Measurement of CO2 assimilation by plants in the field and the laboratory

Zn2+-induced changes at the root level account for the increased tolerance of acclimated tobacco plants

“…Indeed, if the increase in stomatal limitation is the dominant cause of the reduction in A n (Fig. 2c), then C i must decrease (Long and Hallgren, 1985; Bednarz et al , 1998). Therefore, given that in non-acclimated plants the declines in g s were paralleled by declines in A n and C i , these results would support the view that photosynthesis was limited by the low leaf conductance resulting from stomatal closure (Medrano et al , 2002).…”

Loss of photosynthetic efficiency in the shade. An Achilles heel for the dense modern stands of our most productive C4crops?

“…On a subset of these, modulated fluorescence measurements were made, as in Yin et al (2014), to derive operating quantum yield of PSII photochemistry (Φ PSII ) using a multiphase flash protocol (Loriaux et al , 2013). Light response curves were described by a four-parameter non-rectangular hyperbola and fit by a maximum-likelihood routine (Long and Hällgren, 1993). The four parameters are the initial slope of the response, the y -axis intercept, which represents dark respiration ( R d ), the upper asymptote ( A sat ), and a convexity factor (θ) describing the rate of transition between the initial slope and asymptote with respect to Q.…”

“…the absolute maximum quantum yield of CO 2 assimilation $({\Phi }_{{\text{CO}}_{\text{2}}\text{max,abs}})$ (Long et al , 1993). ${\Phi }_{{\text{CO}}_{\text{2}}\text{max,app}}$ is the key determinant of efficiency of leaf photosynthesis under light-limiting conditions (Baker et al , 1988; Long, 1993; Long and Hällgren, 1993; Long et al , 1993; Singsaas et al , 2001; Long et al , 2006). …”

A hairy-leaf gene, BLANKET LEAF, of wild Oryza nivara increases photosynthetic water use efficiency in rice

“…Light was provided by a metal halide lamp (LS-M180; Sumita Optical Glass Inc., Japan) at a photosynthetic photon flux density of 400 (ML) or 1500 μmol m −2 s −1 (HL). The CO 2 concentration and water vapor pressure in the reference and sample air volumes were monitored with an infrared gas analyzer (Li-6262; LI-COR, Lincoln, NE, USA) and used to calculate P n and T r as described by Long and Hallgren (1985). WUE p was calculated as P n / T r .…”