The impact of red and blue light-emitting diode illumination on radish physiological indices

• Published in: Central European journal of biology 2011-10, Vol.6 (5), p.821-828
• Main Authors: Samuolienė, Giedrė, Sirtautas, Ramūnas, Brazaitytė, Aušra, Sakalauskaitė, Jurga, Sakalauskienė, Sandra, Duchovskis, Pavelas
• Format: Article
• Language: English
• Subjects: Biochemistry; Biomedical and Life Sciences; Biotechnology; Carbohydrates; Cell Biology; Chlorophyll; Human Genetics; Hypocotyl; Immunology; Leaf dry weigh; Life Sciences; Research Article; Root:shoot ratio
• ISSN: 1895-104X; 2391-5412; 1644-3632; 2391-5412
• DOI: 10.2478/s11535-011-0059-z

The objective was to evaluate the effect of different combinations of red (638 nm) and blue (455 nm) light produced by solid-state light-emitting diodes (LEDs) on physiological indices (net assimilation rate, hypocotyl-to-leaf ratio, leaf area, leaf dry weight, hypocotyl length and diameter, plant length, developed leaves), variation of photosynthetic pigments and non-structural carbohydrates in radish ( Raphanus sativus L., var. ‘Faraon’). Lighting experiments were performed under controlled conditions (total PPFD - 200 μmol m −2 s −1 ; 16 h photoperiod; 14/18°C night/day temperature). The LED conditions: 638 nm; 638 + 5% 455 nm; 638 + 10% 455 nm; 638 + 10% 455 + 731 nm; 638 + 10% 455 + 731 + 669 nm. Our results showed that radishes grown under red (638 nm) alone were elongated, and the formation of hypocotyl was weak. The net assimilation rate, hypocotyl-to-leaf ratio, and leaf dry weight also were low due to the low accumulation of photosynthetic pigments and non-structural carbohydrates in leaves. The supplemented blue (455 nm) light was necessary for the non-structural carbohydrates distribution between radish storage organs and leaves which resulted in hypocotyl thickening. Red alone (638 nm) or in combination with far-red (731 nm), or red669 for radish generative development was required.