Certain cells of more highly evolved plants were far more efficient in the conversion of raw materials into proteins, vitamins and the like. Originally, inedible parts were produced too, the stalk, which might or might not be used for food, and the leaves and roots. On a planet with plenty of room, this made little difference. But on an overcrowded planet, or one with a poisonous atmosphere, and especially on a ship where space was at a premium, normal methods could not be used.
In the plant machine were certain cells which had been selected because of their ability to produce a variety of nutrients. The inedible parts of the plant were replaced by machinery. Instead of roots to draw water and minerals from the soil, there were pumps and filters. Instead of stems to elevate that material to the leaves, there were hoses. Instead of entire leaves to perform photosynthesis, there were only those cells most efficient at the process. There were no seeds, tubers, roots, nor fleshy stalks to store the food. Collecting trays replaced them. There was no waste space; nothing was produced that couldn't be eaten.
There was an additional problem of reconciling the various cell fluids and different rates of growth. In part, that was accomplished by the plant machinery; the rest depended on the plant mechanic. His job was akin to that of a factory manager. In a sense, the plant machine was nothing more than a highly organized and complex factory, of which the productive units were the actual cells.
Alsint went along the aisles. Dials and gauges everywhere—a continuous record was kept of every stage. Each record was important, but nothing that could be reduced to a formula. The plant was not in bad shape, considering. At his instructions, Larienne made certain adjustments.
"Why reduce the light?" she asked. "I thought this unit grew better with stronger light."
"It does, within limits."
"I was within those limits."
"You were, but consider this. The plant from which these cells came grow fastest in early summer, but it isn't edible at that time. In late summer, it is. The light change merely corresponds to original conditions."
Partly convinced, she nodded. "What kind of plant was it?"