259529
Select one of the following pairs of important features distinguishing Gnetum is from Cycas and Pinus and showing affinities with angiosperms.
1 Perianth and two integuments.
2 Embryo development and apical meristem.
3 Absence of resin duct and leaf venation.
4 Presence of vessel elements and absence of archegonia
Explanation:
Gnetum is a genus of gymnosperms, the sole genus in the family Gnetaceae and order Gnetales. - They are tropical ever green trees, shrubs and lianas, unlike other gymnosperms they possess vessel elements in the xylem. - Gnetum has no archegonia, some free nuclei present as eggs but vessles are present. The female gametophyte initially is partially developed and developed fully after fertilization. - The presence of short apices is the characteristic of Gnetum which is also found is angiosperms. - The ovules of the Gnetum are also enclosed.
AIIMS-2008
Plant kingdom
259530
Cycas is classified as a gymnosperms due to its
1 Motile sperms
2 Fruit formation
3 Naked ovule
4 Phycnoxylic wood
Explanation:
Cycas is classified as a gymnosperms. In this plant ovules are not enclosed by any ovary wall (naked ovule) and remain exposed, both before and after fertilization. - Most of the seed plants have pollen, which contain and transports the sperm to fertilize the egg. - As pollen is resistant to desiccation, the sperm can be transported between plants across large distances without drying up. - The gymnosperms (naked seed plants) consists of four phyla: conifers, cycads, gingkoes and gnetophytes. Cycads produce pollen, but the sperm still swims down the pollen tube using flagella. As it also has a naked seed, it is classified as gymnosperm.
AIIMS-2014
Plant kingdom
259537
Transfusion tissue for lateral conduction of water and food are found in
1 roots of gymnosperms
2 stem of gymnosperms
3 leaves of gymnosperms
4 leaves of angiosperms
5 None of the above
Explanation:
Transfusion tissue or hydrostereom for conduction of water and food are found in leaves or leaflets of pinus and cycas. It is the tissue that is found characteristically around the vascular bundles of gymnosperm leaves consisting of parenchyma, lignified and non-lignified tracheids with bordered pits. - The root system present in the gymnosperm is the taproot system. In some plants coralloid roots are found. - The stem of gymnosperms can be branched or unbranched - Angiosperm leaves typically have a blade or lamina, a flattened part with high chloroplast concentration.
CMC Vellore-2015
Plant kingdom
259539
Wood of Cycas is:
1 pycnoxylic only
2 polyxylic only
3 manoxylic and polyxylic
4 none of the above
Explanation:
Secondary wood in cycas is manoxylic wood. It is a non-compact wood with large amount of parenchyma large pith and cortex mixed with xylem tracheids. It lacks vessels and is not used commercially as it is not durable. - Pycnoxylic wood is a compact strong wood with large no. of xylem tracheids or wood and a small amount of cortex and pith with little parenchyma. - Polyxylic wood is a dense wood with a high amount of secondary xylem.
259529
Select one of the following pairs of important features distinguishing Gnetum is from Cycas and Pinus and showing affinities with angiosperms.
1 Perianth and two integuments.
2 Embryo development and apical meristem.
3 Absence of resin duct and leaf venation.
4 Presence of vessel elements and absence of archegonia
Explanation:
Gnetum is a genus of gymnosperms, the sole genus in the family Gnetaceae and order Gnetales. - They are tropical ever green trees, shrubs and lianas, unlike other gymnosperms they possess vessel elements in the xylem. - Gnetum has no archegonia, some free nuclei present as eggs but vessles are present. The female gametophyte initially is partially developed and developed fully after fertilization. - The presence of short apices is the characteristic of Gnetum which is also found is angiosperms. - The ovules of the Gnetum are also enclosed.
