Structure and life cycle of
Ectocarpus
Ms. Inderveena Sharma
H.O.D.
Botany Department
• Habitat: Marine brown alga found attached to
rocks and stones in cold seas.
• Vegetative structure
Plant body is macroscopic, multicellular, filamentous,
branched and heterotrichous differentiated into
Prostrate system – filamentous irregularly branched &
attached to substratum
Erect system – arise from prostrate system and
consists of many branched which are uniseriate
(single row of cells)
Branching is lateral and tapers into series of elongated
cells
Cells are uninucleate and possess one or many
irregular band shaped or discoid chromatophores.
Reserve food material is oil, mannitol and laminarian
starch but not starch.
Asexual reproduction: by biflagellate zoospores
produced in unilocular and plurilocular sporangia. It
always occurs in sporophytic plant body.
Plurilocular sporangia developed on diploid plant body
produce diploid zoospores which germinate into diploid
thalli.
Stages in development of plurilocular
sporangium & liberation of zoospres
Stages in development of
unilocular sporangium
Sexual reproduction
• Produced by fusion of two
biflagellated
motile
gametes
produced
in
plurilocular
gametangia
in
gametophytic
plants.
• Fusion occurs between gametes
from different plants (dioecious) or
from same plants (monoecious)
• Sexual fusion may be Isogamous (fusing gametes are
identical in size, shape, structure
and activity)
Physiological anisogamous (fusing
gametes are identical in size,
shape, structure but differ in
activity)
Morphologically anisogamous (fusing
gametes are unequal in size)
Diploid plant bearing unilocular
& plurilocular sporangium
Isogamous reproduction in Ectocarpus
Anisogamous reproduction
in Ectocarpus
Life cycle of Ectocarpus
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