Figure 2. The GA/ABA ratio in the SAM of soybean lines isogenic for E genes of
Clark cv. Average data for 2010-2012 growing seasons. (A) The GA/ABA ratio of
the control plant group are shown at LD (16h); (B) the GA/ABA ratio of the
experimental plant group, which were grown for 14d at SD (9h). Sampling points
were accordant to the experimental group: before daylength shortening (0), on the 7th
(7d) and 14th (14d) days of photoperiod shortening
Source: developed by the author
There was the following pattern in the GAs/ABA ratio in leaves of soybean lines
at the end of experiment (14
th
day) under different photoperiodic conditions. The two
ND lines (e1E2e3 and e1e2e3), that are faster than others investigated lines switch to
flowering, had an approximately equal level of this ratio at both 16h and 9h
photoperiods. The SD lines Е1Е2Е3, Е1е2е3 and one ND line е1е2Е3 displayed higher
GAs/ABA ratio in the leaves at 9h photoperiod than that at 16h photoperiod.
Thus, in SD lines non-inductive photoperiod (16h) led to accumulation of IAA
and especially GAs in the leaves against an insignificant increase of ABA content
during the first week of the experiment. Consequently, the IAA/ABA and GAs/ABA
was increase. Further towards the end of the experiment, however, there was a decrease
in the content of growth-stimulating hormones, especially GAs.
Short-day condition led to decrease of IAA and ABA contents in leaves of SD
lines against a decrease of GAs content towards the end of the experiment. A similar
tendency was observed in ND lines е1е2Е3. The ND lines е1е2е3 and е1Е2е3
displayed gradual accumulation of GAa and ABA and a decrease in the content of IAA
in the leaves at both 16h and 9h photoperiods. At the same time, the dynamics of the
0,0
10,0
20,0
30,0
40,0
50,0
60,0
70,0
80,0
0d
7d
14d
0d
7d
14d
G
A
s?
A
BA
ra
ti
o
Е1Е2Е3
Е1е2е3
е1Е2е3
е1е2Е3
е1е2е3
A
B
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