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2 main kinds of fruit: dry vs. fleshy Figure 38.9 Classification of Fleshy Fruits

One carpel / one flower Many flowers Many carpels / one flower

Figure 38.9 Classification of Fleshy Fruits

There are 3 main kinds of simple fruits…

Berry: All parts of pericarp are fleshy/pulpy except for exocarp (skin)

This grape is a berry.

Berry: All parts of pericarp are fleshy/pulpy except for exocarp (skin)

A pepo is a berry with a thick, inseparable rind.

Berry: All parts of pericarp are fleshy/pulpy except for exocarp (skin)

A hesperidium is a berry with a leathery, separable rind.

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Drupe (stone fruit): Usually one-seeded with a stony endocarp, fleshy mesocarp, and a thin and skin-like exocarp . Pome: develops from flower with inferior ovary and compound pistil.

Receptacle / floral tube becomes major fleshy part of the fruit.

From receptacle

Outer limit of pericarp

Dry fruits: dehiscent vs. indehiscent. Dehiscent fruits split open at maturity

Indehiscent fruits do not split open at maturity

Fruit and Seed dispersal •  Fruits protect seeds during development and

sometimes aid in their dispersal •  Fleshy fruits or seeds are adapted to animal

dispersal •  Dry fruits can be adapted to air or water dispersal,

animal dispersal, or to release the seeds at maturity •  Seeds themselves often have their own dispersal-

adapted morphology, and adaptations for survival and germination

Dry fruits: dehiscent vs. indehiscent. Dehiscent fruits split open at maturity

Indehiscent fruits do not split open at maturity

Fruit adaptations that enhance seed dispersal: Red berries are animal dispersed, while dandelion fruits are wind-dispersed (right).

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Dandelion fruit dispersal via wind Figure 30.x2 A bird eating berries containing seeds that will be dispersed later with the animal's feces.

Some fruits, such as these burrs, hitch a ride on the fur of animals

The seeds of many plants have elaiosomes—fleshy attachments which attract ants. Ants carry the seeds back to their nests, eat the elaiosome, and often discard the seed. (One example is our native wild ginger, Asarum caudatum)

Don’t forget: many plants also reproduce asexually. Two examples: the maternity plant (Kalanchoe, left), aspen (Populus) groves (right) Seed adaptations for survival and

germination •  Many seeds exhibit dormancy, a temporary condition of

low metabolism and no growth or development. Some seeds can survive like this for decades or more. What are the potential benefits of dormancy?

•  Dormancy in some seeds is simply broken by favorable environmental conditions, but others only germinate after specific cues

•  What would you expect the cues to be for seeds living in deserts, fire-prone habitats (such as California chaparral), or at high latitudes? How about for seeds borne in berries eaten by mammals?

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Figure 38. 8 Review: Three types of seed structure Figure 38. 8 Review: Three types of seed structure

Figure 38. 8 Review: Three types of seed structure The four steps of seed germination: 1. imbibition of water, 2. enzyme digestion of stored food, 3. embryo begins growth and radicle is pushed through the seed coat, and 4. shoot tip grows toward soil surface.

Germination of a barley seed is shown below.

Figure 38.10 Two ways that young shoots break through the soil surface. Figure 38.7 The development of a dicot plant embryo

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Figure 38.7 The development of a dicot plant embryo Figure 38.7 The development of a dicot plant embryo

Figure 38.7 The development of a dicot plant embryo