Soil salinization has become a major issue around the
world in
recent years, as it is one of the consequences of climate change as
sea levels rise. It is crucial to lessen the severe consequences of
soil salinization on plants. A pot experiment was conducted to regulate
the physiological and biochemical mechanisms in order to evaluate
the ameliorative effects of potassium nitrate (KNO3) onRaphanus sativusL. genotypes under salt stress.
The results from the present study illustrated that the salinity stress
induced a significant decrease in shoot length, root length, shoot
fresh weight, shoot dry weight, root fresh weight, root dry weight,
number of leaves per plant, leaf area chlorophyll-a, chlorophyll-b,
total chlorophyll, carotenoid, net photosynthesis, stomatal conductance,
and transpiration rate by 43, 67, 41, 21, 34, 28, 74, 91, 50, 41,
24, 34, 14, 26, and 67%, respectively, in a 40 day radish while decreased
by 34, 61, 49, 19, 31, 27, 70, 81, 41, 16, 31, 11, 21, and 62%, respectively,
in Mino radish. Furthermore, MDA, H2O2initiation,
and EL (%) of two varieties (40 day radish and Mino radish) ofR. sativusincreased significantly (P< 0.05) by 86, 26, and 72%, respectively, in the roots and also
increased by 76, 106, and 38% in the leaves in a 40 day radish, compared
to the untreated plants. The results also elucidated that the contents
of phenolic, flavonoids, ascorbic acid, and anthocyanin in the two
varieties (40 day radish and Mino radish) ofR. sativusincreased with the exogenous application of KNO3by 41,
43, 24, and 37%, respectively, in the 40 day radish grown under the
controlled treatments. Results indicated that implementing KNO3exogenously in the soil increased the activities of antioxidants
like SOD, CAT, POD, and APX by 64, 24, 36, and 84% in the roots and
also increased by 21, 12, 23, and 60% in the leaves of 40 day radish
while also increased by 42, 13, 18, and 60% in the roots and also
increased by 13, 14, 16, and 41% in the leaves in Mino radish, respectively,
in comparison to those plants grown without KNO3. We found
that KNO3substantially improved plant growth by lowering
the levels of oxidative stress biomarkers, thereby further stimulating
the antioxidant potential system, which led to an improved nutritional
profile of bothR. sativusL. genotypes
under normal and stressed conditions. The current study would offer
a deep theoretical foundation for clarifying the physiological and
biochemical mechanisms by which the KNO3improves salt
tolerance inR. sativusL. genotypes.