Seedling Recruitment
,
'1.4
1.3
>. 1.2
' 0)
0)
'-" 1.1
0::
(.!)
0::
A
b
b
a
0.9 +----+--,-------.---,--------.----,
1.4
1.3
'>. 1.2
' 0)
0)
......... 1.1
0::
(.!)
0::
8%
16%
36%
60%
80%
LIGHT LEVELS (% PAR)
B
c
c
a
0 .9 +---+---,------.----.------,
400
550
700
850
WATER LEVELS (I m· 2 yr" ' )
93
Fig. 7.2. Relative growth rate (RGR) in weight of potted holm oak seedlings under different A
light levels and B water levels. The lowest water treatment has not been included because of its
low survival rate (see Fig. 7.1). Bars are 1 SE. Letters indicate significantly different values
(P and physiological components (NAR, net assimilation rate). NAR of holm
oak seedlings changed significantly along both light and water gradients,
while LAR was only affected by light (Fig. 7.3). The fact that water availability
did not modify the leaf area of seedlings but greatly increased their NAR (up
to the 700 L m- 2 year- 1 level) indicates that the growth increment of wellwatered plants is not due to an increment in their assimilation surface but to
an increase in their photosynthetic capacity. In fact, well-watered plants exhibited the highest photosynthetic rates during most of the year (Espelta