Double Fertilization and Seed Formation

Questions and Answers

Match the following terms with their definitions related to seed structure:

Embryo = Part of the seed that will develop into the new plant Testa = A tough and hard seed coat which protects the seed before germination Radicle = First part of the new plant to emerge from the seed, develops into the root Plumule = Emerges soon after the radicle, develops into the shoot

Match the types of seeds with their characteristics:

Endospermic seeds = Food required by the developing embryo is stored in the endosperm Non-endospermic seeds = Food is stored in seed leaves called cotyledons Monocots = Plants that have one cotyledon Dicots = Plants that have two cotyledons

Match the following stages of seed formation with their descriptions:

Zygote = Forms the seed embryo Endosperm nucleus = Divides rapidly to form a food storage tissue Ovule = Develops into the seed Integuments = Thicken and toughen to form the testa

Match the type of fruit development with its method:

Genetic selection = Propagating plants that produce very few seeds Asexual propagation = Producing seedless fruits by clonally reproducing selected plants Watermelons = An example of seedless fruit developed for the consumer market Seed dispersal = Function of fruit to protect the seed and allow for its distribution Signup and view all the answers

Match the fertilization process terms with their roles:

Double fertilization = Process where one sperm fertilizes the egg and another fuses with two polar nuclei Ovule wall = Toughens up to form the seed coat Food reserves = Used in the early stage of germination Dormancy = State of the seed when it is fully formed and dried out Signup and view all the answers

Match the following seed dispersal methods with their descriptions:

Animal Dispersal = Fruit is eaten by an animal and seeds pass through its digestive system Wind Dispersal = Seeds are light and have a large surface area for wind transport Self-dispersal = Pea pods dry and split, causing seeds to spring out Water-dispersal = Seeds have air pockets to float and disperse in water Signup and view all the answers

Match the following terms with their definitions:

Dormancy = Period of reduced growth despite suitable conditions Auxins = Plant hormones used to induce fruiting without fertilization Seed Dispersal = Process of spreading seeds away from the parent plant Germination = Process by which a seed develops into a new plant Signup and view all the answers

Match the following advantages of dormancy with their purposes:

Avoiding adverse conditions = Prevents damage to new growth during harsh conditions Reducing competition = Allows more time for seeds to disperse before germination Maturing embryos = Gives time for seeds to develop properly before conditions improve Delaying germination = Ensures seeds do not sprout too early in unfavorable conditions Signup and view all the answers

Match the following examples with their dispersal methods:

Sycamore = Wind Dispersal Tomato seeds = Animal Dispersal Gorse = Self-dispersal Yellow water lily = Water-dispersal Signup and view all the answers

Match the following types of plant hormones with their functions:

Auxins = Promote fruit development without fertilization Gibberellins = Stimulate seed germination and elongation Cytokinins = Promote cell division and growth Ethylene = Regulates fruit ripening Signup and view all the answers

Match the following components of seeds with their descriptions:

Testa = Waterproof covering that prevents water entry Cotyledon = Stores nutrients for the developing embryo Embryo = Young plant that will develop into a new plant Endosperm = Supplies energy during germination Signup and view all the answers

Match the following processes with their stages in seed formation:

Pollination = Transfer of pollen to stigma Fertilization = Fusion of male and female gametes Seed Development = Formation of seeds after fertilization Fruit Development = Maturation of the ovary into fruit Signup and view all the answers

Match the following factors affecting germination with their influences:

Moisture = Activates enzymes for growth Temperature = Affects metabolic rates in seeds Oxygen = Essential for respiration during germination Light = Stimulates certain types of seed germination Signup and view all the answers

Match the following biological phenomena with their meanings:

Apomixis = Asexual reproduction through seed formation without fertilization Parthenogenesis = Development of an embryo without fertilization Somatic embryogenesis = Formation of an embryo from somatic cells Vegetative propagation = Asexual reproduction through vegetative parts of a plant Signup and view all the answers

Study Notes

Double Fertilisation and Seed Formation

After fertilisation, the ovule swells, and its wall toughens to form the seed coat (testa).
The zygote develops into the seed embryo while the triploid endosperm provides food storage.
The outer wall of the ovule, known as integuments, thickens to form the testa.
Once formed, the seed dries out and enters a dormant state.

Seed Structure

Embryo: The future plant developed from the zygote.
Testa: A hard seed coat that protects the seed until germination.
Radicle: The first part to emerge from the seed, developing into the root.
Plumule: Emerges after the radicle and becomes the shoot.
Cotyledons: Seed leaves containing food reserves for early germination; monocots have one cotyledon, dicots have two.

Types of Seeds

Monocots (like maize and wheat) store food in the endosperm, classified as endospermic seeds.
Dicots (like broad beans) store food in cotyledons, classified as non-endospermic seeds.

Fruit Formation

The fruit serves to protect seeds and facilitate their dispersal.
Seedless fruits, like watermelons, can be produced by:
- Genetic selection for low-seed plants.
- Using hormones like auxins to induce fruit without fertilisation.

Seed Dispersal Methods

Animal Dispersal: Animals eat fruit, and seeds pass through their digestive systems, necessary for germination in some plants (e.g., tomatoes).
Wind Dispersal: Seeds are lightweight with a large surface area to be carried by the wind, as seen in sycamore and dandelion seeds.
Self-dispersal: Pods dry, curl, and split open to release seeds, e.g., in gorse plants.
Water Dispersal: Seeds with air pockets float for dispersal, like yellow water lilies.

Dormancy

Dormancy refers to a state of metabolic inactivity in seeds, even when germination conditions are favorable.
Advantages:
- Avoids adverse conditions that could harm growth.
- Allows time for seed dispersal to reduce competition.
- Provides time for embryo maturation.

Breaking Dormancy in Agriculture

Seeds maintain dormancy through a waterproof testa that prevents water entry, delaying germination.

Plant Reproduction Overview

Sexual reproduction involves fertilisation of gametes, while asexual reproduction does not.
Sexual reproduction in plants typically occurs through flower structures.

Functions of Flower Parts

Sepals: Protect the flower before and during its opening.
Petals: Bright and often fragrant to attract pollinators.
Stamens:
- Male reproductive part composed of:
  - Anther: Produces pollen (male gametes).
  - Filament: Supports the anther.
Carpel:
- Female reproductive part with:
  - Stigma: Captures pollen.
  - Style: Connects stigma to ovary.
  - Ovary: Contains ovules which develop into embryos.
Nectary: Produces nectar to attract pollinators.

Gamete Development

Female Gametes: Formed in the ovule, a diploid megaspore mother cell undergoes meiosis, producing four haploid megaspores; three degenerate, leaving one that divides mitotically to create eight nuclei, forming the embryo sac.
Male Gametes: Located in the anther, diploid microspore mother cells undergo meiosis to produce four haploid microspores.

Studying That Suits You

Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

Description

This quiz explores the process of double fertilization, focusing on the transformation of the ovule into a seed. It covers the development of the zygote, the formation of the seed embryo, and the role of the endosperm in providing nutrients. Dive into the intricate stages of seed formation and understand the structural changes that take place.