Question

Palisade parenchyma is well developed in:
A. Mesophytes
B. Heliophytes
C. Sciophytes
D. Hygrophytes

Answer 1

As you know, all the plants have basic types of cells that are present in all plants such as xylem, phloem, storage cells etc.; but every species of plant has some different or specialized cells which develop in response to their environment to ease their growth and survival.

Complete answer:
In a plant, there are various kinds of specialized cells present which have a specific function. For example, some cells have their designated function to perform photosynthesis and some only have the function to store the synthesized food, some have the function to transport the food or water to the leaves or some may just have the function to provide the structural support to the plant.
The cells present in leaves are epidermis, mesophyll cells, vascular bundle, and stomatal cells. The epidermal cells are the cells which line the outer surface of the leaves. These contain specialized cells used for gaseous exchange and are called stomata. The mesophyll cells have two types: palisade mesophyll and spongy mesophyll cells. Palisade mesophyll cells are specialized by having numerous chloroplasts to perform photosynthesis and make food whereas the spongy mesophyll cells are loosely packed and lie near the vascular bundles and help in the transport of materials to and fro from the vascular bundles. The third type of cells, vascular bundles run all over the plant and transport the food and water all over the plant.
Mesophytes are plants that are not confined to dry or wet environments. These are found in temperate regions and inhabit the rural areas. These plants make up the largest group of terrestrial plants.
Heliophytes are the plants that are found in the region where the solar irradiations are high. The halophytic plants have thin leaves and waxy cuticles to reduce transpiration. These plants have a well-developed palisade parenchyma and vary from others by having double palisade layers.
Sciophytes are the plants that can thrive in low light. These plants have larger photosynthetic units that are chlorophyll than the normal plants and get saturated and perform photosynthesis in low light such as 20% light.

Note: All the plants in the ecosystem have evolved various mechanisms to cope up with the changing environment. For example, the plants in more sunlight exposed areas have minimized their flattened leaves to thin leaf like structures to minimize the transpiration loss or the plants in less sunlight exposed areas have developed their leaves by having a large number of chloroplasts to fulfill their plant energy needs.