3. A thick protective coat (the seed integument) formed from the megasporangium.
4. Some seeds are modified to aid in their dispersal. For example, pine seeds possess papery wings that catch in air currents and help to disperse the new generation.
1. The single fertilization produces the diploid embryo.
2. The food source is the haploid megagametophyte.
C. Flowering plant seeds
1. Double fertilization produces both the diploid embryo and the triploid endosperm
food source (see Lecture 20-Flowering plants).
2. Two classes based on number of cotyledons (modified seed leaves):
i. primary food source fleshy food-storing cotyledons which have absorbed
ii. example: bean
D. Most important family of seeds used for food: bean or pea family
1. Seeds of bean or pea family high in protein and oil
E. Many seeds pressed for oil: sunflower, sesame, peanut, soybean
II. The fruit
III. Types of dispersal
B. Wind dispersal
C. Water dispersal - air spaces and corky floats- example:
with fibrous husk
D. Dispersal by animals
IV. Types of fruits
B. Aggregate fruit develops from one flower with many ovaries
C. Multiple fruit- develops from ovaries of several flowers borne together on same stalk (ex- pineapple)
D. Accessory fruit- fruit in which the edible part is primarily tissue other than ovary tissue
(ex- apple and strawberry - edible flesh from the receptacle)
V. Illustrations of various fruits and fruit types (from Texas A&M):