Quantitative evaluation of the counterbalance between photosynthetic stimulation and depression caused by low partial pressure of O2 and CO2 in alpine atmospheres

Determination of photosynthetic parameters Vcmax and Jmax for a C3 plant (spring hulless barley) at two altitudes on the Tibetan Plateau

“…Alpine plants have greater leaf nitrogen use efficiency (Terashima et al, 1995) and greater efficiency of CO 2 uptake (Oechel and Vourlitis, 1996), as a consequence of greater leaf and palisade layer thicknesses (Körner et al, 1991), greater leaf nitrogen content per unit leaf area (Körner, 1989), greater leaf dry mass and higher partitioning coefficients for leaf nitrogen in Rubisco and in bioenergetics (Niinemets and Tenhunen, 1997). The positive effects of these factors on photosynthesis at high altitudes compensate for, or even exceed, the negative effect from the decrease in CO 2 partial pressure with increasing altitude (Körner et al, 1991;Sakata et al, 2007).…”

“…Therefore, the Tibetan Plateau would likely be a preferred location for research on the photosynthetic performance of plants subjected to global climate change. To date, most research of the photosynthetic responses of alpine plants to changes in either CO 2 partial pressure or temperature has not been concentrated on the photosynthetic model parameters but rather on simple contrast analyses for photosynthetic measurements at extreme altitude (Cabrera et al, 1998;García-Núñez et al, 2004;Zhang et al, 2005;Sakata et al, 2007), especially on the Tibetan Plateau (Liu and Yang, 2001;Liu et al, 1999). Therefore, because Vc max and J max are two key parameters in the photosynthetic model (Farquhar et al, 1980), further research on these parameters should be conducted on plants of the Tibetan Plateau.…”

Atmospheric CO2 captured by biogenic polyamines is transferred as a possible substrate to Rubisco for the carboxylation reaction

“…Rubisco must be activated by CO 2 and Mg 2+ to function. Conditions consisting of 10 mM MgCl 2 , 10 mM NaHCO 3 , pH 7.8, and 0 °C for 10 min have been used for activation treatment 33 . To verify whether polyamines supply CO 2 for Rubisco, we used polyamine solutions sufficiently incorporating CO 2 for the activation treatment of Rubisco instead of NaHCO 3 usually used as carbonate source.…”

Effects of internal conductance and Rubisco on the optimum temperature for leaf photosynthesis in Fallopia japonica growing at different altitudes

“…The habitat of F2250 had a lower temperature and lower atmospheric pressure than did the habitat of K0100. Under lower atmospheric pressure, the lower CO 2 partial pressure suppresses leaf photosynthesis, which partly compensates for photosynthetic stimulation caused by the lower O 2 partial pressure (Terashima et al 1995;Sakata and Yokoi 2002;Sakata et al 2007). The CO 2 concentration near Rubisco should be affected by leaf temperature because this affects the solubility of CO 2 and the rate of ribulose 1,5-bisphosphate carboxylation by Rubisco.…”

“…Terashima et al (1995) predicted that mitigation of the O 2 -inhibition would partly compensate for photosynthetic suppression caused by the low CO 2 partial pressure at high altitudes. Since photosynthesis depends on the concentrations of CO 2 and O 2 near Rubisco, it was also shown that the degree of the photosynthetic suppression at low atmospheric pressure depends on both internal conductance (g i ) and the amount of active Rubisco (e), which determine the drop in partial pressure of CO 2 from the intercellular air spaces to the Rubisco active site (Sakata and Yokoi 2002;Sakata et al 2007).…”