HORT350 Exam 3:

What does a mature ovule (seed) contain?

Grafting Budding Scion Stock Interstock Graft Union Double working Incompatibility Vascular Cambium Callus Topworking Graft Incompatability Seed propagation Seedling myrmecochory: seed dispersal by ants

Elaisome: fleshy structures that are attached to seeds Microsporogenesis: pollen development

Tapetum: nutritive cell layer of a pollen cell Exine: outer pollen layer that provides protection Megasporogenesis: ovule development Histodifferentiation Recalcitrant Dehiscence Endogenous Exogenous Vivipary Apomixis Parthenocarpy

What is histodifferentiation?

What is a seed?

A sexual reproductive unit; end product of a process of growth and development within the parent plant

What does a mature ovule (seed) contain?

embryo

endosperm (storage tissue)

seed coat (protective outer covering) We also discuss several other topics like Who is maximilien robespierre?
We also discuss several other topics like What are the four main subdisciplines of general anthropology?

What are the 3 stages of seed development?

What are the stages of dicot embryo development?

1. histodifferentiation 2. cell expansion 3. maturation drying

What is histodifferentiation? The differentiation of embryo and endosperm through cell division, embryo reaches cotyledon stage, weight increases rapidly

What are the stages of dicot embryo development?

1. Proembryo 2. Globular 3. Heart 4. Torpedo 5. Cotyledon

(Diced Potatoes Gotta Hate To Cry)

What are the stages of monocot embryo development? Don't forget about the age old question of Define glycocalyx.

1. Proembryo 2. Globular

3. Scutellar 4. Coleoptilar

(Marlatt's Problem Got Super Crappy)

What happens during cell expansion? Accumulation of food reserves

During maturation drying, what occurs? the seed reaches physical maturation, loses lots of water and the vascular connection with the mother plant (funiculus) is lost leaving a scar on the seed coat called the hilum Don't forget about the age old question of Why study management?

What are the differences between the two types of seed drying? Orthodox are able to withstand maturation drying, allows the seed to become quiescent or dormant until conditions are right to germinate Recalcitrant are unable to withstand maturation drying and the seeds must not dry below 30-50% moisture We also discuss several other topics like What is the unit of unit vector?

Name the requirements of environmental conditions when selecting an area for seed production:

precipitation

humidity

rainfall during harvest

•

vernalization

soil type, fertility, moisture

ability to isolate cross-pollinated crops

When are seeds ready to be harvested? When it will not impair the germination or seed vigor, but if they are collected too late they will be lost to dehiscence or herbivory; if too early there will be insufficient embryo development, poor quality and short-lived If you want to learn more check out Why does marginal product eventually diminish?

What are the major types of fruit and seed processing/handling?

• dry, indehiscent fruits (grains, achenes, samaras, nuts)

dry, dehiscent fruits (follicles, pods, capsules, siliques, cones)

fleshy fruits (tomato, apples, plums)

List some of the considerations of seed treatments:

•

uniformity

adherence

no reduction in seed quality

• safe handling

• uniform size and shape for mechanical sowing

• color

What are some of the seed technologies/enhancements?

priming

• pellets/grading

multi-seed pellets

coating

PGR treated seed

•

disease treatment

•

testing

Benefits of seed technologies:

easier handling

• less skips

less doubles

higher germination

uniform germination

•

faster germination

What does the seed coating Intellicote do? allows early planting, less stunted growth and less rot

What conditions are required for germination initiation?

viable

subjected to appropriate environmental conditions

any primary (and/or secondary) dormancies overcome

Explain viability. the embryo is alive; capable of germination after all the necessary conditions are met

What conditions are important for longevity?

• cold, dry, lower oxygen conditions

• can be maintained in seed banks

What happens during the imbibition stage? there is a rapid uptake of water based on water potential

What occurs during the lag phase? mobilization of interior organelles mitochondria maturation, increases respiration protein synthesis use of pre-existing stored energy enzyme production; loosening of cell walls

Radicle emergence. Explain.

germination has occurred

radicle curves downward

What is primary dormancy?

