Plant Biology: Embryo Structure

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Questions and Answers

What tag color is provided for breeder seed?

Golden yellow (correct)

Green

White

Blue

Which of the following is NOT a seed class defined by AOSCA?

Foundation seed

Commercial seed (correct)

Nuclear seed

Breeder seed

What is the primary role of the father of seed technology, Dr. Robb Fraley?

Improving seed characteristics (correct)

Seed certification

Seed testing

Seed pathology

What is the main purpose of seed production?

To improve seed and crop management Signup and view all the answers

Which type of seed is produced directly by the breeder before further multiplication?

Nuclear seed Signup and view all the answers

Who is recognized as the father of seed testing?

Fredrick Nobbe Signup and view all the answers

What is the genetic purity of breeder seeds?

100% Signup and view all the answers

What type of seeds have the endosperm that persists until maturity?

Albuminous seeds Signup and view all the answers

What is the seed tag color for breeder seeds?

Golden Yellow Signup and view all the answers

Which of the following examples represents a non-endospermic monocot?

Pothos sp Signup and view all the answers

Which structure develops from the outer integument of an ovule?

Testa Signup and view all the answers

Which seed type has the highest genetic purity?

Nucleus Seed Signup and view all the answers

Which seed type is produced by progressive farmers under supervision?

Certified Seed Signup and view all the answers

Which appendage is associated with the seed of Paddy?

Awn Signup and view all the answers

What is the physical purity percentage of foundation seeds?

98% Signup and view all the answers

What type of germination allows the cotyledons to remain below ground while the epicotyl elongates?

Hypogeal germination Signup and view all the answers

What is the main function of the seed coat?

To protect the embryo from mechanical injury and drying out Signup and view all the answers

Certification is required for which type of seed?

Foundation Seed Signup and view all the answers

Which of the following is a characteristic of exalbuminous seeds?

They completely consume the endosperm during seed development Signup and view all the answers

What is the seed tag size for certified seeds?

15 x 7.5 cm Signup and view all the answers

Which is true about nucleus seeds?

They are limited in quantity. Signup and view all the answers

Which type of seed classification categorizes seeds based on their endosperm?

Based on Endosperm Signup and view all the answers

Which of the following options correctly identifies a method of pollen dissemination?

Hydrophily Signup and view all the answers

What is the primary role of the antipodal cells in the embryo sac?

Nourishment during embryo development Signup and view all the answers

What type of seed germination is characterized by the cotyledons remaining buried in the soil?

Hypogeal Germination Signup and view all the answers

Which type of seeds would be classified as recalcitrant?

Forest and horticultural crops Signup and view all the answers

During fertilization in angiosperms, how many male nuclei participate?

Two Signup and view all the answers

Which of the following is NOT a type of pollen dissemination method?

Metallophily Signup and view all the answers

What is the minimum genetic purity required for Foundation seed?

99.5% Signup and view all the answers

Which crop has a minimum physical purity requirement of 95%?

Carrot Signup and view all the answers

Which of the following crops requires a pure seed percentage of 98%?

Other crops Signup and view all the answers

Which of the following is designated as an inseparable other crop seed for Barley?

Wheat Signup and view all the answers

What is the minimum physical purity percentage for the crop Groundnut?

96% Signup and view all the answers

Which seed class has the highest genetic purity requirement?

Breeder/Nucleus Signup and view all the answers

What percentage of pure seed is required for soybean?

97% Signup and view all the answers

What is the primary purpose of the buff color seed tag?

Production of breeder seed Signup and view all the answers

Which category of seed production has a higher isolation distance requirement?

Hybrid seed production Signup and view all the answers

What distinguishes orthodox seeds from recalcitrant seeds?

Orthodox seeds can withstand freezing while recalcitrant cannot. Signup and view all the answers

In seed production, what is a key characteristic of hybrid seed production compared to varietal seed production?

Requires managed control pollination Signup and view all the answers

Which size is associated with certified seed production based on the tag specifications?

15 x 7.5 cm Signup and view all the answers

What type of seed care is typically required for hybrid seed production?

High care Signup and view all the answers

What is a common characteristic of seeds produced under a breeder seed system?

Not meant for general distribution Signup and view all the answers

Which type of seed cannot undergo dormancy and loses viability quickly when dried?

