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 two lectures we have a brief look at what biotechnology actually mea...
Oct 30, 2012•48 min
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 two lectures we have a brief look at what biotechnology actually mea...
Oct 30, 2012•43 min
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 two lectures we have a brief look at what biotechnology actually mea...
Oct 30, 2012
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 vascular bundles, or steeles, are arranged in a circle in dicots,...
Sep 24, 2012•49 min
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 vascular bundles, or steeles, are arranged in a circle in dicots,...
Sep 24, 2012
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 that are found in the middle lamella, primary wall, and secondary w...
Sep 24, 2012•49 min
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 that are found in the middle lamella, primary wall, and secondary w...
Sep 24, 2012
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 freely available from our sun is converted into chemical energy in the f...
Sep 24, 2012•51 min
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 freely available from our sun is converted into chemical energy in the f...
Sep 24, 2012
After finishing our quite extensive foray into leaf structure, function, and modifications, we finally start to look at what is arguably the main purpose of leaves: absorbing light energy, and using that energy to fix carbon dioxide. In this lecture we will discuss the discovery of photosynthesis, and the general principle of the process. Copyright 2012 La Trobe University, all rights reserved. Contact for permissions.
Sep 16, 2012•40 min
After finishing our quite extensive foray into leaf structure, function, and modifications, we finally start to look at what is arguably the main purpose of leaves: absorbing light energy, and using that energy to fix carbon dioxide. In this lecture we will discuss the discovery of photosynthesis, and the general principle of the process. Copyright 2012 La Trobe University, all rights reserved. Contact for permissions.
Sep 16, 2012
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 swell (increase in turgor) and shrink (decrease in turgor), thereby...
Sep 14, 2012•40 min
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 swell (increase in turgor) and shrink (decrease in turgor), thereby...
Sep 14, 2012
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 Trobe University, all rights reserved. Contact for permissions....
Sep 11, 2012•32 min
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 Trobe University, all rights reserved. Contact for permissions....
Sep 11, 2012
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 stimulate seed germination, an effect that is taken advantage of ...
Sep 10, 2012•45 min
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 stimulate seed germination, an effect that is taken advantage of ...
Sep 10, 2012
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 quickly. In climacteric fruits like banana or tomato ethylene accelerate...
Sep 10, 2012•43 min
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 quickly. In climacteric fruits like banana or tomato ethylene accelerate...
Sep 10, 2012
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 scientist - and look at specific effects of the phytohormone auxin, such...
Sep 04, 2012•48 min
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 scientist - and look at specific effects of the phytohormone auxin, such...
Sep 04, 2012
Plants can't do it all by themselves. In order to get the most out of the soil and, indeed, the air, most plants form symbiotic relationships with bacteria and fungi. We take a look at Anabaena, root nodules, and mycorrhizae. Roots are often modified to form "survival structures" containing sugars or proteins. Carrots, cassava, batata and yam are typical examples that are used as food sources by humans. In the last part of this lecture we briefly touch on global and local soil problems like eros...
Sep 03, 2012•42 min
Plants can't do it all by themselves. In order to get the most out of the soil and, indeed, the air, most plants form symbiotic relationships with bacteria and fungi. We take a look at Anabaena, root nodules, and mycorrhizae. Roots are often modified to form "survival structures" containing sugars or proteins. Carrots, cassava, batata and yam are typical examples that are used as food sources by humans. In the last part of this lecture we briefly touch on global and local soil problems like eros...
Sep 03, 2012
Roots anchor plants in soil, are responsible for the uptake of water and nutrients, and control which molecules are ultimately taken up by the plant. In this lecture we take a look at the root morphology of monocots and dicots, how lateral roots aad root hairs are formed, and describe different pathways for the transport of water and solutes in the roots. Copyright 2012 La Trobe University, all rights reserved. Contact for permissions.
Sep 02, 2012•40 min
Roots anchor plants in soil, are responsible for the uptake of water and nutrients, and control which molecules are ultimately taken up by the plant. In this lecture we take a look at the root morphology of monocots and dicots, how lateral roots aad root hairs are formed, and describe different pathways for the transport of water and solutes in the roots. Copyright 2012 La Trobe University, all rights reserved. Contact for permissions.
Sep 02, 2012
In this lecture we take an introductory look at the role of soil in plant growth. We will briefly go over how soil is formed, what makes a good soil or a bad soil, what nutrients can typically be found, and how nutrient cycles critically involve soil. Copyright 2012 La Trobe University, all rights reserved. Contact for permissions.
Aug 28, 2012•44 min
In this lecture we take an introductory look at the role of soil in plant growth. We will briefly go over how soil is formed, what makes a good soil or a bad soil, what nutrients can typically be found, and how nutrient cycles critically involve soil. Copyright 2012 La Trobe University, all rights reserved. Contact for permissions.
Aug 27, 2012
