Mastering Plant Growth: Understanding Phytochromes and Plant Hormones

Mastering Plant Growth: Understanding Phytochromes and Plant Hormones

Learning Objective

At the end of the lesson, you will be able to understand the role of phytochromes in flowering plants and the functions of plant growth hormones in stem elongation.

What do you already know about phytochromes and plant hormones?

Phytochromes in Flowering Plants

Phytochromes are pigments found in the leaves of flowering plants, existing in two interchangeable forms: P660 and P730.

Light Absorption and Conversion

P660 absorbs red light and rapidly converts to P730, while P730 absorbs far-red light and slowly converts to P660 in the dark.

Critical Length of Night

Understanding the concept of a critical length of night required to remove P730, essential for the flowering of short-day plants.

Flowering in Short-Day and Long-Day Plants

P730 removal is necessary for short-day plants to flower, whereas non-removal allows long-day plants to flower.

Artificial Manipulation of Photoperiod

Artificial manipulation of the photoperiod affects the levels of P660 or P730, allowing plants to flower out-of-season.

Plant Growth Hormones

Plant growth hormones include auxins for cell elongation, cytokinins for cell division, and gibberellins for internodal region elongation.

Interactive Element: Hormone Functions

Engage in a hands-on activity or demonstration to illustrate the functions of auxins, cytokinins, and gibberellins in plant growth.

Write down 3 things you learned in this lesson.

Have students enter three things they learned in this lesson. With this they can indicate their own learning efficiency of this lesson.

Write down 2 things you want to know more about.

Here, students enter two things they would like to know more about. This not only increases involvement, but also gives them more ownership.

Ask 1 question about something you haven't quite understood yet.

The students indicate here (in question form) with which part of the material they still have difficulty. For the teacher, this not only provides insight into the extent to which the students understand/master the material, but also a good starting point for the next lesson.