Agriculture Reference
In-Depth Information
Age-Dependent Decline in Photosynthetic Capacity
Once a leaf attains full photosynthetic capacity,
A
max
then gradually decreases with
leaf age (Hardwick et al. 1968; Jurik et al. 1979; Oren et al. 1986; Martin et al.
1994; Mediavilla and Escudero 2003a; Castro-Diez et al. 2005; Warren 2006; Reich
et al. 2009). In herbaceous plants with short-lived leaves, the decline is linear and
relatively fast (Leopold and Kriedmann 1975; Šesták 1981; Hodanova 1981; Erley
et al. 2002; Kikuzawa 2003). In deciduous broad-leaved trees, once full photosyn-
thetic capacity is attained it is maintained fairly steady until immediately before
leaffall and then declines quickly (Jurik 1986; Koike 1990), although in some
Alnus
and
Betula
species with fairly rapid leaf turnover the time trend is closer to that of
herbaceous species (Koike 1990; Kikuzawa 2003; Miyazawa and Kikuzawa 2004).
Kitajima et al. (2002) also reported this fairly rapid linear decline in photosynthetic
capacity associated with high leaf turnover in two early successional tropical trees
in Panama (Fig.
2.10
). In five trees with longer-lived leaves in this seasonally dry
tropical forest, the decline in photosynthetic capacity with leaf age was more
gradual (Kitajima et al. 1997), as was also the case for tropical species in a Costa
Rican plantation (Hiremath 2000). Similarly, in evergreen conifers with longer-
Cecropia
Urera
30
slope =
−
0.287**
slope =
−
0.191**
25
20
15
10
5
0
10
slope = 0.145***
slope = 0.091***
8
6
4
2
0
0 020 0 0
Leaf Age since Full Expansion (d)
50
60
70
0 020 0 050 0 0
Fig. 2.10
Linear decline in photosynthetic capacity associated with rapid growth and high leaf
turnover in early successional Panamanian trees.
d
, days. (From Kitajima et al. 2002)
