Mnemonics: Sexual Reproduction in Flowering Plants | Biology Class 12 - NEET PDF Download

This document will help you remember important information about Sexual Reproduction in Flowering Plants in a fun and easy way. Inside, you'll find mnemonics—memory tricks—that will make it easier for you to remember key concepts, examples related to Sexual Reproduction in Flowering Plants.

 Whether you're studying for an exam, preparing for a quiz, or simply looking to enhance your understanding of Sexual Reproduction in Flowering Plants, these mnemonics will serve as valuable memory tools. Utilize them alongside your regular study routine to reinforce your knowledge and increase your recall ability.

Happy mnemonic learning!

1. Structure of Microsporangium ( wall layers)

"Every Man Taps Dancing"

• Every: Epidermis
• Man: Middle layers
• Taps: Tapetum
• Dancing: Endothecium

2. Structure of anatropus ovule

"Fun Happy Children Made New Ice Embryo"

• Fool: Funicle
• Happy: Hilum
• Children: Chalaza
• Made: Micropyle
• New: Nucellus
• Ice: Integuments
• Embryo: Embryo

 The ovule is a small structure attached to the placenta by means of a stalk called funicle. 

The body of the ovule fuses with funicle in the region called hilum. Thus, hilum represents the junction between ovule and funicle. 

Each ovule has one or two protective envelopes called integuments.
 Integuments encircle the nucellus except at the tip where a small opening called the micropyle is organised. 

Opposite the micropylar end, is the chalaza, representing the basal part of the ovule. 

Enclosed within the integuments is a mass of cells called the nucellus.

 Cells of the nucellus have abundant reserve food materials. 

Located in the nucellus is the embryo sac or female gametophyte. 

An ovule generally has a single embryo sac formed from a megaspore.

3. Types of Self Pollination

Auto  CC Gear X

• Auto: Autogamy
• C: Chasmogamous Flowers 
• C: Cleistogamous Flowers
• Gear: Geitonogamy
• X: Xenogamy

Pollination in flowering plants can be classified into three types based on the source of pollen:

1. Autogamy: Pollination occurs within the same flower. This can include flowers that self-pollinate due to close proximity of anthers and stigma, such as in chasmogamous and cleistogamous flowers, the latter of which do not open and are always autogamous.

2. Geitonogamy: Pollen is transferred to a different flower but on the same plant. Functionally similar to cross-pollination, it is genetically equivalent to self-pollination since the pollen comes from the same genetic source.

3. Xenogamy: Pollen is transferred from the anther of one plant to the stigma of a different plant, ensuring genetic diversity by combining different pollen types. This is the only type that introduces genetically different pollen to the stigma.

4. Steps of Artifical Hybridisation

"Elephants Bears Play Sleep Roar"

• Elephants: Emasculation
• Bears: Bagging
• Play: Pollen collection
• Sleep: Stigma pollination
• Roar: Re-bagging

Artificial hybridization is a crucial technique in crop improvement programs, focusing on controlled pollination to ensure genetic quality. The process involves several key steps:

1. Emasculation: This involves the removal of anthers from bisexual flowers using forceps before the anthers release pollen. This step is essential to prevent self-pollination.

2. Bagging: After emasculation, flowers are covered with bags, usually made of butter paper, to protect the stigma from unwanted pollen and external contamination.

3. Pollination: Once the stigma of the bagged flower is receptive, pollen grains from the selected male parent are carefully applied to the stigma.

4. Rebagging: After pollination, the flowers are covered again to secure the pollination process and allow the fruit to develop without interference.

5. Steps of Pollen Pistil Interaction

"Good People Gently Enter School Duh!!!!"

• Good: Germination on stigma
• People: Pollen tube growth through style
• Gently: Guided through micropyle
• Enter: Enters ovule
• School: Sperm release
• Duh: Commences double fertilization

(a) Pollen grains germinating on the stigma; (b) Pollen tubes growing through the style; (c) L.S. of pistil showing path of pollen tube growth; (d) enlarged view of an egg apparatus showing entry of pollen tube into a synergid; (e) Discharge of male gametes into a synergid and the movements of the sperms, one into the egg and the other into the central cell

6. Outbreeding Devices

"Synced Separates Self, Uniting Diverse Pairs"

• Synced: Synchronous maturation - Pollen release and stigma receptivity are not synchronized.
• Separates: Spatial separation - Anthers and stigma are placed at different positions to prevent pollen contact.
• Self: Self-incompatibility - Genetic mechanism that prevents self-pollen from fertilizing the ovules.
• Uniting: Unisexual flowers - Production of male and female flowers on the same or different plants to prevent self-pollination.
• Diverse: Dioecy - Male and female flowers are present on separate plants.
• Pairs: Prevents both autogamy and geitonogamy by having unisexual flowers and/or being dioecious.