Video Transcript
Plants can also be reproduced
asexually by a process called grafting. The diagram gives a basic outline
of this process. In which of the following scenarios
is grafting effective? (A) When the two plants are closely
related. (B) When the two plants are
distantly related. Or (C) when the two plants do not
produce flowers.
Grafting, as illustrated in the
diagram, is the process of attaching the tissue of two different plants
together. Generally, the shoot, or scion, of
one plant is cut off. And then it is attached to the
rootstock of another plant. If the grafting is successful, the
shoot can then continue to grow, while receiving nutrition and support from the
rootstock. Grafting is commonly used to
quickly replicate a desirable plant, faster and more reliably than may be possible
through natural reproduction.
Fruit and nut trees are very
commonly grafted with the shoot of a plant already known to produce well. This way, farmers can be more sure
of the quality of the crop that will be produced. Fruit and nut trees produce
flowers, which are fertilized before developing into the fruits or nuts which are
harvested. So, grafting is used very commonly
in flowering plants and works well. Therefore, we can eliminate
(C).
In order for a graft to be
successful, the shoot must be accepted by the rootstock so that the tissues of the
two plants heal together, essentially creating one plant. In order for this to happen, the
genetic profile of the tissues must be as similar as possible so that the vascular
tissues of the two plants will in fact heal together and the shoot or scion will be
accepted by the rootstock. The more genetically similar the
two plants are, the more likely that the graft will be successful.
So, the correct answer to this
question is (A). Grafting is effective when the two
plants are closely related.
