Question

Itching causing _____crystals are found in colocasia leaves.
A. Calcium carbonate
B. Calcium oxalate
C. Calcium sulphate
D. Calcium chloride

Answer 1

Hint:In colocasia leaves the compound is present in a crystal form which is further divided into raphides crystals and druses crystals which cause irritation in the mouth and higher dose can cause severe effects.

Complete step by step answer:
The calcium oxalate crystals are the common component present in colocasia leaves, which play a very important role in causing itching and protection from herbivores. It is derived from toxic oxalic acid It also helps in regulation of calcium and metal sequestration. During the studies of calcium oxalate in colocasia leaves, it is found that two general types of calcium oxalate crystals are present named as raphides and druses. The raphides are mainly of two types; they are defensive and non-defensive. Both are present in the bundles containing elongated crystals having specialized cells known as idioblasts. Druses are the spherical crystals which are distributed all over the leaves. The raphides can easily move in the lining of the mouth, throat and gastrointestinal tract which cause intense burning and irritation, swelling and cause choking in even small amounts. If larger doses of calcium oxalate is taken other symptoms like stomach pain, breathing problem suffocation can also occur if the oesophagus is blocked due to swelling of tissues.
Thus, itching causing calcium oxalate crystals are found in colocasia leaves.
Therefore, the correct option is B.

Note:
The calcium oxalate crystals can be converted back to calcium and oxalic acid. The effect of the crystal in the mouth can be reduced by rinsing the mouth with vinegar.