Unravelling salinity-induced growth and biochemical changes in greengram (Vigna radiata L.) with principal component analysis

The impact of global warming on the environment is affecting soil quality and water supplies, which in turn is impacting agricultural production. The rise in salt concentrations in soil and water systems due to increased evaporation rates from warming temperatures and changing precipitation patterns is a major concern. This salinity poses a threat to crop development, especially for sensitive species like the green gram (Vigna radiata L.), a protein-rich legume consumed globally. Understanding the effects of salinity on green gram growth and physiological responses is essential due to its importance as a significant food source.

A pot experiment was conducted at ADAC and RI, Trichy, with varying EC values (less than 1, 2, 4, 6, 8, 10 and 12 dS/m) to study the effects of different saline irrigation levels. The experiment utilized the green gram variety VBN 2 in a randomized design with three replications. Growth parameters including plant height, number of leaves and branches, blooming period, root, shoot and leaf lengths were measured. Biochemical characteristics such as protein concentration, reducing sugars, proline and chlorophyll levels were also analyzed. The study evaluated the impact of these characteristics on salinity tolerance using principal component analysis (PCA).

Salinity stress negatively affected growth and metabolic reactions in greengram. The VBN 2 variety exhibited better growth and biochemical reactions at a moderate salinity level of 2 dS/m compared to higher salinity levels, indicating moderate salt tolerance. Plant height, leaf growth and flowering time improved with lower salinity levels but decreased significantly at higher salt levels. Important characteristics such as plant height, chlorophyll content and proline accumulation were key factors in determining the plant’s ability to tolerate salt stress, as indicated by PCA analysis.