Angiosperms Two Groupings: Monocot and Dicot Based off: Morphological characteristics DNA analysis

How does a plant flower? Light Controlled  photoperiodism (is the plants response to light.) Plants response to light involving relative lengths of day/night Controls flowering Happens in conjunction with availability of pollinators and necessary resources

Plant Type Flowering and Light Examples Long-day plants Bloom when days are longest and nights shortest (midsummer) Radishes, spinach, and lettuce Short-day plants Bloom in spring, late summer, and autumn when days are shorter Poinsettias, chrysanthemums, and asters Day-neutral plants Flower without regard to day length Roses, dandelions, and tomatoes Night length is controlling factor

Plants time dark period Inactive (Pr) Active (Pfr) Phytochrome red Pr Pr DAY TIME 660 nm 730 nm Slow conversion Pfr Rapid conversion Pfr Phytochrome Far-red Plants time dark period Pfr Promoter for long-day plants Activates specific genes in shoot apex Inhibitor for short-day plants Changes DNA transcription (gene expression)-allowing plants to produce flowers.

Methods for controlling flowering: Controlled greenhouses Covering plants for appropriate time periods

Animal Pollinated Flower Stigma: Sticky top of carpel on which pollen lands Anther: Part of stamen which produces the make sex cells, pollen Style: Structure of the carpel that supports the stigma Ovule: Base of carpel in which the female sex cells develop Filament: Stalk of stamen that holds up the anther The entire female part is called the “carpel”. The entire male part is called the “stamen”. Sepal: Protect the developing flower while in the bud Petal: Often are colorful to attract pollinators Receptacle

Complete vs Incomplete Flowers Complete: has all 4 basic parts: sepal, petals carpel, and stamen. Incomplete: lacks one of the 4 basic parts Staminate flowers: only have stamens and no carpels Carpellate flowers: only have carpels

Pollination Pollen Movement: wind/animal vector/water Coevolution of insects and flowers Flower colors: Red- conspicuous to birds Yellow and orange- noticed by bees Scented: can be located at night. Attraction: color/smell 2 types: Self-pollination: same plant pollination  less genetic variance Cross-pollination: pollen from one plant goes to stigma of another  increases variation Problem: harder to pollinate  travelling pollen

Fertilization 1. Pollen germinates to produce pollen tube 2. Pollen tube grows down style

3. Within pollen tube is the nucleus that will produce the sperm. 5. 2 sperm moves into ovule 4. Pollen tube attaches to ovary opening 1 – fertilizes egg  zygote 2 – fertilizes 2 polar nuclei  endosperm  cotyledon

Plants have 2 different generation cycles. Gametophyte generation- which is haploid Produces the plant gametes by mitosis Sporophyte generation- which is diploid Produces spores by meiosis. These generations alternate with each other.

Internal Structure of Seeds Hypocotyl: separate root from shoot Testa: Tough, protective outer coat Embryonic shoot and root: Become the new plant when germination occurs Cotyledon: Seed leaves that function as nutrient storage structures Micropyle: Scar of the opening where the pollen tube entered the ovule Seed maturation: Dehydration (10-15% of weight) Dormancy period (variable)

Conditions needed for germination: 1. Water – rehydrate the dried seed tissues 2. Oxygen – aerobic respiration to produce ATP 3. Appropriate temperature - enzyme action 4. Other specific conditions No light needed

Germination: Absorb water to rehydrate the seed Release gibberellin (gibberelic acid) Plant Hormone Produces Amylase- caused by the release of gibberellin Hydrolyzes Maltose into glucose, which can be used in cellular respiration Cell respiration Further hydrolyzed into glucose Converted into cellulose-so that the cell walls may be produced.

Pollination vs fertilization They are 2 very different things!!! Pollination- is the process by which pollen is places on the female stigma. Fertilization-happens when the male and female sex cells unite to form a diploid zygote.

Next Class Quiz 9.4 Review Plant dissection  possibility Start seed germination EXAM TUESDAY!!!