Read the following five statements (I to V) and select the option with all correct statements.
I Mosses and lichens are the first organisms to colonise a bare rock.
II .Selaginella is a homosporous pteridophyte.
III. Coralloid roots in Cycas have VAM.
IV. Main plant body in bryophytes is gametophytic, whereas in pteridophytes it is sporophytic.
V. In gymnosperms, male and female gametophytes are present within sporangia located on sporophyte.
I, III and IV
II, III and IV
I, IV and V
I, IV and V
C.
I, IV and V
I, IV and V are correct statements.
II. Selaginella species are creeping or ascendant plants and produce heterospores (megaspores and microspores).
III. Caralloid roots are developed in Cycas. It produces as cluster at base of stem. It is dichotomously branched and greenish brown in colour. It contains algal zone in the cortex. This algal zone contains Nostoc and Anabaena.
A prokaryoticv autotrophic nitrogen-fixing symbiont is found in
Cycas
Cicer
Pisum
Pisum
A.
Cycas
The coralloid root of cycas is symbiotically associated with nitrogen fixing blue -green algae, Anabaena Cycadae and Nostoc punctiforme. These blue-green algae (Cyanobacteria) are prokaryotic, photosynthetic and autotrophic.
Read the following five statements and answer as asked to them
I. In Equisetum the female gametophyte is retained on the parent sporophyte.
II. In Ginkgo male gametophyte is not independent.
III. The sporophyte in Riccia is more developed than that in Polytrichum.
IV. Sexual reproduction in Volvox is isogamous.
V. The spores of the above statements are correct?
Two
Three
Four
Four
D.
Four
The spore of Equisetum germinate shortly after shedding and give rise to form prothallus. Prothalli of Equisetum are basically monoecious and the gametophytes are rarely seen.
The simplest known sporophyte among bryophytes is that of Riccia while highest evolved known is Bryopsida (Polytrichum, Pogonatum).
Sexual reproduction in Volvox is oogamous type.
The spores in slime molds (e.g., Physarum) are haploid, unicellular usually globose with smooth, spiny or reticulately thickened cell walls.
Gymnosperms are also called soft wood spermatophytes because they lack
cambium
phloem fibres
thick-walled tracheids
thick-walled tracheids
D.
thick-walled tracheids
Gymnosperms lack xylem fibres. Large amount of parenchymatous cells are present with secondary xylem tracheids. So, these are also known as softwood spermatophytes.
The second stage of hydrosere is occupied by plants like
Azolla
Typha
Salix
Salix
D.
Salix
Hydrosere originating in a pond starts with colonisation of some phytoplanktons which forms the pioneer plant community. The stages are
1st- Bacteria, Blue-green algae, Algae
2nd- Hydrilla Potamogeton, Vallisneria
3rd -Nelumbo, Nymphaea, Trapa, Azolla, Wolffia
4th-Typha, Sagitaria
5th- Juncus, Cyperus
6th- Salix, Populus, Almus
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