Is foliar spray of proline sufficient for mitigation of salt stress in Brassica juncea cultivars?

Abstract

The effects of foliar application of proline (20 mM) on growth, physio-biochemical, and yield parameters were assessed in two Brassica juncea (L.) Czern & Coss cultivars, namely, Varuna and RH-30, at different levels (2.8, 4.2, or 5.6 dsm(-1)) of NaCl in soil. At 29 days after sowing (DAS), plants were sprayed with either 20 mM proline or water in the presence or absence of NaCl stress. The NaCl negatively affected parameters related to growth, photosynthesis, and yield in both varieties but more in RH-30 than in Varuna. Exogenous application of proline counteracted the effects of salt stress in Varuna only, by increasing the antioxidative capacity of the plants. Moreover, proline was not effective in alleviating the detrimental effects of higher salt concentrations on the studied parameters. Proline application to unstressed plants increased growth, photosynthesis, and yield parameters in both varieties; however, the effects were more prominent in Varuna than in RH-30.

Effect of seed priming on growth and physiological traits of five Jordanian wheat (Triticum aestivum L.) landraces under salt stress

“…Increased chlorophyll content by CaCl2 priming have been previously reported (Farooq et al, 2009;Afzal et al, 2012;Joshi et al, 2013) and is suggested to be the result of both a decrease in the activity of chlorophyllase (Issam et al, 2012) and reduction of reactive oxygen species released during stress (Sevengor et al, 2011). More recently the priming induced proline accumulation is proved to play an important role in protecting chlorophyll from degradation (Hayat et al, 2012;Wani et al, 2016). The results showing that CaCl2 priming reduced H2O2 content and increased proline accumulation in stressed wheat seedlings extended support to these assumptions.…”

Exogenous application of calcium to 24-epibrassinosteroid pre-treated tomato seedlings mitigates NaCl toxicity by modifying ascorbate–glutathione cycle and secondary metabolites

“…Foliar application of proline in B . juncea also mitigated the salt driven changes and overwhelmed the salt stress changes in growth, photosynthesis, and yield parameters 97 . Ca is an important signaling molecule and is involved in proline biosynthesis 98 .…”

How Does Proline Treatment Promote Salt Stress Tolerance During Crop Plant Development?

“…Thus, new alternative approaches to allow crops to efficiently tolerate salt stress are needed. Indeed, the use of exogenous compounds, which are both ecofriendly and easily available, such as silicon (Zhu and Gong, 2014;Rizwan et al, 2015), trehalose (Nounjan et al, 2012), glycine betaine (Hossain and Fujita, 2010), and proline (Hoque et al, 2008;Deivanai et al, 2011;Wani et al, 2016), is a sustainable approach to overcoming the negative effects of salt stress on seed germination, plant growth, and productivity.…”