Post on 29-Dec-2015
Plant SciencePlant ScienceCSES 1203CSES 1203
Dr. SkulmanDr. Skulman
Week IWeek I
Seed GerminationSeed Germination
Seed GerminationSeed Germination
Is germination the beginning of a plant’s life Is germination the beginning of a plant’s life cycle or the end or is it both beginning and end?cycle or the end or is it both beginning and end?
Annual seed bearing plants do the following Annual seed bearing plants do the following things according to the calendar:things according to the calendar: SpringSpring-seed is planted, germination follows,-seed is planted, germination follows, SummerSummer-plants grow, flower, and form seed,-plants grow, flower, and form seed, FallFall-seed ripens, is harvested or falls from plant,-seed ripens, is harvested or falls from plant, WinterWinter-seed is dormant or in storage,-seed is dormant or in storage, SpringSpring-seed is planted, yearly cycle is complete.-seed is planted, yearly cycle is complete.
TaxonomyTaxonomy
KingdomKingdom-All plants (500,000 species)-All plants (500,000 species)DivisionDivision-Seed producers (spermatophyta), -Seed producers (spermatophyta),
and non-seed producers and non-seed producers ClassesClasses : :
** gymnosperm (naked gymnosperm (naked seed)seed)** angiospermangiosperm (seed (seed produced produced in in an ovary) normal an ovary) normal flower.flower.
We will examine angiosperm germinationWe will examine angiosperm germination
Requirements for germinationRequirements for germination
Proper temperatureProper temperature, varies by species, varies by species WaterWater OxygenOxygen LightLight (not for all species, some grasses) (not for all species, some grasses)
Seed dormancySeed dormancy
Resting period for seed between harvest Resting period for seed between harvest and plantingand planting
Can last from several weeks to many Can last from several weeks to many yearsyears
Dormancy delays germination until Dormancy delays germination until conditions become favorableconditions become favorable Soybeans in ArkansasSoybeans in Arkansas
Harvested in Fall (followed by winter-unfavorable)Harvested in Fall (followed by winter-unfavorable) Planted in Spring (conditions now favorable)Planted in Spring (conditions now favorable)
Role of water in germinationRole of water in germination
Water absorbed by seed from soilWater absorbed by seed from soil Water causes seed to swellWater causes seed to swell Releases hormones in seedReleases hormones in seed Hormones stimulate enzymes to break Hormones stimulate enzymes to break
down down stored starchstored starch to to glucoseglucose (C (C66HH12120066))
Glucose is a simple plant sugar that is Glucose is a simple plant sugar that is used to provide energy for germinationused to provide energy for germination
Roles of Temperature and Oxygen Roles of Temperature and Oxygen in Germinationin Germination
OxygenOxygen- all living cells require oxygen for - all living cells require oxygen for respiration; plant cells of root, stem and respiration; plant cells of root, stem and leaves are actively growingleaves are actively growing
TemperatureTemperature- physiological reactions - physiological reactions within plants are influenced by within plants are influenced by temperature; too high or too low stops temperature; too high or too low stops reactions in plantsreactions in plants
Moncots and dicotsMoncots and dicots
Dicots:Dicots: Examples, oak trees, beans, clover, shrubsExamples, oak trees, beans, clover, shrubs Leaves have netted venationLeaves have netted venation Taproot systemTaproot system
MonocotsMonocots:: Examples-corn, grass, wheat, rice, cattailsExamples-corn, grass, wheat, rice, cattails Long, slender leaves with parallel veinsLong, slender leaves with parallel veins Fibrous root systemFibrous root system
Class Seed Germination Discussion Questions: 1. As a farmer, why would you want seed to germinate all at the same time?
2. Why do farmers/gardeners till their land before planting seed?
3. In the spring some farmers will apply herbicides to the soil for weed control. Why would extended herbicidal activity be an advantage?
2. Barley grain is used to make beer and wiskey. However, the grain cannot be useddirectly, but must first be modified. What is this “modification”?
Malting – a process where the grain is initially germinated and then oven dried to different stages of color.