Plants - Unit 4

Plant diversity

Refers to the variety of plant species and their relative abundance within a specific ecosystem.

Bryophytes

No vascular tissue, reproduce by spores.

Pteridophytes

Vascular, reproduce by spores.

Gymnosperms

Vascular, seeds in cones.

Angiosperms

Vascular, seeds in fruits/flowers.

Monocots

One cotyledon, parallel veins.

Dicots

Two cotyledons, branching veins.

Roots

Absorb water/nutrients, anchor plant.

Taproot

A type of root (e.g., carrot).

Fibrous root

A type of root (e.g., grass).

Stems

Support + transport water/sugars.

Leaves

Photosynthesis + transpiration.

Dermal tissue

Outer layer, protection (e.g., epidermis).

Ground tissue

Photosynthesis, storage, support (e.g., mesophyll).

Xylem

Moves water up (transpiration pull, capillary action).

Phloem

Moves sugar both ways (translocation via pressure flow).

Meristems

Regions of plant growth.

Apical meristem

Grows in height.

Lateral meristem

Grows in width (cambium).

Asexual reproduction

Methods include runners, cuttings, bulbs.

Stamen

Male reproductive part (anther + filament).

Carpel/Pistil

Female reproductive part (stigma, style, ovary).

Pollination

Transfer of pollen to stigma.

Fertilization

Sperm + egg → seed.

Fruit

Developed from ovary, protects seeds.

Photosynthesis

O₂ production, carbon cycle.

Tropisms

A plant's growth in response to a stimulus, directional (toward or away).

Phototropism

Response to light (e.g., stem bends toward light).

Gravitropism

Response to gravity (roots grow down, shoots grow up).

Nastic movement

A reversible movement in response to a stimulus, regardless of direction.

Circumnutation

The circular or helical movement of a growing plant tip.