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Garden with Insight v1.0 Help: Plant drawing next day functions: add new and remove lost biomass from plant parts

On nearly every day the model plant is alive, it either increases or decreases its total biomass. We will consider increase first. After the model plant next-day routine are finished, the model plant reports its change in biomass to the drawing plant. The model plant has four biomass partitions: roots, shoots, flowers/fruits, and storage organ. The roots and storage organ are not drawn, so only the shoot and reproductive biomass change is reported to the drawing plant.

The drawing plant has a whole assemblage of internodes, leaves, meristems (buds), inflorescences, flowers, and fruits. The drawing plant first asks each of its vegetative parts (internodes, leaves, vegetative meristems) how much biomass they would like for growth. Then the drawing plant partitions the new growth according to the demands of the plant parts. The same thing goes on for the reproductive plant parts (inflorescences, flowers, fruits, reproductive meristems).

Vegetative meristems demand biomass to create internodes and leaves. Internodes and leaves demand biomass to try to grow to optimal size. Reproductive meristems demand biomass to create inflorescences. Inflorescences demand biomass to grow to optimal size, but don't demand biomass to make flowers -- they create flower buds based simply on a schedule of days. Flower buds demand biomass to grow to optimal size. Flowers demand biomass to create (set) a fruit. Fruits demand biomass to grow to optimal size. For more information on how the different plant parts grow and create other parts, see the next-day functions for each.

All of the plant parts grow either by linear growth functions (meristems, internodes, inflorescences, flowers) or S-shaped growth functions (leaves, fruits). Both linear and S-shaped growth is always bounded in speed by a minimum number of days required for any plant part to reach its optimal size. This "speed limit" simulates physical limitations on the speed of growth. In addition, some of the plant parts stop demanding biomass after a number of days because they are too old to grow any more. Most leaves and other plant parts in reality will not keep growing forever but stop even if the plant is still growing. This allows the plant to concentrate its resources on newer leaves which have better photosynthetic efficiency.

If the total amount of vegetative or reproductive biomass has decreased, the drawing plant asks each plant part how much live biomass it has. Each plant part keeps track of both living and dead biomass. The total amount of newly dead biomass (vegetative or reproductive) is removed proportionately from all plant parts, which means they move it into their "dead" pool. You could argue that this method is not realistic, since plants often lose whole leaves and stems while other parts remain intact. Possibly a weighting scheme to lose older plant parts more quickly would help make this more realistic. We have been working on such a weighting scheme but haven't worked out the problems with it.

More on the biomass partitioning submodel
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Updated: March 10, 1999. Questions/comments on site to
Copyright © 1998, 1999 Paul D. Fernhout & Cynthia F. Kurtz.