Recalcitrant seeds Signup and view all the answers

What financial aspect is generally associated with hybrid seed production?

Higher profit Signup and view all the answers

For which type of seed production is seed changed every generation?

Hybrid seed production Signup and view all the answers

Study Notes

Seed Structure

Embryo

Immature plant that develops into a new plant under suitable conditions.
Monocots possess one cotyledon; dicots usually have two cotyledons; gymnosperms can have two or more.
Monocot Examples: Wheat, corn, rice, sugarcane, palm.
Dicot Examples: Peas, beans, tomatoes, oak.

Endosperm

Albuminous Seeds: Endosperm persists at maturity, found mainly in monocots.
Exalbuminous Seeds: Endosperm consumed during seed development, found in most dicots.
Endospermic Monocots: Maize, barley, rice.
Non-endospermic Seeds in Dicots: Peas, lentils, sunflower.
Reserved food: Carbohydrates in cereals, proteins in legumes, fats in castor and peanuts.

Seed Coat

Comprised of two layers: outer layer (Testa) and inner layer (Tegmen).
Protects embryo from injury and drying.
Unitegmic Ovules: Single integument.
Bitegmic Ovules: Two integuments; seed coat may derive from both.

Appendages of Seed

Awn: Paddy.
Hilum: Pulses.
Caruncle: Castor, tapioca.
Aril: Nutmeg.
Wings: Moringa.

Germination Classification

Hypogeal Germination: Epicotyl elongates, cotyledons below ground. Examples include gram, maize, coconut.

Seed Technology

Involves methods for improving genetic and physical characteristics of seeds.
Key figures: Dr. Robb Fraley (Father of Seed Technology), Frederick Nobbe (Seed Testing), Paul Neergaard (Seed Pathology).

Classes of Seed

Nuclear Seed: Initial seed for variety development; genetic purity 100%.
Breeder Seed: Progeny of nuclear seed; 100% genetic purity.
Foundation Seed: Produced from breeder seeds; 99.5% genetic purity.
Certified Seed: Progeny of foundation seeds; 99% genetic purity.

Characteristics of Good Quality Seed

Genetic Purity

True to type and consistent with breeder's defined traits.
Breeder/Nucleus: 100%, Foundation: 99.5%, Certified: 99%.

Physical Purity

Composition of seed lots; should be maintained at 96-98%.
Minimum standards for crops vary; e.g., carrot 95%, okra 99%.

Pure Seed Percentage

Bhindi: 99%, other crops: 98%, soybean and jute: 97%.

Other Crop Seed Designation

Barley, wheat, and oats must be free from other crop seeds.

Classification of Seeds

By Usage: Cereals, oil seeds, pulses, vegetables.
By Cotyledons: Monocots and dicots.
By Endosperm Type: Endospermic (cereals) vs. Non-endospermic (legumes).
By Germination Type: Hypogeal vs. Epigeal.
By Storage Behavior: Orthodox and recalcitrant seeds.

Pollination

Pollen transfer can be self-pollinated (autogamy) or cross-pollinated (allogamy).
Pollination mechanisms include:
- Wind (anemophily),
- Water (hydrophily),
- Insects (entomophily),
- Birds (ornithophily).

Fertilization

Fusion of male and female gametes forms an embryo.
Embryo sacs consist of 7 cells and 8 nuclei.

Seed Production and Certification

Seed Types Definition: Genetic purity and tag color indicate seed class.
- Nucleus Seed: 100% purity, buff tag.
- Breeder Seed: 100% purity, golden yellow tag.
- Foundation Seed: 99.5% purity, white tag.
- Certified Seed: 99% purity, azure blue tag.

Generation System of Seed Multiplication

Includes three generations: Breeder, Foundation, Certified.
Varietal production requires a single parent; hybrid production needs multiple parents with more stringent care.

Seed Types Based on Storage Behavior

Orthodox Seeds

Viable long-term in low temperature with low moisture.
Tolerant of freezing and dehydration; allows dormancy.

Recalcitrant Seeds

Quickly lose viability below 12% moisture.
Sensitive to freezing; unable to undergo dormancy; important for in-situ conservation.

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Description

Explore the fascinating world of plant embryos with this quiz. Learn about the differences between monocotyledons and dicotyledons, including examples of each. Test your knowledge on the seed structure and its significance in plant development.