| Comments |
"At the assay light intensity of 2000 µmol photons/m^2/sec, A [net photosynthesis]
was lower in the RNAi line, though only significant as a trend (P=0.10), while gs [stomatal conductance to water vapor] and ci [intercellular CO2 partial pressure] did not differ significantly between control
and RNAi lines (Table 2). The ratio of A to ci in New Mexico–grown
wild-type plants was ~25% higher than that of the wild-type
plants grown in Germany, suggesting that the New Mexico plants
either had a higher photosynthetic capacity (greater amounts or
more active Rubisco) or a higher gi. Applying these data to the
Evans et al. (1986) model, [researchers] calculated that the mesophyll
conductance for CO2 (gi) in the RNAi line is 21% lower (or ri [resistance to
CO2 diffusion inside leaves] is 27%
higher) than for the control line. Since cc=ci-(A/gi), this equates
with a 1.7 Pa (13%, P=0.16) lower cc in the RNAi line (Table 2).
Lower rates of photosynthesis in the RNAi line have the effect of
increasing the calculated cc, so it is not surprising that the cc
decrease is only a trend." See note beneath table |