Movement of chloroplasts around the cell is called cyclosis or cytoplasmic streaming. Other organelles such as mitochondria are also streaming, along with the chloroplasts. This movement is on intracellular tracks called microfilaments, composed of actin proteins. The organelles are attached to the actin filaments by myosin, a motor protein. These proteins transform the chemical energy in ATP into mechanical energy leading to change in protein conformation and the protein molecule “walks” down the actin filament.
In leaf cells under bright sunlight, chloroplasts may have the ability to “move into the shade” of other chloroplasts, called photorelocation. Chloroplasts gather in areas irradiated with weak light to maximize photosynthesis (the accumulation response), and move away from areas irradiated with strong light to minimize damage of the photosynthetic apparatus (the avoidance response). The processes underlying these chloroplast movements can be divided into three parts: photoperception, signal transduction, and chloroplast movement.
Elodea is a genus of 6 species of aquatic plants often called the waterweeds described as a genus in 1803. Elodea is native to North and South America and is also widely used as aquarium vegetation. It lives in fresh water (Wikipedia). Chloroplasts can move in all plants but are particularly visible in Elodea.
I used my Leitz Laborlux 11 microscope today to view a thin slice of Elodea leaf with a bright light from the side to stimulate movement.
Video of chloroplast movement in Elodea, Leitz Laborlux 11 microscope, 40x objective:
Video of chloroplast movement in Elodea, Leitz Laborlux 11 microscope, 100x objective:
In the next photo, look carefully – there are many tiny organelles visible apart from the more obvious chloroplasts:
Another attempt at this – some fantastic images and video – I wonder what all those very small moving objects in the cells are? Organelles or another organism?
For photosynthesis plants use wavelengths that chlorophyll molecules can absorb, and these are blue (410-460 nm) and red (630-670 nm) light. There are 2 types of chlorophyll: a (max absorption at 430 and 662 nm) and b (max absorption at 453 and 642 nm) (http://answers.yahoo.com/question/index?qid=20060906053251AArv13c)
Cellular Turbulence. Rhys and I went with the family to the Big Bang Show at the NEC in Birmingham. On the Zeiss stand were a number of microscopes – and on one of them some Elodea showing chloroplast movement around the cell. This pond weed has particularly mobile chloroplasts and the site is amazing. This movement is referred to as cyclosis or cytoplasmic streaming.
See the photo and video below – wow! I wonder what the small things are, much smaller than chloroplasts? Organelles or parasitic protozoa or bacteria? Magnifications here using x32 and x63 objectives so bacteria would show up at this magnification.
Some facts about chloroplasts:
Chloroplasts are organelles, specialized compartments, in plant and algal cells. The main role of chloroplasts is to conduct photosynthesis, where the photosynthetic pigment chlorophyll captures the energy from sunlight and converts it and stores it in the energy-storage molecules ATP and NADPH while freeing oxygen from water. They then use the ATP and NADPH to make organic molecules from carbon dioxide in a process known as the Calvin cycle. Chloroplasts carry out a number of other functions, including fatty acid synthesis, much amino acid synthesis, and the immune response in plants. The number of chloroplasts per cell varies from one, in unicellular algae, up to 100 in plants like Arabidopsis and wheat (from https://en.wikipedia.org/wiki/Chloroplast)
The average chloroplast is about 3 µm (micrometers) in diameter. In one square millimeter of the surface of a leaf, there are about half a million chloroplasts (from www.answers.com/Q/What_is_the_size_of_a_chloroplast)
Chloroplasts in vascular plants range from being football to lens shaped and as shown in Figure 1, have a characteristic diameter of ≈4-6 microns (BNID 104982, 107012), with a mean volume of ≈20 μm3 (for corn seedling, BNID 106536). In algae they can also be cup-shaped, tubular or even form elaborate networks, paralleling the morphological diversity found in mitochondria. Though chloroplasts are many times larger than most bacteria, in their composition they can be much more homogenous, as required by their functional role which centers on carbon fixation. The interior of a chloroplast is made up of stacks of membranes, in some ways analogous to the membranes seen in the rod cells found in the visual systems of mammals. The many membranes that make up a chloroplast are fully packed with the apparatus of light capture, photosystems and related complexes. The rest of the organelle is packed almost fully with one dominant protein species, namely, Rubisco, the protein serving to fix CO2 in the carbon fixation cycle. The catalysis of this carbon-fixation reaction is relatively slow thus necessitating such high protein abundances (from http://book.bionumbers.org/how-large-are-chloroplasts/)
Components of cells seen in photos and video:
Today’s photos and video:
If you want the wow factor go straight to the videos at bottom of page using x63 objective! I am quite excited by the views with the x63 objective below as this is first time I have used it so successfully with this microscope. The slide is turned upside down and Kohler illumination has been achieved using my “new” (second hand off ebay) NA 0.9 bright field condenser with Zeiss 475638 illuminator collimation tube (at least I think that is what it is for!).
The slide was prepared using free hand sections of Elodea leaf using razor blade put on slide with drop water and covered with cover slip. Edges of cover slip help firmly to slide by electrical insulating tape strips and then slide turned upside down and put on microscope stage (upside down as Zeiss IM microscope is an inverted microscope).
Photo of Elodea leaf section (cut free hand with razor blade) x32 objective, bright field, Zeiss IM microscope, showing cell walls and chloroplasts:
Photos of Elodea x63 objective bright field, now also shows small inclusions much smaller than chloroplasts – in later videos these are shown to move as well as chloroplasts:
Videos – first two videos are with x32 objective, bright field:
Videos – next videos used x63 objective, bright field: