Environmental Preconditioning, with Special Reference to Forestry

Abstract

In the morphogenesis of the plant, early ecological influences (and just how early is not known) can carry through to expression in later stages of development and behaviour; therefore, phenotypic expression is frequently to be understood most simply in the context of preconditioning. Examples from the literature emphasize that the immature seed is preconditioned by the milieu of the parent plant, that past climatic conditions influence phenology, and that flowering is frequently triggered by early—acting environmental signals. The possible role of Preconditioning in three aspects of forest science—provenance trials, tree seed orchards, and acclimatization–is examined, and the conclusion is drawn that ecological preconditioning is a fertile field for stury and experimentation.

Differentiation in habitat response in taxodium distichum, taxodium mucronatum, platanus occidentalis, and liquidambar styraciflua from the United States and Mexico

“…Mature grass plants can be easily transplanted and can be observed for numerous phenological and morphological attributes. The trees are usually studied from seedling populations and are subject to pre-conditioning interpretations such as presented by Rowe (1964). Despite the difficulties of tree studies, the present investigation supports the idea that a local forest ecosystem is composed of a unique combination of genetically distinctive populations.…”

Studies on the Descendancy of Four Populations of Koekelaere Pines: <i>Pinus nigra</i> Arnold, subsp. <i>laricio</i> (Poiret) Maire, cv. <i>Koekelaere</i>

“…These differences were attributed either to genetic differences linked to the particular origin of the various stands, or to the pre conditioning of the seeds (Rowe, 1964;Dur rani, 1958;Cull is, 1977).…”

Genecology of 20 paper birch (Betula papyrifera Marsh.) provenances from British Columbia and northern Idaho.

“…Consequently, any nursery with an environment greatly different from that of the seedlot origin may alter seedling germination behaviour in the nursery as well as seedling growth and development after planting (Campbell and Sorensen 1984;Hawkins 1998). Furthermore, the timing of preconditioned developmental stages in the home environment may become out of phase in the new environment (Rowe 1964). "Sensitive periods for preconditioning seem to be at the time of initiation and formation of buds and seeds, and also at the time when growth commences following a dormant or resting stage" (Rowe 1964 p. 402).…”

“…"Sensitive periods for preconditioning seem to be at the time of initiation and formation of buds and seeds, and also at the time when growth commences following a dormant or resting stage" (Rowe 1964 p. 402). For example, when northern provenances grown at southern nurseries are planted in the north, their flushing phenology may be out of phase with that of the local populations (Hawkins 1998) because 9 bud flush phenology depends not only on the present (growing) environment, but also on the environment in which the buds were formed (Rowe, 1964). However, whether these effects are temporary or persistent is yet to be determined (Hawkins 1998).…”