The greater photosynthetic capacity exhibited by the transgenic
lines translated into an increase in biomass and seed yields
(Table 2). Significant correlations were readily evident between
starch turnover and leaf area (r2 ∼
0.74) or dry weight (r2 ∼
0.82) in
the WT and WT transgenic lines (Supplementary Fig. 1), indicating
that the enhanced photosynthetic capacity as well as the increased
carbon and energy stored in this transient reserve were utilized
for plant growth. The larger vegetative biomass also resulted in
increasing seed yields. With growth under ambient CO2, seed
biomass per plant was increased by 25% in TLUp1-9 compared to
WT and 52% compared to TL46, and with growth in high CO2 by 7%
and 53% respectively (results not shown). Seed weight per grain did
not differ significantly among the plant lines. The increased photosynthetic
capacity may increase sink development since source
activity can control sink metabolism [25].