The condition developed at the end of seed development. There are two types: exogenous and endogenous

What are the types of exogenous primary dormancy?

physical

chemical: inhibitors are present in fruit and seed covering

tissue

What are the types of endogenous primary dormancy?

physiological: embryo lacks growth potential

o non-deep: stratification or photodormancy to

overcome

O

intermediate: moderate chilling period

se o deep: long period of chilling morphological: immature embryo; requires more than 30 days

to germinate

morphophysiological: under-developed embryo and physical

-> overcome by alternating warm and cold stratification

What is secondary dormancy? occurs to imbibed seeds that are subjected to unfavorable environmental conditions causing them to reenter a (deep) dormancy

needs multiple cycles to germinate

do not let dry out

List some of the considerations of seed treatments:

•

uniformity

adherence

no reduction in seed quality

• safe handling

• uniform size and shape for mechanical sowing

• color

What are some of the seed technologies/enhancements?

priming

• pellets/grading

multi-seed pellets

coating

PGR treated seed

•

disease treatment

•

testing

Benefits of seed technologies:

easier handling

• less skips

less doubles

higher germination

uniform germination

•

faster germination

What does the seed coating Intellicote do? allows early planting, less stunted growth and less rot

What conditions are required for germination initiation?

viable

subjected to appropriate environmental conditions

any primary (and/or secondary) dormancies overcome

Explain viability. the embryo is alive; capable of germination after all the necessary conditions are met

What conditions are important for longevity?

• cold, dry, lower oxygen conditions

• can be maintained in seed banks

What happens during the imbibition stage? there is a rapid uptake of water based on water potential

What occurs during the lag phase? mobilization of interior organelles mitochondria maturation, increases respiration protein synthesis use of pre-existing stored energy enzyme production; loosening of cell walls

Radicle emergence. Explain.

germination has occurred

radicle curves downward

What is primary dormancy?

The condition developed at the end of seed development. There are two types: exogenous and endogenous

What are the types of exogenous primary dormancy?

physical

chemical: inhibitors are present in fruit and seed covering

tissue

What are the types of endogenous primary dormancy?

physiological: embryo lacks growth potential

o non-deep: stratification or photodormancy to

overcome

O

intermediate: moderate chilling period

se o deep: long period of chilling morphological: immature embryo; requires more than 30 days

to germinate

morphophysiological: under-developed embryo and physical

-> overcome by alternating warm and cold stratification

What is secondary dormancy? occurs to imbibed seeds that are subjected to unfavorable environmental conditions causing them to reenter a (deep) dormancy

needs multiple cycles to germinate

do not let dry out

What are environmental factors influencing germination?

• temperature

water

light gases

germinations aids:

o hormonal

LOUBO "instant smoke"

What are the effects of hormones on seed development?

Auxin: normal embryo and endosperm development; fruit

development

Gibberellins: embryo growth; fruit growth; germination

Cytokinins: cell division stages of embryogenesis

ABA: seed maturation

Ethylene: some role, not fully understood yet

What is vivipary? Germination of seed without maturation drying

What is apomixis? Asexual seed production, creates clonal duplicate of mother plant, common in citrus, grasses, rosaceae and asteraceae

What is parthenocarpy? formation of fruit without fertilization, common in cucumbers two types:

vegetative: fruit development without pollination

stimulative: pollination occurs, but not required

What are the multiple ways of parthenocarpy occurring?

1. aborted embryo (stenospermocarpy) 2. chromosome inheritance/genetics 3. plant hormone Gibberellins upon fertilization, GA levels

increase

stua

Stages of Seed Development

Stages of Seed Development Histo

Maturation differentiation

Cell expansion

drying

Fresh wt

Study Soup

Water wt

Gram weight

StudySoup

Dry wt

Stage 1

| Stage III

Stage 11 Days of Development

Table 4-2