PHYTOTRONICS AND HORTICULTURE
A little later, in 1949, professor F. Went gave the name of "phytotron" to a bigger installation in which plants were moved to recreate desirable climate and environmental conditions for scientific research in plant physiology. Now there are about 20–25 phytotrons in the world, all of which have fundamental or applied research programmes.
A phytotron can be defined as a set of growth chambers in which a number of climatic variables can be simultaneously, but independently, controlled; for example, lighting (the energy level, quality of light, duration of illumination, and so on) temperature, humidity etc. Depending upon individual needs, all kinds of other factors, whether climatic or soil related, can be controlled at least in some part of the establishment; for example: carbon dioxide content, wind speed, artificial rain, separate air conditioning of the air space and the rooting medium, mineral nutrition etc.
Phytotronics is to phytotrons more or less what electronics is to electron: a technology and a method of investigation in a branch of science of which the phytotron is the basal unity. Phytotrons are made for tackling the scientific problems of the relationship between plants and the environment and they have to be designed with this in mind. Phytotronics combines several different techniques and especially air conditioning to control air temperature, humidity, composition, pressure renewal, transport, purification and the like. Heating, refrigeration and illumination engineering are all involved. A knowledge of the characteristics of glass and other transparent media is required and also of screening and blacking out techniques as well as of programming, remote control, recording and programme control by electro-mechanical or electronic means. One might add that a phytotron requires strict continuity of operations and first-class reliability; all this gives an idea of the difficulties to be overcome and the rigour demanded in maintenance. For horticultural and practical needs for plant growing