Question

In girdling experiment on the trunk of a tree, a ring of bark up to the depth of the ______ can be carefully removed.Enable GingerCannot connect to Ginger Check your internet connection
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• A. xylem layer
• B. phloem layer
• C. cortical layer
• D. pith layer

Answer 1

Answer: (B)

The girdling experiment has been used to identify the tissue through which food is transported. In a typical dicot stem, after a few years of primary growth, the phloem layer is present as a ring, which is single and continuous, lying towards the outside of the stem (peripheral position). Being a continuous sheet-like, it can be easily removed.
The girdling experiment was first performed by Hartig in 1837.
It was demonstrated that when the ring of bark portion, which contains the phloem layer and cambium layers, just above the root at the base of the stem, there is an accumulation of food material. This forms a swelling, which is just above the ring which was cut.
This simple experiment shows that phloem is the tissue mainly responsible for translocation of food. In the absence of phloem, the translocation is blocked, as the swelling was due to food accumulation.