Pollination and Fertilization In Angiosperms Pollination 1 Pollination

Pollination 1. Pollination. Where are pollen grains formed? In the anther sacs Where must

Types of Pollination 1. Self-Pollinationa. The transfer of pollen from the anther to the

Types of Pollination (cont…) 2. Cross- Pollination. What do you think cross-pollination is? a.

Agents of Pollination 1. Animalsa. Flowers usually have brightly colored petals/sepals What benefit is

Agents of Pollination (cont…) 3. Watera. Flowers have no attractive petals b. Pollen floats

Germination of the Pollen Grain 1. Sequence of Eventsa. Pollen grain lands on the

Fertilization ***In fertilization, 2 sperm nuclei enter the embryo sac through the micropyle. Double

Summary Describe four agents of pollination: Animal Wind Water Gravity Describe three types of

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Pollination and Fertilization (In Angiosperms)

Pollination 1. Pollination. Where are pollen grains formed? In the anther sacs Where must the pollen grains travel to on the angiosperm? To the stigma of the pistil ***Pollination is the transfer of pollen grains from the anther of the stamen, to the stigma of the pistil. Give me some examples of how this could occur? Birds, insects, wind

Types of Pollination 1. Self-Pollinationa. The transfer of pollen from the anther to the stigma of the same flower. (ex. - lily) b. The transfer of pollen from the anther to the stigma of another flower on the same individual plant. (ex. - corn) **Anthers mostly rise above the stigma

Types of Pollination (cont…) 2. Cross- Pollination. What do you think cross-pollination is? a. The transfer of pollen from the anther of one plant to the stigma on another plant. (ex. - spinach) b. This type of pollination is good for genetic variation 3. Artificial Pollination. What do you think artificial pollination is? a. The transfer of pollen by human beings (ex. - plant breeding)

Agents of Pollination 1. Animalsa. Flowers usually have brightly colored petals/sepals What benefit is this to the plant? It attracts the pollinators b. May give off aroma c. May produce nectar that pollinators use as food 2. Winda. Flowers are not showy, no nectar, no aroma If the pollen is to be transferred to the stigma by the wind, what should the weight of the pollen be? Very light b. Several lightweight pollen grains are formed c. Flowers have large stigmas WHY?

Agents of Pollination (cont…) 3. Watera. Flowers have no attractive petals b. Pollen floats and is transported by water Why would this type of plant not have brightly colored flowers? No need to attract a pollinator 4. Gravitya. In some cases of self-pollination

Germination of the Pollen Grain 1. Sequence of Eventsa. Pollen grain lands on the stigma b. Grain wall ruptures c. Tube cell nucleus---> creates and maintains development of the pollen tube (stigma-->style-->ovary) d. Generative cell nucleus---> undergoes mitosis in pollen tube to form 2 haploid sperm nuclei From the unit on Human Reproduction, what is the definition of fertilization? A sperm cell fuses with an egg cell But in angiosperms, there is double fertilization………….

Fertilization ***In fertilization, 2 sperm nuclei enter the embryo sac through the micropyle. Double Fertilization 1. 1 sperm nucleus + 1 egg cell----> 2 N zygote --->(mitosis)----> embryo 2. 1 sperm nucleus + 2 polar nuclei----> 3 N endosperm nucleus---> (mitosis)---> endosperm *Endosperm= tissue which stores food for developing embryo. 3. Hard seed coat is formed

Summary Describe four agents of pollination: Animal Wind Water Gravity Describe three types of pollination: Self Cross Artificial Explain why angiosperms have double fertilization.