BI266 Lecture 3: Leaves
Document Summary
Leaves of flowering plants associated with leaf gaps and have axillary buds at base. Petiole = stalk (leaves sessile (fixed in one place) if lacking petiole) Pinnately compound leaves = leaflets in pairs along rachis (petiole) Palmately compound leaves = all leaflets attached at same point at end of petiole. Green leaves capture light energy by means of photosynthesis. Photosynthesis = trapping and storing of energy in sugar molecules that are constructed from water and carbon dioxide. Stomata = tiny pores on lower surfaces of leaves. Allow carbon dioxide to enter and oxygen to diffuse out. Guard cells control water loss by opening or closing pore of stomatal apparatus. Wastes from metabolic processes accumulate in leaves and are disposed of when leaves are shed. Plays major role in movement of water absorbed by roots. Transpiration occurs when water evaporates from leaf surface. Guttation = root pressure forces water out hydathodes at tips of leaf veins in some plants.
