3.4 Plant Fertilization notes

• Pollen grain on stigma
• Pollen tube grows down to ovule
• Nucleus travels down tube to ovule and fertilize
• Outside of Ovule forms the seed coat
• Catelydons inside ovule (power pack/food storage)
• Thickening of the walls of ovary to make fruit

3.3b Wind Pollination

• Anther  stigma (by wind)
• Pollen grain adaptation-light weight, wing feature to move through air
• Exposed anther (exposed to the wind)
• Stigma with large surface area to catch pollen (feather like structure)
• In addition- no scent, no petals, no color,

3.3a Insect Pollination

• Pollination by insect
• Pollen (male nuclei) transferred to stigma of another flower
• Attraction of insect to the flower is needed
• Signals to the insect (scents, color petals)
• Value to insects (food nectarines/ pollen protein)

2.81 Photo tropism

• Phototropism= Light Growth Response
• Positive= Growth towards light
• Stem grows upwards
• But if light comes from the side the plant stem bends towards the light
• Plant hormone causes this

2.80 Geotropism

• Geotropic= Gravity growth response
• Root growing downwards= Positive Geotropism
• Root going upwards= Negative Geotropism

2.79 Plants and Stimuli

• Plants respond to stimuli
• Changes in the environment E.g. Temperature or Light
• Plants have receptors that detect stimuli and respond
• Response are growth (Tropism)
• Light= Phototropism Gravity=Geotropism

2.54 Transpiration

·        -Evaporation  of water from the surface of a plant

·         -Heat provided by sunlight

·         -Evaporation from the stomatole pores

·         -Phase change occurs in air space in the spongy layer

·         -Water vapor diffuses down the diffusion gradient and through the stomatole pore