Flower Structure

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Flower Structure

• Jason Gehrke
• 2014C, 2014D, 2022D

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4 Influential Factors

• Plant Hormones
• Daylength
• Nitrogen
• Temperature

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Plant hormones

• Trigger the conversion of the meristem from
  vegetative to floral
• Initiates formation of new parts
• Petals
• Sepals
• Stamen
• Pistils

• http//waynesword.palomar.edu/trmar98.htm

4
Complete/Incomplete Flowers

• Complete Flowers
• Contain four principal parts
• Sepals
• Petals
• Stamen
• Pistil
• Incomplete Flowers
• Missing one of the four principal parts

5
Daylength

• Length of night will initiate flowering
• Two types of lengths
• Long
• Short

• http//waynesword.palomar.edu/trmar98.htm

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Long Day Plants

• Plants flower with decrease in night length
• Days get longer
• Examples
• Wheat
• Oats
• barley

• http//news.minnesota.publicradio.org/features/200
  3/04/24_gundersond_gmwheat/

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Short Day Plants

• Plants flower with increase in night length
• Days get shorter
• Examples
• Soybeans
• Corn
• Sorghum

• http//www.tiscali.co.uk/reference/encyclopaedia/h
  utchinson/m0014425.html

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Calendar of Flowering
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Nitrogen

• Deficiency will cause poor flower formation

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Temperature

• High temperatures will kill flowers (wilt)
• Cold temperatures will also kill the flowers

• http//www.wiretapestry.com/photoalbum/2-1batch/de
  adflowers.jpg

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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

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Flower Structure

• Stamen- Male reproductive organs
• Anther- produces pollen
• Filament- stalk that holds anther to flower
• Pistil
• Stigma- Sticky top of pistil that receives pollen
• Style- tube connects stigma to ovary
• Ovary base of the pistil, holds the eggs

• http//waynesword.palomar.edu/trmar98.htm

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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/cor
  n3.htm

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Pollination

• http//www.biologie.uni-hamburg.de/b-online/e02/02
  d.htm
• Transfer of pollen from the anthers to the stamen

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Fertilization

• Union of the sperm and the egg
• Two sperm cells
• One to fertilize egg
• One to fertilize embryo