Effects of UV-B radiation and water stress on gas exchange of soybeans under two different nitrogen levels
- Univ. of Maryland, College Park (United States)
Due to anthropogenic destruction of stratospheric ozone, UV-B radiation is projected to increase in the near future. Other potential global climate changes in temperature and precipitation patterns raise the need for research into plant responses to multiple environmental stresses. The objective of this study was to document UV-B and water stress effects on gas exchange of soybean (Glycine max Merr.) under two nitrogen levels. Two soybean cultivars differing in sensitivity to UV-B were tested at fluence rates of 19.1 or 8.5 kJ m[sub [minus]2]day[sub [minus]1] (enhance and natural levels of UV-B, respectively). Measurements of photosaturated CO[sub 2] uptake at ambient CO[sub 2] (A). stomatal conductance. photosaturated O[sub 2] evolution at saturating CO[sub 2] (A[sub max]), long term water use efficiency (using [delta][sup 13]C), and nitrogen fixation (using [sup 15]N) were performed. No significant treatment effects on A could be detected. However A[sub max] was significantly increased, and stomatal conductance reduced (p<0.01) by increased UV-B at all levels of water and nitrogen for both cultivars, suggesting a stronger stomal limitation of photosynthesis under UV-B. Water and nitrogen use efficiency also decreased under increased UV-B in both cultivars (p<0.01).
- OSTI ID:
- 6144848
- Report Number(s):
- CONF-930798-; CODEN: BECLAG
- Journal Information:
- Bulletin of the Ecological Society of America; (United States), Vol. 74:2; Conference: 78. annual Ecological Society of America (ESA) meeting, Madison, WI (United States), 31 Jul - 4 Aug 1993; ISSN 0012-9623
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
SOYBEANS
PHOTOSYNTHESIS
ULTRAVIOLET RADIATION
BIOLOGICAL EFFECTS
CARBON DIOXIDE
CLIMATIC CHANGE
NITROGEN
NITROGEN FIXATION
OZONE
PLANT GROWTH
STOMATA
WATER
CARBON COMPOUNDS
CARBON OXIDES
CHALCOGENIDES
CHEMICAL REACTIONS
ELECTROMAGNETIC RADIATION
ELEMENTS
FOOD
GROWTH
HYDROGEN COMPOUNDS
NONMETALS
OPENINGS
OXIDES
OXYGEN COMPOUNDS
PHOTOCHEMICAL REACTIONS
PLANTS
RADIATIONS
SYNTHESIS
VEGETABLES
560140* - Radiation Effects on Plants