Phloem and Gravity

[Dan]

Phloem sends photoassimilates (photosynthetic food) down from the leaves to the rest of the plant. (In this case, tree)

My question is, how fast do the photoassimilates move down the tree through the phloem? Does gravity assist movement? Does it move faster or slower than gravity?

 

[Turkey Creek]

Why would you like to know? I have no answer, just curious as to what spurred the question.

 

[Natty Bumppo]

I'll take a crack at this. In a vacuum objects fall (due to gravity) at 9.8 m/sec/sec. So the sugars in the phloem are certainly not moving faster than that. The movement of those sugars is caused by pressure differences, just like the upward sap flow in maples during the spring. How fast do those sugars move? No idea. Does gravity assist? My guess is that it does.