seed scale ciomplex

1. MADE BY:-
GUIDED BY:-
DEEPAK YADAV
Master of science-m.sc
A.U. PRF.D R MISHRA
PRF, DK CHAUHAN
TOPIC –SEED SCALE COMPLEX

2. SEWARD’s hypotheses -
Perhaps the Lycopsida form a gymnosperm because l.s. of Selaginela
megasporangium it shown megaspore 3 abortive , ligule, sporophyll and
megasporangia.
Sporophyll-bract scale
Ligules- ovuleferous scale
Megasporangiophyll-cone
They are analogous parts
As for as leaf is concerned –Lycopodium. clavatum –they are microsporophyll’s as
that of conifers
Lycopsida- It originate conifer
Filicopsida- It originated Cycas and Pteridosperm

3. FLORIN SEWARd

4. Florin’s hypotheses (SWEDEN, 1894-1965)
Florin 1951 –ovuliferous scale is compound structure and not simple as
proposed by seward.
Lebachia - Ernetiodendron –Voltiza – Pseudovolzia – Olmannia
During carboniferous and permian these plant appeared and source of coal
FLORIN called is “samen schoppen komplex” which means Seed scale
complex .

5. Lebachia, voltzia, psudovoltzia

6. Voltziales and the origin of the
ovuliferous scales
Although the evidence from organography,
comparative anatony, and ontology supports
the view that ovulate cones in the conifers is
a compound strobilous,the phylogenetic
origin of the ovuliferous scales remains to
be explained. The scale is similar to
sporophyll in that it bears ovules, but its
axillary position with reference to a bract
represents a puzziling situation from an
evilutionary point of view, of all the
conflicting and involved theories that have
been proposed during the past century,the
most plausible and best supported view
was advanced by Florin:

7. Florin termed the fertile shoot in
these and other conifers “seed scale
complexes” and belived they support the
view that the compound megasporangiate
strobilus is the primary form in the
coniferales, with the exception of the taxales
(taxaceae). The great man regarded the
taxales as having the separate evolutanory
history because of they lack definable seed
cones: this view has been questioned in
recent years (Miller,1977).

8. In summary, the main trends in seed cone & seed
scale evolutoin have been towards:--
(1)the elimination of all but a few sterile scales,
which became fused into the so-called ovuliferous
scale,
(2)the recurvation of ovules and suppression of their
stalks,
(3)their final incorporation with the lower adaxial
side of the ovuliferous scales in derived conifers. On
the basis of the ground plan-divergence method of
cladistics,Miller(1982) have proposed
a phylogeny of the voltziales and modern-day
families of the coniferales based upon fourteen
characters of the bract, seed scale complex.

16. Mature female Pinus coulteri cone An Aleppo Pine cone
Conifer cone possesing seed scale complex

17. A cone (in formal botanical usage: strobilus, plural strobili) is an organ
on plants in the division Pinophyta (conifers) that contains the
reproductive structures. The familiar woody cone is the female cone,
which produces seeds. The male cones, which produce pollen, are
usually herbaceous and much less conspicuous even at full maturity. The
name "cone" derives from the fact that the shape in some species
resembles a geometric cone. The individual plates of a cone are known
as scales.
The male cone (microstrobilus or pollen cone) is structurally similar
across all conifers, differing only in small ways (mostly in scale
arrangement) from species to species. Extending out from a central axis
are microsporophylls (modified leaves). Under each microsporophyll is
one or several microsporangia (pollen sacs).
The female cone (megastrobilus, seed cone, or ovulate cone) contains
ovules which, when fertilized by pollen, become seeds. The female cone
structure varies more markedly between the different conifer families,
and is often crucial for the identification of many species of conifers.

18. Female cones of the conifer families
Pinaceae cones
Intact and disintegrated fir cones
Young cones of a Colorado Blue Spruce

19. The members of the pine family (pines, spruces, firs, cedars, larches, etc.) have cones
that are imbricate (that is, with scales overlapping each other like fish scales). These
are the "archetypal" cones. The scales are spirally arranged in fibonacci number ratios.
The female cone has two types of scale: the bract scales, derived from a
modified leaf, and the seed scales (or ovuliferous scales), one subtended by
each bract scale, derived from a highly modified branchlet. On the upper-side
base of …..
each seed scale are two ovules that develop into seeds after fertilization by pollen
grains. The bract scales develop first, and are conspicuous at the time of pollination;
the seed scales develop later to enclose and protect the seeds, with the bract scales
often not growing further. The scales open temporarily to receive gametophytes, then
close during fertilization and maturation, and then re-open again at maturity to allow
the seed to escape. Maturation takes 6–8 months from pollination in most Pinaceae
genera, but 12 months in cedars and 18–24 months (rarely more) in most pines. The
cones open either by the seed scales flexing back when they dry out, or (in firs, cedars
and golden larch) by the cones disintegrating with the seed scales falling off. The cones
are conic, cylindrical or ovoid (egg-shaped), and small to very large, from 2–60 cm long
and 1–20 cm broad.

