Use of plant hormones - Higher
There are many different Substances that can modify or control the growth of plants., which have a variety of effects on the growth and development of a plant. These hormones are used in Farming - especially arable or crop farming. and The study of plants and cultivation of plants. to have a specific effect that is advantageous to humans.
Plant hormones that control cell elongation. were the first class of plant hormones to be discovered. Their main function is to help plants grow and auxin stimulates plant cells to Becoming longer.. The tips of the growing stems and roots of a plant are the main places where auxin is produced. The apical meristem is also the location that all other parts of a plant grow from - the stem, leaves and flowers.
Auxins can be used:
- as weed killers
- as rooting powders
- for promoting growth in tissue culture
Weedkillers
Selective weedkillers kill some plants, but not others. This can be useful for getting rid of dandelions on a lawn without killing the grass or weeds that compete with crops such as wheat. The selective weedkiller contains a growth hormone that causes the weeds to grow too quickly and die. Because most weeds have broader leaves than grass or wheat, the weedkiller is absorbed in larger quantities by the weeds.
Selective weedkillers kill plants that some species of animal rely on as a food source. This can result in a reduction of The range of animals and plants in a given area. .
Rooting powder
Plant cuttings can be dipped in hormone rooting powder before planting.
Synthetic Substances that can modify or control the growth of plants. are used to control plant growth. For example, rooting powder contains growth hormones that make stem cuttings develop roots quickly.
Promoting growth in tissue culture
Tissue culture is a technique used to grow whole new plants from small sections of a parent plant.
Hormones, such as auxin, are used to stimulate cell division and elongation.
Fruit ripening
In the food industry fruit is often picked unripe and then transported. This prevents fruit from over-ripening on the journey and allows fruit to be transported long distances.
The fruit is ripened during storage by adding the hormone ethene and then taken to the shops.
Dormancy
Dormancy stops seeds germinating until conditions are ideal for growth. Gibberellins can be used to remove the dormancy of a seed so it can germinate at all times of year. Buds and flowers can also be naturally dormant. Hormones like gibberellins and auxins can also be used to make plants grow bushier, make them flower, or control the growth of hedge plants. Using plant hormones in this way means that humans can control how and when the plant grows, making sure that the plant is available when needed, regardless of the time of year.