Question

Write the difference between homosporous and heterosporous.

Answer 1

Hint: A spore is a unit of either sexual or asexual reproduction that may be adapted for dispersal and for survival, for extended periods of time, in unfavourable conditions. Spores are usually haploid and unicellular in nature and are produced by the process of meiosis in the sporangium of a diploid sporophyte.

Complete answer:
Under favourable conditions, the spore can develop into a new organism using mitotic division thereby producing a multicellular gametophyte, which eventually goes on to produce gametes. Two gametes fuse to form a zygote which then develops into a new sporophyte. This cycle is called the alternation of generations.

Differences between homosporous and heterosporous are as follows.

Homosporous	Heterosporous
Homosporous means produces only one type of spores	Heterosporous means produces two types of spores
These types of pteridophytes are small in structure and cannot be separated by sex	These types of pteridophytes produce two types of spores and can be separated by sex
Spores are generally smaller in size.	Spores are generally small microspores and large macrospores.
Gametophyte is unisexual	The gametophyte is bisexual in nature
Examples are Club mass and puzzle grass	Examples are Salvinia and Selaginella

Vascular plant spores are always haploid. Vascular plants are either homosporous or heterosporous. Plants that are homosporous produce spores of the same size and also type.

Heterosporous plants produce spores of two different sizes which are the larger spore called the megaspore, functioning as a female spore and the smaller spore known as the microspore that functions as a male spore.

Note: Heterosporous plants usually give rise to the two kinds of spores from within separate sporangia, either a megasporangium which produces megaspores or could be a microsporangium that produces microspores. In the case of flowering plants, these sporangia occur within the carpel and anthers, respectively.