Plant hormones

• Plant hormones are unequally distributed throughout the stems and roots, which results in parts of the plant growing in a particular direction.
• Plant hormones are unequally distributed throughout the stems and roots, which results in parts of the plant growing in a particular direction.
• Auxin and geotropism are two types of plant hormones that promote growth within plants.
• Auxins and phototropism are two types of plant hormones.
• Auxin is a plant hormone that promotes growth in plants.
• Auxin and geotropism are other types of plant hormones.
• Geotropism is a response to the stimulus of gravity, where parts of the plant grow in the direction of the force of gravity.
• Required practical activity 8 involves investigating the effect of light or gravity on the growth of newly germinated seedlings.
• The force of attraction between all objects, including plants, is greater when the object has more mass.
• Germination is the beginning of plant growth, and the plant will continue to grow if the correct conditions are available.
• Plants respond to gravity by growing in the opposite direction to the force of gravity, this is known as a negative geotropism.
• Mustard or cress seeds are a good choice for this investigation because they grow fast and their roots and stems are clearly visible.
• When a root grows in the direction of the force of gravity, this is known as a positive geotropism.
• The independent variables for this investigation are to place plants in light and dark conditions.
• Geotropism is caused by an unequal distribution of auxin.
• Plant hormones are unequally distributed throughout the stems and roots, which results in parts of the plant growing in a particular direction.
• Other suitable independent variables are: different colours of light, intensity of light or the direction light comes from.
• Auxins and phototropism are topics related to plant hormones.
• The dependent variable is the mean height of seedlings.
• In a root placed horizontally, the bottom side contains more auxin and grows less, causing the root to grow in the direction of the force of gravity.
• Auxin and geotropism are topics related to plant hormones.
• Control variables are the number of seeds on each dish, how much they are spread out, the volume of water the seedlings are given, the temperature they are kept at.
• The opposite happens in a stem, when a stem placed horizontally, the bottom side contains more auxin and grows more, causing the stem to grow upwards against the force of gravity.
• Gibberellins, which are a group of plant hormones responsible for growth and development, are important for initiating seed germination.
• Put cotton wool into three petri dishes, and add the same volume of water to each dish.
• Low concentrations of Gibberellins can be used to increase the speed of germination, and they stimulate cell elongation.
• Plant hormones are unequally distributed throughout the stems and roots, which results in parts of the plant growing in a particular direction.
• Add ten seeds to each dish and place them in a warm place where they won’t be disturbed.
• Gibberellins can be used to promote flowering and increase fruit size.
• Allow the seeds to germinate, and add more water if the cotton wool dries out.
• Seed dormancy must be broken for seeds to germinate, and this can be done by using gibberellins.
• Auxins and phototropism are topics in the AQA Biology (Single Science) specification on Homeostasis and response.
• Once the seeds have germinated, ensure the petri dishes each contain the same number of seeds, and remove any extra seeds if necessary.
• Ethene, the simplest alkene, consisting of two carbon atoms joined by a double bond, surrounded by four hydrogen atoms, is a hydrocarbon.
• Auxins are a family of plant hormones that control cell elongation.
• One petri dish will sit in full light on a windowsill, the second will be in a dark cupboard, and the final dish will be placed in partial light.
• A compound that contains hydrogen and carbon only, gas speeds up ripening in bananas and other fruit.
• Ethene controls cell division during plant growth.
• Every day for one week, measure the height of each seedling and record the results in a table.
• You must record the height of the individual seedlings on each day.