Plant responses to UV-B irradiation are modified by UV-A irradiation
- NASA/Goddard Space Flight Center, Greenbelt, MD (United States) Univ. of Maryland, College Park (United States)
The increasing UV-B radiation (0.28-0.32 [mu]m) reaching the earth's surface is an important concern. Plant response in artificial UV-B irradiation studies has been difficult to assess, especially regarding photosynthetic pigments, because the fluorescent lamps also produce UV-A (0.32-0.40[mu]m) radiation which is involved with blue light in pigment synthesis. Both UV-A and UV-B irradiances were controlled in two glasshouse experiments conducted under relatively high PPFD (> 1300[mu]mol m[sup [minus]2] s[sup [minus]1]) at two biologically effective daily UV-B irradiances (10.7 and 14.1 kJ m[sup [minus]2]); UV-A irradiances were matched in Controls ([approximately]5, 9 kJ m[sup [minus]2]). Normal, chlorophyll-deficient, and flavonoid-deficient isolines of soybean cultivar, Clark, were utilized. Many growth/ pigment variables exhibited a statistically significant interaction between light quality and quantity: in general, UV-A radiation moderated the damaging effects of UV-B radiation. Regression analyses demonstrated that a single negative function related photosynthetic efficiency to carotenoid Content (r[sup 2] =0.73, P[le]0.001), implying a [open quotes]cost[close quotes] in maintaining carotenoids for photoprotection. A stomatal limitation to photosynthesis was verified and carotenoid content was correlated with UV-B absorbing compound levels, in UV-B irradiated plants.
- OSTI ID:
- 6144858
- 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
PLANTS
BIOLOGICAL RADIATION EFFECTS
ULTRAVIOLET RADIATION
RESPONSE MODIFYING FACTORS
CAROTENOIDS
CHLOROPHYLL
MITIGATION
PHOTOSYNTHESIS
STOMATA
BIOLOGICAL EFFECTS
CARBOXYLIC ACIDS
CHEMICAL REACTIONS
ELECTROMAGNETIC RADIATION
HETEROCYCLIC ACIDS
HETEROCYCLIC COMPOUNDS
HYDROCARBONS
OPENINGS
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
PHOTOCHEMICAL REACTIONS
PHYTOCHROMES
PIGMENTS
PORPHYRINS
PROTEINS
RADIATION EFFECTS
RADIATIONS
SYNTHESIS
TERPENES
560140* - Radiation Effects on Plants