Interaction of temperature and irradiance effects on photosynthetic acclimation in two accessions of Arabidopsis thaliana

Abstract

The effect of temperature and irradiance during growth on photosynthetic traits of two accessions of Arabidopsis thaliana was investigated. Plants were grown at 10 and 22 °C, and at 50 and 300 μmol photons m(-2) s(-1) in a factorial design. As known from other cold-tolerant herbaceous species, growth of Arabidopsis at low temperature resulted in increases in photosynthetic capacity per unit leaf area and chlorophyll. Growth at high irradiance had a similar effect. However, the growth temperature and irradiance showed interacting effects for several capacity-related variables. Temperature effects on the ratio between electron transport capacity and carboxylation capacity were also different in low compared to high irradiance grown Arabidopsis. The carboxylation capacity per unit Rubisco, a measure for the in vivo Rubisco activity, was low in low irradiance grown plants but there was no clear growth temperature effect. The limitation of photosynthesis by the utilization of triose-phosphate in high temperature grown plants was less when grown at low compared to high irradiance. Several of these traits contribute to reduced efficiency of the utilization of resources for photosynthesis of Arabidopsis at low irradiance. The two accessions from contrasting climates showed remarkably similar capabilities of developmental acclimation to the two environmental factors. Hence, no evidence was found for photosynthetic adaptation of the photosynthetic apparatus to specific climatic conditions.

Fig. 1

Temperature effects on photosynthesis per unit leaf area of leaves of two Arabidopsis accessions (CVI-0 and Hel-1) grown at temperatures of 10 and 22 °C and irradiances of 50 and 300 μmol photons m⁻² s⁻¹. The light saturated rate of CO₂ assimilation (A _sat), the net CO₂ assimilation rate at the growth irradiance (A _growth), and the electron transport rate (ETR) at the growth irradiance (continuous line) and at saturating irradiance (dashed line) are shown. Means (n = 4) are shown, in the case of A _sat and A _growth with SE but for ETR without. Abbreviations of the treatments as indicated in the legend are LTLL (low temperature and low irradiance), LTHL (low temperature and high irradiance), HTLL (high temperature and low irradiance), HTHL (high temperature and high irradiance). Large symbols refer to measurements at the growth temperature

Fig. 2

The response of net photosynthesis (A _n) to the intercellular CO₂ partial pressure (C _i) measured at 10 °C (upper panels) and 22 °C (lower panels). A representative example (from n = 3) is shown for all treatment combinations and the two Arabidopsis accessions CVI-0 and Hel-1. Large symbols refer to measurements at ambient CO₂ (38 Pa). The data were fitted to the model of Farquhar et al. (1980) to derive values for J _max and V _Cmax and to draw the lines as shown

Fig. 3

The carboxylation capacity (V _Cmax) expressed per unit Rubisco measured at 10 °C (upper panels) and 22 °C (lower panels). The Arabidopsis accession CVI-0 and Hel-1 were grown at temperatures of 10 °C and 22 °C and irradiances of 50 (LL) and 300 (HL) μmol photons m⁻² s⁻¹. Means + SE are shown (n = 3). The dots indicate measurements at the growth temperatures

Fig. 4

The intercellular CO₂ partial pressure (C _i) where photosynthesis is co-limited by carboxylation capacity and the regeneration of RuBP (co-limitation C _i) measured at 10 °C (upper panels) and 22 °C (lower panels). The Arabidopsis accession CVI-0 and Hel-1 were grown at temperatures of 10 and 22 °C and irradiances of 50 (LL) and 300 (HL) μmol photons m⁻² s⁻¹. Means + SE (n = 3) are shown. The dots refer to measurements at the growth temperatures; the single crosses indicate that J _max could not be reliably estimated meaning that the co-limitation C _i was high; the double crosses indicate where photosynthesis at the co-limitation C _i was not limited by V _Cmax and J _max but by V _Cmax and TPU

Fig. 5

Temperature dependence of the change in photosynthetic rate as a result of a decrease in [O₂] from 21 % (atmospheric) to 1 % (mean ± SE; n = 4). The electron transport rate (ETR; upper panels) and the CO₂ assimilation rate at the growth irradiance (A _growth; lower panels) are shown. When limitation by triose-phosphate utilization (TPU) does not play a role, the A _growth and ETR are expected to increase and to remain constant, respectively. Symbols and treatments as in Fig. 1