20. Araucariaceae cones
Members of the Araucariaceae (Araucaria, Agathis, Wollemia) have
the bract and seed scales fully fused, and have only one ovule on
each scale. The cones are spherical or nearly so, and large to very
large, 5–30 cm diameter, and mature in 18 months; at maturity, they
disintegrate to release the seeds. In Agathis, the seeds are winged
and separate readily from the seed scale, but in the other two
genera, the seed is wingless and fused to the scale.

21. Podocarpaceae cones
Berry-like Podocarpus cone

22. The cones of the Podocarpaceae are similar in function, though
not in development, to those of the Taxaceae (q.v. below), being
berry-like with the scales highly modified, evolved to attract birds
into dispersing the seeds. In most of the genera, two to ten or
more scales are fused together into a usually swollen, brightly
coloured, soft, edible fleshy aril. Usually only one or two scales at
the apex of the cone are fertile, each bearing a single wingless
seed, but in Saxegothaea several scales may be fertile. The fleshy
scale complex is 0.5–3 cm long, and the seeds 4–10 mm long. In
some genera (e.g. Prumnopitys), the scales are minute and not
fleshy, but the seed coat develops a fleshy layer instead, the cone
having the appearance of one to three small plums on a central
stem. The seeds have a hard coat evolved to resist digestion in the
bird's stomach, and are passed in the bird's droppings.

23. Cupressaceae cones
Juniper "berries", which are used to flavor gin, are actually modified cones.
Giant Sequoia cones

24. Members of the cypress family (cypresses, arborvitae, junipers,
redwoods, etc.) differ in that the bract and seed scales are fully fused,
with the bract visible as no more than a small lump or spine on the
scale. The botanical term galbulus (plural galbuli; from the Latin for a
cypress cone) is sometimes used instead of strobilus for members of this
family. The female cones have one to 20 ovules on each scale. They
often have peltate scales, as opposed to the imbricate cones described
above, though some have imbricate scales. The cones are usually small,
0.3–6 cm long, and often spherical or nearly so, like those of Nootka
Cypress, while others, such as Western Redcedar, are narrow. The scales
are arranged either spirally, or in decussate whorls of two (opposite
pairs) or three, rarely four. The genera with spiral scale arrangement
were often treated in a separate family (Taxodiaceae) in the past. In
most of the genera, the cones are woody and the seeds have two
narrow wings (one along each side of the seed), but in three genera
(Platycladus, Microbiota and Juniperus), the seeds are wingless, and in
Juniperus, the cones are fleshy and berry-like.

25. Tetraclinis cones

26. Sciadopityaceae cones
The cones and seeds of Sciadopitys (the only member of the
family) are similar to those of some Cupressaceae, but larger,
6–11 cm long; the scales are imbricate and spirally arranged,
and have 5-9 ovules on each scale.

27. Taxaceae and Cephalotaxaceae cones
Berry-like yew cone

28. Members of the yew family and the closely related
Cephalotaxaceae have the most highly modified cones of any
conifer. There is only one scale in the female cone, with a
single poisonous ovule. The scale develops into a soft, brightly
coloured sweet, juicy, berry-like aril which partly encloses the
deadly seed. The seed alone is poisonous. The whole 'berry'
with the seed is eaten by birds, which digest the sugar-rich
scale and pass the hard seed undamaged in their droppings,
so dispersing the seed far from the parent plant.

29. Cycadaceae cones
This group of cone-bearing plants retains some types of
'primitive' characteristics. Its leaves unfurl, much like ferns.
There are three extant families of Cycads of about 305
species. It reproduces with large cones, and is related to the
other conifers in that regard, but it does not have a woody
trunk like most cone-bearing families.

30. Welwitschiaceae cones
A unique cone-bearing plant in the Order Welwitschiales,
Welwitschia mirabilis is often called a living fossil and is the
only species in its genus, which is the only genus in its
family, which is the only family in its Order. The male cones
are on male plants, and female cones on female plants.
After emergence of the two cotyledons, it sets only two
more leaves. Those two leaves then continue to grow longer
from their base, much like fingernails. This allows it great
drought tolerance, which is likely why it has survived in the
desert of Namibia, while all other representatives from its
order are now extinct.

31. REFERENCE:-
MORPHOLOGY AND EVOLUTION OF
VASCULAR PLANTS;
E M GIFFORD; A S FOSTER
GOOGLE;WIKIPEDIA, CONIFER
CONE

32. Thank you…..