Fruits, seeds and germination

Embryo forms from upper part of the zygote

Fig. 31.7a-d, p. 536

Globular stage

Heart -shapped stage

vacuole

nucleus

Single celled zygote

Capsella

Fig. 31.7e -g, p. 536

embryo’s shoot tip

EMBRYO SPOROPHYTE

embryo’s root tip

cotyledon

cotyledon

endosperm

mature embryo within ovule

A fruit (mature ovary) cut open to show seeds (mature ovules).

seed coat

Triploid (3n) tissue provides for rapid production of nutrients and growth hormones for the developing embryo

Three types of seed

Dicot: Endosperm is used in formation of cotyledons during seed formation

Dicot: Endosperm remains as a food source in the seed for use at germination

Monocot: Endosperm is a food source in the seed for use at germination

•The purple structures are starch grains. •What is this tissue stained with?

http://www.uri.edu/artsci/bio/plant_anatomy/images.html#lab_1

Storage parenchyma in bean cotyledon

Cross section of the seed coat of a bean

Macrosclereids: column shaped, longer than wideOsteosclereids: bone shaped, elongated with swollen ends

Macrosclereids

Osteosclereids

Correspondence between flower and fruit in the pea plant

Stigma Seed

Ovule

Pericarp

Ovary wall

Sepal

Types of Fleshy FruitsSimple

Aggregate

Multiple

Single ovary of one flower

Many ovaries of one flower

Many ovaries of many flowers

Pineapple Festival" ©Ann Cecil

1) Hydration (or imbibition) - Seeds must take up water. A seed will absorb water only if the seed coat and / or other coverings are permeable. Water is absorbed by osmosis, driven by the existence / buildup of high solute concentration in the seed cells.

Germination involves 4 major processes:

4) Carbohydrate, fat and protein reserves in the cotyledons

or endosperm are mobilized to support the renewed development of the embryo.

3) Enzyme activation - soon after seed hydration, respiratory enzymes are activated, and food reserves, such as starch, are metabolized to produce the fuel (mostly ATP) for synthesis of other enzymes needed for such growth.

2) Breaking dormancy which initiates metabolism.

Nutrient mobilization during germination of barley seed

The embryo releases hormones called gibberellins as signals to the aleurone, the thin outer layer of the endosperm. The aleurone synthesizes and secretes enzymes that hydrolyze starch

Maltose

Hordeum vulgare L

Adding water, the steeping process, is to start germination. Germination is activated when moisture levels in the barley (12 - 13%) are brought up to 43 - 45%. The steeped barley requires periods of rest and aeration in order to

provide adequate oxygen for germination. Steep cycles last approximately 44 hours.

Steeping

After settling, the wort is cooled, then pumped into fermentation tanks where yeast is added. The yeast uses the sugar in the wort to create alcohol and carbon dioxide.  

A mash of water and malted barley is heated, activating enzymes naturally present in the malted barley, causing it to convert starch into sugar which the brewing yeast can later ferment.

The mash is pumped into a brewing vessel where barley husks are filtered out. When the sugary water, "wort" has completely dripped through the husks, absorbing their flavour, the husks are removed and the boil begins. (Husks are sold as cattle feed.)

The boil is where the unique hop flavour is added. Varying the type and quantity of hops is what gives each beer its particular flavour and aroma.

Brewing

“Michelob ULTRA, the latest brand from Anheuser-Busch, is a smooth, refreshing lager with 95 calories, 4.2 percent alcohol by volume and 2.6 grams of carbohydrates per 12-oz. serving.”

“The special choice of grains, combined with the extended mash process, produces a smooth, refreshing beer with fewer carbohydrates”

“Michelob ULTRA is brewed using the finest pale two-row and Munich six-row barley, select grains, all-imported hops and a pure cultured yeast strain.”