i want know,plz, what does determine carbohydrate in which direction
transport or store and how does the leaf stop its carbohydrate transport to a
other parts of plant. BRBR

As you apparently know already, leaves manufacture sugar all during the growing
season. It is transported wherever it is needed for further growth. In the
fall, with shorter daylength, all the sugar in the leaves is transported to the
roots for winter storage. Then the leaves fall. In the spring, there is a surge
of sugar transport back up the tree to the buds, which is why we collect maple
sap in the spring.
As long as the leaf is green and growing, it is making sugar & sending it to
other parts of the plant.

the carbohydrate storage of fuit is full and transport should be supressed?
BRBR

I think what you are asking is, does the plant stop making sugar when it is
full of ripe fruit? They are not directly connected, except that fruit is
usually ripe in the fall. The main reason leaves stop making sugar is short
daylength in the fall. In most tropical areas, there is a wet and dry season,
and trees prepare for the dry season the way trees in cold climates prepare for
winter. In the rainforest, where there are no seasons, leaves make sugar all
year long.
Iris,
Central NY, Zone 5a, Sunset Zone 40
"If we see light at the end of the tunnel, It's the light of the oncoming
train."
Robert Lowell (1917-1977)