BIO1L- Morphology of Leaf PDF

UNIT 3 MORPHOLOGY OF LEAF Leaf developed from the plumule of the germinating seed. External Structure of the Leaf External Structure of the Leaf Blade/Lamina: the broad or green expanded part of the leaf that carries function such as photosynthesis, transpiration and respir...

UNIT 3 MORPHOLOGY OF LEAF Leaf developed from the plumule of the germinating seed. External Structure of the Leaf External Structure of the Leaf Blade/Lamina: the broad or green expanded part of the leaf that carries function such as photosynthesis, transpiration and respiration. Apex/Tip: the tip of the leaf. Margin: the edge of the leaf External Structure of the Leaf Midrib: the central vein or stiff middle portion of the leaf. Vein: the skeletal network of the blade. Venules - the small veins attached to the main vein. External Structure of the Leaf Base: lower part of the leaf where the leaf attaches to the petiole or stem. Petiole: the stalk that connects the leaf to the stem. Stipules: usually pair of green-small leaf-like appendages found at the base of the petiole TWO TYPES OF LEAF 1.Simple Leaf 2.Compound Leaf  Simple Leaf Compound Leaf One single blade. With one lamina or blade Divided into two or more blade-like attached to the node. Example: Gumamela segments or leaflets. Example: Makahiya leaf. leaf.  How can we say it is a leaflet? A leaflet is not directly attached to the main stem or branch of the plant. Instead, it is connected to a rachis or central stalk, which holds all the leaflets together to form one whole compound leaf. Unlike a true leaf, a true (simple) leaf is directly attached to the main stem or branch of the plant, such as in the case of a Gumamela leaf.  TYPES OF COMPOUND LEAF 1.PINNATELY 2. PALMATELY COMPOUND LEAF COMPOUND LEAF Sub-Types Sub-Types Paripinnate Unifoliate Imparipinnate Bifoliate Unipinnate Trifoliate Bipinnate Quadrafoliate Tripinnate Multifoliate Pinnate - have leaflets arranged along the rachis (stalk) 1. Unipinnate: Leaflets are arranged on one side of the rachis or along the length, typically forming a single row. Example: Some legumes (e.g., Coriander). Paripinnate: Leaflets are paired evenly along the rachis, no terminal leaf at the tip. Imparipinnate: Leaflets are arranged along the rachis with one terminal leaflet, resulting in an odd number of leaflets. Example: Rose (Rosa spp.).  Bipinnate: Each leaflet is further divided into smaller leaflets, resembling a feather divided twice. Example: Mimosa (Mimosa pudica). Tripinnate: Leaflets are divided into even smaller leaflets, resulting in a more intricate structure. Example: Some species of acacia leaf. Palmate - which leaflets radiate from apex to the petiole Unifoliate: A single leaflet arising from the petiole. Bifoliate: Two leaflets arise from the petiole. Trifoliate: Three leaflets arise from the petiole. Example: Clover (Trifolium spp.).  Quadrafoliate: Four leaflets arise from the petiole. Example: Some species of Oxalis. Multifoliate: More than four leaflets arise from the petiole, typically many leaflets radiating from a single point. Example: Horse chestnut (Aesculus hippocastanum). PHYLLOTAXY Phyllotaxy - the manner of arrangement of the leaves in the stem. 1.Opposite - appearing in pairs, the leaves are at the same level on the opposite nodes of the stem. Ex: Guava and Sampaguita 2.Whorled or Verticillate - when three or more leaves arise from the same plane around the stem. 3.Fascicled or tufted - when bundle of three or more leaves arise in a cluster from a point on the stem. Ex: Asparagus 4.Alternate or Ranked - when leaves are arranged alternately in the stem. LEAF VENATION 1.Parallel Venation: Veins run parallel to each other 2.Reticulate Venation: Veins form a net-like pattern LEAF MARGINS Entire: Smooth edges. Serrate: Saw-like edges. Lobed: Deep indentations along the margin.  Conduct an advanced research for Unit 4 and present your HOMEWORK: findings in a short coupon bond. Handwritten or Encoded (Use Arial font with a font size of 11). ) 1.What is Transpiration, Guttation and Photosynthesis? 2.What are the physiological processes behind guttation, and how does it differ from transpiration? Include examples of plants that exhibit guttation and the conditions that promote this phenomenon. 3.How do variations in light intensity and carbon dioxide concentration influence the rate of photosynthesis in plants? REFERENCES: