Free proline accumulation during development of two wheat cultivars with water stress

SUMMARY The course of free proline accumulation in leaves, stems, roots and ears was examined during the development of the wheat cultivars Yecora and Generoso grown in the field with or without irrigation. More negative values of leaf water potential were associated with higher amounts of free proline in the various organs. In most cases, proline accumulated more readily with increasing water stress before heading than after ear emergence in the leaves, stems and roots of both varieties. Differences between the two cultivars concerning the sensitivity of the mechanisms inducing proline accumulation to water stress existed mainly in the reproductive phase: Generoso accumulated proline more readily than Yecora. There is evidence that the increased amounts of free proline in Generoso can be associated with more effective dehydration and drought avoidance mechanisms.