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https://archive.org/stream/biorxiv-10.1101-003103/biorxiv-10.1101-003103_djvu.txt
Alternating irradiation by red and blue light
The effect of R/B irradiation was extremely different from RB and
monochromatic light irradiation. Most growth characteristics, such as FW, DW and leaf
size, were the highest under R/B irradiation. Table 2 and Fig. 4 show the results of three
cultivars under different light conditions (control, RB, and R/B). As shown in Fig. 4a,
the FW (blue column) of Summer Surge under R/B was almost two times as heavy as
the control. The FW of the control for Summer Surge at 2 1 days was 4. 7 g, whereas the
FW under R/B was 9.3 g. Despite the fact that the light quantity and its source in the
R/B condition were equal to those in the RB condition, the FW under R/B condition was
66% higher than that under RB. The DW (red column) showed the same tendency, in
which the DW under RB (0.29 g) was slightly higher than that of the control (0.24 g) and
the DW under R/B (0.55 g) was twice as that of the control for Summer Surge (Fig. 4a).
Additionally, the dry matter ratio under R/B was significantly higher than that of the
control. The growth of Black Rose in this experiment was inferior to Summer Surge, but
the growth acceleration effect of R/B was also observed, and R/B was the best of the
three conditions (Fig. 4b). The FW under R/B was 3.1 g, which was 200% higher than
that of the control (1.0 g). As shown in this figure, the DW of Black Rose was 0.06 g
(control), 0.15 g (RB), and 0.19 (R/B). However, the growth of Green Span did not differ significantly by light condition (Fig. 4c). The FW was 6.4 g in the control, 5.6 g under RB,
and 6.0 g under R/B, respectively. There was no statistically significant difference
between the three conditions for DW and dry matter ratio, although the dry matter
ratio under R/B was slightly less than that of the control and that under RB (Table 2).
Regarding the leaf growth of Summer Surge under three light irradiation
conditions, the leaf blade under R/B was the longest and the widest of all three
conditions (Table 2). The mean leaf length and width under R/B was 14 cm and 11 cm,
respectively, which was 28% longer and 43% wider than that of the control. In contrast,
the mean leaf number (6.3) under R/B was significantly smaller than that of the control
(7.
. For Black Rose, the size of the leaf blade under R/B was largest of all three
conditions (Table 2), but the leaf size of Green Span was not significantly different
among the three conditions (Table 2). Regarding the stem elongation, neither RB nor
R/B affected the elongation in Summer Surge (Table 2). Its elongation parameters
(petiole length and main stem length) under R/B were smallest among the three
conditions. On the contrary, stem elongation under R/B was observed in Black Rose and
Green Span (Table 2). The elongation effect under R/B was stronger in Green Span, in
which the main stem length (3.9 cm) under R/B was 2.6 times longer than that of the
control (1.5 cm). Figure 5 shows the plant habitat of Summer Surge under each
condition, 21 days after seeding. Supplemental data is shown in the flip drawings of the
growth of Summer Surge under each light condition.
Interval of red and blue light
The interval of red and blue light influenced the growth of Summer Surge
considerably. Table 3 shows the effect of irradiation interval on the growth of Summer
Surge. The FW varied depending on the red: blue intervals, and the maximum FW was
recorded at 12 h: 12 h. The FW for 12 h: 12 h (9.3 g) was about twice that of the FW for 1
h: 1 h and 2.8 times as heavy as that of 48 h: 48 h. The dry matter ratio ranged from
0.057 to 0.077, and the maximum dry matter ratio was recorded under the 48 h: 48 h
condition. The leaf size parameters were largest under the 12 h: 12 h condition (Table 3).
The number of leaves under each R/B condition was fewer than that of the control.
Concerning the stem elongation parameters, the maximum petiole length (1.8 cm, 6 h: 6
h) and the maximum main stem length (l.l cm, 1 h: 1 h) were recorded under different
conditions (Table 3).
