Fruits, seeds, and soils exam 3

Fruit

a mature flower ovary containing plant embryos, remaining part of flower after it has been pollinated/fertilized. Fruit will produce future seed.

Argemone albiflora

white prickly poppy, petals fall off when pollinated, fruit splits open and seeds inside fall out

Seed

miniature plant surrounded by a protective covering called a seed coat, “a plant in a nutshell”

How is a seed alive

measured by its respiration rate, process that uses energy and burns sugars and emmits CO2 and water

What are the seeds of a maple tree (acer)

double winged samaras

Seed germination

embryo imbibes (soaks) water and begins to grow. Water moves into seed, primary root (radicle) emerges, cotyldons come above ground.

Process cotyldons play in seed germination

store sugars for the plant. they eventually shrivel up once all the food inside them is used up

Seed viability

the ability of a seed to germinate and grow normally (how much sugar is there to germinate and grow)

Seed longevity

how long a seed remains viable, they lose viability over time by respiring

Factors that affect seed longevity

species and storage conditions. Storing seeds in colder temperatures reduces respiration rate, so they will lose viability slower when placed in 20-30% relative humidity and 40 degrees F. Place them in the fridge!!

Seed longevities

most vegetable seeds: 2-4 yrs/annuals: 1-3 yrs/herbaceous perennials 2-4 yrs/ wood plants: varies from 1-10 yrs

The Nelumbo Lotus

seed that stayed viable for 1300 years! found at the bottom of a lake bed. after planting, the plants died because the DNA had a half life, DNA strands were destroyed, so seed could germinate but couldn’t sustain life

What is required for successful germination

media (soil) that contains oxygen and water, moisture, warmth, and light

How to let seeds germinate better

bringing seeds closer to surface will germinate them because the seed has access to light, put mulch to prevent weed seeds from popping up, don’t cultivate the soil because it brings weed seeds closer to the surface to germinate more

What is the order in which parts of a plant grow out of a seed

1. Radicle 2. Shoot 3. Leaves

Vivipary

latin for live birth, when seeds germinate IN the fruit. example: seeds growing inside tomato plant

“Come true from seed”

seeds will germinate into plants that look just like their parents. ex; species and variety

Cultivars

DO NOT come true from seed. will be genetically different from parent. ex: ‘Forest Pansy’ ‘Hearts of Gold’

Why propagate seeds

diversity (benefit environment/biodiversity and decrease monoculture), inexpensive, easy, fun

Types of dormancy in plant seeds

Physical and Physiological

Physical dormancy in seeds

seed coat is impervious to water (water can’t get in because of thick seed coat) if water could get in the seed could germinate, compromise seed coat so it will imbibe water. ex: redbud seeds

Physiological dormancy in seeds

biochemical dormancy; even though water can get in, seed WONT germinate. ex; maple seeds

How is physical dormancy in seeds broken in nature?

nature weathering, freezing/thawing, rain, animal digestion

Scarification

process of weakening seed coat to allow water to get in so seeds would germinate. compromised seed coat

Types of scarification

Mechanical (scrap seed against something), Hot water treatment (seeds in hot water for 24 hours, get water hot and then take off burner and let them sit), Sulfuric acid (DANGEROUS)

When do you scarify seeds

scarify in spring 1-2 days before planting

Stratification

form of breaking physiological dormancy, seeds exposed to 60-90 days in moist media (seeds in moistened bag of potting soil) at temps 31-41 F, then place in growing conditions for germination (fridge)

Direct stratification

put seeds in pots and then put in fridge, take out to germinate in outside conditions

Explain the process of temperature and moisture in relation to breaking physiological dormancy

seeds go from warm/dry to cold/moist to warm/moist

What potting mix should you buy

any potting mix is usually fine, stay away from “seed starting” potting mix; it’s a marketing scam

How to extract seeds from a Callicarpa americana (American beautyberry)

fruits turn red they are ready to be picked, collect fruit put in jar of water, shake jar, seeds will come out of fruit, collect seeds, refrigerate until spring then plant!

Callicarpa americana ‘Welch’s pink’

pink fruits, was incorrectly written as a cultivar when it is just a botanical variety, comes true from seed

Cornus florida 

native american dogwood, white flowers

Cornus kousa

edible red weird looking fruit, collect fruit and clean off pulp, stratify for 120 days

Quercus Alba (white oak)

keystone plant, host for caterpillars, collect acorns from it, the ones that float are not viable because they have more air than embryo. Cover seeds in wet paper towels and set outside, radical will emerge. When it goes dormant put in soil.

Buckeye

hummingbirds like red flowers, plant in fall after abscission