Leaves Flashcards
a membranous outgrowth at the base of the blade of most grasses
Ligule
What is the leaf trace?
leaf traces act like the plant’s veins that connect the vascular system of a plant to its leaves through the petiole
Found at the leaf base, plays a crucial role in the shedding of leaves
Abscission zone
Drop their leaves and become dormant during a part of the year. Store food to maintain metabolism while leafless
Deciduous plants
_____ is a plant’s growth response to touch or contact
Thigmotropism
a small leaf-like structure at the leaf base of some plants, serving various functions such as protection and support
Prophylls
When a plant contains two forms of leaves that differ in size and shape
Leaf dimorphism
large, compound leaves typically found in ferns and some other plants
Fronds
Functions of Leaves
Absorbs light, protection against herbivores, and stores nutrients (starch)
Draw the structure of a leaf
apex, margin, veins, midrib, base, lamina, petiole, axillary bud, stipule
Describe the appearance of simple leaves
flat, undivided, with or without petiole
Pinnately vs Palmately leaves
Pinnately: leaflets forms in odd or even pairs along the central stalk / Palmately: leaflets are attached from the same point
Alternate name of central stalk
Rachis
Types of pinnate leaves
Unipinnate, Bipinnate, Tripinnate,
Three types of ground tissue
Parenchyma, Collenchyma, Sclerenchyma
Economic importance of leaves
Nutrition, Flavor, Medicinal, Sustaining life
The two sides of horizontally oriented leaves
Palisade Mesophyll (upper side) - light absorption / Spongy Mesophyll (lower side) - gas exchange
Vertically Oriented Leaves
Found in monocots, lacks palisade and spongy layers - uniform mesophyll cells
Venation in Dicot vs Monocot
Dicot: netted venation / Monocot: parallel venation
sun leaves vs shade leaves
Sun leaves are adapted to high light intensity and are typically smaller, thicker, and have fewer stomata, while shade leaves are the opposite and has more chlorophyll
Environmental factors affecting leaf variation
Sunlight and moisture
Three types of plants according to moisture
Mesophytes (Moderate), Xerophytes (Little water), Hydrophytes (Aquatic)
Peltate leaves
Shield-like leaves (petiole attached to middle of lamina
Perfoliate leaves
Leaf is pierced by the stem
Pulvinus leaf
swollen area at leaf base
Stomatal Transpiration
It is the dominant transpiration that accounts for water loss in plants. It is also responsible for the release of water vapor through the stomata.
Water vapor directly diffuses through the cuticle (cuticular pores) and out to the atmosphere
Cuticular transpiration