because lower epidermis is not covered with dust which falls from above.
Typically, the lower epidermis has more stomata compared to the upper epidermis. This arrangement helps plants regulate gas exchange, such as carbon dioxide intake and oxygen release, more efficiently.
upper epidermis for sure>>>
Because in leaves it is mostly the upper side facing the sun and receiving light for photolysis of water by the chlorophyll present in the chloroplasts of palisade layer cells hence the palisade layer in dorsiventral leaves is present below the upper epidermis of leaves.
Stratum Basale or Germinativum Some 10-25% of the cells in the stratum Basale are melanocytes, and their branching processes extend among the surrounding cells, reaching well into the more superficial Stratum Spinosum layer. Occasional Merkel cells are also seen in this stratum.
Because lower epidermis remains away from the light and in the absence of light the water loss through transpiration is minimized.
Typically, the lower epidermis has more stomata compared to the upper epidermis. This arrangement helps plants regulate gas exchange, such as carbon dioxide intake and oxygen release, more efficiently.
tissues are layers of similar cells. the outside layer of a leaf is called the epidermis tissue. the epidermis is made of flat cells . this layer is like the top layer of your skin. it protects the plant.
upper epidermis for sure>>>
The dermis is more cellular than the epidermis. The dermis contains a variety of cells, including fibroblasts, macrophages, and mast cells, which play important roles in maintaining the structure and function of the skin. In contrast, the epidermis primarily consists of keratinocytes, which are responsible for producing the protein keratin that helps to form the skin's protective barrier.
Epidermal cells are important to the leaf because depending on the climate that the plant resides within, the plant may create more than one epidermal layer. The purpose of this/these layer is to retain water, and some plants have a cuticle formed on the outside of the epidermis to prevent the loss of water too. In order to bring in CO2 from the air, leaves contain stoma which are essentially small pores in the lower epidermal layer that can open or close based on the plants needs. Guard cells on each side of stoma regulate gas exchange, as well as the loss of water.
guard cells
Because in leaves it is mostly the upper side facing the sun and receiving light for photolysis of water by the chlorophyll present in the chloroplasts of palisade layer cells hence the palisade layer in dorsiventral leaves is present below the upper epidermis of leaves.
Melanin is the dark pigmentation contained in skin. It is contained in melanocytes, which are the cells which produce melanin. The purpose of melanin is to filter out harmful radiation from the sun. Mostly it does not. The best way is to use a sunscreen with SPF of 30 or more.
Guard cells have more chloroplasts than any other dermal cells because they need energy to facilitate the opening and closing of stomata for gas exchange and water regulation in plants.
The actively dividing cells of the epidermis stain darkly due to their high content of nucleic acids and proteins, which are prevalent in cells undergoing division. These components take up stains more intensely, allowing for better visualization under a microscope. Additionally, the presence of more organelles, such as ribosomes, contributes to this darker staining appearance. This characteristic is particularly evident in the basal layer of the epidermis, where cell division is most active.
Dicot leaf is also called dorsiventral leaf as it has both dorsal and ventral side with identifiable features. The protective layer is named as Epidermis and there is both upper and lower epidermis. In dorsiventral leafs the lower epidermis which is also called abaxial side will have more number of stomata compared to the adaxial side or upper epidermis. The gap between the two epidermis is termed as mesophyll and in dicot leaf we can see a differentiated mesophyll region. The region is differentiated into palisade and spongy tissue. The region just below upper epidermis have elongated parenchyma cells with chlorophyll filled in and they are called Palisade tissues. This is the main reason behind dark green colour at upper side of a dicot leaf.
The root cell's job is to gather minerals and and take it up the roots to the onion.