Saturday, 17 November 2012

VARIOUS WAYS PLANTS DISPERSE THEIR SEEDS AND FRUITS

1. Seeds and fruits can be dispersed by
(a) water
(b) wind
(c) animals
(d) an explosive mechanism

2. The seeds and fruits have special characteristics which help the agent to disperse the seeds.

Water
  • Some plants disperse their fruits and seeds with the help of water. These plants live near seas, rivers and marshes.
  • The fruits have waxy and waterproof coverings to prevent water from entering the fruits.
  • Air spaces enable the fruits to float in the water.
  • The lotus fruit is light, spongy, and has air spaces.

  • The pong-pong tree lives near water and its fruits have waxy skins.
  • The coconut fruit is covered by a waxy skin. It has a husk that can trap air and  a very hard shell.
  • The seeds of mangrove trees germinate when they are still attached to the parent tree.
  •   The seedlings float in the water and are then washed up on the sand.

Wind





* angsana have dry walls shaped like wings.







*dandelion seeds have fine hairs.







* cotton seeds are very light.

Characteristics of the seeds or fruits:
  • Small
  • Light
  • Dry
  • Wing-lie structure
  • Fine hairs
Other examples: petrea and clematis fruits, frangipani seeds



Explosive mechanism


                balsam plant
  
     * Dry and hard when ripe
    * When matured, the fruit wall will split and curl suddenly, throwing the seeds out.                                                                                                                               

                                                                                                                                        







                                                                                                                               ladies' finger



Animals

Characteristics
  • Big seeds
  • Brightly coloured fruits
  • Fragrant
  • Fleshy fruits
  • Edible


* Eat the fruits but discard the seeds.





Examples:


Characteristics
  • Small seeds
  • Hard seeds
  • Fragrant
  • Fleshy fruits
  • Edible
  • Brightly coloured fruits





* Eat the fruits as well as the seeds and pass out the seeds in the faeces.




Examples:




Characteristics
  • Dry
  • Have hooks
  • Not edible
  • Light
  • Have spines


* Transport fruits that stick to the body of the animals.




Examples:
                                                                                              mimosa


love grass




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