High temperature and salt stress response in French bean (Phaseolus vulgaris)

Abiotic stresses, such as high temperature, and salt stress are major factors which reduce crop productivity. Effects of high temperature (46-48° C) and salt stress (0.4 M) on French bean (Phaseolus vulgaris), a major vegetable crop, were evaluated in terms of antioxidants and antioxidant enzymes in S-9 cultivar. Both stresses caused similar responses in the plant. Oxidative stress indicators such as H2O2, TBARS, glutathione, ascorbic acid, and proline were significantly elevated. Similarly, antioxidant enzyme, guaiacol-specific peroxidase (POX) was significantly elevated. Other enzymes, Beta-amylase and acid phosphatase (AP) activities were marginally enhanced. However, stresses had contrasting effects on glutathione reductase (GR) and catalase (CAT), which were drastically reduced in temperature stress, and elevated in salt stress. No variations were observed in AP, POX, and CAT isozymes. Patterns of GR and Beta-amylase isozymes differed between temperature and salt stress. SDS-PAGE indicated entirely different sets of proteins in temperature and salt stressed seedlings. Growth rate and fresh mass were affected to same extent, relative to their respective controls. DNA damage was more pronounced under temperature stress than under salt stress. Response mechanism of French bean appears to involve some players which are common to both the stresses, and few specific to individual stress.