Advertisements
Advertisements
Question
Mention two strategies evolved to prevent self-pollination in flowers.
Solution
Continued self-pollination decreases the vigour and vitality of a particular race. Thus, flowering plants have developed many devices to discourage self-pollination and to encourage cross-pollination.
- Dichogamy: Maturation of anther and stigma at different times in a bisexual flower prevent self-pollination.
- Self-sterility: (or self-incompatibility) - Due to the presence of the self-sterile gene in some flowers, pollen grains do not germinate on the stigma of that flowers. e.g.,- tobacco, potato.
- Herkogamy: The anther and the stigma are placed at different positions or have a mechanical barrier so that anthers cannot come in contact with the stigma of the same flower. Ex : Hibiscus, Gloriosa.
- Heterostyly: Styles of the flowers of the same species are in different heights.
- Male sterility: The pollen grains of some plants are not functional. Such plants set seeds only after cross-pollination.
Notes
Students can refer to the provided solutions based on their preferred marks.
APPEARS IN
RELATED QUESTIONS
With the help of a suitable example, explain protandry.
Describe the characteristic features of wind pollinated flowers.
List the different types of pollination depending upon the source of pollen gain.
Make a list of any three outbreeding devices that flowering plants have developed and explain how they help to encourage cross-pollination.
What is bagging technique?
Compare the characteristic features of insect pollinated and wind pollinated flowers. Explain how the respective features assist in pollination.
Fill in the blanks with suitable words.
Different timings for the maturation of gynoecium and androecium is called ________.
Differentiate between geitonogamy and xenogamy.
Coelacanth was caught in South Africa. State the significance of the discovery of Coelacanth in the evolutionary history of vertebrates.
At which stage pollen grains are shed from the anther in Angiosperms?
Pollination by water occurs in ______.
Triple fusion in Capsella bursa pastoris is fusion of male gamete with ______.
The flower which possesses both androecium and gynoecium is called perfect or ______.
During Hybridization process anther of the bisexual flower is removed before it dehisces is called ______.
Insect pollinated flowers are ______.
In the dioecious aquatic plant shown, identify the characteristics of the male flowers that reach the female flowers for pollination:
| Size of the flower | Colour of flower | The characteristic feature of pollen grain | |
| A | small | brightly coloured | Lightweight and non-sticky |
| B | large | colourless | large and sticky |
| C | small | white | small, covered with mucilage |
| D | large | colourless | non-sticky |
Advantage of cleistogamy is:
Which of the following floral adapation are adapted by hydrophilous flowers?
Describe any three adaptations in hydrophilous flowers.
