Video Transcript
Which of the following is not a
method of waste excretion by a plant? (A) Waste products are stored in
leaves, which then drop off. (B) Waste is stored in resins that
are excreted from trunks and branches. (C) Waste products are stored in
fruits, which then drop off. (D) Waste products are released in
a gaseous form via the tracheae in the stem. Or (E) waste products can be
excreted into the surrounding soil.
To answer this question, let’s look
at some methods plants use for waste excretion.
Certain plants can generate waste
products in the form of mineral salts or acids. These compounds are then converted
into crystals and stored in the cytoplasm or vacuole of certain plant cells. The insoluble crystals accumulate
in the cells of leaves, bark, or fruit. These are eventually shed, and the
plant is free from toxic substances. Should this process not happen, the
potentially toxic compounds could spread to different parts of the plant and cause
harm.
From this explanation, we can
conclude that options (A) and (C) are both methods of waste excretion by a plant and
can therefore be excluded as possible answer options, as this question is looking
for a choice that is not a method of waste excretion by a plant.
Let’s look at another method of
waste excretion by a plant. Some plants can store certain waste
products in resins or gums, which accumulate in old xylem vessels. Some plants may also produce these
substances in response to injuries. These resins or gums get excreted
via bark on the trunks of trees, leaves, or stems. So option (B) is also a method of
waste excretion by a plant.
Another method of waste excretion
in plants is through their roots into soil. This includes excretion of organic
acids, amino acids, and sugars. Option (E) is therefore also a
method of waste excretion by plants and cannot be our answer.
The last method we will look at is
excreting gaseous waste products. Certain plants can excrete excess
quantities of gaseous waste products via stomata, which are pores in the epidermis
of leaves, or lenticels, which are openings on the surface of stems and roots,
through which gas exchange can take place with the atmosphere. Option (D) mentions gaseous waste
products. However, the statement is not quite
right. Waste products are released in a
gaseous form via lenticels in the stem and not via tracheae, as stated in option
(D). This means that we have found the
correct answer to this question.
The option which is not a method of
waste excretion in plants is (D). Waste products are released in a
gaseous form via the tracheae in the stem.
