10 Questions
What is the main reason for the preservation of pollen grains as fossils?
Presence of sporopollenin
At what stage are pollen grains mainly shed?
2-celled stage
What is the purpose of pollen tablets as food supplements?
To provide nutrients
What is the main component of exine?
Sporopollenin
What is the name of the plant that causes pollen allergy?
Both a and b
What is the primary characteristic of parthenocarpic fruits?
They do not have embryo and endosperm.
What is the role of Gibberellic acid in parthenocarpy?
It stimulates the maturation of the ovary without fertilization.
What is a common feature of parthenocarpic fruits such as bananas and pineapples?
They are seedless and pulpy.
What is the significance of the year 1902 in the context of parthenocarpy?
It is the year when parthenocarpy was first introduced in cultivation.
What is the name given to fruits that are produced through parthenocarpy?
Virgin fruits
Study Notes
Structure of Pollen Grains
- Pollen grains are spherical in shape and consist of two layers: exine and intine.
- Exine is composed of sporopollenin, a resistant material that can withstand high temperatures and strong acids and alkali.
- Sporopollenin is absent at the germ pores.
Preservation of Pollen Grains
- The presence of sporopollenin allows pollen grains to be well preserved as fossils.
Development of Pollen Grains
- Pollen grains are typically shed at a 2-celled stage, consisting of a vegetative cell and a generative cell, when they are mature.
Allergenic Effects of Pollen Grains
- Pollen grains from many species can cause severe allergies and bronchial afflictions, leading to chronic respiratory disorders.
- Parthenium, also known as carrot grass, is a notable example of a pollen-producing plant that causes allergies.
Nutritional Value of Pollen Grains
- Pollen grains are rich in nutrients and are used in food supplements, such as pollen tablets.
- In Western countries, pollen products are marketed as performance-enhancing supplements for athletes and race horses, available in various forms like tablets and syrups.
Parthenocarpy
- Parthenocarpy is a process where fruits are produced without fertilization of ovules.
- Fruits produced through parthenocarpy are seedless and do not have an embryo or endosperm.
- Parthenocarpic fruits are also known as seedless or virgin fruits.
History of Parthenocarpy
- The process of parthenocarpy was first introduced in 1902.
Parthenocarpy in Plant Cultivation
- Parthenocarpy is introduced in plant cultivation alongside a range of plant hormones.
- One example of a plant hormone involved in parthenocarpy is Gibberellic acid.
- The hormone promotes the maturation of the ovary without fertilization, resulting in the production of big and pulpy fruits.
Examples of Parthenocarpic Fruits
- Banana is a type of parthenocarpic fruit.
- Pineapple is a type of parthenocarpic fruit.
- Cucumber is a type of parthenocarpic fruit.
- Watermelon is a type of parthenocarpic fruit.
This quiz covers the structure and composition of pollen grains, including their shape, layers, and preservation as fossils.
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