Foliar Spray of Proline Enhanced the Photosynthetic Efficiency and Antioxidant System in Brassica juncea

Abstract

The present study was carried out to screen out the best concentration of proline, applied exogenously as foliar spray, which will have beneficial effects on growth and physio-biochemical parameters in two varieties of Brassica juncea ). The proline concentrations tested in this experiment were 0, 10, 20 or 30 mM. The foliar spray was done at 29 days after sowing (DAS) and sampling at 60 DAS. Out of these concentrations, 20 mM proline was found best. The proline treatment significantly increased the growth, net photosynthetic rate and related attributes, SPAD value of chlorophyll, leaf carbonic anhydrase activity and quantum yield of photosystem II, as well as proline content and activity of antioxident enzymes also increased in both the varieties at 60 d stage of growth. The result was more pronounced in the 'Varuna' than in 'RH-30'.

Morphological, Physiological, Biochemical and Molecular Response of Barley (H. Vulgare L.) to Water Deficiency

“…To boost plant tolerance to abiotic stressors and maintain a high relative water content, plants may accumulate low-molecularweight substances such as proline [76] perhaps, via buffering the cellular redox potential [77]. Proline's function as an osmolyte or osmoprotectant in the leaves of drought-stressed plants is controversial [78,79]. Indeed, it has been established that proline confers drought tolerance on plants by enhancing the antioxidant system rather than by promoting osmotic adjustment [80].…”