(a) Enumerate the advantages of Artificial seeds.
(b) Write in detail about Autogenic succession and Allogenic succession.

Explanation

(a) Artificial seeds have many advantages over the true seeds as follows :
• Millions of artificial seeds can be produced at any time at low cost.
• They provide an easy method to produce genetically engineered plants with desirable traits.
• It is easy to test the genotype of plants.
• They can potentially stored for long time under cryopreservation method.
• Artificial seeds produce identical plants.
• The period of dormancy of artificial seeds is greatly reduced, hence growth is faster with a shortened life cycle.
(b) Autogenic succession
Autogenic succession occurs as a result of biotic factors. The vegetation reacts with its environment and modifies its own environment causing its own replacement by new communities. This is known as autogenic succession.
Example : In forest ecosystem, the larger tres produce broader leaves providing shade to the forest floor area. It affects the shrubs and herbs which require more light (heliophytes) but supports the shade tolerant species (sciophytes) to grow well.
Allogenic succession Allogenic succession occurs as a result of abiotic factors. The replacement of existing community is caused by other external factor (soil erosion and leaching, etc.,) and not by existing organisms.
Example : In a forest ecosystem soil erosion and leaching alter the nutrient value of the soil leading to the change of vegetation in that area.