EFFECT OF PACLOBUTRAZOL ON MANGO SEEDLINGS UNDER SALT STRESS CONDITIONS
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Date
2008
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Abstract
The present investigation entitled “Eff
ect of paclobutrazol on mango seedlings
under salt stress conditions” was carried ou
t during 2007-2008 at the Division of Fruits
and Horticultural Technology, Indian Agricu
ltural Research Institute, New Delhi.
Nucellar seedlings of Olour in
pots were treated with different levels of paclobutrazol
i.e.
0.0 mg PBZ/pot (control), 750 mg PBZ/pot
(P1) and 1500 mg PBZ/pot (P2) after 30
days of establishment. Two levels of salts were taken for study
i.e.
S1 (25 g NaCl/pot)
and S0 (0.0 g NaCl/pot, control).
Observations on survivability, grow
th, physiological and biochemical
parameters and tissue nutrient
status were recorded. The se
edling survivability after 60
days under NaCl stress was 57.45% less than
non-salinized seedlings. It was also
evident that paclobutrazol application significantly increased the su
rvivability of mango
seedlings under NaCl stre
ss and higher dose of PBZ
(1500 mg PBZ/pot) was more
effective. Growth parameters
viz.
seedling height, diameter, number of leaves, root
length, number of secondary roots and fresh
and dry weight of shoot and root were
reduced as a result of NaCl treatment. Howe
ver, the negative effect of NaCl on growth
parameters was reduced by treat
ing the plants with PBZ. Moreover, the PBZ also had
protective effect on physiological and bi
ochemical parameters like photosynthetic
pigments, membrane injury index, relative water content, total phenols, proline and
antioxidant enzymes in mango plants under
NaCl stress. The sodium and chloride
uptake and accumulation in leaves and root
s was also reduced by application of
paclobutrazol on mango seedlings under NaCl stress.
The higher dose
i.e.
1500 mg PBZ/pot was found
most effective in improving
most of the growth, physiological and biochemical parame
ters of mango plants under
NaCl stress. The protective e
ffect of paclobutrazol agains
t NaCl stress was due to
enhanced photosynthetic pigments, proline, phenolic compounds, reduced sodium and
chloride uptake and its accumulation in tissues
and more importantly increased activity
of antioxidant enzymes.
Description
t-7971