Other than TLUp1-9, individual plants from the remaining transgenic
lines also showed considerable variation in leaf morphology,
growth rates and plant development compared to WT. Differences
in phenotypic variation, and subtle differences in morphology and
chlorophyll content, were reduced by crossing the three transgenic
lines as well as a fourth transgenic TLUp1-3 to WT. F3 and subsequent
generations of homozygous transgenic lines, containing
the wildtype (WT) and mutant AGPase-LS, were grown together
with WT and the starch deficient line TL46, under a light intensity
of 450 mol quanta m−2 s−1 and ambient CO2 (370 ppm). The
four transgenic lines (WTUp1-3, WTUp1-9, WTUp2-1 and WTUp3-2) had
chlorophyll profiles similar to that seen for WT plants and substantially
more than those in the TL46 background (Table 2). They also
showed substantial increases in CO2 assimilation rates compared to
those measured for the TL46 transgenic lines which were slightly or
significantly higher than WT. Compared to WT, the lowest increases
in CO2 assimilation rate were exhibited by WTUp1-3 and WTUp2-1.
These two transgenic lines also contained the lowest levels of leaf