Question

One of the following is wrong for comparison between dicot and monocot stem. In dicot stem
A. Vascular bundles are arranged in ring and in monocots they are scattered
B. Vascular bundles are oval and in monocots wedge shaped
C. Truth pith is present and absent in monocot stem
D. There is no protoxylem lacuna

Answer 1

Angiosperms are the flowering plants which are divided into two groups: monocots and dicots. Monocot seeds have one ‘seed leaf’ called cotyledon whereas dicots have two cotyledons.

Complete answer:
Monocot stems have scattered vascular bundles. The vascular bundles are generally present near the outside edge of the stem. The vascular bundles present in dicot stems are in the form of ring arrangement. The vascular bundles of monocot stem are present near the outside edge of the stem. The large parenchyma surrounds the bundles in the cortex region. There is no pith present in monocots. In dicot stems, the bundles are arranged in a ring surrounding parenchyma cells in a pith region. Protoxylem lacuna is the space present in the protoxylem of vascular bundles surrounded by parenchyma cells. It is absent in dicot stems.

Hence, the correct answer is option (B).

Additional information:
Monocots have only one seed whereas dicots have two seeds inside the seed coat. Monocot leaves have parallel veins whereas dicot leaves have veins that are scattered. The stems of monocots are usually unbranched and fleshy whereas the stem of dicots are usually tough. The petals of the flower of monocots come in multiples of three whereas the petals of the flower of dicots come in multiples of four or five.

Note: The cotyledon part of angiosperms is an embryonic leaf that is the first leaf (or leaves) to appear when a seed is germinating. Cotyledons are not true leaves and perform photosynthesis. True leaves grow after the seed has germinated. Cotyledons last for a few days after the seed germinates or last up to a year.