Abstract:
Tomato plants (Lyocpersiconesculentum Mill. cv. Rio Grand) grown in plastic bags were
gradually exposed to water stress by reducing the amount of irrigation water by 0, 20 and 40% to
reach 100, 80 and 60% of field capacity (FC)during vegetative and reproductive phases. The
plants were foliar sprayed by GA3 solution (0, 50 and 100 ppm), three times at beginning of
water stress treatment during vegetative stage.The results showed that the treatment of water
stress (80% of FC) with a concentration of 50 ppm of GA3 maintained the fresh and dry weight
of shoots(FWS and DWS), while the values were increased with 100 ppm of GA3 treatment. In
contrast, the fresh and dry weight of fruits (FWF and DWF) were decreased under the influence
of water stress at 80% of FC, while the production under the influence of water stress was
aborted by 60% of FCtreatment in the presence or absence of GA3 treatment. The values of the
fruit number(FN) and the fruit volume (FV)weredecreased due to effect of water stress treatment
by 80% of FC, while the value of total soluble solids (TSS) in fruits was increased with this
treatment. The period of maturity date(MD) was not affected by all treatments in this experiment,
while the period of flowering date(FD) was shortened with a decrease in the applied field
capacity. The water use efficiency(WUE) value of the shoots was increased under the influence
of treatment with water stress at 80% of FC with GA3 treatment, and on the contrary, the WUE
value of fruits and plants decreased dramatically under the influence of this condition. The
results showed that the role of GA3 under conditions of water stress did not have a positive
effect on fruiting process despite the improvement in the growth of vegetative parts. It appears
that the effect of treatment with GA3 on tomato plants depends mainly on the type and
development of the growing part of the plant |
