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Effects of incandescent radiation on photosynthesis, growth rate and yield of 'Waldmann's Green' leaf lettuceEffects of different ratios incandescent (ln) to fluorescent (Fl) radiation were tested on growth of 'Waldmann's Green' leaf lettuce (Lactuca sativa L.) in a controlled environment. After 4 days of treatment, dry weight, leaf area, relative growth rate (RGR), net assimilation rate (NAR), leaf area ratio (LAR) and photosynthetic rate (Pn) were greater for plants grown at 84 rather than 16% of total irradiance (82 W m-2) from ln lamps. Although leaf dry weight and area were 12-17% greater at 84% ln after the first 8 days of treatment, there were no differences in RGR or Pn between treatments during the last 4 days. If 84% ln was compared with 50% ln, all cumulative growth parameters, RGR, NAR and Pn were greater for 84% ln during the first 4 days of treatment. However, during the second 4 days, RGR was greater for the 50% ln treatment, resulting in no net difference in leaf dry weight or area between treatments. Shifting from 84 to 50% ln radiation between the first and second 4 days of treatment increased plant dry weight, leaf area, RGR and NAR relative to those under 84% ln for 8 days continuously.
Document ID
20040089857
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
Authors
Knight, S. L.
(Purdue University West Lafayette, IN 47907, United States)
Mitchell, C. A.
Date Acquired
August 21, 2013
Publication Date
January 1, 1989
Publication Information
Publication: Scientia horticulturae
Volume: 35
ISSN: 0304-4238
Subject Category
Man/System Technology And Life Support
Funding Number(s)
CONTRACT_GRANT: NCC2-100
Distribution Limits
Public
Copyright
Other
Keywords
NASA Program CELSS
Non-NASA Center
NASA Discipline Life Support Systems
NASA Discipline Number 61-10

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