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) on Raphanus sativus L.
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, H2O2 initiation, and EL (%) of
two varieties (40 day radish and Mino radish) of R. sativus increased 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) of R. sativus increased with the exogenous application of KNO3 by 41, 43, 24, and 37%, respectively, in the 40 day radish
grown under the controlled treatments. Results indicated that implementing KNO3 exogenously 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 KNO3 substantially
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 both R. sativus L. 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
KNO3 improves salt tolerance in R. sativus L. genotypes. |
