BI111 Lecture Notes - Lecture 10: Brassica Oleracea, Meristem, Gibberellin
Document Summary
Cultivars-not different species but different breeding groups-derived from ancestors. Each one represents a change in selection in parts of the brassica oleracea. To understand diversity of plant structures and life histories, need to understand role that signal response pathways play in their growth and development. Hormones and environment stimuli alter behaviour of target cells: signal molecules bind to receptors in target cells, elicit cellular response (different response in different tissue) By means of a response pathway, signal can: Induce changes in cells shape or internal structure. Influence cells metabolism: alter gene activation and rate of protein synthesis, set in motion events that modify existing cell proteins. Some hormones and growth factors bind to receptors at target cells plasma membrane, on er, or in cytoplasm. Binding triggers release of internal second messengers that diffuse through cytoplasm and provide main chemical signal that alters cell functioning. Reaction sequence amplifies cells response to signal. Gibberellins stimulate growth, including the elongation of stems.
