100
_ .. .:;- -a
-'
en 90
,- -. -
~
- -- - / -
0
:/ ..
;:
en 80
en
~
Cl
70
(ij
c:
I.0
.6> 60
-
~
.!: 50
en
0>
·0
0>
40
c.
en
v
()
30
C
-
0>
-
~
20
/
0>
-Il..
10
-
"'u
8
12
16
20
24
Average January minimum temperature (0C)
70
en
b
.. ;.,-.~
0
60
;:
.. ~ ..
en
en
~
Cl
50
'h. • --.
"--v
J...-.
NADP-ME
()
:~
(ij
ifc: 40
'I::.~'
0
I::.
'6,..,.1::.
.6>
ti. ~ I::.fi~NAD-ME
~
30
.!:
I::.
~ I::. I::.
0>
C.
~
~ 20
a I::. t . . .
v
()
- -:,,--~
c
~ ~ ... -0>
10
•
. .. "-~
- p
-
PCK
0>
Il..
0 u 200
300
400
500
600
700
800 900
Median annual rainfall (mm)
Fig. 25.5a. The relationship of the relative occurrence of C3 and C4 native grass species in
regional grass floras in Australia and average January minimum temperature COC) (subdivisional area-weighted mean) taken from Hattersley (1983). Linear regression y =
-32.46 + 5.71 x (r2 = 0.92). The regional grass floras correspond to subdivisions on a
State by State basis, as used by Hattersley (1983). b The relationships of the relative
occurrence of native C4 grass species of the NADP-ME, NAD-ME and PCK C4 types in
Australia, on a regional C4 grass flora basis, and median annual rainfall (mm, as lowest
value per subdivision) taken from Hattersley (1992). C4 type for species was assigned on a
biochemical basis (that is, by assay of the activity of the relevant C4 acid decarboxylating
enzyme: NADP-malic enzyme (NADP-ME), NAD-malic enzyme (NAD-ME) or phosphoenolpyruvate carboxykinase (PCK). Linear regressions NADP-ME, y = 39.5 +
0.031x, NAD-ME Y = 53.3 - 0.040x, PCK Y = 7.06 + 0.009x