AIIMS-2008
Plant kingdom
259530
Cycas is classified as a gymnosperms due to its
1 Motile sperms
2 Fruit formation
3 Naked ovule
4 Phycnoxylic wood
Explanation:
Cycas is classified as a gymnosperms. In this plant ovules are not enclosed by any ovary wall (naked ovule) and remain exposed, both before and after fertilization. - Most of the seed plants have pollen, which contain and transports the sperm to fertilize the egg. - As pollen is resistant to desiccation, the sperm can be transported between plants across large distances without drying up. - The gymnosperms (naked seed plants) consists of four phyla: conifers, cycads, gingkoes and gnetophytes. Cycads produce pollen, but the sperm still swims down the pollen tube using flagella. As it also has a naked seed, it is classified as gymnosperm.
AIIMS-2014
Plant kingdom
259537
Transfusion tissue for lateral conduction of water and food are found in
1 roots of gymnosperms
2 stem of gymnosperms
3 leaves of gymnosperms
4 leaves of angiosperms
5 None of the above
Explanation:
Transfusion tissue or hydrostereom for conduction of water and food are found in leaves or leaflets of pinus and cycas. It is the tissue that is found characteristically around the vascular bundles of gymnosperm leaves consisting of parenchyma, lignified and non-lignified tracheids with bordered pits. - The root system present in the gymnosperm is the taproot system. In some plants coralloid roots are found. - The stem of gymnosperms can be branched or unbranched - Angiosperm leaves typically have a blade or lamina, a flattened part with high chloroplast concentration.
CMC Vellore-2015
Plant kingdom
259539
Wood of Cycas is:
1 pycnoxylic only
2 polyxylic only
3 manoxylic and polyxylic
4 none of the above
Explanation:
Secondary wood in cycas is manoxylic wood. It is a non-compact wood with large amount of parenchyma large pith and cortex mixed with xylem tracheids. It lacks vessels and is not used commercially as it is not durable. - Pycnoxylic wood is a compact strong wood with large no. of xylem tracheids or wood and a small amount of cortex and pith with little parenchyma. - Polyxylic wood is a dense wood with a high amount of secondary xylem.
259529
Select one of the following pairs of important features distinguishing Gnetum is from Cycas and Pinus and showing affinities with angiosperms.
1 Perianth and two integuments.
2 Embryo development and apical meristem.
3 Absence of resin duct and leaf venation.
4 Presence of vessel elements and absence of archegonia
Explanation:
Gnetum is a genus of gymnosperms, the sole genus in the family Gnetaceae and order Gnetales. - They are tropical ever green trees, shrubs and lianas, unlike other gymnosperms they possess vessel elements in the xylem. - Gnetum has no archegonia, some free nuclei present as eggs but vessles are present. The female gametophyte initially is partially developed and developed fully after fertilization. - The presence of short apices is the characteristic of Gnetum which is also found is angiosperms. - The ovules of the Gnetum are also enclosed.
AIIMS-2008
Plant kingdom
259530
Cycas is classified as a gymnosperms due to its
1 Motile sperms
2 Fruit formation
3 Naked ovule
4 Phycnoxylic wood
Explanation:
Cycas is classified as a gymnosperms. In this plant ovules are not enclosed by any ovary wall (naked ovule) and remain exposed, both before and after fertilization. - Most of the seed plants have pollen, which contain and transports the sperm to fertilize the egg. - As pollen is resistant to desiccation, the sperm can be transported between plants across large distances without drying up. - The gymnosperms (naked seed plants) consists of four phyla: conifers, cycads, gingkoes and gnetophytes. Cycads produce pollen, but the sperm still swims down the pollen tube using flagella. As it also has a naked seed, it is classified as gymnosperm.
AIIMS-2014
Plant kingdom
259537
Transfusion tissue for lateral conduction of water and food are found in
1 roots of gymnosperms
2 stem of gymnosperms
3 leaves of gymnosperms
4 leaves of angiosperms
5 None of the above
Explanation:
Transfusion tissue or hydrostereom for conduction of water and food are found in leaves or leaflets of pinus and cycas. It is the tissue that is found characteristically around the vascular bundles of gymnosperm leaves consisting of parenchyma, lignified and non-lignified tracheids with bordered pits. - The root system present in the gymnosperm is the taproot system. In some plants coralloid roots are found. - The stem of gymnosperms can be branched or unbranched - Angiosperm leaves typically have a blade or lamina, a flattened part with high chloroplast concentration.
