The daisy closes its flowers when the light begins to fade in the evening. Many flowers close up at night or when the weather is cold. They get the maximum amount of light in this way. This is particularly noticeable in a field of sunflower where nearly every flower faces in the same direction. A number of plants bend round during the day and thus remain facing the Sun. Another kind of bending movements is shown by the leaves of several plants. Other bendings movements include the bending of roots towards water. This time the plants are responding to gravity and the movements are called geotropisms.

If you grow some seedling and then lay them down flat in the dark, you will find that the stems start to grow up again and the roots try to grow down again. Bending movements caused by light are called phototropisms. Bending movements which depend on the direction of the stimulus are called tropisms. This bending movement is very useful for the plant because it helps it to get as much light as possible. If you grow a plant in a room with only one window, you will soon notice that the plant bends towards the window. A tree growing in the middle of a wood has a very different shape from the same kind of tree growing in the middle of a field, because the growth pattern of a plant is flexible. The poor performance of APSIM-wheat was observed for the simulation of the growth to maturity duration (with 187 d and 216 d for the simulated and observed values, respectively) and grain yield (with 29 for the simulated and observed values, respectively). One of the differences between the higher plants and the higher animals is that the plants do not have a fixed shape or size.

Plant growth apsim