Summary
This study was undertaken to evaluate water stress effects during vegetative, flowering, and podfilling stages of cowpea plants (Vigna unguiculata L.) grown under natural field conditions in southern California on seed yield and protein and free amino acid content of the cowpea seeds.
The lowest concentration of N was found in the seeds of the control treatment plants while the seed yield from these treatments was the highest as compared with the N concentration and yield of seeds from plants subjected to water stress during flowering and podfilling stages. The concentration of N in the seeds was inversely related to the seed dry weight yield.
Protein arginine,-threonine,-serine,-cystine,-valine,-methionine, and-isoleucine were significantly affected by water stress at the three growth stages. There was no consistent pattern in the effect of water stress on the individual amino acids. The sum of protein amino acids in the cowpea seeds was not significantly influenced by the various treatments since some of the protein amino acids increased and others decreased producing an averaging effect on the figures comprising the sums of the amino acids.
Water stress during the flowering and pod-filling stages increased the free amino acid pool, and at the same time, inhibited incorporation of the amino acids into the protein chain-thus lowering the protein amino acid fraction simultaneously.
With the exception of methionine plus cystine, the essential amino acids in the seeds were present at concentrations equal to or greater than recommended by the World Health Organization and FAO. It is of particular importance to note that the concentration of lysine in the cowpeas was substantially higher than that found in wheat grain. It is also important to note that the amount of essential amino acids per gram of protein was not measurably affected by the water stress treatments during any of the growth stages.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
References
Bligh, E. E. and Dyer, W. J. 1959 A rapid method of total lipid extraction and purification. Can. J. Biochem. Physiol.37, 911–917.
Bressani, R., Elias, L. G. and Valiente, A. T. 1963 Effect of cooking and of amino acid supplementation on the nutritive value of black beans (Phaseolus vulgaris L.) Br. J. Nutr.17, 69–78.
Duncan, D. B. 1955 Multiple range and multipleF tests. Biometrics11, 1–142.
Hiler, E. A., Van Bavel, C. H. M., Hossain, M. M. and Jordan, W. R. 1972 Sensitivity of southern peas to plant water deficits at three growth stages. Agron. J.64, 60–64.
Huxley, P. A. and Summerfield, R. J. 1976 Effects of day length and day/night temperatures on growth and seed yield of cowpea cv. KZ 809 grown in controlled environments. Ann. Appl. Biol.83, 259–271.
Labanauskas, C. K., Bingham, F. T. and Cerda A. 1978 Free and protein amino acids, and nutrient concentrations in wheat grain as affected by phosphorus nutrition at various salinity levels. Plant and Soil49, 581–593.
Labanauskas, C. K., Luxmoore, R. J. and Stolzy, L. H. 1974 Soil temperature and soil aeration effects on protein and free amino acid concentrations in wheat grain. Plant and Soil41, 351–363.
Labanauskas, C. K., Shouse, P. and Stolzy, L. H. 1981 Effects of water stress at various growth stages on seed yield and nutrient concentrations of field-grown cowpeas. Soil Sci.131, 249–256.
Labanauskas, C. K., Stolzy, L. H. and Handy, M. F. 1981 Protein and free amino acids in wheat grain as affected by soil types and salinity levels in irrigation water. Plant and Soil59, 299–316.
Porter, W. M., Maner, J. H., Axtell, J. D. and Keim, W. F. 1974 Evaluation of the nutritive quality of grain legumes by an analysis for total sulfur. Crop Sci.14, 652–654.
Shouse, P., Dasberg, S., Jury, W. A. and Stolzy, L. H. 1981 Growth stage water deficit effects on plant-water potential, dry matter production, seed yield, and water use efficiency of field-grown cowpeas. Agron. J.73, 333–336.
Snedecor, G. W. 1956 Statistical Methods. 5th ed. Iowa State College Press, Ames, IA.
Spackman, D. H., Stein, W. H. and Moore, S. 1958 Automatic recording apparatus for use in the chromotography of amino acids. Anal. Chem.30, 1190–1206.
Summerfield, R. J., Huxley, P. A., Dart, P. J. and Hughes, A. P. 1976 Some effects of environmental stress on seed of cowpea [Vigna unguiculata (L.) Walp] cv Prima. Plant and Soil44, 527–546.
Thompson, J. R., Morris, C. J. and Gering, R. K. 1959 Purification of plant amino acids for paper chromotography. Anal. Chem.31, 1028–1031.
Turk, K. J., Hall, A. E. and Asbell, C. W. 1980. Drought adaptation of cowpea: I. Influence of drought on seed yield. Agron. J.72, 413–421.
Waines, J. G., Labanauskas, C. K., Handy, M. F., Gill, B. C. and Lehman, W. F. 1978 Protein and amino acid profiles of normal and yellow-berry bread wheat. Crop Sci.18, 590–592.
Wein, H. C., Littleton, E. J. and Ayanaba, A. 1979 Drought stress of cowpea and soybean under tropical conditions.In Stress Physiology in Crop Plants. Eds. H. Mussell and R. C. Staples. Wiley Interscience, New York pp 283–301.
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Labanauskas, C.K., Shouse, P., Stolzy, L.H. et al. Protein and free amino acids in field-grown cowpea seeds as affected by water stress at various growth stages. Plant Soil 63, 355–368 (1981). https://doi.org/10.1007/BF02370036
Received:
Issue Date:
DOI: https://doi.org/10.1007/BF02370036