Abstract:
Considering the salinity issue three studies were conducted to find out the effect of
salt stress on morph-physiological and biochemical changes of wheat (BARI Gom26)
as well as mitigation of the adverse effect through exogenous application of
Ascorbic Acid (AsA), Silicon (Si) and Gibberellic Acid (GA3). The performances of
secondary seeds were also evaluated. The studies were conducted at the net house
and plant physiology laboratory of Agronomy department, Sher-e-Bangla
Agricultural University, Dhaka, Bangladesh. In field experiment, four levels of salt
stress (0, 50, 80, 120 mM NaCl) were applied on growing media of wheat seedling at
20 days after sowing and grown up to harvest where in laboratory experiment salinity
were applied 3 days after sowing grown upto 10 days. In both experiments AsA (2
mM ascorbic acid), Si (200 µM SiO
2
), GA3 (100 µM gibberallic acid) were applied
as foliar spraying (several times with interval) in another set of respective salt stress
treatments. In field study salt stress decreased plant growth, biomass, water status
and yield attributes by altering ionic balance, hampering osmotic status and reducing
chlorophyll (chl) content. In the laboratory experiment, salt stress increased reactive
oxygen species (ROS) generation and lipid peroxidation which contributes to
alteration of osmotic status and chl content as well as growth and biomass of the
plant. However, foliar application of AsA, Si and GA3 on salt affected plant
decreased ROS generation, lipid peroxidation and proline production; increased
water status and chlorophyll pigments which contribute in improved growth and
yield of wheat seedling in contrast to respective stress. Moreover, the findings of the
third experiment confirmed that AsA, Si and GA3 enhanced the performance of
secondary seeds originated from the first experiment. Considering the results of all
experiments GA3 performed better than the AsA and Si in mitigating salt stress.
Description:
A Dissertation
Submitted to the Faculty of Agriculture,
Sher-e-Bangla Agricultural University, Dhaka,
in partial fulfillment of the requirements
for the degree of
DOCTOR OF PHILOSOPHY
IN
AGROMONY
