LABORATORY REVIEW
TRANSPIRATION
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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adding a layer of oil on the water inside the measuring cylinder
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smear the leaves surface with vaseline
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cut the shoots under water
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start with same weight s
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limit the number of leaves
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Detailed explanation-1: -The whole apparatus must be airtight. The cut stem must be fixed to the end tube underwater. Leaves of the desired shoot must be dry before cutting. There should not be any air bubbles in the apparatus.
Detailed explanation-2: -It is crucial to avoid air bubbles in the assembled potometer. The plant stem must be cut under water to prevent airlocks forming in the xylem. All fittings must be tight so that the only way the apparatus can lose water is by the plant transpiring.
Detailed explanation-3: -The following precautions must be taken before using Ganong’s Potometer: When a twig is freshly cut from a plant, make sure that it is immediately placed under water (only the cut region). After that, a tiny portion is cut while it is still under water.
Detailed explanation-4: -The washing line method is used to prove that most water loss occurs from the lower surface of the leaf. 1. Cut the shoot under water to prevent air bubbles entering the xylem of the stem and ensure the cut is diagonal to increase the surface area available for water uptake.
Detailed explanation-5: -Cut at an oblique angle to increase the surface area for water absorption. Ensure that the leaves of the shoot remain dry to prevent the obstruction of stomata by water droplets. 3. Whilst still underwater, insert the shoot tip into the rubber tubing of the potometer.