Acclimation of Two Distinct Plant Species, Spring Barley and Norway Spruce, to Combined Effect of Various Irradiance and CO₂ Concentration During Cultivation in Controlled Environment

Abstract

The short-term acclimation (10-d) of Norway spruce [Picea abies (L.) Karst] to elevated CO 2 concentration (EC) in combination with low irradiance (100 µmol m -2 s -1 ) resulted in stimulation of CO 2 assimilation (by 61 %), increased total chlorophyll (Chl) content (by 17 %), significantly higher photosystem 2 (PS2) photochemical efficiency (F v /F m ; by 4 %), and reduced demand on non-radiative dissipation of absorbed excitation energy corresponding with enhanced capacity of photon utilisation within PS2. On the other hand, at high cultivation irradiance (1 200 µmol m -2 s -1 ) both Norway spruce and spring barley (Hordeum vulgare L. cv. Akcent) responded to EC by reduced photosynthetic capacity and prolonged inhibition of F v /F m accompanied with enhanced non-radiative dissipation of absorbed photon energy. Norway spruce needles revealed the expressive retention of zeaxanthin and antheraxanthin (Z+A) in darkness and higher violaxanthin (V) convertibility (yielding even 95 %) under all cultivation regimes in comparison with barley plants. In addition, the non-photochemical quenching of minimum Chl a fluorescence (SV 0 ), expressing the extent of non-radiative dissipation of absorbed photon energy within light-harvesting complexes (LHCs), linearly correlated with V conversion to Z+A very well in spruce, but not in barley plants. Finally, a key role of the Z+A-mediated non-radiative dissipation within LHCs in acclimation of spruce photosynthetic apparatus to high irradiance alone and in combination with EC was documented by extremely high SV 0 values, fast induction of non-radiative dissipation of absorbed photon energy, and its stability in darkness.

Spectral composition of photosynthetically active radiation penetrating into a Norway spruce canopy: the opposite dynamics of the blue/red spectral ratio during clear and overcast days

“…We suggest that this difference of the spectral composition may both affect light harvesting in the different parts of canopy during the sunny days and contribute to the signals driving synthesis and/or degradation of light harvesting complexes. As shown earlier for Norway spruce needles the Chl a/b ratio rapidly changes during the transfer of a plant from the understorey of the canopy to the direct solar radiation (Š punda et al 1993), but sometimes Chl a/b ratio is not affected during acclimation of low irradiance (100 lmol m -2 s -1 ) plants to high irradiance (1,200 lmol m -2 s -1 ) conditions (Kurasová et al 2003). The latter case was reported particularly for the plants acclimated in the growth chambers, where the spectral composition of low irradiance is the same as that of high irradiance.…”

Acclimation of Norway spruce photosynthetic apparatus to the combined effect of high irradiance and temperature

“…Chl a/b and Chl a+b/Car x+c were estimated spectrophotometrically (UV/VIS 550, Unicam, England) from pigment extracts in 80% acetone with a small amount of MgCO 3 according to Lichtenthaler (1987). The VAZ content expressed per projected needle area was estimated via gradient reversed-phase high-performance liquid chromatography (TSP Analytical, USA) according to Färber and Jahns (1998) with a minor modification (Kurasová et al, 2003). The details have been described in our previous work (Štroch et al, 2008a).…”

Regulation of the excitation energy utilization in the photosynthetic apparatus of chlorina f2 barley mutant grown under different irradiances

“…Analyses were carried out with gradient pump (Spectra Series P4000) and the autosampler AS3000 with 50 ll sample loop (both TSP Analytical, USA). The detailed description is given in our previous report [24]. The middle segments of 2 h dark-adapted leaves were used for the pigment analysis.…”

“…It has been suggested that the sustained Z + A may be involved in protective (Z + A)-dependent energy dissipation [24,49]. The retention of Z + A is usually accompanied with the suppressed F V =F M [8,50].…”