Effect of CO sub 2 enrichment and high photosynthetic photon flux densities (PPFD) on rubisco and PEP-case activities of in vitro cultured strawberry plants

Journal Article · Sat Apr 01 04:00:00 EST 1989 · Plant Physiology, Supplement; (USA)

OSTI ID:6867679

Desjardins, Y; Beeson, R; Gosselin, A ^[1]

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1. Laval Univ., Quebec (Canada)

Standard growing conditions in vitro (low light and CO{sub 2}) are not conducive to autotrophy. An experiment was conducted to improve photosynthesis in vitro in the hope of increasing survival in acclimatization. A factorial experiment was elaborated where CO{sub 2} and PPFD were supplied to in vitro cultured strawberry plants in the rooting stage. Activities of carboxylating enzymes were determined after 4 weeks of culture. The activities of non-activated and activated rubisco and PEP-Case were measured after extraction of the enzymes and a reaction with NaH{sup 14}CO{sub 3} followed by scintillation counting spectroscopy. High CO{sub 2} concentration significantly increased net assimilation rates (NAR) by 165% over the control for both 1650 and 3000 ppm CO{sub 2}. High PPFD only increased NAR by 12 and 35% for 150 and 250 {mu}mol{center dot}m{sup {minus}2}{center dot}s{sup {minus}1} respectively over the control. Plants grown at 3000 ppm CO{sub 2} had the highest level of chlorophyll/g FW with 97% more than the control. The activity of PEP-Case was the highest at high light levels and high CO{sub 2} with rates of 1.65 for 1650 ppm versus 1.22 mmol CO{sub 2} mg{sup {minus}1} chl. h{sup {minus}1} at 250 {mu}mol{center dot}m{sup {minus}2}{center dot}s{sup {minus}1}. There was no difference in PEP activity at low light levels. The rubisco activity was lower at 1650 and 3000 ppm CO{sub 2}. Increases in NAR correlate more closely to the PEP-Case than to Rubisco activity. Physiological significance of high activity of PEP-Case over rubisco will be discussed.

• OSTI ID: 6867679
• Journal Information: Plant Physiology, Supplement; (USA), Journal Name: Plant Physiology, Supplement; (USA) Vol. 89:4; ISSN PPYSA; ISSN 0079-2241
• Country of Publication: United States
• Language: English

Related Subjects

550201 -- Biochemistry-- Tracer Techniques
560300* -- Chemicals Metabolism & Toxicology
59 BASIC BIOLOGICAL SCIENCES
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
BIOLOGICAL EFFECTS
CARBON 14 COMPOUNDS
CARBON COMPOUNDS
CARBON DIOXIDE
CARBON OXIDES
CHALCOGENIDES
ELEMENTARY PARTICLES
ENZYME ACTIVITY
FOOD
FRUITS
GROWTH
ISOTOPE APPLICATIONS
LABELLED COMPOUNDS
MASSLESS PARTICLES
OXIDES
OXYGEN COMPOUNDS
PHOTONS
PLANT GROWTH
STRAWBERRIES
TRACER TECHNIQUES