In:
HortScience, American Society for Horticultural Science, Vol. 34, No. 3 ( 1999-06), p. 532A-532
Abstract:
CO 2 enrichment increases efficiency of light utilization and rate of growth, thereby reducing the need for supplemental lighting and potentially lowering cost of production. However, during warmer periods of the year, CO 2 enrichment is only possible intermittently due to the need to vent for temperature control. Previous research investigated the separate and combined effects of daily light integral and continuous CO 2 enrichment on biomass accumulation in lettuce. The current research was designed to look at the efficiency with which lettuce is able to utilize intermittent CO 2 enrichment, test the accuracy with which growth can be predicted and controlled, and examine effects of varying CO 2 enrichment and supplemental lighting on carbon assimilation and plant transpiration on a minute by minute basis. Experiments included application of various schedules of intermittent CO 2 enrichment and gas exchange analysis to elucidate underlying physiological processes. Same-day and day-to-day adjustments in daily light integrals were made in response to occasional CO 2 venting episodes, using an up-to-the-minute estimate of growth progress based on an integration of growth increments that were calculated from actual light levels and CO 2 concentrations experienced by the plants. Results indicated lettuce integrates periods of intermittent CO 2 enrichment well, achieving expected growth targets as measured by destructive sampling. The gas-exchange work quantified a pervasive impact of instantaneous light level and CO 2 concentration on conductance and CO 2 assimilation. Implications for when to apply supplemental lighting and CO 2 enrichment to best advantage and methods for predicting and controlling growth under intermittent CO 2 enrichment are discussed.
Type of Medium:
Online Resource
ISSN:
0018-5345
,
2327-9834
DOI:
10.21273/HORTSCI.34.3.532A
Language:
Unknown
Publisher:
American Society for Horticultural Science
Publication Date:
1999
detail.hit.zdb_id:
2040198-X
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