Groom: Flood tolerance of two Banksia species 
Table 1 
Growth parameters of Banksia littoralis seedlings before and after an exposure to an extended flooding regime. Values are mean ± SD 
for 4 plants. % change indicates an increase (+) or decrease (-) in relation to the pre-flooding data. P values based on a f-test comparing 
well-watered and flooded data. RGR = relative growth rate; LAR = Leaf area ratio. 
Before 
Flooding 
72 days of flooding 
% change 
Well- 
watered 
Flooded 
P 
Well-watered 
Flooded 
Dry weight (g) 
Total 
0.66 ± 0.06 
1.80 ± 0.36 
1.30 ± 0.19 
0.0415 
+173 
+97 
Shoot 
0.24 ± 0.03 
0.49 ± 0.11 
0.70 ± 0.13 
0.0465 
+104 
+192 
Roots 
0.42 ± 0.06 
1.31 ± 0.28 
0.60 ± 0.16 
0.0042 
+212 
+43 
Root:shoot ratio 
1.80 ± 0.29 
2.75 ± 0.52 
0.88 ± 0.31 
0.0009 
+53 
-51 
RGR - total (mg g* 1 day 1 ) 
13.9 
9.4 
RGR - shoot (mg g* 1 day 1 ) 
23.6 
12.7 
LAR (mm 3 /mg shoot) 
5.60 ± 0.42 
4.46 ± 0.23 
3.48 ± 0.52 
0.0143 
-20 
+39 
Seedling height (cm) 
10.6 ± 2.1 
14.6 ± 3.8 
14.8 ± 3.2 
0.7979 
+38 
+39 
104 days of flooding 
Dry weight (g) 
Total 
1.70 ± 0.44 
1.89 ± 0.80 
0.8103 
+158 
+186 
Leaves & shoots 
0.77 ± 0.28 
1.06 ± 0.40 
0.2939 
+221 
+342 
Roots 
0.93 ± 0.27 
0.84 ± 0.54 
0.5373 
+121 
+100 
Root:shoot ratio 
1.30 ± 0.52 
0.80 ± 0.40 
0.1754 
-28 
-55 
RGR - total (mg g* 1 day 1 ) 
9.1 
10.1 
RGR - shoot (mg g* 1 day 1 ) 
11.2 
14.3 
LAR (mm 2 /mg shoot) 
3.79 ± 0.55 
3.17 ± 0.28 
0.0918 
-32 
-43 
Seedling height (cm) 
13.6 ± 3.6 
13.9 ± 2.5 
0.8253 
+28 
+31 
their weight recorded after drying for 24 h at 60°C. Leaf 
area was measured on fresh samples using a digital 
image analyser (WinDIAS, Delta-T Devices, Cambridge, 
UK). Stem lengths were also recorded. Relative growth 
rates (RGR) were calculated on a shoot and total dry 
biomass basis as described by McGraw and Garbutt 
(1990). 
Results 
Banksia littoralis 
After 72 days of flooding, flooded B. littoralis seedlings 
were significantly smaller (total dry weight) than the 
well-watered seedlings, with more dry mass allocated to 
their stem and leaves, but less leaf area per shoot weight 
(Table 1). The root:shoot ratios of well-watered seedlings 
were 53% greater than pre-flood seedlings, in contrast to 
flooded seedlings where root:shoot ratios were 51% 
lower. Overall shoot mass of flooded seedlings was 
significantly greater than that of the well-watered 
controls (Fig 1) whereas root mass was significantly 
lower. There was no significant difference between 
flooded and well-watered seedlings in any of the growth 
parameters measured after 104 days of flooding (Table 
1). Well-watered seedlings had a greater relative growth 
rate than flooded seedlings after 72 days, in contrast to 
relative growth rate after 104 days. There was no seedling 
mortality during the 104 days of flooding. 
There were significant declines in g s , Opg,, and F y /F m 
Table 2 
Stomatal conductance (g s ), maximum (F v /F m ) and actual quantum yield (<D ren ) of Photosystem II photochemistry of Banksia littoralis 
seedlings before and after exposure to an extended flooding regime. Values are mean ± SD for 4 plants. % change indicates an increase 
(+) or decrease (-) in relation to the well-watered data. P values based on a f-test comparing well-watered and flooded data. 
Before Flooding 
Well-watered 
17 days of flooding 
Flooded 
P 
% change 
g s (mol m* 2 s' 1 ) 
0.19 ± 0.07 
0.25 ± 0.02 
0.11 ± 0.04 
0.0407 
-56 
4>psi. 
0.43 ± 0.12 
0.44 ± 0.03 
0.19 ± 0.04 
0.0008 
-57 
F /F 
v m 
0.84 ± 0.02 
0.82 ± 0.02 
0.68 ± 0.09 
0.0299 
-17 
74 days after flooding 
g s (mol nr 2 s' 1 ) 
0.18 ± 0.06 
0.07 ± 0.02 
0.0164 
-61 
^PSII 
0.44 ± 0.06 
0.32 ± 0.05 
0.1230 
-28 
F /F 
v m 
0.86 ± 0.02 
0.76 ± 0.08 
0.0454 
-12 
117 
