Plants
Characteristics:-multicellular/ eukaryotic
-cell walls made of cellulose
-autotrophic (carry out photosynthesis by
use of chlorophyll)
Types of Response: -Tropisms: Movement toward or away from environmental stimuli (ex. Light or Gravity)
-Phototropism: response to light / Stems move toward light- positive phototropism. Roots move away from light- negative phototropism. (meristem: cells that elongate to allow the plant to bend toward sunlight)
-Geotropism: (Gravitropism) allows plants to grow toward or away from the pull of gravity. Positive geotropism growth downward/ Negative geotropism growth upward
-Thigmotropism: where plant parts move in response to touch (ex. Mimosa plant/ Venus fly trap/ vines)
Cells: -meristem: cells that elongate to allow the plant to bend toward sunlight
-guard cells: cells that regulate the size of the stoma
-Stoma: tiny pore in the epidermis of a leaf. Used for gas exchange.
Terms:
-Auxins: Plant hormone that makes roots form and buds grow.
-Germinate: to sprout or grow.
-Tap root: root that grows down (carrot)
-Transpiration: Plants releasing water vapor through its stomata in the leaves.
-Turgor pressure: the pressure inside a cell that is exerted against the cell wall by water.
Plant life cycles have two alternating phases, a diplod (2N) phase and a hyploid (N) phase, known as Alternation of Generations. It’s a reproductive cycle where one generation of offspring arises from spores. (mitosis and meiosis alternate to produce the two types of reproductive cells- Gametes and Spores) pap p.552/ biology p.562
-Diploid Phase (2N)- The Sporophyte (spore-producing plant)
-Haploid Phase (N)- The Gametophyte (gamete-producing plant)
Botanists divide the plant kingdom into four groups based on three important features:
- water conducting tissue
- seeds
- flowers
Seedless Nonvascular p. 565- 566
Bryophytes/ Hepaticophyta/ Anthocerophyta: pap p.556
-Have life cycles that depend on water for reproduction.
-Lack vascular tissue which consists of a type of plant tissue
specialized to conduct water. Instead they absorb water by
osmosis.
Examples: mosses, liverworts, and hornworts
Seedless Vascular Plants:
Psilophyta/ Lycophta/ Arthrophyta/ Perophyta: pap p.561
-Have a transport system to conduct water and nutrients
throughout the plant. Biology p.566-567
Plant Vascular Tissue:
Xylem-a transport subsystem containing key cells called tracheids. This system carries water upward from the roots to every part of a plant. Tracheids are hollow cells with thick cell walls that resist pressure (example- drinking straw).
Phloem-transports solutions of nutrients and carbohydrates produced by photosynthesis down and stores them in the roots.
*Both move fluid through the plant, even against theforce of gravity.
example: club mosses, horsetails, ferns
Water transport:
Capillary action- the tendency of water to rise in a thin
tube. The thinner the tube the higher the water will rise.
Ability of water molecules to stick to one another and to the walls of a tube. (Cohesion and Adhesion)
Seed Bearing Vascular Plants:
-Divided into two groups: Gymnosperms and Angiosperms
Gymnosperms: (Cone Bearers)
-Reproduce with seeds that are exposed.
-Bear their seeds directly on the surfaces of cones.
-Include the conifers, such as pines and spruces, as well as palm-like plants called cycads, ancient ginkgoes, and the very weird gnetophytes
Angiosperms: (Flowering Plants)
-Also called flowering plants.
-Bear their seeds within a layer or tissue that protects
the seed. Example- Fruit
-Include grasses flowering trees and shrubs, and all
wildflowers and cultivated species of flowers
-Make up almost 90 % of all living species of plants
-Two classes with in angiosperms:
(named for the number of seed leaves, or cotyledons)
*Cotyledons-is the first leaf or the first pair of leaves produced by the embryo of a seed plant
-Monocots- include corn, wheat, lilies, orchids and palms.
-Dicots- include roses, clover, tomatoes, oaks and daisies.
-There are three categories of plant life spans:
-Annual- Life cycle within one growing season
-Biennial- Life cycle in two years
-Perennial- live for more than two years
Parts of a flower:-Stamen: male reproductive structures of a flower. Consist of the anther (produces pollen) and the filament (structure that supports the anther).
-Pistil/ Carpel: Female reproductive structures of a flower. Consists of the stigma (sticky end), style (supports the stigma), and the ovary (contains ovules/ female gamete)
-Petal: attracts pollinators/ colorful part of the flower.
-Sepal: Protects the flower bud (green leaf structures)
-Ovule: structure within the ovary of a plant contains reproductive cells and develops into seed after fertilization.