4.4.3 Fertilization and Seed Development

• What is the equation for fertilization in plants?

  $Male\ gamete +$$Female\ gamete \longrightarrow Zygote$
• During fertilization, male and female gametes fuse to form a single cell
• Pollen tube growth ensures the male gamete reaches the ovule for fertilization.
• Steps of pollen tube growth

  1️⃣ Pollen grain lands on the stigma

  2️⃣ Pollen tube forms and extends down the style

  3️⃣ Pollen tube carries male gametes to the ovary

  4️⃣ Fertilization occurs in the ovule
• Match the stage of pollen tube growth with its key event:

  Germination ↔️ Pollen grain hydrates and grows a tube

  Pollen tube extension ↔️ Tube grows through style

  Male gamete transport ↔️ Gametes travel within the tube

  Fertilization ↔️ Male and female gametes fuse
• Fertilization results in the formation of a zygote
• The pollen tube carries male gametes to the ovary.
• Steps of pollen tube growth

  1️⃣ Pollen grain lands on the stigma

  2️⃣ Pollen tube forms and extends down the style

  3️⃣ Pollen tube carries male gametes to the ovary

  4️⃣ Fertilization occurs in the ovule
• Match the structure with its role in sperm cell delivery:

  Stigma ↔️ Receives pollen grains

  Pollen Tube ↔️ Transports male gametes

  Ovule ↔️ Contains female gametes

  Male Gametes ↔️ Sperm cells for fertilization
• In angiosperms, double fertilization involves one male gamete fusing with the egg cell and another fusing with the two polar nuclei
• Double fertilization in angiosperms results in the formation of both the zygote and the endosperm.
• What is the equation for double fertilization in angiosperms?

  \text{Male Gamete } + \text{ Egg Cell } + \text{ Two Polar Nuclei } \longrightarrow \text{ Zygote } + \text{ Endosperm}</latex>
• Arrange the steps of pollen tube growth in the correct order.

  1️⃣ Pollen grain lands on the stigma and germinates

  2️⃣ Pollen tube forms and extends down the style

  3️⃣ Pollen tube carries male gametes to the ovary

  4️⃣ Fertilization occurs when male gamete fuses with the female gamete
• What structure transports male gametes to the ovary during pollen tube growth?

  Pollen tube
• During germination, the pollen grain hydrates and begins to grow a tube
• Fertilization in pollen tube growth results in the formation of a zygote.
• Match the structure with its role in sperm cell delivery.

  Stigma ↔️ Receives pollen grains

  Pollen Tube ↔️ Transports male gametes to the ovule

  Male Gametes ↔️ Fertilize egg cells

  Ovule ↔️ Contains female gametes
• What guides the pollen tube through the style during its extension?

  Chemical attractants
• Arrange the steps in the process of sperm cell delivery to the ovule.

  1️⃣ Pollen grain lands on the stigma

  2️⃣ Pollen tube forms and grows down the style

  3️⃣ Male gametes are transported within the pollen tube

  4️⃣ Fertilization occurs in the ovule
• What is formed when a male gamete fuses with a female gamete during fertilization?

  Zygote
• The stigma is responsible for transporting male gametes to the ovule.

  False
• Male gametes are responsible for fertilizing egg cells
• Match the double fertilization event with its outcome.

  Male Gamete + Egg Cell ↔️ Diploid Zygote

  Male Gamete + Two Polar Nuclei ↔️ Triploid Endosperm
• What is the ploidy of the zygote formed during double fertilization?

  Diploid
• What is the function of the endosperm in angiosperms?

  Provides nutrients
• Double fertilization in angiosperms results in the formation of a zygote and endosperm.
• Arrange the events of double fertilization in angiosperms in the correct order.

  1️⃣ Male gamete fuses with egg cell to form diploid zygote

  2️⃣ Male gamete fuses with two polar nuclei to form triploid endosperm
• What structure is formed from the fusion of a male gamete and two polar nuclei during double fertilization?

  Endosperm
• The endosperm in angiosperms is triploid.
• Match the double fertilization outcome with its ploidy.

  Zygote ↔️ Diploid

  Endosperm ↔️ Triploid
• The zygote formed during double fertilization has a ploidy of diploid
• What does the zygote develop into after double fertilization?

  Embryo
• Arrange the stages of embryo development in angiosperms in the correct order.

  1️⃣ Zygote

  2️⃣ Proembryo

  3️⃣ Globular Embryo

  4️⃣ Heart-shaped Embryo

  5️⃣ Torpedo Embryo

  6️⃣ Mature Embryo
• What is the final stage of embryo development in angiosperms?

  Mature embryo
• Mitosis is essential for the development of the embryo from the zygote.
• Arrange the developmental stages of the embryo in the correct sequence.

  1️⃣ Zygote

  2️⃣ Proembryo

  3️⃣ Globular Embryo

  4️⃣ Heart-shaped Embryo

  5️⃣ Torpedo Embryo

  6️⃣ Mature Embryo
• The zygote undergoes rapid mitosis and cell differentiation to form the embryo
• The globular embryo is characterized by its spherical cell mass
• Which stage marks the beginning of cotyledon development in the embryo?

  Heart-shaped Embryo
• The mature embryo is ready to germinate