Photosynthetic responses of beans to water stress in the field.

Book Title: NA
Year Published: 1998
Month Published: NA
Author: Pastenes, C. ; Porter, V. H. ; Baginsky, C. ; Horton, P.
Book Group Author: NA

The effects of water stress on photosynthesis were assessed in field studies in Chile with Phaseolus vulgaris cv. Orfeo Inia and Arroz Tuscola. Water stress was imposed by withholding drip irrigation for 10 days. Plant responses were measured from 0800 to 1800 h. The water potential for control plants was -0.5 MPa and for stressed plants -1.3 MPa in plants with 4 leaves measured at 1200 h. Maximum CO2 assimilation was observed in the morning in control and stressed plants, decreasing during the afternoon, but in stressed plants this decrease occurred faster than in control plants. Control plants achieved a higher maximum rate of photosynthesis from 1000 h to 1200 h and maintained higher CO2 assimilation for a longer period of time. Independent of water supply, plants closed their stomata from midday onwards and closed their leaves in response to high irradiance. It is concluded that the plants avoided photoinhibition even under water stress, maintaining a high proportion of photosystem II centres in an open state. Even though leaf movements prevented photosystem II over-excitation and/or heat stress in water-stressed plants, adequately watered plants were unable to reach light saturation of photosynthesis during the day.

Pages: 2561 - 2564
Volume: NA
Number: NA
Journal: Photosynthesis: mechanisms and effects. Volume IV.Proceedings of the XIth International Congress on Photosynthesis,Budapest, Hungary, 17-22 August, 1998
Journal ISO: NA
Organization: NA
Publisher: NA
ISSN: 0792355458792355474

cultivars, diurnal variation, drought, drought resistance,irrigation, leaves, legumes, nastic movements, photosynthesis, plantwater relations, stomatal movement, trickle irrigation, vegetablelegumes, vegetables, water stress, Chile, Fabaceae, Phaseolus vulgaris,Phaseolus, Papilionoideae, Fabaceae, Fabales, dicotyledons, angiosperms,Spermatophyta, plants, eukaryotes, South America, America, DevelopingCountries, Threshold Countries, Latin America, carbon assimilation,carbon dioxide fixation, cultivated varieties, drought tolerance, greenbean, snap bean, vegetable crops, watering, Plant Water Relations(FF062), Plant Production (FF100), Plant Physiology and Biochemistry(FF060), Environmental Tolerance of Plants (FF900), Soil WaterManagement (Irrigation and Drainage) (JJ800) (Revised June 2002)[formerly Soil Water Management]

Source: EBSCO
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