Effect of salt stress on seed germination, morphology, biochemical parameters, genomic template stability, and bioactive constituents of Andrographis paniculata Nees

High level of salinity present in the soil severely affects plant growth and metabolism, eventually reduces crop productivity. In the present study, we have made an effort to obtain detailed insight on the effect of various levels of salinity on various physiological, biochemical, genetic, and phytochemical parameters of Andrographis paniculata genotype, CIM-Megha, in an attempt towards development of a salt-tolerant variety. The results showed that maximum seed germination efficiency was observed at 100 mM among the various salt concentrations. Moreover, with the increase in salt concentration, the overall growth of the plant was stunted. High salinity had a negative effect on photosynthetic pigments, free cysteine content, non-protein thiol content, and nitrate reductase activity. However, proline accumulation and phenol content were found to increase with the increasing salt concentration. The results from the study demonstrated that activities of CAT and APX antioxidant enzymes increased with the applied salt stress. The accumulation of reactive oxygen species in response to salinity is the most important DNA-damaging factor causing a decrease in the genomic template stability of the plant. Quantification of important bioactive constituents (andrographolide, neo-andrographolide, and 14-DDA) was done through HPLC, and the results showed high variability in constituents. In summary, Andrographis paniculata could be grown at large scale in saline areas having up to 100 mM salt concentration.

Automated summary

The study found that Andrographis paniculata exhibited maximum seed germination efficiency at a 100 mM salt concentration, but overall plant growth was stunted with increasing salt levels. High salinity negatively impacted plant growth and metabolism, leading to an increase in antioxidant enzyme activity.