External parts of the leaf: Leaf Blade- Wide flattened area of leaf for concentrating sunlight on photosynthetic cells. Petiole- Short stem that attaches leaf to main stem or branch. Node- Growth region of stem where leaves or new branches arise. Axillary bud- Baby leaf or stem (next years growth). Midrib- large center vein from which all other leaf veins extend
Internal parts of the leaf: Upper Epidermis- consists of a single layer of cells covered by cuticle. Palisade mesophyll- Most photosynthesis takes place here. Spongy mesophyll- composed of closely packed irregular shape cells surrounded by air spaces. Guard Cells- are specialized cells located in the leaf epidermis of plants. Stomata- is a microscopic pore on the surface (epidermis) of land plants. Chloroplasts- are organelles found in plant cells and other eukaryotic organisms that conduct photosynthesis. Lower epidermis- We will see vascular bundle here and stomata.
Types of a Leaf:1. ACCORDING TO THE PETIOLE:Petiolated- leaves that have a petiole.Sessile- leaves without petiole.2. ACCORDING TO THE BLADE:Simple Leaf- shows an undivided blade or, in case ithas divisions, they do not reach the midrib.Compound Leaf- has a fragmented blade, withdivisions reaching the midrib.3. ACCORDING TO THE EDGE:Entire Leaves- have a smooth margin.Sinuate Leaves- have little curves with smoothedges like waves.
Dentate Leaves- have little teeth at the margin. Serrate Leaves- have little bent teeth like those of a saw. Lobed Leaves- have divisions that do not arrive the center of half blade.4. ACCORDING TO THE SHAPE OF THE BLADE: Elliptic Leaves- ellipse-shaped. Lanceolate Leaves- spear-shaped. Acicular Leaves- needle-shaped. Ovate Leaves- egg-shaped. Cordate Leaves- heart-shaped. Hastate Leaves- halberd-shaped. Linear Leaves- strip-shaped.
5. ACCORDING TO THE VEINS:Parallel-veined Leaves- the veins run at the samedistance to each other, like in canes.Pinnate Leaves- there is a main nerve, called midrib,from which the other nerves derive, remembering aplume.Palmate Leaves- the nerves diverge from the mainpoint such as the fingers do in the palm of the hand.6. ACCORDING TO THE ARRANGEMENT ALONG THESTEM:Alternate- springing one per node at different levelsof the stem.Opposite- two per node, facing opposite sides ofthe stem.
Whorled- several leaves disposed at the same level around the stem. Rosulate- forming a rosette, like a ring around the stem.
StemsThey support the leaves and flowers and they carry water and food from place to place within the plant.Support of leaves and reproductive structures.
External parts of the stem: Lenticel-it function as a pore, providing a medium for the direct exchange of gases between the internal tissues and atmosphere. Terminal bud- is the main area of growth in most plants. Lateral bud- it is capable of developing into a branch shoot or flower cluster. Leaf scar- is the mark left on a stem after a leaf falls.
Internal parts of the stem:Phloem- bark, carries manufactured foods down.Xylem- wood, carries water and minerals up.Cambium- separates the 2 and produces all new cells.
Types of a Stem: HERBACEOUS STEM - They do not have developed ligneous stiffened structures. LIGNEOUS STEM: - They have developed rigid, stiffened structures, what we normally know as “wood”.
RootsThe organ of a plant that typically lies below the surface of the soil.absorb water and minerals form soil and conduct to stemThe anchor of the plant.Used for Propagation.
Parts of the root: Primary root- originates at germination stage from the radicle of the seed. Secondary root- arise from the primary root. Root cap- envelope and protects the young roots. Root hairs- ensure efficient absorption of nutrients.
Types of a Root: FIBROUS ROOTS- It is usually formed by thin, moderately branching roots growing from the stem. TAPROOT- is an enlarged, somewhat straight to tapering plant root that grows downward. It forms a center from which other roots sprout laterally. Plants with taproots are difficult to transplant. AERIAL ROOTS- are roots above the ground. They are almost always adventitious. They are found in diverse plant species, including epiphytes such as orchids.
Seeda small embryonic plant enclosed in a covering called the seed coat, usually with some stored food.attractive to birds who eat and spread seeds.
Parts of a Seed: Radicle- The mature embryo consists of an embryonic root. Epicotyl- is the portion of the embryonic stem above the point at which the stem is attached to the cotyledon(s). Hypocotyl- is the portion below the point of attachment. It is connected to radicle. Cotyledon- is described as a seed leaf that stores food in the form of starch and protein for use by the embryo. Embryo- is the young multicellular organism before it emerges from the seed. Endosperm- is a source of stored food, consisting primarily of starches. Seed coat- consists of one or more protective layers that encase the seed. An embryo of a monocotyledon (monocot) plant has one cotyledon, while that of a dicotyledon (dicot) plant has two cotyledons.
Types of a Seed: Dicots are seeds that have two parts, such as a bean seed. Monocots are seeds that only have one cotyledon, such as the corn seed.
FruitThe ripened seed-bearing part of a plant when fleshy and edible.In other words, it is any fleshy material covering a seed or seeds.
Parts of a Fruit: Pericarp- surrounds the seed or seeds. Exocarp- is the outermost part of the pericarp, and is often the visible skin or peel of the fruit. It consists of the epidermal and sub epidermal layers of fruits. Mesocarp- is the middle layer of the pericarp between the exocarp and endocarp. In mango, the mesocarp is the edible, fleshy portion that is eaten between the skin and the seed. Endocarp- is the innermost layer of the pericarp, the part that immediately encloses the seeds. It occurs in various forms and texture ranging from thin and papery to hard and stony as in the fruit type called drupe.
Types of a Fruit: Simple Fruits: These fruits are produced by flowers containing one pistil, the main female reproductive organ of a flower. Aggregate Fruits: These fruits are developed from flowers which have more than one pistils. They consist of mass of small drupes that develops from a separate ovary of a single flower. Multiple Fruits: These fruits are developed not from one single flower but by a cluster of flowers. Accessory Fruits: These fruits are developed from plant parts other than the ovary.
FlowerThepart of the plant that makes the seeds.
Parts of the Flower Petals- are actually leaves. Usually bright colors to attract pollinating insects. Stamen- male part of the flower. Anther- a sac-like structure on top of filament, contains pollen. Pistil - female part of the flower. Ovary- egg cells develop here. Grows to become fruit or seed coat.
Types of a FlowerComplete- contains 4 main parts.Incomplete- does not have all 4 main parts.Perfect- has stamen and pistil.Imperfect- lacks stamen or pistil.