Sporocarp of Marsilea
:
•Marselia is heterosporous and Leptosporangiate: It bears two kinds of spores; microspores and megaspores produced inside microspoarngium and megasporangium
•Sporangia are formed inside specialized structures called sporocarps
•Sporocarps are formed from the petiole of the leaf
•When young it is green and soft with hairs. On maturity becomes hard and turns brown
•Each sporocarp is attached to the petiole by means of stalk called pedicel.
Origin of Sporocarp of Marsilea: Two views
• 1. Laminar concept
by Bower: Sporocarp is formed by the fusion of one or more leaflets or pinnae
2. ‘Whole leaf concept’ by Johnson: Sporocarp is formed by the
whole leaf
Morphology of Sporocarp:
- Each sporocarp is oval or oblong body or bean seed shaped
- The portion where the sporocarp attaches with the pedicel is called the raphe
- Above Raphe the sporocarp has two horn shaped parts called tubercles.
Image credits
•Bean shaped structure with bilateral symmetry
•Thick wall consists of three layers.
Single layered epidermis wit h stomata
•Hypodermis consist of outer layer of thick walled cells and inner layer of thin
walled cells and contain chloroplast.
•Below hypodermis is a gelatinous ring
of parenchymatous cells more prominent at the dorsal
side.
•The central cavity contains 2 rows of elongated sori one in each half. The no. of sori may vary from 2-20
•Each sorus arise from the placentum
•Each sorus
is surrounded by its own indusium. It contains a megasporangium at the tip and 2 microsporangia one on either side of the placentum
•Each sporangium has a separate vascular
connection
