Plant Science

Over thousands of years, humans have "domesticated" wild type plants and animals through selective breeding. Examples from the plant world include the breeding of modern hybrid maize from teosinte, or the development of modern wheat from emmer.

As our knowledge of genomics and molecular technologies advances, we have developed much more precise and potentially more versatile ways to modify plants: genetic modification.

In these t...

Over thousands of years, humans have "domesticated" wild type plants and animals through selective breeding. Examples from the plant world include the breeding of modern hybrid maize from teosinte, or the development of modern wheat from emmer.

As our knowledge of genomics and molecular technologies advances, we have developed much more precise and potentially more versatile ways to modify plants: genetic modification.

In these t...

The transition from water to land required plants to develop efficient transport pipelines for water and nutrients to the leaves, and for energy-rich carbohydrates (from photosynthetic carbon dioxide fixation) to tissues that require energy (e.g. roots, storage organs etc.).

Xylem and phloem are found together in vascular bundles and transport water (unidirectionally) and photosynthates (bidirectionally), respectively. While these...

The transition from water to land required plants to develop efficient transport pipelines for water and nutrients to the leaves, and for energy-rich carbohydrates (from photosynthetic carbon dioxide fixation) to tissues that require energy (e.g. roots, storage organs etc.).

Xylem and phloem are found together in vascular bundles and transport water (unidirectionally) and photosynthates (bidirectionally), respectively. While these...

A very important part of plant cells is located outside the cells themselves: plant cell walls.

Composed of numerous different building blocks (mostly polysaccharides, but also proteins and, particularly in cells that contribute to structural strength, lignins), cell walls determine the shape of the cells and provide a counterforce to the osmotically generated turgor pressure.

In this lecture we look at the major polysaccharides ...

A very important part of plant cells is located outside the cells themselves: plant cell walls.

Composed of numerous different building blocks (mostly polysaccharides, but also proteins and, particularly in cells that contribute to structural strength, lignins), cell walls determine the shape of the cells and provide a counterforce to the osmotically generated turgor pressure.

In this lecture we look at the major polysaccharides ...

So how does photosynthesis actually work?

In this lecture we explore the structures that capture light energy, photosystems 1 and 2, and how that light energy is harnessed to generate NADPH, and to build up a proton gradient across the thylakoid membrane. Just like in a hydroelectric plant, the proton gradient drives a little "turbine" that generates ATP. In this "light reaction" part of photosynthesis, light energy that is freel...

So how does photosynthesis actually work?

In this lecture we explore the structures that capture light energy, photosystems 1 and 2, and how that light energy is harnessed to generate NADPH, and to build up a proton gradient across the thylakoid membrane. Just like in a hydroelectric plant, the proton gradient drives a little "turbine" that generates ATP. In this "light reaction" part of photosynthesis, light energy that is freel...

Leaves have features that prevent uncontrolled water loss such as cuticles and wax layers. Because these impermeable layers also prevent diffusion of carbondioxide into the leaf air space plants have developed structures that act like valves and control the flow of water vapour and carbondioxide: stomata.

The central opening, called pore or aperture, is surrounded by two guard cells that contain chloroplasts. The guard cells can ...

Leaves have features that prevent uncontrolled water loss such as cuticles and wax layers. Because these impermeable layers also prevent diffusion of carbondioxide into the leaf air space plants have developed structures that act like valves and control the flow of water vapour and carbondioxide: stomata.

The central opening, called pore or aperture, is surrounded by two guard cells that contain chloroplasts. The guard cells can ...

Leaves are the main "organs" of plants responsible for capturing light energy, and converting it through fixation of carbondioxide into chemical energy in the form of sugars.

In this lecture we look at modified leaves that serve as adaptations to lack or excess of water, lack of nutrients, and as protective structures to prevent herbivory. We also take a look at the structural oganisation of a "typical" leaf.

Copyright 2012 La Tr...

Leaves are the main "organs" of plants responsible for capturing light energy, and converting it through fixation of carbondioxide into chemical energy in the form of sugars.

In this lecture we look at modified leaves that serve as adaptations to lack or excess of water, lack of nutrients, and as protective structures to prevent herbivory. We also take a look at the structural oganisation of a "typical" leaf.

Copyright 2012 La Tr...

The third and final lecture on plant hormones is about brewing beer and Prince. No, of course not, but both are used as examples for the effects of gibberellins and abscisic acid.

Gibberellins were first discovered in "foolish rice" (or bakanae) where a fungal infection results in increased levels of gibberellins and very long, extended internodes. They are a large group of compounds (more than 120 gibberellins are known) and also...

The third and final lecture on plant hormones is about brewing beer and Prince. No, of course not, but both are used as examples for the effects of gibberellins and abscisic acid.

Gibberellins were first discovered in "foolish rice" (or bakanae) where a fungal infection results in increased levels of gibberellins and very long, extended internodes. They are a large group of compounds (more than 120 gibberellins are known) and also...

This lecture is about specific effects of two groups of plant hormones: cytokinins, and ethylene.

The main effects of cytokinins are stimulation of cell proliferation, and stimulation of growth of shoots from undifferentiated tissue (callus) in plant tissue culture. Together with auxins, cytokinins regulate apical dominance which determines the growth pattern of plants.

Ethylene is a gas and as such diffuses very easily and quic...

This lecture is about specific effects of two groups of plant hormones: cytokinins, and ethylene.

The main effects of cytokinins are stimulation of cell proliferation, and stimulation of growth of shoots from undifferentiated tissue (callus) in plant tissue culture. Together with auxins, cytokinins regulate apical dominance which determines the growth pattern of plants.

Ethylene is a gas and as such diffuses very easily and quic...

As we saw in previous lectures, plants are "rooted" to one spot. As a consequence they can not avoid adverse conditions such as drought, heat, cold etc. yet are able to survive seemingly extreme conditions. Almost all aspects of plant development and physiology are influenced and directed by plant hormones.

In today's lecture we look at the discovery of plant hormones in general - watch out for the appearance of an unlikely scient...