Plant Transport and Physiology

Lenticel is a pore in the stem of a woody plant, showing a raised spot that may be filled with a powdery substance. The pore permits air to reach tissue below the surface. Stomata are present in leaves, Sieve plates are present in phloem tissue for the transport of carbohydrates and Pits are the characteristic depressions on the cell walls for the transport of water and minerals.

Plants do not have a nervous system or blood; they use chemical messengers called phytohormones to coordinate growth and physiological responses.

Percolation is the downward movement of water through soil pores, which results in the loss of surface water into deeper soil layers.

In spinach, leaves have modified functions. They are modified to store food and water. They store their food in leaves. So, leaves of spinach are a rich source of nutrition and are frequently consumed. 

Epistomatic stomata is having stomata on the upper surface of the leaf. This type of stomata is mostly found in aquatic plants. Aquatic plants float on the surface of the water and therefore stomata are not found in the lower epidermis. Stomata are found on the upper epidermis because for direct exchange of gases between the leaf and the atmosphere. 

The cuticle is comprised of polymers of wax. This layer is present on the surface of the epidermis of leaf and stem. This is the waxy and waterproof layer. This layer prevents the loss of water from the leaves and stem. This protective layer allows the retention of the water. This helps to reduce the loss of water in the form of water vapour by transpiration. 

Stomata are the openings surrounded by the guard cells that are specialized epidermal cells. These are present on the underside of the leaves and perform the functions of exchange of gases and transpiration.

A lenticel is a porous tissue consisting of cells with large intercellular spaces in the periderm of the secondarily thickened organs and the bark of woody stems and roots of dicotyledonous flowering plants. It functions as a pore, providing a pathway for the direct exchange of gases between the internal tissues and atmosphere through the bark, which is otherwise impermeable to gases. A hydathode is a type of secretory tissue in leaves, usually found in angiosperms, that secretes water through pores in the epidermis or margin of leaves, typically at the tip of a marginal tooth or serration.
Hydathodes are mainly found in aquatic plants and in some herbaceous plants growing in moist places.
A stoma (plural stomata) is a pore, found in the epidermis of leaves, stems and other organs that is used to control gas exchange.
Aerenchyma is the spaces or air channels in the leaves, stems and roots of some plants, which allows exchange of gases between the shoot and the root.
Thus, the correct answer is option A.

• A leaf is said to be hypostomatous where stomata are present on abaxial surface only (lower surface). Most tree species of dicotyledons possess such leaves. Ex. Ficus, Nerium etc.
• Hypostomatous plants are non-aquatic plants in which stomata are present on the lower surface because their function is to regulate the amount of water in the leaf and being on the bottom prevents it from absorbing too much water in the rain or transpirating too much in the sun.

A lenticel is a porous tissue consisting of cells with large intercellular spaces in the periderm of the secondarily thickened organs and the bark of woody stems and roots of dicotyledonous flowering plants. It functions as a pore, providing a pathway for the direct exchange of gases between the internal tissues and atmosphere through the bark, which is otherwise impermeable to gases. The shape of lenticels is one of the characteristics used for tree identification. So, lenticels helps in gaseous exchange and not in transpiration or vegetative propagation. 

Leaf cuticle is protective covering on leaf epidermis and is composed of cutin, an insoluble heterogenous lipid polymer of long chain substituted aliphatic acids. Hence, it serves as water impervious layer to prevent water loos through transpiration. Stomata are the organs of transpiration which are present in the epidermis and their opening and closing are regulated by the change in turgidity of guard cells. Thus, the correct answer is C.

The unicellular hair-like structures present on the surface of the root are known as trichomes. These are finger-like projections of the cells in the regions of the root. The trichomes act like the root hairs. They are involved in the process of absorption of water and minerals from the soil. They also help to increase the surface area for absorption. 

Veins have vascular tissues xylem and phloem. Xylem fulfills the requirement of water of the leaves. Phloem transport food energy to the leaves. They also provide support for the leaf.

Stoma (plural stomata) is a pore, found in the epidermis of leaves, stems and other organs that is used to control gas exchange. The pore is bordered by a pair of specialized parenchyma cells known as guard cells that are responsible for regulating the size of the opening.
Dicotyledons usually have more stomata on the lower epidermis than the upper epidermis. Monocotyledons, on the other hand, usually have the same number of stomata on the two epidermis.
In plants with floating leaves, stomata may be found only on the upper epidermis and submerged leaves may lack stomata entirely.
Thus, the correct answer is option B.