Nevertheless, it is clear that the limitation by TPU at temperatures lower than 22 °C was less in low compared to high irradiance grown HT-plants. Apparently, the HTHL Arabidopsis operated at a capacity of triose-phosphate processing that is close to the supply from the chloroplast in the growth conditions, whereas HTLL-plants had a larger capacity relative to the SBE-��-CD cost supply. This growth irradiance effect is unknown. The larger capacity of triose-phosphate processing relative to its supply requires investments that

is not utilized in the growth conditions, and thus further contributes to inefficient utilization of available resources for leaf functioning at low irradiance in Arabidopsis. Comparison of the two accessions Growth temperature and irradiance

effects were much stronger than the differences WH-4-023 research buy between the two accessions, if there were any. This is evident from the high F values for particularly the irradiance effects. F values for the accession effects were low and not significant in many cases (Table 1). Significant differences that were found include the following (Table 2). Chlorophyll contents and LMA in high temperature grown CVI-0 were higher than for Hel-1. The temperature and irradiance effects on V Cmax were somewhat stronger Autophagy Compound Library datasheet in Hel-1. The growth temperature effect on A sat per unit chlorophyll was somewhat stronger in CVI-0 and the irradiance effect on V Cmax per chlorophyll was somewhat stronger in Hel-1. These two capacity variables per chlorophyll were measured on different sets of leaves, which is likely to be the reason for these slightly different temperature and irradiance effects. The conclusion is that the two accessions were remarkably similar in their acclimation to the combination of temperature and irradiance. Differences were expected in the comparison of CVI-0 and Hel-1 that originate from such widely different climates. The small differences that were found are not consistent with the expectation that the CVI-0 accession has a better capability of photosynthetic acclimation to high irradiance, Meloxicam and the Hel-1 accession to low temperature and/or low irradiance. The number of accessions is not sufficient

to draw definitive conclusions on the absence of climatic differentiation in photosynthetic adaptation in Arabidopsis. However, if these two accession are representative, then its absence would contrast with, e.g., Solidago virgaurea that showed differences between ecotypes in acclimation to irradiance (Björkman and Holmgren 1963), Atriplex lentiformis with ecotypic differentiation in temperature acclimation (Pearcy 1977), and Plantago asiatica that showed some intraspecific altitudinal variability in plasticity of the J max /V Cmax ratio (Ishikawa et al. 2007). It would also contrast with other traits of Arabidopsis as among others pertaining to seed dormancy and flowering time (Koornneef et al. 2004; Stinchcombe et al. 2004), differentiation at the molecular level (Hancock et al.