Question

In Ruellia and Justicia, dispersal of seeds takes place by
A. Jaculator mechanism
B. Censer mechanism
C. Winged seeds
D. Parachute mechanism

Answer 1

The movement and dispersal of seeds away from the original location is termed as seed dispersal. Due to limited modes of mobility, they rely upon a variety of dispersal vectors to transport their propagules. The patterns of seed dispersal are determined by the dispersal mechanism and this has important implications for the morphological and genetic structure of plant populations.

Complete answer:
The dispersal of seeds can be done by wind, gravity, water, ballistic (jaculator), and animals. The mechanism for dispersal include-

Jaculator mechanism-
• In this, the capsules are produced by the pollinated flowers that have small hook-like outgrowths called retinaculum or jaculators attached to the seeds.
• There comes a phase when the capsule dries, it breaks open and the retinaculum throws the seeds away from the parent plant.
• This is an explosive dispersal or jaculator or ballistichory mechanism of dispersal.
• The Justicia plants produce pods that can disperse seeds more than 10 feet away by this mechanism and the Mexican Petunia (Ruellia) has small petunia-shaped flowers.

Hence, the correct answer is option (B).

Additional information:
Some other mechanisms involved in dispersal-

Parachute mechanism- It involves the propagation of seeds in which appendages are already provided and they act like parachutes helping them to float. Eg- Pappus.
Censer mechanisms- Seeds are discharged through small openings and only a few can escape.
Winged seeds- Seeds of some plants like Moringa oleifera, Cinchona, etc., are provided with wings developed from the testa.

Note: The process of dispersal of seeds is done by different means. The two main distinctions include abiotic vectors such as the wind and biotic vectors like a bird. The biotic and abiotic factors play equally important roles in the dispersal mechanism. When dispersal is successfully done it leads to pollination.