Kingdom Plantae: Introduction, Structure, and Function

Intro Trees, grasses, flowers, ferns, and mosses Primary producers on earth: -contribute oxygen, carbon fixation > 250,000 species Botany: the study of plants Classified by their structure Structure: see figure 24.2.1 on page 508 Organelles: see figure 24.2.2 on page 508

Characteristics: Cell wall: -made of cellulose Primary cell wall: -first cell wall made, surrounded by a layer of pectins -forms middle lamella Secondary cell wall: -woody plants -adds more structural support -contains lignins Plasmodesmata -small channels that connect plant cells to one another (share nutrients & water)

Vascular and Nonvascular Plants -use a system on interconnected tubes to transport water and nutrition -examples: trees, flowers, grasses, bushes, etc. Xylem: transport water & minerals from roots to rest of the plant Phloem: transports glucose (nutrition) from photosynthesis to all parts of the plants Nonvascular plants: -grow in moist environments, small in size -no tube network, use diffusion -examples: mosses, liverworts, and hornworts

General Plant Reproduction Reproduce by spores, seeds, both, or neither Used to classify plants Spore -small, one cell, no protective coating Seed -larger, multicellular, protective coating -contain embryo + endosperm

Monocots & Dicots

Three General Plant Tissue Types Parenchyma: unspecialized tissue, found throughout the plant Collenchyma: thicker primary cell walls, provide structural support Sclerenchyma: thick secondary cell walls, fill with lignin and become wood Vegetative organs: roots, stem, leaves Reproductive organs: flower, cone, etc.

Meristem Tissue: Specialized tissue where growth takes place Tips of roots and stems Apical meristem = growth in length Lateral meristem = growth in girth

Roots Anchor plant; absorb water and minerals from the soil Two types of root systems: taproot – one main root fibrous – many roots of equal size Layers: Epidermis, cortex, endodermis, pericycle Vascular cambium: contains xylem & phloem

Stem Leaves or branches form at the nodes Monocot vs. Dicot (page 518)

Bark Layers: inner bark, cork cambium, outer bark Outermost protective layer of woody stems Growth rings: rings of dead xylem cells; tell age, health, climate

Leaves Primary photosynthetic organ of plant exchange gas, absorb sunlight Monocot: veins run parallel Dicot: veins are netted cuticle: waxy covering, limits water loss Guard cells close the stomata (openings) to limit water loss

Importance of Water in Plants Necessary for photosynthesis, turgor pressure, hydrolysis, and transport Turgor pressure: keeps stems upright and leaves full Water is drawn into the central vacuoles by osmosis Nastic movements: movement due to changes in plant’s environment as a result of changes in turgor pressure.

Water and Transportation Critical for transport of nutrients and food throughout the plant Cohesion-tension theory: water molecules “stick” together Translocation: movement of glucose from leaves to rest of plant