Flower Structure
Jason Gehrke
2014C, 2014D, 2022D
4 Influential Factors

Plant Hormones
 Daylength
 Nitrogen
 Temperature
Plant hormones

Trigger the
conversion of the
meristem from
vegetative to floral
 Initiates formation of
new parts




http://waynesword.palomar.edu/trmar98.htm

Petals
Sepals
Stamen
Pistils
Complete/Incomplete Flowers

Complete Flowers

Contain four principal
parts
•
•
•
•

Sepals
Petals
Stamen
Pistil
Incomplete Flowers

Missing one of the four
principal parts
Daylength

Length of night will
initiate flowering
 Two types of lengths



http://waynesword.palomar.edu/trmar98.htm
Long
Short
Long Day Plants

Plants flower with
decrease in night
length
 Days get longer
 Examples



Wheat
Oats
barley

http://news.minnesota.publicradio.org/features/2003
/04/24_gundersond_gmwheat/
Short Day Plants

Plants flower with
increase in night
length
 Days get shorter
 Examples



Soybeans
Corn
Sorghum

http://www.tiscali.co.uk/reference/encyclopaedia/hut
chinson/m0014425.html
Calendar of Flowering
Nitrogen

Deficiency will cause
poor flower formation
Temperature

High temperatures
will kill flowers (wilt)
 Cold temperatures
will also kill the
flowers

http://www.wiretapestry.com/photoalbum/21batch/deadflowers.jpg
Flower Structure

Sepals- modified
leaves often green
and small
 Petals- large and
colorful, aid in
attracting insects and
other pollinators

http://waynesword.palomar.edu/trmar98.htm
Flower Structure

Stamen- Male
reproductive organs



Pistil




http://waynesword.palomar.edu/trmar98.htm
Anther- produces pollen
Filament- stalk that holds
anther to flower
Stigma- Sticky top of
pistil that receives pollen
Style- tube connects
stigma to ovary
Ovary base of the pistil,
holds the eggs
Corn Different from the Norm

Tassel- male floral
structure hold pollen
 Ear- female floral structure
 Silt- elongated styles to
catch pollen
Pictures to the right:
http://www.hort.purdue.edu/ext/senior/vegetabl/corn3.htm
Pollination

http://www.biologie.uni-hamburg.de/b-online/e02/02d.htm

Transfer of pollen from the anthers to the
stamen
Fertilization


Union of the sperm and the egg
Two sperm cells


One to fertilize egg
One to fertilize embryo