Diurnal differences were observed in the rates of photosynthesis
and transpiration and in stomatal conductance
between the parent and somatic hybrid lines, however,
the three characteristics were coincident at four time points
9 a.m. (dawn ? 4 h), 12 a.m. (dawn ? 7 h), 15 p.m.
(dawn ? 10 h) and 18 p.m. (dawn ? 13 h). The photosynthetic
and transpiration rates and stomatal conductance were
lowest at 9 a.m. (dawn ? 4 h) and reached a maximum at
12 a.m. (dawn ? 7 h). They thereafter declined through
15 p.m. (dawn ? 10 h) and 18 p.m. (dawn ? 13 h)
(Fig. 10). Interestingly, at all four time points, the photosynthetic rates, stomatal conductances and transpiration
rates were all higher in the somatic hybrids than in the
two parents. The three characteristics were lowest in the
wild cotton G. trilobum, with intermediate characteristics in
the upland cotton (Coker 312).