Articles
GROWTH INHIBITION OF COLEUS UNDER COLOURED PLASTIC FILMS
Article number
435_13
Pages
141 – 148
Language
Abstract
The influence of altered light quality and quantity on Coleus blumei x hybrids was investigated using selective filters in the greenhouse: Mist Blue, Lagoon Blue, Pale Red an a Neutral filter.
Blue (B) : red (R) ratios (B = 400–500 nm, R= 600–700 nm) under Pale Red, Mist Blue, Lagoon Blue and Neutral were 0.14, 0.57, 1.05 and 0.28. Differences in R : far red (FR) ratios (FR= 725–735 nm) were relatively small.
PPFD at plant level differed with transmission rate of the filters, which was 51% for Mist Blue, 43% for Pale Red, 31% for Neutral and 24% for Lagoon Blue.
Plants under the Lagoon Blue filter were reduced in height and internode length, resulting in a growth inhibition of 25% after 10 weeks while under Pale Red stem elongation was increased by 27%. Plant characteristics under Mist Blue and Neutral were comparable.
Total leaf area as well as petiole length and area of one adult leaf were smaller under Lagoon Blue.
Plants under the brighter filters produced more dry weight.
Nevertheless the percentage dry to fresh weight was highest for Lagoon Blue and proportionally more dry weight was stored in the leaves (86%) compared to Neutral (81%) and Pale Red (75%). We suggest therefore that sugar translocation is altered under different coloured filters.
Blue (B) : red (R) ratios (B = 400–500 nm, R= 600–700 nm) under Pale Red, Mist Blue, Lagoon Blue and Neutral were 0.14, 0.57, 1.05 and 0.28. Differences in R : far red (FR) ratios (FR= 725–735 nm) were relatively small.
PPFD at plant level differed with transmission rate of the filters, which was 51% for Mist Blue, 43% for Pale Red, 31% for Neutral and 24% for Lagoon Blue.
Plants under the Lagoon Blue filter were reduced in height and internode length, resulting in a growth inhibition of 25% after 10 weeks while under Pale Red stem elongation was increased by 27%. Plant characteristics under Mist Blue and Neutral were comparable.
Total leaf area as well as petiole length and area of one adult leaf were smaller under Lagoon Blue.
Plants under the brighter filters produced more dry weight.
Nevertheless the percentage dry to fresh weight was highest for Lagoon Blue and proportionally more dry weight was stored in the leaves (86%) compared to Neutral (81%) and Pale Red (75%). We suggest therefore that sugar translocation is altered under different coloured filters.
Our results demonstrate that covering plants with pigmented plastic films can be used to control growth of Coleus, which can be an alternative to the use of chemical growth regulators.
Authors
E. Oyaert, Pierre C. Debergh, E. Volckaert
Keywords
Coleus blumei x hybrids, light quality, light quantity, sugar translocation
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