Exogenous Ca2+ alleviates nitrogen and water deficit, and improves growth of wheat (Triticum aestivum) seedlings exposed to high temperature

Abstract

This study was designed to examine whether exogenous Ca 2? would improve nitrogen nutrition, water status and growth of high temperature (HT)-stressed wheat (Triticum aestivum) seedlings. Wheat plants were exposed to 35/30 and 25/20°C as temperature control. Some of HT-stressed plants were simultaneously treated with 4 mM Ca 2? . External Ca 2? could obviously improve growth of HT-exposed wheat seedlings indicated by the biomass. Compared with Ca 2? -untreated plants, total nitrogen content showed a significant increase in Ca 2? -treated plants under HT stress, this primarily resulted from enhanced nitrate reductase activity and depressed loss of ammonium through photorespiration. External Ca 2? application could also increase leaf relative water content and alleviate osmotic stress via increased K ? ion and water-soluble carbohydrates in HT-stressed plants. Whereas free proline content showed remarkable decline in Ca 2? -treated plants at HT stress.

Effect of Exogenous Calcium on the Heat Tolerance in Rosa hybrida ‘Carolla’

“…The increase in SS and Pro is likely related to Ca 2+ enhancing the activity of starch metabolism enzymes such as α and β-amylases [40], as well as the activity of P-5-CR and γ-glutamyl kinase in the Pro biosynthetic pathway [55]. External calcium could alleviate cell membrane leakage [56] and osmotic stress, induce osmotic adjustment, and maintain plant growth under stress [57]. Research showed that Ca 2+ stabilizes the cell membrane surface, affects the pH of cells, and keeps solutes from leaking out of the cytoplasm [55].…”