Biology – 328 Lab Plants and People

Objective To understand what a fruit is To study different parts of fruit To learn different types of fruits

Background

Different parts of a fruit Exocarp – Outermost layer Endocarp – Innermost layer Mesocarp – Middle layer Pericarp - All three layers not recognizable Rind - Thick leathery covering exocarp (eg, water melons) or fusion of exocarp and mesocarp (eg. Orange) Accessory fruit – Fruits not derived from ovary e.g. apple

Classification of fruits Simple fruit – Fruit from a single flower and single ovary Aggregate fruit – Fruit from a single flower but several ovaries eg. Blackberry, strawberry Multiple fruit – Fruit from multiple flowers in the same peduncle eg. Pineapple, Mulberry

Simple fruits Dry dehiscent fruit – Pericarp dries and splits open when ripe. Follicle – 1 locule that splits along one suture e.g. Sweet gum Legume/pod – 1 locule and splits along 2 sutures e.g. Beans Capsule – 3 or more locules and splits in 3 or more sutures e.g. Okra

Simple fruits Dry indehiscent fruit – Pericarp dries but does not split when ripe Samara – 1 or 2 seeded with pericarp flattened into wings e.g. maple Grain/Caryopsis – 1 seeded fruit with seed fused to pericarp e.g. corn Achene – 1 seeded fruit with seed free from pericarp e.g. sunflower Nut – 1 seeded fruit enclosed in husk e.g. Pecan

Simple fruits Fleshy fruit- Pericarp doesn't dry when ripe Berry – entire pericarp is fleshy e.g. Grape Pepo – Exocarp is a hard rind e.g. Melons Hesperidium – Exocarp and mesocarp is a hard rind, endocarp has juice vesicles e.g. Orange Drupe or stone – a single seeded fruit fuzzy or smooth skin, fleshy mesocarp and a hard stony endocarp e.g. Peach Pome – Fleshy receptacle, hypanthium with papery pericarp e.g. Apple

Today’s Lab Carefully examine the fruits, paying special attention to their morphology, structure, family and scientific name, and geographic origin. During the exercise, answer the following questions for each fruit observed. 1. What is the fruit type? 2. How many carpels are present? 3. How might they might be dispersed in nature.

Summary Today’s Lab Types of fruits and characteristics Next week’s lab – Major Families I Quiz on Fruits