Botany Quiz: Growth Stages of Bean and Corn Plants

Sexual Reproduction in Flowering Plants

• Sexual reproduction in plants involves the fusion of gametes, forming seeds and fruits.
• Flowers are the reproductive structures of plants.
• Flower parts include petals, sepals, stamen, and pistil (carpel).
• Petals attract pollinators; sepals protect the flower bud.

Pollination

• Pollination is the transfer of pollen from the anther to the stigma.
• Types include self-pollination (within the same flower) and cross-pollination (between different flowers).
• Cross-pollination increases genetic diversity and adaptation to changing environments.
• Agents of pollination include wind, water, insects, birds, and other small animals.

Wind-Pollinated Flowers

• Small, inconspicuous petals or no petals.
• No scent or nectar.
• Large quantities of light, dry pollen.
• Long filaments and large anthers for wind dispersal.
• Large, feathery stigmas to catch pollen.

Insect-Pollinated Flowers

• Large, brightly colored petals (to attract insects).
• Often scented and/or produce nectar to attract insects.
• Smaller quantities of rough or sticky pollen that adheres to insects.
• Stiff filaments and anthers inside the flower.
• Small, stiff, sticky stigmas to capture pollen from insects.

Fertilization

• After pollination, the male gamete reaches the female gamete for fertilization.
• A pollen grain lands on the stigma and develops a pollen tube.
• The tube grows, carrying the male gamete through the style to the ovary.
• The male gamete fuses with the female gamete to form a zygote.
• Each ovule develops into a seed.
• The ovary wall develops into the fruit.
• The fruit protects and helps disperse the seeds.

Seed Formation

• Zygote develops into an embryo.
• Ovule transforms into the seed, with a seed coat (testa).
• Embryo develops from a young shoot (plumule), radicle (root), and cotyledons (food stores).
• Parts of a seed include the embryo, cotyledons, and seed coat.

Fruit Formation

• Ovary develops into fruit, forming pericarp (fruit wall).
• Types of fruits include true fruits (develop from ovary only) and false fruits (develop from other flower parts).
• Functions of fruits include seed protection and dispersal.

Seed Dispersal

• Seeds must be spread from the parent plant.
• Methods include wind, water, and animal dispersal.
• Wind-dispersed seeds are light and have wings or feathery structures.
• Water-dispersed seeds float.
• Animal-dispersed seeds are in fleshy fruits or have hooks or barbs.
• Mechanical dispersal involves fruits that burst open.

Germination

• Germination needs water, oxygen, and suitable temperature for seeds to sprout.
• Water softens the seed coat and activates enzymes.
• Oxygen is needed for respiration.
• Suitable temperature activates enzymes.

Growth Patterns in Plants

• Three main conditions for seed germination are water, oxygen, and suitable temperature.
• Annual plants complete their life cycle in one season.
• Beans (dicots) and corn (monocots) have different growth patterns.
• Bean: epigeal germination (cotyledons above ground).
• Corn: hypogeal germination (cotyledons below ground).
• Stages of growth after germination include seedling, vegetative, flowering, and fruit formation.