Plant structures

• Guard cells control the opening and closing of stomata to regulate gas exchange between plants and their environment.
• Stomata are small openings on the underside of leaves, surrounded by guard cells.
• The epidermis is the outermost layer of cells that covers all above-ground plant parts.
• The epidermis is the outermost layer of plant tissue that protects against water loss and pathogens.
• Epidermal cells have waxy cuticles covering them to prevent water loss.
• The epidermis is composed of two layers - an upper layer called the cuticle and a lower layer called the palisade mesophyll.
• Cuticle helps prevent water loss from transpiration.
• Microscope are used to observe the cross-sections of leaves.
• What is the role of chlorophyll?to absorb light energy for photosynthesis
• The top of the leaf is exposed to the most light, where cells specialized for trapping light, called palisade mesophyll, are located
• Palisade mesophyll cells are packed full of chlorophyll, the green chemical that plants use to absorb light
• Leaves have a large surface area to trap as much sunlight as possible
• The bottom of the leaf contains stomata, little pores that open up to allow carbon dioxide to diffuse in
• Guard cells control the opening and closing of stomata to regulate the entry of carbon dioxide
• Epidermis cells below the palisade mesophyll and above the spongy mesophyll produce a waxy coating called the cuticle to seal the leaf
• The cuticle prevents unwanted intruders and helps retain important reactants like water
• The epidermis cells and cuticle make up the leaf's protective outer layer
• Stomata are located around the lower epidermis and cuticle, regulated by guard cells
• What is the thing that connects the leaf and stem called?

  petiole

  
• The petiole connects the leaf and the stem so that all leaves can be evenly distributed and absorb more sunlight.
• 4 common leaf shapes are elliptic, fan-shaped, round and cordate.
• The leaf blade contains chlorophyll for making food (with sunlight).
• The vein is part of the transportation system. Water and food can be sent to other parts of the plant.
• The upper and lower epidermis contain a cuticle layer for protection and the prevention of water loss.
• The mesophyll layer contains a lot of chlorophyll to give the leaf colour,
• The stoma is found on the lower epidermis. Oxygen and carbon dioxide pass through the stomata for gas exchange.
• What is a stoma?

  A stoma is a pore formed by 2 kidney-shaped cells called guard cells.
• Stomata allow carbon dioxide to enter the leaves for photosynthesis .
• The oxygen produced in photosynthesis diffuses into the atmosphere through stomata
• When there is a lack of water, the guard cells close. It prevent evaporation through stomata .
• When there is a lot of water inside the plant, the guard cells open. It allows water to leave the [lants through stomata.
• The climate of the tropical rainforest is hot and wet. It is important that water falls off the leaves quickly to prevent rotting and bacteria or fungus growth.
• Bacteria and fungus on leaves may affect the photosynthetic rate because of the blockage of sunlight absorbtion.
• Therefore, many plants in rainforests have drip tip leaves. the drip tip is the pointed end of the leaf. This tip, along with the waxy covering makes it easier for water to run off the leaves.
• Drip tip can also reduce the size of droplets falling from leaves. This prevents damage to the leaves below and reduces the impact of rainfall on the ground which keeps soil in its place.
• Iodine is a solution for testing the presence of starch. When iodine is added to starch, it turns int oa blue-black color.
• The leaf produces starch during photosynthesis
• Leaves undergo transpiration.
• Transpiration is a process in which the water leaves the plant via its stomata and lenticels into the atmosphere.
• Transpiration provides a pulling force which helps water to move upwards from the roots to the leaves.