RESULTS
Plant growth
Changes in the total plant dry weight and leaf area of
both cultivars after transfer to different light conditions
are shown in Fig. 2. Up until 35 days after germination,
the total plant dry weight and leaf area of Sasanishiki
and the leaf area of Nipponbare did not differ between
the light quality treatments, while those of Sasanishiki
were significantly higher in the RB-grown plants than
in the R-grown plants after 42 days. In Nipponbare,
although there was no significant difference in the total
plant dry weight between the light quality treatments
at 42 and 49 days after germination, the total plant dry
weight tended to be higher in the RB-grown plants than
in the R-grown plants. The final (56 days after germination)
total plant dry weight of Sasanishiki and Nipponbare
grown under RB conditions was 20% and 33% higher
than that of each cultivar grown under R conditions,
respectively. The total leaf area of Sasanishiki and
Nipponbare grown under RB conditions was 30% and
35% greater than the area of the plants grown under R
conditions, respectively (Fig. 2). The biomass allocation
to the roots (56 days after germination) was significantly
higher in the RB-grown plants than in the R-grown
plants, and the allocation to leaf sheaths was appreciably
lower in the RB-grown plants for both cultivars 56 days
after germination (Table 1). The biomass allocation to
the leaf blades tended to be higher in the RB-grown
plants than in the R-grown plants, although there was
no significant difference between the light quality treatments
in Sasanishiki. Tillers were not observed (there
was only one stem) in any plants, irrespective of the
cultivars and light quality treatments at 56 days after
germination. The leaf stage tended to be more advanced
in the RB-grown plants than in the R-grown plants in
both cultivars (8.2–8.3 and 7.8–7.9, respectively) 56 days
after germination. Plant length tended to be greater in
the RB-grown plants than in the R-grown plants in both
cultivars 56 days after germination (data not shown).