Groom: Flood tolerance of two Banksia species 
Table 3 
Growth parameters of Banksia prionotes seedlings before and after an exposure to an extended flooding regime. Values are mean ± SD 
for 4 plants, including some recently dead plants. See Table 1 for details on statistics and abbreviations. 
72 days of flooding 
% change 
e 
Before 
Flooding 
Well- 
watered 
Flooded 
P 
Well-watered 
Flooded 
Dry weight (g) 
Total 
0.53 ± 0.14 
1.14 ±0.51 
0.70 ± 0.17 
0.1604 
+115 
+32 
Shoot 
0.34 ± 0.10 
0.57 ± 0.26 
0.41 ± 0.12 
0.3735 
+68 
+21 
Roots 
0.22 ± 0.064 
0.57 ± 0.25 
0.30 ± 0.08 
0.6370 
+159 
+36 
Root:shoot ratio 
0.57 ± 0.14 
1.01 ±0.12 
0.72 ± 0.22 
0.0791 
+77 
+22 
RGR - total (mg g" 1 day' 1 ) 
RGR - Shoot (mg g” 1 day 1 ) 
LAR (mm 2 /mg shoot) 
5.37 ± 0.89 
10.6 
7.2 
6.22 ±1.37 
3.9 
2.6 
3.61 ± 0.51 
0.0205 
+16 
-33 
Seedling height (cm) 
0.9 ± 0.4 
1.6 ± 0.8 
0.8 ± 0.3 
0.0323 
+78 
-11 
resulting from flooding on the 17 th day (Table 2), 
resulting in 17% to 56% decreases in relation to pre-flood 
values. After 74 days of flooding, all three variables were 
less than those of well-watered seedlings (Fig. 2), 
although there was no significant different in O psn 
between well-watered and flooded seedlings (Table 2). 
Stomatal responses were overall linearly positively 
correlated with Opg,, (r = 0.65, P < 0.05), with B. litloralis 
possessing a higher £ s at a given d> reu than B. prionotes. 
There was no significant difference in the physiology 
of seedlings after 8 days recovery from flooding 
compared with well-watered seedlings (Fig 2 a-c). This 
was despite O psn and g s displaying greater values than 
the well-watered controls. was the only parameter 
to show significant differences after 18 days of recovery 
(P = 0.0454). There was no significant physiological 
difference between recovered and control plants after 38 
days of recovery (Fig 2 a-c). 
Banksia prionotes 
After 28 days of flooding 22% of B. prionotes seedlings 
had died. An additional 14 seedlings died 4 days later 
taking the cumulative mortality to 45%. After 53 days of 
flooding seedling mortality was 83%. The experiment 
was concluded after 72 days, with only two of the 
original 60 seedlings still alive. All seedlings used to 
monitor post-flooding recovery died after 8 days. 
After 72 days of flooding the percentage difference in 
dry weight increased by 21 to 36% (Table 3) compared to 
pre-flood values, and was less than that for control plants 
(68 to 159%). This difference between flooded and well- 
watered plants is reflected by the relative growth rate 
values over the same time period. There was no 
significant difference in total dry weights, the weights of 
the stem and roots, or root:shoot ratios (Table 3) between 
well-watered and flooded after 72 days of flooding. 
Despite this, well-watered seedlings were significantly 
taller (P = 0.0323), and produced more leaf area per shoot 
dry weight. Throughout the period of flooding, total, 
shoot and root dry weights of flooded seedlings were 
consistently less than that of the well-watered seedlings 
(Fig 1), but there was no significant difference between 
the two treatments. 
After 17 days of flooding there was a significant 
decline in stomatal conductance (g s ), compared with that 
of pre-flooded seedlings (P = 0.0097). This was despite no 
significant difference in g s between well-watered and 
flooded treatments measured on the 17 th day, attributed 
to the larger standard deviation of well-watered 
seedlings. After 38 days of flooding g s was <0.01 mol m' 2 
s' 1 and remained so when remeasured after 54 days (Fig 
2 ). 
There was a significant decline in actual (<I> ) and 
maximum (F v /F m ) efficiency of photosystem II 
Table 4 
Stomatal conductance (g s ), maximum (F v /F m ) and actual quantum yield (O ren ) of Photosystem II photochemistry of Banksia prionotes 
seedlings before and after exposure to an extended flooding regime. See Table 2 for details. 
Before Flooding 
Well-watered 
17 days of flooding 
Flooded 
P 
% change 
g s (mol m' 2 s* 1 ) 
0.14 ± 0.05 
0.13 ±0.11 
0.04 ± 0.01 
0.2765 
-69 
(b 
^PSII 
0.41 ± 0.05 
0.43 ± 0.02 
0.24 ± 0.09 
0.0312 
-44 
F /F 
0.80 ± 0.04 
0.84 ± 0.02 
0.60 ± 0.15 
0.0222 
-29 
54 days after flooding 
P 
g s (mol nr 2 s* 1 ) 
0.12 ± 0.06 
<0.01 
_ 
_ 
O 
PSII 
0.54 ± 0.06 
0.15 ±0.11 
0.0044 
-72 
F /F 
v f m 
0.84 ± 0.01 
0.11 ±0.08 
0.0001 
-87 
119 
