Describe the physiological changes that occur in a seed during germination
- Germination starts with the rapid uptake of water by the seed through the micropyle by a process called ambition. Water then moves from cell by osmosis.
- The water causes swelling of the embryonic tissue thereby rapturing the seed coat and also activates gibberellins.
- Gibberellins diffuse to the aleurone layer whereby they cause the synthesis and activation of hydrolytic enzymes such as amylase and proteases.
- Amylase catalyzes the breakdown of starch to glucose while proteases catalyze hydrolysis of proteins to amino acids.
- Glucose and amino acids are translocated from the storage centre (endosperm or cotyledon) of the seed to the growing regions of the embryo.
- Here glucose is used in respiration and in the formation of cellulose and other cell wall materials. Amino acids are used to make proteins, which are enzymes and structural components of protoplasm.
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