Plant Reproduction

Introduction

• A flower has a set of adaptations– Petals have modified leaves– Entire flower is a highly modified branch

• Flower shape, scent, color attracts insects, thereby ensuring the reproduction of the plant

Flower

• Function– To produce seeds for reproduction

Terminology

• Whorl– Arrangement of three or more leaves,

petals, or other organs radiating from the plant

• Non-essential flower parts – Not directly involved in reproduction

• Essential flower parts– Directly involved in reproduction

Parts of the Flower

• Receptacle– Base of the flower

Parts of the Flower

• Sepals– Non-essential parts of the flower– Compose the first whorl– Collectively

known as the calyx

Parts of the Flower

• Petals– Non-essential parts of the flower

• Compose the second whorl• Collectively known as the corolla

Parts of the Flower

• Stamen– Essential flower parts

• Compose the third whorl• Male reproductive organ

–Anther : Produces pollen (contains sperm cells)

–Filament : Supports the anther

Parts of the Flower

• Carpels– Essential flower parts– Compose the last, fourth whorl– Usually fused to make a single pistil– Female reproductive organ

Carpels vs. Pistils

• (A) shows a single pistil consisting of several fused carpels

• (B) shows several pistils, each consisting of a single carpel

Parts of the flower

• Female reproductive organ– Ovary : Swollen base of the pistil (contains

ovules, which contain egg cells)– Style: Stalk of the pistil– Stigma: Tip of the pistil, sticky to capture falling

pollen

Types of Flowers

• Perfect– Has both pistils and

stamens in the same flower– Have all 4 whorls of modified leaves

• Imperfect– Has either pistil or stamens in the same flower– Missing one or more flower parts – Two types

• Monoecious• Dioecious

Imperfect Flowers

• Monoecious– “Same house”– Separate male and female flowers on the

same plant– Example

• Corn

Imperfect Flowers

• Dioecious– “Two houses”– Flowers are all male or all female on the

same plant– Example

• Ginko tree–Most are male–Female produces seeds with foul odor