Select one of the following pairs of important features distinguishing Gnetum from Cycas and Pinus and showing affinities with angiosperms
Perianth and no integuments
Embryo development and apical meristem
Absence of resin duct and leaf venation
Presence of vessel elements and absence of archegonia
D.
Presence of vessel elements and absence of archegonia
Unlike Cycas and Pinus, Gnetum shows the occurrence of vessel elements and the complete absence of archegonia in female gametophyte. Thus, Gnetum shows affinities with angiosperms. Besides its resembles with angiosperms in several other aspects like presence of tetrasporic embryo sac, free nuclear divisions in the embryo sac, two cotyledonous embryo, etc
Match the following and select correct option.
Column1 Column2
A. Pteris 1) Gymnosperm
B. Cycas 2) Bryophyte
C. Sphagnum 3) Algae
D. Sargassum 4) Pteridophyta
A-(4), B-(2), C-(1), D-(3)
A-(4), B-(1), C-(2), D-(3)
A-(2), B-(3), C-(4), D-(1)
A-(1), B-(4), C-(3), D-(2)
Which of the following are homosporous pteridophytes?
I. Selaginella
II. Lycopodium
III. Salvinia
IV. Equisetum
I and IV only
II and III only
II and IV only
III and IV only
Select the mismatched pair out of the following
Rhizome - Dryopteris, Nelumbo nucifera
Corm - Crocus sativus, Amorphophallus
Sucker -Curcuma domestica, Zingiber officinale
Tuber -Helianthus tuberosus, Solanum tuberosum
Assertion: Endomycorrhiza of forest trees contribute to the efficient nutrient cycling in tropical forest ecosystems.
Reason: The fungi that formendo-mycorrhizal associations with plants make nutrient ions available to them.
If both assertion and reason are true and reason is the correct explanation of assertion.
If both assertion and reason are true but reason is not the correct explanation of assertion.
If assertion is true but reason is false.
If both assertion and reason are false.
Pick the correct group consisting of all genera exhibiting homospory
Lycopodium, Psilotum, Selaginella, Equisetum
Equisetum, Pteris, Salvinia, Psilotum
Salvinia, Pteris, Lycopodium, Selaginella
Equisetum, Psilotum, Lycopodium, Pteris
The lack of fruit formation in gymnosperm is due to
absence of fertilization
lack of seeds
naked ovule
sheding of immature seed
