Gibberellin is a plant growth regulator involved in barley seed germination. Its production is stimulated when water is absorbed. State the location where gibberellin is synthesised in a barley seed during germination.
Using Fig. 5.1, describe how the germination index of barley seeds varies with water potential.
Suggest explanations for the pattern shown in Fig. 5.1.
During barley seed germination, gibberellin triggers the synthesis of enzymes. State the name of one of these enzymes and the exact location where it is synthesized.
Some plants are grown commercially for their flowers, and many of these are short-stemmed varieties. Two factors that influence stem height are: • gibberellin • the $Le/le$ gene. The $Le/le$ gene has two alleles, $Le$ and $le$. Suggest one advantage of growing a flowering-plant variety with short stems.
Explain how the $Le/le$ gene and gibberellin are involved in determining stem height in plants.