Explain the structure of vegetative cells and alternation of generation in Phaeophyta

plant-kingdom
cbse

#1

Phaeophyta :
(a) Vegetative cells possess cellulose wall mostly covered by a gelatinous coating of algin.
(b) The thallus is differentiated into a hold fast, a stipe and leaf like photosynthetic organ.
© The life cycle of brown algae shows alternation of generations between a diploid sporophyte (2n) haploid (n) gametophyte.
(d) Sporophyte produces sporangia. They . bear spores after meiosis. The spores divide by mitosis and produce the gametophytes. Two types of gametophytes in kelps, are : (i) one produces sperm (ii) other produce eggs. The sperms and eggs fuse to form zygote.
(e) The zygote grows into a mature sporophyte.
(f) Gametes as well as the zoospores are pyriform.
(g) Sexual reproduction may be isogamous,heterogamous or oogamous e.g., Bodanella (fresh water form) Ectocarpus, Dictyota, Laminaria, Fucus and Saragassum (Gulf weed).