Experiments to deepen understanding of the pathways and rates of water transport in plants and the potential for vascular transport.
Operation method
Experiments on the pathways and rates of water transport in plants and the potential of vascular transport
Principle
Water is transported in plants mainly through xylem ducts and tubular cells, both of which are dead cells. When transpiration is strong, water transport is mainly driven by the transpirational pull of the leaves, and even more so in the case of cut-off roots. Thus, when an isolated leaf or branch is inserted into a colored solution, the liquid is rapidly drawn into and transported along the duct, and the color of the liquid can be used to indicate the pathway of transport, and the rate of transport can be approximately calculated.
Materials and Instruments
Radish Move 1. Pour about 5 ml of red ink into a 10 ml flat-bottomed finger-shaped tube, then select a radish leaf, dry the water on the leaf surface, cut the leaf from the base of the petiole with a razor blade, quickly insert the leaf into the red ink, and hold the leaf up to the light, so that the red ink can be clearly seen rising along the leaf veins. The rate of water transport (m-h-1) can be roughly calculated by selecting a point in the upper part of the main vein and calculating the time taken from the insertion of the petiole into the red ink to the arrival of the red ink at this point and the distance between this point and the cut of the petiole. Remove the petiole and re-cut a section about 1 cm long and observe how many vascular bundles are present in the section? Where is the red ink distributed? For more product details, please visit Aladdin Scientific website.
Red ink Eosin solution
Single-sided blades Scalpels Flat-bottomed finger tubes Finger tube holders
2. Take another leaf and use a scalpel to strip the vascular bundles at the base of the petiole in a section about 2 cm long (removing the thin-walled tissue of the petiole), insert the two lateral vascular bundles into red ink and the remaining three into water,, and, after 10 min, observe in which portion of the leaf blade the veins turn red? Take another leaf and do a similar treatment, but instead of inserting the remaining three vascular bundles in water, expose them to the air without making them absorb water, and after the same time observe that the whole leaf will turn all red. Try to explain this observation.
3. another potted radish plant, choose two leaves, with a scalpel will be a section of the petiole of the thin-walled cells all peeled off, one of the leaves only to stay connected to the midvein, the other leaf leaves only a lateral veins, the wound is not protected in a few days of regular observation, you can see that the leaves by such a serious cut, but still do not wilt, which means that one of the vascular bundles left behind have to bear the burden of more than one vascular bundles to perform the transport of water function, it can be seen that metabolism, "the" water, not exposed to air, not to absorb water, the whole leaf will turn red. This shows that there is a great potential for metabolic "compensation".