In tomato, fruit growth and quality depend on water and assimilates
import in it. The amount of water uptake by tomato fruit is more than 90% of
the total fruit weight. Johonson et al. (1992) have provided the direct evidence
that the fruit growth is closely linked to the movement of water to the fruit.
There are two distinct pathways for transport of water, minerals and photo
assimilates in to fruit. Mostly water and minerals are transported through xylem
while photo assimilates are moved via phloem tissue. However, some of
studies have shown that phloem also serves as the main route for water into
sink organs. It was estimated that 60-95% of water enters through phloem,
while only 5-40% of water enters through the xylem in fruits of tomato (Ho et
al., 1987). In this experiment a dye will be introduced through fruit pedicel to
allow staining of lignin wall around the xylem vessel that could ensure the
functionality and/or conductivity of xylem vessels in fruit pedicel. The rate of
water uptake by fruit per day will be determined from the excised fruit. At the
same time growth rate of intact and excised fruit will be determined during this
study. Moreover, cell layers as well as cell diameter in developing fruit pericarp
will also be counted during the whole growth period. The research work has
been undertaken to study the relation of fruit enlargement with development of
xylem tissue in pedicel, cell expansion in pericarp and the rate of water uptake
of developing tomato fruit.