Podcast
Questions and Answers
What occurs during pollen inhibition?
What occurs during pollen inhibition?
What is the term used to describe the entry of the pollen tube into the ovules?
What is the term used to describe the entry of the pollen tube into the ovules?
What is the product of syngamy in angiosperms?
What is the product of syngamy in angiosperms?
In angiosperms, what precedes the development of the embryo?
In angiosperms, what precedes the development of the embryo?
Signup and view all the answers
What type of embryo do dicotyledonous plants have?
What type of embryo do dicotyledonous plants have?
Signup and view all the answers
What characteristic defines the mature dicotyledonous embryo?
What characteristic defines the mature dicotyledonous embryo?
Signup and view all the answers
What process results in the formation of seeds without fertilisation in some angiosperms?
What process results in the formation of seeds without fertilisation in some angiosperms?
Signup and view all the answers
What developmental stage does the embryo pass through after the globular stage?
What developmental stage does the embryo pass through after the globular stage?
Signup and view all the answers
What is formed from the primary endosperm nucleus in angiosperms?
What is formed from the primary endosperm nucleus in angiosperms?
Signup and view all the answers
Which event occurs first during compatible pollination in angiosperms?
Which event occurs first during compatible pollination in angiosperms?
Signup and view all the answers
Study Notes
Flower Morphology and Structure
- Flowers are highly adapted to ensure formation of fruits and seeds, the end products of sexual reproduction in angiosperms
- Humans have had an intimate relationship with flowers since ancient times, using them for aesthetic, ornamental, social, religious, and cultural purposes
Parts of a Flower
- A typical flower consists of stigma, style, ovary, and thalamus
- Ovary contains ovules, which are attached to the placenta by a stalk called funicle
- Ovules have one or two protective envelopes called integuments, which encircle the nucellus except at the tip where a small opening called the micropyle is organized
Structure of an Ovule
- Each ovule has a small stalk called funicle, which fuses with the body of the ovule at the hilum
- Integuments encircle the nucellus, which contains reserve food materials
- Located in the nucellus is the embryo sac or female gametophyte
Pollination and Fertilisation
- Emasculated flowers are covered with a bag to prevent contamination with unwanted pollen
- Pollen grains are collected from the male parent and dusted on the stigma, and the flowers are rebagged
- Pollen-pistil interaction involves events from landing of pollen grains on the stigma to the pollen tube entering the embryo sac
Double Fertilisation
- Double fertilisation occurs in flowering plants, involving two fusion events: syngamy and triple fusion
- One male gamete fuses with the egg cell to form a diploid zygote, and the other male gamete fuses with the two polar nuclei to form a triploid primary endosperm nucleus
Seed and Fruit Formation
- As ovules mature into seeds, the ovary develops into a fruit
- Seed coats are formed from hardened integuments, with the micropyle remaining as a small pore
- Fruits may be fleshy or dry and have evolved mechanisms for dispersal of seeds
- In some species, the thalamus also contributes to fruit formation, forming false fruits
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
Description
Explore the fascinating world of flower structures and the process of sexual reproduction in angiosperms. Learn about the morphology, structure, and adaptations that enable the formation of fruits and seeds. Discover the intricate relationship between human beings and flowers throughout history.
