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 Petals Sepals Stamen Pistils

Complete/Incomplete Flowers  Complete Flowers Contain four principal parts Contain four principal parts SepalsSepals PetalsPetals StamenStamen PistilPistil  Incomplete Flowers Missing one of the four principal parts Missing one of the four principal parts

Daylength   Length of night will initiate flowering  Two types of lengths Long Short

Long Day Plants  Plants flower with decrease in night length  Days get longer  Examples Wheat Wheat Oats Oats barley barley  /04/24_gundersond_gmwheat/

Short Day Plants  Plants flower with increase in night length  Days get shorter  Examples Soybeans Soybeans Corn Corn Sorghum Sorghum  chinson/m 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  1batch/deadflowers.jpg

Flower Structure  Sepals- modified leaves often green and small  Petals- large and colorful, aid in attracting insects and other pollinators 

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

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:

Pollination   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