What is heterospory and seed habit in pteridophytes?
What is heterospory and seed habit in pteridophytes?
Explanation: Heterospory is considered a precursor to seed habit, as present in a few genera of pteridophytes, e.g. Selaginella and Salvinia. They produce two types of spores, microspores and megaspores.
What is seed habit in pteridophytes?
The adoption of heterospory and the retention and germination of a single megaspore within megasporangium to form a female gametophyte, led to the phenomenon of “seed habit”, a characteristic feature of the spermatophytes.
What is the significance of heterospory in seed habit?
– Heterospory is thus considered an important step in evolution as it is a precursor to the seed habit. – Heterospory evolved first in pteridophytes such as Selaginella and Salvinia. – The seed habit is the most complex and evolutionary successful method of sexual reproduction. – It is found in vascular plants.
Is seed formed in pteridophytes?
A pteridophyte is a vascular plant (with xylem and phloem) that disperses spores. Because pteridophytes produce neither flowers nor seeds, they are sometimes referred to as “cryptogams”, meaning that their means of reproduction is hidden.
What are heterospory in pteridophytes?
Heterospory is a phenomenon in which two kinds of spores are borne by the same plant. The spores differ in size, structure and function. The smaller one is known as microspore and larger one is known as megaspore. Such Pteridophytes are known as heterosporous and the phenomenon is known as heterospory.
What is a seed habit?
‘Seed habit’ involves the origin and formation of seed from non-seed bearing. plant and it involves in following changes in non-seed bearing plants:– 1. Production of two kinds of spore i.e. evolution of heterospory.
What is seed habit?
Seed habit is considered as the adaptation of heterospory and retention and germination of single megaspore within a megasporangium. It is considered as the most advanced and successful method of sexual reproduction adopted by terrestrial plant mostly.
What is heterospory give examples of heterosporous pteridophytes?
Selaginella and Salvinia are two examples of heterosporous pteridophytes. These pteridophytes consist of two types of spores, large spores that germinate to produce female gametophyte and small spores germinate to produce male gametes.
What is seed habit in pteridophytes PDF?
Seed Habit in Pteridophytes: The adoption of heterospory and the retention and germination of a single megaspore within megasporangium to form a female gametophyte, led to the phenomenon of “seed habit”, a characteristic feature of the spermatophytes.
What are Heterosporous pteridophytes?
Heterosporous refers to the plants producing different types of spores that are different in structure, size and function. They produce two kinds of spores, smaller microspores and bigger megaspores. Most pteridophytes are homosporous, i.e. they produce all spores of a similar kind.
What is heterospory give example?
HETEROSPORY :- THIS IS A CONDITION IN WHICH AN ORGANISM (PLANTS)PRODUCE TWO DIFFERENT TYPES OF GAMETES (MORPHOLOGICALLY)i.e, ONE LARGE GAMETE AND THE OTHER BEING A SMALL GAMETE OR FLAGELLATED AND NON-FLAGELLATED GAMETES IS KNOWN AS HETEROSPORY. EXAMPLE:- Selaginella,Salvinia.
What are Heterosporous Pteridophytes?