Question

Explain dichogamy with example.

Answer 1

Hint: Dichogamy is the ripening of reproductive organs of plants i.e. stamen and pistil to prevent self-pollination. This process is done by hermaphrodites for maintaining cross-pollination. The plant can be intrafloral or Interflora based on the species.

Complete step by step answer:
Dichogamy is the process of maturation of the anthers and the stigma of a flower. The maturation occurs at different times in different plants. Protandry is when the anthers are the first to mature in the flowers of the plant. Protogyny is when the stamen are the first to mature in the flowers of the plant. This process takes place only in the bisexual flowers. In the case of unisexual flowers, it takes place in monoecious and dioecious plants. The process is said to be complete if the stigmas get matured after the wilting of stamens or if the stamens get matured after the wilting of stigmas. If one of the plants attain sexual maturity and the other has not then dichogamy is said to be incomplete.
For example Cruciferae, Rosaceae, Ranunculaceae, etc shows dichogamy
Protandry occurs in the flowers of Jasmine, Sunflower, etc.
Protogyny occurs in the flower of Rose, Ashoka, etc.
Dichogamy or 'dichogamy' was first discovered by Sprengel in the late 1790s. He designates hermaphrodite flower whose sex organs mature at different intervals of time. The same condition was first described by Kolreuter but it was further recognized by Sprengel. He named the male-female sequence as 'dichogamy androgyny' and the female-male sequence as 'dichogamy gyanendra'. These sequences are further known as protandry and protogyny. Scientists find it more desirable to call all dichogamy as heterodichogamy which is the condition where both protandry and protogyny exist among the individuals of the species. A scientist named Delpino called dichogamy as a general law of cross-pollination. He meant that all morphological or physiological adaptations are for cross-fertilization. But the final theory confirmed was of Sprengel which was the maturation of stamen and pistil at different intervals of time.

Note: The oldest living rose is 1000 years old which grows on the wall of the Cathedral of Hildesheim in Germany all over the world. The most expensive rose is about 5 million dollars which was a 2006 variety and took 15 years to grow. The tallest rose bush recorded is over 23 feet tall. Ashoka helps in many health benefits of the human body such as it helps in encouraging urine flow and treating conditions that cause painful urine.