Proline Enhances Resistance and Recovery of Oilseed Rape after a Simulated Prolonged Drought

Abstract

This study was carried out to evaluate the effect of exogenous proline on the growth, biochemical responses, and plant recovery of drought-stressed oilseed rape plants after renewed irrigation. The experiment was conducted under controlled laboratory conditions. After 21 days of cultivation, 3–4 leaf stage seedlings were sprayed with proline (1 mM), then subjected to prolonged drought stress for 8 days to achieve a severe water deficit, next, irrigation was resumed and recovery was assessed after 4 days. The results show that exogenous application of proline reduced the drought-induced growth inhibition of seedlings while maintaining relative water content (RWC) and growth parameters closer to those of irrigated plants. Proline had a positive effect on chlorophyll accumulation and membrane permeability while decreasing ethylene, H2O2, and MDA levels. Moreover, after 4 days of recovery, the H2O2 content of the proline-treated plants was significantly lower (2-fold) and the MDA content was close to that of continuously irrigated plants. Thus, all these biochemical reactions influenced plant survival: after drought + proline treatment, the number of surviving plants was two times higher than that of drought-treated plants. The findings show that exogenous proline has antioxidant, osmotic, and growth-promoting properties that improve the drought tolerance of winter oilseed rape plants and is, therefore, beneficial for drought adaptation in oilseed rape.

Photosynthetic gas exchange, plant water relations and osmotic adjustment of three tropical perennials during drought stress and re-watering

“…Various studies align with the increase in proline levels in DS-treated plants [ 39 , 40 ], and large proline accumulation is usually associated with DS tolerance [ 41 ]. It was reported that proline has antioxidant and osmotic properties that improve the drought tolerance of oilseed rape [ 42 ]. Thus, C .…”