Plant Structure and Function Unit 9 Plant Structure and Function

Learning Objectives Structure and functions of plant tissue, leaves, roots and stems. Discuss – using examples – the four major plant divisions Describe the three primary cell types that make up plant tissue Describe the structure and function of the tissue types found in plants Explain how roots and stems not only provide support, but also allow for the storage and transportation of nutrients throughout the plant Make a drawing of the structures found in a typical leaf

Learning Objectives Describe the stages in a plant's life cycle. Compare the sporophyte stage in a plants life cycle to the gametophyte stage

Origins of plant life Land plants evolved from green algae Both multicellular eukaryotes Both use photosynthesis to produce food Both use chlorophyll Both use starch as storage product Both have cell walls made of cellulose

Plant Adaptation Land plants have evolved adaptations that allow them to live on land Retaining moisture Cuticle – waxy layer stomata Transporting resources Vascular system – collection of specialized tissues that bring water and nutrients up from roots and disperse sugars down from the leaves

Growing upright Reproducing on land Lignin – provides structure and support, allows plant to grow upwards toward the sun Reproducing on land Pollen Seeds – contains plant embryo

Plant Diversity

Bryophytes 24000 species Live in moist environments Mosses, liverworts Live in moist environments Non-vascular land plants Grow close to ground or on surfaces where they can absorb nutrients directly Fertilization requires free water Allow sperm to swim and fertilize eggs

Bryophytes Liverworts – thin leathery body that grows flat on most soil or still water

Bryophytes Mosses Most common bryophytes Do not have leaves, but have leaf like structures that are one cell thick arranged in spirals

Pteridophytes 300 million years old Club mosses, horsetails, ferns Vascular plants that reproduce using spores Fertilization requires free water Cuticle and stomata present

Pteridophytes Club Mosses 11oo species Not true mosses Wet, shady habitats Oldest living group of vascular plants Some look like tiny pine trees (Lycopodium)

Pteridophytes Horsetails 25 species Swamps, wetland areas Tan, scale-like leaves that grow in whorls around tubular stem

Pteridophytes Ferns 12000 species Wet, humid habitats Leaves – fronds

Seed Plants Vascular Cuticle and stomata present Free water not needed for fertilization Gymnosperm Naked seeds (not enclosed in fruit) Angiosperm Flowering plants Seeds enclosed in fruit

Gymnosperm Conifers 550 Species Mostly evergreen Pollen and seed-baring cones Pollen produced in male cones Egg produced in female cones

Gymnosperm Cycads 130 species Look like palm trees with large cones Tropical climates Very slow growing - endangered

Gymnosperm Ginkgo One species Native to china Closely resembles fossil ancestors

Angiosperms Flowering plants Dominate the plant kingdom Flower – reproductive structure, protects plants gametes and fertilized eggs Dominate the plant kingdom Protect seeds with fruit Peach Wings attached to maple seed Dandelion fluff

Angiosperms Monocots Parallel veins in long narrow leaves Flower occurs in multiples of 3 Bundles of vascular tissue scattered throughout the stem

Angiosperms Dicots Leaves with net-like veins Flowers occur in multiples of four or five Vascular tissue arranged in rings Embryo has two seed leaves (peanuts)