Vergara - 1976 - Physiological and morphological adaptability of ri

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Physics of controlled environment
and plant growth
K. J. Mitchell, R. Robotham, and l. Warrington
SUMMARY
is given to the basic physics of controlled-environment facilities
Consideration with regard to standards for Future design and operation of such facilities for
crop studies.
A fundamental distinction between controlled-environment facilities is whether
the plant-growing space is naturally or artificially lit. The implications of this are
examined for capital and running costs. for operating flexibility in environmental
control. and for ability to produce results of direct significance to field situations.
Results indicate that artificially lit space can cost the same or less than naturally
lit space, can allow greater flexibility in environmental control for equivalent cost.
and can effectively duplicate outside conditions.
Effects of light. temperature. humidity. and soil water on growth. development.
and water use in controlled conditions are presented to illustrate the conclusions.
INTRODUCTION
A major aim of agricultural practice is to use and modify the natural environment
so that the productivity of plants which are valuable to man can be enhanced.
To achieve this. the interaction of those plants with their environment.
particularly climatic environment. must bc examined and understood.
The climatic environment is a complex of interacting physical factors. To
understand the significance. for production, of individual factors within that
complcx—tcmpcraturc. light. humidity, ctc.—cacl1 must bc brought under
control and manipulated independently-b Hence, the dCl/Clflpltltillt of thc phytotron,
whcrc some or all of thcsc factors can be varied independently, without
the irregularities and tinceitainties of natural climate. and with the capabilitj.’
of examining a number of alternatives simultaneously’.
Organizers of this symposium have kindly suggested a title which allows a
broad approach: “Physics ofcontrolled environment and plant growth."
On the one hand. there can be a general review of the wide-ranging series of
results which are building up from controlled-environment research. On the
other hand, there can be consideration of selected sets of factors. rather more
K. J. ilfitcheil. R. Roborliam, 1. llkrrrmglon. Plant Physiology Division, Division of Scientific and
Industrial Research (DSIR). Palmerston North. New Zealand.