Drought and UV stress response in Spilanthes acmella Murr., (tooth-ache plant)

Abstract

In the present investigation, experiments were conducted to investigate the growth, morphological, anatomical and biochemical responses of to UV and drought stresses in Spilanthes acmella (toothache plant). Results were shown that both UV and drought treatments retarded plant growth. Although there was no significant difference in the internal structure of leaf and stem. Morphometric changes such as curling of leaves and shiny surface due to waxy coatings were noticed in plants grown under UV radiation however these changes were absent in water stressed plants but yellowing was observed in the entire leaves. Chlorophyll content and relative water content in leaves were significantly affected by UV and drought. Relative water content markedly increased in UV treated plants and reduced in drought. In UV treated plants chlorophyll a, chlorophyll band total chlorophyll contents were considerably decreased than the drought treated plants. The carotenoid, flavonoids and anthocyanins concentration increased in both treatments. Changes in contents of antioxidative metabolites under the stresses were observed. Free proline and MDA accumulations also showed significant increase in droughttreatment than in UV treatment. During drought condition the catalase activity decreased as compared with the control plant whereas UV treated plants showed increase in the catalase activity.

Keywords

• Antioxidants
• Biochemical response
• Morphology
• Stress
• UV absorbing pigments