CMC Vellore-2015
Plant kingdom
259539
Wood of Cycas is:
1 pycnoxylic only
2 polyxylic only
3 manoxylic and polyxylic
4 none of the above
Explanation:
Secondary wood in cycas is manoxylic wood. It is a non-compact wood with large amount of parenchyma large pith and cortex mixed with xylem tracheids. It lacks vessels and is not used commercially as it is not durable. - Pycnoxylic wood is a compact strong wood with large no. of xylem tracheids or wood and a small amount of cortex and pith with little parenchyma. - Polyxylic wood is a dense wood with a high amount of secondary xylem.
259529
Select one of the following pairs of important features distinguishing Gnetum is from Cycas and Pinus and showing affinities with angiosperms.
1 Perianth and two integuments.
2 Embryo development and apical meristem.
3 Absence of resin duct and leaf venation.
4 Presence of vessel elements and absence of archegonia
Explanation:
Gnetum is a genus of gymnosperms, the sole genus in the family Gnetaceae and order Gnetales. - They are tropical ever green trees, shrubs and lianas, unlike other gymnosperms they possess vessel elements in the xylem. - Gnetum has no archegonia, some free nuclei present as eggs but vessles are present. The female gametophyte initially is partially developed and developed fully after fertilization. - The presence of short apices is the characteristic of Gnetum which is also found is angiosperms. - The ovules of the Gnetum are also enclosed.
AIIMS-2008
Plant kingdom
259530
Cycas is classified as a gymnosperms due to its
1 Motile sperms
2 Fruit formation
3 Naked ovule
4 Phycnoxylic wood
Explanation:
Cycas is classified as a gymnosperms. In this plant ovules are not enclosed by any ovary wall (naked ovule) and remain exposed, both before and after fertilization. - Most of the seed plants have pollen, which contain and transports the sperm to fertilize the egg. - As pollen is resistant to desiccation, the sperm can be transported between plants across large distances without drying up. - The gymnosperms (naked seed plants) consists of four phyla: conifers, cycads, gingkoes and gnetophytes. Cycads produce pollen, but the sperm still swims down the pollen tube using flagella. As it also has a naked seed, it is classified as gymnosperm.
AIIMS-2014
Plant kingdom
259537
Transfusion tissue for lateral conduction of water and food are found in
1 roots of gymnosperms
2 stem of gymnosperms
3 leaves of gymnosperms
4 leaves of angiosperms
5 None of the above
Explanation:
Transfusion tissue or hydrostereom for conduction of water and food are found in leaves or leaflets of pinus and cycas. It is the tissue that is found characteristically around the vascular bundles of gymnosperm leaves consisting of parenchyma, lignified and non-lignified tracheids with bordered pits. - The root system present in the gymnosperm is the taproot system. In some plants coralloid roots are found. - The stem of gymnosperms can be branched or unbranched - Angiosperm leaves typically have a blade or lamina, a flattened part with high chloroplast concentration.
CMC Vellore-2015
Plant kingdom
259539
Wood of Cycas is:
1 pycnoxylic only
2 polyxylic only
3 manoxylic and polyxylic
4 none of the above
Explanation:
Secondary wood in cycas is manoxylic wood. It is a non-compact wood with large amount of parenchyma large pith and cortex mixed with xylem tracheids. It lacks vessels and is not used commercially as it is not durable. - Pycnoxylic wood is a compact strong wood with large no. of xylem tracheids or wood and a small amount of cortex and pith with little parenchyma. - Polyxylic wood is a dense wood with a high amount of secondary xylem.
