The growth and development of the wheat triticum aestivum cultivar warimba apex the effects of photoperiod on spikelet production and sucrose concentration in the apex
Mohapatra, P.K.; Aspinall, D.; Jenner, C.F.
Annals of Botany 49(5): 619-626
ISSN/ISBN: 0305-7364 Accession: 006685120
Spring wheat (T. aestivum cv. Warimba) plants were grown in a controlled environment (20.degree. C) in 2 photoperiods (8 or 16 h). In the 1st instance, plants were maintained in each of the photoperiods from germination onwards at the same irradiance (375 .mu.E [einsteins] m-2 s-1). In the 2nd case, all plants were grown in a long photoperiod until 4 days after double-ridge initiation when half the plants were transferred to a short photoperiod with double the irradiance (16 h photoperiod at 225 or 8 h at 475 .mu.E-2 s-2). The rates of growth and development of the apices were promoted by the longer photoperiod in both experiments. Shoot dry wt gain was proportional to the total light energy received per day; the dry wt of the shoot apex increased with increasing photoperiod even when the total daily irradiance was constant. The principal soluble carbohydrate present in the shoot apex was sucrose, although low concentrations of glucose and fructose were present in the apices of long photoperiod plants late in development. Sucrose concentration was invariably greater in the slow-growing apices of short photoperiod plants, but rose to approach this level in the long photoperiod plants when the terminal spikelet had been initiated.