Phaseolus acutifolius A. Gray is a potential source of stress‐tolerant traits for Phaseolus vulgaris L. through interspecific hybrids. The objective of this study was to quantify the effects of water‐deficit stress on vegetative growth, shoot relative water content (RWC), and leaf concentrations of proline, polyamines, and related metabolites in P. vulgaris compared with P. acutifolius. Stress‐induced changes in N metabolism putatively related to stress tolerance have not been investigated previously in P. acutifolius. Replicate pots, each containing three 5‐d‐old plants in 18.9 L of soil with 4 L of available water, were subjected to water deficit by withholding water (terminal drought) or were maintained under well‐watered (control) conditions. Compared with controls, stressed plants of both species accumulated approximately 55% less shoot dry matter. Root dry matter accumulation was inhibited to a greater degree in P. acutifolius (≈ 70% for two genotypes) than in P. vulgaris (14 and 27% for two genotypes). P. acutifolius maintained greater shoot RWC than P. vulgaris. In droughted plants of P. acutifolius, leaf arginine and proline concentrations did not change, total polyamine (Σ agmatine + putrescine + spermidine + spermine) concentrations decreased, and ammonia increased compared with controls. In P. vulgaris, water deficit increased concentrations of arginine (>30%) and proline (>300%), whereas total polyamine and ammonia concentrations did not change compared with controls. In all four genotypes examined, proline concentration was inversely related to RWC (R2 0.90). Leaf proline concentration is an indicator of plant water status in Phaseolus but not of tolerance or sensitivity of vegetative growth to water deficit.
The objective of this study was to quantify the effect of salinity on the capacity of leaves of Phaseolus vulgaris L. and P. acutifolius A. Gray to synthesize arginine de novo and to determine the relative ability of the two species to tolerate salinity during the vegetative growth phase. Research into the effect of salinity on P. acutifolius relative to P. vulgaris is limited. Plants were hydroponically cultured until age 5 d and then salinized for 16 d with 40 mM NaCl plus 20 mM CaCl2. Salination caused greater reduction (P < 0.05) P. acutifolius shoot dry weight (35 and 43% for two lines) than P. vulgaris [<25% for Linden and Ferry Morse 53 (FM 53) cultivars]. Root growth was unaffected in both species. Salt reduced the capacity of leaves of P. acutifolius to incorporate NaH14CO3 but not [14C]citrulline into arginine plus urea (ΣA + U) per gram fresh weight tissue (80% for both lines, P < 0.05). Arginine de novo synthesis in P. vulgaris was unaffected. Incorporation of NaH14CO3 into ΣA ÷ U was increased by added ornithine but remained lower (P < 0.05) in salinized P. acutifolius leaves than in control leaves, suggesting that ornithine availability was not the single factor limiting arginine de novo synthesis during salination. Salination reduced activities of glutamine synthetase and carbamylphosphaste synthetase per milligram protein in P. acutifolius (both lines, 50%) and FM 53 (20–40%) but not Linden. Thus,enzyme reaction(s) leading to the formation of citrulline in arginine de novo synthesis in leaves of P. acutifolius are more affected by salt than those in P. vulgaris.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.