Plant Adaptations: Vascular vs. Non-Vascular

• Plants are multicellular eukaryotes containing chloroplasts for photosynthesis.
• They are non-motile, fixed in one spot, and have cell walls made of cellulose.
• Plants respond to their environment.
• The first plants lived in water.

Major Adaptations to Land

• Protection from drying out for leaves and stems.
• A vascular system transports water, nutrients, and wastes.
• Stems and leaves provide support and facilitate photosynthesis.

Non-Vascular Plants

• Lack a vascular system for transporting nutrients, water, or waste.
• The earliest land plants were non-vascular.
• Reproduction requires a moist surface for gametes to swim.
• Produce spores, not seeds.
• Substances move via osmosis and diffusion, limiting growth.

Vascular Plants

• Ferns were the first vascular plants.
• Have vascular tissue for material transport, enabling taller growth.
• True roots anchor the plant and absorb water and minerals.
• Leaves are photosynthetic and absorb gases.
• Still reproduce using spores.

Plants with Seeds

• Seeds allow sexual reproduction without water for gamete transfer.
• Seeds contain an embryo, food supply, and waterproof coat.
• Gymnosperms produce "naked seeds' such as pine cones.
• Angiosperms are flowering plants with seeds protected in fruit, attracting animals for seed dispersal.

Monocots and Dicots

• Two classes of angiosperms, differing in seed leaf number.
• Monocots have one seed leaf, dicots have two.
• Angiosperms share plant parts but differ in organization, affecting root, stem, and leaf structure.
• Roots and stems differ due to vascular bundle patterns.

Vascular Bundles

• Xylem and phloem are the two vessel types in vascular bundles.
• Xylem carries water and minerals from roots to stems, leaves, and flowers.
• Phloem carries sugars between plant cells.

Xylem

• Xylem transports water and is formed from dead tracheid cells.
• Water enters roots from the soil through osmosis.
• Water evaporates from leaves through transpiration.

Phloem

• Phloem is formed from living sieve tube elements.
• Sugar dissolved in water moves up and down the plant via translocation.

Monocot Characteristics

• Fibrous, networked roots.
• One seed leaf.
• Scattered vascular tissue.
• Parallel leaf veins.
• Flower parts in multiples of three.

Dicot Characteristics

• Taproots, like dandelions.
• Two seed leaves.
• Vascular tissue in an outer ring.
• Network of leaf veins.
• Flower petals in multiples of four or five.

Root Functions

• Anchor the plant.
• Absorb water and minerals.
• Protect the soil from erosion.
• Transport water through xylem.

Root Structure: Zones

• Zone of maturation: cells differentiate into specialized types.
• Zone of elongation: promotes deeper root penetration.
• Meristematic region: rapid mitosis of undifferentiated cells.
• Root cap: protects the meristematic region.

Water and Nutrient Absorption

• Root hairs extend from the epidermis, increasing surface area.
• Water enters from the soil by osmosis, flowing through the xylem.
• Nutrients like nitrates, phosphates, potassium, and magnesium dissolve in water and enter the roots.

Stems

• Annual plants have green stems, growing from seeds yearly.
• Perennial plants have woody stems, like trees and shrubs

Stem Functions

• Support leaves for light exposure.
• Transport water and minerals via xylem.
• Transport sugar via phloem.
• Specialized functions: Stolons (strawberries) for asexual reproduction; Rhizomes (irises) with underground stem buds for asexual reproduction; Tubers (potatoes) for starch storage.

Leaf Functions

• Trap light for photosynthesis, producing glucose.
• Exchange gases (CO2 and O2).
• Water loss by transpiration aids water uptake from roots.
• Provide food, shade, habitat, and oxygen for organisms.

Deciduous vs. Needles

• Deciduous leaves are wide, capturing more light, and flat, increasing surface area for gas exchange.
• Needles have a thick, waxy coating to save water, can photosynthesize all year, have low wind resistance, and survive ice and snow.

Leaf Structure

• Cuticle: A waxy layer that protects the leaf and reduces water and gas loss.
• Epidermis: Provides support, is transparent for sunlight, the lower epidermis has stomata and guard cells.
• Palisade cells: Located under the upper epidermis, contains chloroplasts, is the site of photosynthesis.

Stomata

• Found on the leaf's underside, opening and closing according to CO2 needs for photosynthesis and water conservation.
• Designed for gas exchange (CO2 in, O2 out).

Spongy Mesophyll

• Loosely packed cells near the leaf's bottom with large air spaces for gas diffusion.
• Water vapor moves into these spaces and exits through stomata via transpiration.

Vascular Bundles

• Xylem and phloem are found in leaf veins.
• Xylem carries water and minerals to cells, and phloem carries glucose to other plant cells.

Explore plant adaptations to land, focusing on vascular and non-vascular plants. Discover how vascular systems enable taller growth and efficient transport, contrasting with the limitations of non-vascular plants that rely on osmosis and diffusion.