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Where do mosses grow?
Mosses grow in moist, shaded areas in hills and foot hills.
Mosses grow in moist, shaded areas in hills and foot hills.
See lessWhich pteridophyte is used in scrubbing and polishing?
Equisetum stems
Equisetum stems
See lessGive two examples of ferns.
Selaginella, Equisetum.
Selaginella, Equisetum.
See lessWhat are the main food reserves in algae?
Starch
Starch
See lessWho first initiated the phylogenetic system of classification?
Engler and Prantl (1887-1899).
Engler and Prantl (1887-1899).
See lessWhy Ginkgo biloba is called living fossil? Explain how is it useful for horticulturists. What are its important features? Why horticulturists prefer to grow only male plants?
Ginkgo biloba has not changed for last several millions of years, Since its appearance in triassic period. So, it is also called living fossil. Horticulturists are interested in Ginkgo as it has natural immunity to several plant diseases. Important features are as follows (i) The plant is a tall treRead more
Ginkgo biloba has not changed for last several millions of years,
See lessSince its appearance in triassic period. So, it is also called living
fossil.
Horticulturists are interested in Ginkgo as it has natural
immunity to several plant diseases.
Important features are as follows
(i) The plant is a tall tree of upto 30 m height.
(ii) Leaves are fan-shaped.
(iii) Leaves have furcate venation.
(iv) Dwarf shoots of female plant bear distinct
megasporangiate structures.
(v) Endosperm of roasted seed is edible.
Horticulturists prefer to grow only male plants, as female
plants give unpleasant smell.
What is heterospory? Briefly comment on its significance. Give two examples.
Heterospory is the phenomenon in which a plant produces two types of spores, namely microspores and megaspores. Heterospory is significant in the following ways (i) Microspores give rise to male gametophyte and megaspores give rise to female gametophyte. (ii) Female gametophyte is retained on the paRead more
Heterospory is the phenomenon in which a plant
See lessproduces two types of spores, namely microspores
and megaspores.
Heterospory is significant in the following ways
(i) Microspores give rise to male gametophyte and
megaspores give rise to female gametophyte.
(ii) Female gametophyte is retained on the parent
plant. The development of zygote takes place
within the female gametophyte.
(iii) This leads to formation of seeds.
Examples All gymnosperms and all
angiosperm, Pinus, Gnetum. neem, peepal. etc.
Describe the important characteristics of gymnosperms.
Characteristics of gymnosperms are as follows (i) Naked-seeded plants, i.e., their ovules are exposd and not enclosed in ovaries. Hence, the seeds are naked without fruits. (ii) Tap root system is present. They show synbiotg association with fungi to form mycorrhizae or with N2-fixing cyanobacteriaRead more
Characteristics of gymnosperms are as follows
See less(i) Naked-seeded plants, i.e., their ovules are exposd
and not enclosed in ovaries. Hence, the seeds are
naked without fruits.
(ii) Tap root system is present. They show synbiotg
association with fungi to form mycorrhizae or with
N2-fixing cyanobacteria to form coralloid roots as in
Cycas.
(iii) Leaves are large and needle-shaped.
(iv) Vascular tissues are well-developed.
(v) Gymnosperms are heterosporous.
(vi) Pollination by wind and deposited in ovules.
(vii) Fertilisation occurs in archegonia.
(viii) Retention of female gametophyte inside the
ovule and the ovules on the sporophytic plant
for complete development is responsible for
the development of seed habit.
What is the advantage of development of seed habits in seed plants?
Seed habit developed in extinct pteridosperms Cycadofilicales. It is a group intermediate betw cycads and ferns. The habit made the seed p independent of the requirement of external sources water at the time of fertilisation. In seedless vasculu plants, the gametophyte must develop on moist soil a tRead more
Seed habit developed in extinct pteridosperms
See lessCycadofilicales. It is a group intermediate betw
cycads and ferns. The habit made the seed p
independent of the requirement of external sources
water at the time of fertilisation. In seedless vasculu
plants, the gametophyte must develop on moist soil
a thin sheet of water. The latter is required for
swimming of sperms for reaching the female sex organ,
As a result, seedless vascular plants could never
true land plants. They were popularly called
amphibian of plant kingdom
Each plant or group of plants has some phylogenetic significance in relation to evolution. Cycas, one of the few living members of gymnosperms is called as 'relic of the past". Can you establish a phylogenetic relationship of Cycas with any other group of plants that justifies the above statement.
Cycas is called the 'relic of the past.' It has following properties to justify this (i) Monoxylic wood through secondary growth started (ii) Shedding of seed when embryo is still immature. (iii) Arrangement of microsporangia in all defined sori. Phylogenetically, Cycas is related to pteridosperms (Read more
Cycas is called the ‘relic of the past.’
See lessIt has following
properties to justify this
(i) Monoxylic wood through secondary growth started
(ii) Shedding of seed when embryo is still immature.
(iii) Arrangement of microsporangia in all defined sori.
Phylogenetically, Cycas is related to pteridosperms (sed
ferns) and through them to ferns from which it seems to
have evolved. It can be ascertained by the presence Of
(i) leaf-like megasporophyll
(ii) persistence of leaf bases.