{[ promptMessage ]}

Bookmark it

{[ promptMessage ]}

lecture 2-22 plants IV - Chapter 39(pp.788-802 Plant...

Info iconThis preview shows pages 1–6. Sign up to view the full content.

View Full Document Right Arrow Icon
Chapter 39 (pp.788-802) – Plant hormones: Development and responses Learning objectives: Explain what etiolation is. What is de-etiolation? Describe the signal pathways associated with de-etiolation. Describe the two main mechanisms by which a signaling pathway can activate an enzyme. Know the major functions of these plant hormones: • auxins • cytokinins • gibberellins • brassinosteroids • abscisic acid • ethylene. Be able to discuss the role of hormones in examples such as cell elongation, cell differentiation, leaf abscission, seed dormancy, seed germination, fruit ripening, plant stress… Explain why 2,4-D is an effective weed killer
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Review: Signal transduction pathway steps: 1. Reception Internal and external signals are detected by receptors (proteins) – that change in response to specific stimuli (ligands) 2. Transduction Signals are transferred (and amplified) to proteins that cause specific responses 3. Response One or more cellular activities are regulated, usually by increased activity of certain enzymes
Background image of page 2
At  the  time  of  germi-nation,  the  seedling  plant  has  single ‘root-shoot axis’. Primary growth  consists of  the elongation and branching  of the root(s) and shoot(s).   Secondary growth  is a progressive thickening of  roots and shoots that can continue for many years  following their initial (primary) growth, and is restricted  to ‘woody’ plants such as trees or bushes. 
Background image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Plants have signal transduction pathways A potato left growing in darkness Will produce shoots that do not appear healthy, and will lack elongated roots These are morphological adaptations for growing in darkness Collectively referred to as etiolation Figure 39.2a (a) Before exposure to light. A dark-grown potato has tall, spindly stems and nonexpanded leaves—morphological adaptations that enable the shoots to penetrate the soil. The roots are short, but there is little need for water absorption because little water is lost by the shoots.
Background image of page 4
Background image of page 5

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Image of page 6
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}