| dc.description.abstract | Soybeans, scientifically known as Glycine max L. Merrill., play a vital role as a key source
of protein, oil, and essential micronutrients in both human diets and animal feed. Due to
its exceptional nutritional value and health advantages, soybean has emerged as a crucial
and cost-effective agricultural crop worldwide. Nevertheless, drought stress, being the
primary abiotic constraint, can severely impact the growth, development and yield of
soybean, especially in semi-arid and arid regions across the world. In this project, the aims
were to find out whether the soybeans transformed with a soybean cytokinin metabolic
gene isopentenyl transferase (IPT) could display better drought stress tolerance. As a part
of the project, this thesis research reported the results of three common drought stress
indicators in two transgenic soybean lines (T1 and T2) compared to the wild-type (WT)
when they were challenged with water deficit at the flowering stage, including cellular
hydrogen peroxide (H2O2) content, degree of lipid peroxidation of membrane based on
malondialdehyde (MDA) levels and degree of cellular ion leakage. The analyses revealed
that there was no difference in these studied genotypes under normal conditions. However,
the non-transgenic plants displayed higher contents of MDA (by around two-fold), H2O2
(by 1.5-2.1 times), and electrolyte leakage (by 1.5-1.9 times) than in both T1 and T2
transgenic lines under the drought conditions, especially with significantly higher levels
for the first two parameters according to statistical analyses. When comparing the
performance between the two transgenic genotypes, there was no clear evidence for a line
with better performance than the other. Taking these data together, it is implied that the
transgenic plants might suffer less adverse effects caused by drought stress, with lower
reactive oxygen species such as H2O2 and less damage in the membrane structure.
Therefore, the use of IPT gene might contribute to a better soybean tolerance to drought
stress, which is worthy to investigate further | en_US |
