the plant at the left most, where received the slightest light, barely grow, and the plant at the right most, grow the largest, which grows towards light comming from the torch to the side of the chamber, but not towards the torch.... and the middle, grows in a rate of median, which receives a fraction of light comming from beneath, which the other fraction was blocked by the surface of shelf above. Why does the plant reveicing the least light grow the least???

 

And my conclusion for when geotropism contradicting phototropism, although plant grows towards light, it will not grow downwards for the most light resource, contradicting geotropism. Is this right??

 

ps, here, plant means seedling in my case...

 

 

thanks for any explanation

 

Albert

[albertlee]

ohhh! sorry...

 

post under the wrong category. see here instead:

http://www.scienceforums.net/forums/showthread.php?p=155863#post155863

 

sorry