The effects of deficiency of cryptochrome 1 (CRY1), phytochrome B2 (phyB2) and the photoreceptor signalling DET-1 protein (hp-2 mutant) on photosynthesis and pro-/antioxidant balance in Solanum lycopersicum exposed to high-intensity blue light [HIBL, 72 h, 500/1,000 μmol(photon) m-2 s-1] were studied. Noticeable photoinhibition of photosynthesis and PSII was found in all these variants. However, the greatest decrease in photosynthesis and PSII activity was observed in the cry1 mutant. The difference among the other options was less pronounced. This low resistance of the cry1 mutant to HIBL is associated with reduced photosynthetic pigments, phenols, and anthocyanins. It appears that under HIBL, CRY1 and, to a lesser extent, phyB2 are required to maintain photosynthesis and antioxidant defence, mitigating blue light-induced oxidative stress. This study expands our understanding of the defence functions of CRY1 and highlights its importance in adapting the photosynthetic apparatus to HIBL.

• Klíčová slova
• Chl a fluorescence, blue irradiation, high irradiance, photoinhibition, photosynthetic activity, tomato,
• MeSH
• antioxidancia metabolismus   MeSH
• fotosyntéza * účinky záření   fyziologie   MeSH
• fotosystém II (proteinový komplex) metabolismus   MeSH
• kryptochromy * metabolismus   genetika   MeSH
• modré světlo MeSH
• mutace MeSH
• rostlinné proteiny * metabolismus   genetika   MeSH
• Solanum lycopersicum * účinky záření   metabolismus   fyziologie   genetika   MeSH
• světlo * MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• antioxidancia MeSH
• fotosystém II (proteinový komplex) MeSH
• kryptochromy * MeSH
• rostlinné proteiny * MeSH

The effects of additional far-red light (FRL) on the photosynthetic and growth parameters of Lactuca sativa plants grown for 30 d and on the photosynthetic activity of the plants under high irradiance [4 h; 1,500 μmol(photon) m-2 s-1] were studied. The plants were grown under coloured light-emitting diodes at a ratio of red light (RL): blue light (BL): green light (GL): far-red light (FRL) = 0.7:1:0.3:0.4 or RL:BL:GL:FRL = 0.7:1:0.3:0.8 (test, T). Additional FRL led to an increase in plant biomass, height, and leaf area but to a decrease in photosynthesis and respiration rates. However, PSII activity was greater in plants with additional FRL. It is suggested that the increase in biomass occurred mainly due to an increase in leaf area but not in photosynthesis. In addition, PSII in the experiment was less resistant to high irradiance. The possible direct and indirect influences of the FRL on growth and photosynthesis were considered.

• Klíčová slova
• Lactuca sativa, chlorophyll a fluorescence, far-red light, growth, photosynthesis, red light,
• Publikační typ
• časopisecké články MeSH