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- Indehiscent

• Dry Fruits That Do Not Split at Maturity (Indehiscent)

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Fruits - Indehiscent

• Achene- a single-seeded in which the is attached to the pericarp only at its base

• The pericarp, the , is easily separated from the seed.

• Ex. Sunflower, dandelion Fruits - Indehiscent

• Nut- achene variation- one seeded, dry fruit with a hard, thick pericarp; develops with a cup or cluster of at base

• Ex- , , Fruits - Indehiscent

• Grain ()- a dry fruit in which the pericarp is tightly fused to the seed

• Ex- corn, , Fruits - Indehiscent

• Samara- a dry fruit whose pericarp extends around the seed in the form of a wing

• Ex. , ash Fruits - Indehiscent

• Schizocarp- a twin fruit that separates at maturity into two one-seeded fruitlets

• Ex- , , Fruits

• Aggregate Fruits- derived from a single with several to many pistils

• Individual pistils mature as a clustered unit on a single

• Ex- raspberries,

Fruit

- derived from several to many individual in a single

• Ex. Pineapple, fig, Osage orange, mulberries Fruit and

• Wind Dispersal

 Small and Lightweight .

 May have attachments like wings or hairs to help give them lift.

 Example- maple, ash, dandelion

• Animal Dispersal

 Seeds can pass through an animal’s digestive tract.

 Some fruits and seeds have spines or thorns that catch in fur or feathers.

 Oils attract . Fruit and Seed Dispersal

• Water Dispersal

 Some fruits contain trapped air.

 Some have a waxy coating.

 Both means help the seed to float.

 Example-

• Mechanical Ejection of Seeds

 Capsules dry and split in a way that flings the seeds far from the parent .

 Example witch How Seeds Form

is the transfer of from an anther to a .

• This may occur by wind or pollinating insects, or other animals.

• Wind pollinated flowers usually lack showy floral parts and since they don’t need to attract a .

• Their non-showy flowers, however, do produce a lot of pollen to increase the likelihood that a pollen grain will land on a receptive stigma. Corn- pollinated by wind How Seeds Form

• Brightly colored flowers, those with distinct markings or patterns on , containing fragrance or nectar, are most likely pollinated by insects, birds, or other animals. Birds, Butterflies, and Bats How Seeds Form

• The surface of the stigma contains a chemical which activates the pollen, causing it to grow a long tube down the inside of the style to the inside the .

• Fertilization is the union of the male sperm nucleus from the pollen grain and the female found in the ovary.

• If fertilization is successful, the will develop into a seed. How Seeds Form

• Self-pollinating are capable of fertilizing themselves. That is, pollen from a single plant unites with an egg on the same plant.

• In some plants, self-pollination may take place before the flower even opens.

• In others, complex floral structure decrease the probability that pollen from another plant will reach the ovule. How Seeds Form

• Cross-pollination occurs when pollen from one plant fertilized the ovule of a genetically different plant.

• The surface of the stigma of self- incompatible plants recognized its own pollen and prevents it from , or causes the pollen to grow so slowly that it is not likely to reach the ovule before another pollen grain fertilized the ovule. How Seeds Form

• Many fruit require cross-pollination for fruit development. How Seeds Form

• Structure

- storage organs that function as first seed .

 Plumule - .

- Stem above .

- Stem below attachment point.

- Stem tip developing into a .

Germination

• Germination is the beginning or resumption of seed growth.

 Seed must be viable.

 Some require period of .

 Scarification

- After Ripening

 Favorable Environmental Factors

- Imbibe water Germination of Dicot Seeds- ex.

• 1. The radicle begins to grow and emerges from the seed to form the first root, called the primary root. • 2. The hypocotyl elongates, pushing its way out of the seed and above the soil. • 3. Below the soil, secondary begin to branch off of the primary root. • 4. When the hypocotyl emerges into the , it straightens out and the epicotyl becomes visible, revealing a pair of true leaves and the apical of the plant. • 5. The leaves expand and begin to do . Germination of Monocot Seed- ex. corn

• 1. The radicle grows first, piercing the kernel and growing downward into the soil to form the primary root. • 2. The primary of the shoot grows upward, pushing its way out of the kernel and the soil. • 3. Once the primary leaf reaches the light, it pushes through the and begins to expand. • 4. Under the soil, lateral roots begin to develop from the primary root. • 5. In corn and other monocots, adventitious roots called prop roots also develop from the stem and push their way into the soil. How Seeds Grow

• Viability of most seeds is significantly extended when the seeds are stored under conditions of low temperatures and kept dry.

 A few species produce seeds with no period of dormancy.

- Vivipary How Seeds Grow

• Viviparous plants produce seeds that germinate before they detach from the parent.

• In many , the germinates and grows under its own energy while still attached to its parent.

• Some drop into the water and are dispersed by currents, but others develop a heavy straight taproot that commonly penetrates mud when the seedling drops, thereby effectively planting the seedling. How Seeds Grow Poa alpina, a grass which shows vivipary: the seeds germinate while still Red seeds germinate attached to the mother plant. while still on the parent .