Plant reproduction

• What is the organ responsible for sexual reproduction in a plant?

  The flower
• What are the male and female gametes in plants?

  Male is pollen, female is ovule
• What is pollination?

  Transfer of pollen to the stigma
• What occurs during self-pollination?

  Pollen from the same plant fertilizes itself
• What is the only source of variation in self-pollination offspring?

  Mutation, independent assortment, and crossing over
• Why is self-pollination beneficial in stable environments?

  It ensures successful plants in stability
• How do plants prevent self-pollination?

  Chemical self-incompatibility and irregular structures
• What are the features of dicotyledonous, insect-pollinated flowers?

  • Colourful and scented corolla
  • Stigma collects pollen from insects
  • Petals are often striking
• What is cross-pollination?

  Pollen from one plant fertilizes another plant
• What contributes to variation in cross-pollination offspring?

  Meiosis, mutation, and genetic material from two parents
• Why are species more likely to survive environmental changes through cross-pollination?

  Due to genetic variation in offspring
• Where do pollen grains develop?

  In anthers
• What process occurs to produce a tetrad of haploid cells?

  Meiosis
• What happens to the haploid pollen grain after meiosis?

  Mitosis forms generative and tube nuclei
• What do ovules develop into after fertilization?

  Seeds
• What does the triploid endosperm develop into?

  Endosperm tissue for food storage
• What is the micropyle?

  A pore in the testa
• What are the conditions necessary for germination?

  Temperature, water, and oxygen
• What is the optimum temperature range for germination?

  1°C to 30°C
• Why is water important for germination?

  It makes cells turgid and mobilizes enzymes
• What happens during germination of a broad bean seed?

  Water enters, swelling the seed and splitting the testa
• What is the role of gibberellin in maize seed germination?

  It stimulates amylase production to break down starch
• What is the function of amylase in maize germination?

  To break down stored starch in the endosperm
• What are the stages of seed development after fertilization?

  • Ovule develops into a seed
  • Diploid zygote forms a diploid embryo
  • Triploid endosperm forms food storage tissue
  • Integuments develop into the testa
  • Micropyle becomes a pore in the testa
  • Ovary develops into a fruit wall
• What are the differences between broad bean and maize seed germination?

  Broad bean:

  • Non-endospermic seed
  • Water enters through micropyle
  • Starch and proteins mobilized from cotyledons

  
  

  Maize:

  • Endospermic seed
  • Gibberellin released to stimulate amylase
  • Starch broken down in endosperm