Genetics x Environment

Competition among plants, as illustrated by the release of allelopathic nitrogenous compounds, is a function of the interaction of gene products released into the environment. This topic has been reviewed by Putnam (111). 

Inside forest trees under water stress, the plugging of sieve-plate pores with P-protein is an almost instantaneous reaction to pressure release in active sieve tubes. P-protein plugs, or slime plugs, are now thought of as the first line of defense against the loss of assimilates. Wound callose further strengthens the cell s defenses but at variable rates (44 cf.. Sect. 5.1.3.4). 

The transport processes in wood have been reviewed by Siau (124). He has shown that permeability and steady-state moisture movement relate to the structure and chemical composition of wood. 

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A genetic x environment interaction is frequently present but can be managed in trials within the same breeding zone. For example, geneticists usually focus on those families that show consistent response across various sites within a breeding zone to avoid complicated deployment schemes. Ecologists may like to study G x E interactions. Geneticists prefer to circumvent the issue. 

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