Agriculture Reference
In-Depth Information
(White 1979; Jones 1985; Maillette 1987; Hallé 1986; Watson 1986; Room et al.
1994). Shoot growth arises in meristematic tissues associated with the apex of the
shoot (apical buds) or in terms of branching with the base of leaves (lateral buds).
Buds contain a short stem with leaf primordia and embryonic leaves, essentially
a partially developed, preformed shoot (Kikuzawa 1982; Jones and Watson 2001).
Embryonic leaves have partially developed lamina with distinguishable venation;
leaf primordia are too early in development for features of the mature leaf to be
discerned. Buds are usually, but not always, enveloped by bud scales, which confer
a degree of protection from dessication and herbivory (Kikuzawa 1982; Nitta and
Ohsawa 1998). Shoots have a degree of autonomous regulation over their dormancy,
growth, and senescence but also interact with other shoots in a coordinated way to
form the plant canopy as a whole (Thomas 2002; Barthélémy and Caraglio 2007).
Shoot Growth, Buds, and Leaf Emergence
Leaf emergence of Alnus hirsuta
The emergence of leaves, the growth of shoots, and the development of buds
containing future shoots are inextricably interlinked. At budburst, shoot extension
occurs in concert with leaf emergence, and as the bout of extension growth ends,
the development of buds containing future shoots ensues. This sequence is illus-
trated by data from Maruyama (1978) on shoot elongation of deciduous broad-
leaved saplings in a Japanese beech forest showing two contrasting modes of shoot
growth (Fig. 2.2 ). One mode is illustrated by Fagus in which the shoot elongates
and leaves emerge more or less simultaneously in a short burst of growth; this has
been referred to as Fagus -type (Maruyama 1978), flush-type (Kikuzawa 1983,
Search WWH ::




Custom Search