Plant Kingdom Test - 4

The plant body of phaeophyceae is usually attached to the substratum by a holdfast whereas the angiosperms attach to the substratum with the help of  roots.

Phaeophyceae possess chlorophyll a, c, carotenoids and xanthophylls. They vary in colour from olive green to various shades of brown depending upon the amount of the xanthophyll pigment, fucoxanthin present in them

Acetabularia is a genus of green algae, specially of  Polyphysaceae family. It is the largest unicellular organism.

In Ulothrix/Spirogyra reduction division (meiosis) occurs at the time of zygospore germination. Plant body of Ulothrix and Spirogyra, is gametophytic (haploid), they produce zoogametes (n) which fuses to form zygosporic (2n) diploid, which is a resting spore. Onset of favourable condition zygospore undergoes reductional division, or meiosis to produce zoo- meiospores.

Spirogyra is an algae that have long thread like structure having ribbon shaped chloroplast. Spirogyra is found in stagnant water forming green layer around the surface called pond scum.

Being photosynthetic, algae increase the level of dissolved oxygen in their immediate environment.

Kelps are marine algae of class phaeophyceae or brown algae. The body of kelp may reach upto 100 meter long. They vary in colour from olive green to various shades of brown depending upon xanthophyll pigments , fucoxanthin present in  them.

 In Phaeophyceae, food is stored as complex carbohydrates which may be in the form of laminarin or mannitol.

The common forms of Brown algae or Phaeophyceae are Ectocarpus, Dictyota, Laminaria, Sargassum and Fucus.

Green algae usually have a rigid cell wall made of an inner layer of cellulose and an outer layer of pectose.

Agar, one of the commercial products obtained from Gelidium are used to grow microbes and in preparations of ice-creams and jellies.

Fusion between one large, non-motile female gamete and a smaller, motile male gamete is termed as oogamous e.g., Volvox, Fucus.

The algal class Rhodophyta are commonly called as red algae because it contain red pigment, r-phycoerythrin  along with chlorophyll a and d.

The shape of a chloroplast varies from species to species. It may be cup-shaped (e.g., Chlamydomonas), (e.g., Vaucheria), Girdle (e.g., Ulothrix), Stellate or Star-shaped (e.g., Zygnema), Reticulate or net-like (e.g., Cladophora, Oedogonium), Spiral or ribbon or scalariform (e.g., Spirogyra), ovoid or disc or spheroid in higher plants

Green patchy structure that develops around the surface of stagnant water bodies having thread like mass are called pond scum. They are actually a species of green algae ],Spirogyra.