Table 2.

Published scientific reports of foliar application of proline to enhance drought stress tolerance.

Plant	Stress	Observed Effects	Reference
Beta vulgaris	Normal irrigation and 50% field capacity	The application of silicon and proline increased CAT and SOD activity, root and sugar yield, sucrose%, Chl content, phenolic compounds and reduced RWC, MDA and EL	Alkahtani et al., 2021 [92]
Chenopodium quinoa	Normal irrigation and skipping two irrigation times at 45 and 52 days after sowing	Exogenous proline has the greatest effect on photosynthetic pigments, IAA, phenols, free amino acid and proline content, plant height, fresh and dry weight of shoot and root	Elewa et al., 2017 [13]
Triticum aestivum L.	Normal irrigation and drought at 35% water holding capacity	Application of proline at 150 ppm and GABA at 100 ppm were recommended as the most effective concentrations on chl, proline, glycine betaine and total soluble phenolics contents and reduced MDA	Farooq et al., 2017 [93]
Zea mays L.	Full field and 60% field capacity	Application of proline in modulating drought stress by promoting the uptake and accumulation of N, P and K${}^{+}$	Ali et al., 2008 [95]