Capacity for Proline Accumulation During Water Stress in Barley and Its Implications for Breeding for Drought Resistance¹

Abstract

During controlled water stress applied at the threeleaf stage, the barley (Hordeum vulgare L.) cultivars ‘Proctor’ and ‘Excelsior’ showed different rates of free proline accumulation and leaf‐firing. Both processes were faster in Proctor (a drought‐susceptible cultivar) than in Excelsior (a drought‐resistant cultivar). The different rates of proline accumulation during stress in Proctor, in Excelsior, and in a wild barley (H. spontaneum C. Koch) could be attributed to differences in the rate of decline of leaf water potential (ψleaf); at the same ψleaf value, all three genotypes contained similar amounts of free proline.After non‐destructive screening of the F2 generation from a Proctor ✕ Excelsior cross for proline‐accumulating capacity under controlled water stress conditions, F3 seed from plants selected for high and low proline accumulation was obtained. When F3 plants were tested for proline accumulation during controlled stress, the selection for proline accumulation was found to have been effective. Reselection among F3 plants and subsequent testing of the F4 generation confirmed this result.Among individual plants of the F3 generation (which was segregating for the prollne accumulation trait) there was a positive association between the amount of free proline accumulated during stress and the severity of leaf‐firing.Massive proline accumulation is a symptom of severe internal water stress in barley and apparently has no survival value during drought. Although there is heritable variation in the amount of proline accumulated during stress, it is not of practical value in breeding for drought resistance.

Accumulation and consumption of solutes in swards of Lolium perenne during drought and after rewatering

“…66). The rapid consumption of proline after rewatering has been observed in a number of crops (Singb, Aspinall & Paleg, 1972;Sivaramakrishnan et al, 1988), but not in dead tissue (Hanson et al, 1979). It therefore appears that although the leaves in treatment D8 in this experiment were partly damaged, having scorched tips and damaged membranes (see above), the unscorched parts of the laminae were able to recover very rapidly.…”

“…Tbis is supported by the observations of Kemble & McPherson (1954) that perennial ryegrass produced proline when wiited during simulated haymaking; of Sivaramakrishnan et al (1988) that sorghum accumulated proline in leaves when extension growth had ceased and i//^. fell below -2 5 MPa; and of Hanson et al (1979) that proline accumulated only in scorched tissues. In an earlier experiment on these populations (Thomas, 1990), the greater accumulation of proline in leaf blades (an average of 101 /imol g^^,, compared with 31 m easured here) was probably a consequence of the artificial drought technique, which involved adding frequent small volumes of water and resulted in a series of short droughts.…”

Tolerance of Accessions of Glagah (Saccharum spontaneum) to Drought Stress and Their Accumulation of Proline

“…Hanson et al (1979), working with Hordeum vulgare L., suggested that proline accumulation was of no practical use in breeding, even though they found a heritable component to this trait. Ceh et al (2009) found no correlation between proline content and drought-resistance in hops (Humulus lupulus L.) and Ilahi and Dorffling (1982) found that drought-susceptible cultivars of Zea mays had higher proline contents that drought-resistant ones.…”

Cloning and characterization of a novel betaine aldehyde dehydrogenase gene from Suaeda corniculata

“…Proline was extracted from 0.1 g freeze-dried seedlings and spectrophotometrically determined using the acid ninhydrin method described by Hanson et al (1979). To analyze SOD activity, fine powder of seedlings was resuspended in 50 mM potassium phosphate (pH 7.8) containing 0.1 mM EDTA and 1% PVP, and then centrifuged at 12,000 g for 15 min at 4°C.…”