Morphology in Flowering Plants 3 Flashcards
what does androecium made of
Androecium is composed of stamens. Each stamen which
represents the male reproductive organ consists of a stalk or a
filament and an anther. Each anther is usually bilobed and each
lobe has two chambers, the pollen-sacs. The pollen grains are
produced in pollen-sacs. A sterile stamen is called staminode.
different ways in which the stamen exists
Stamens of flower may be united with other members such as
petals or among themselves. When stamens are attached to the
petals, they are epipetalous as in brinjal, or epiphyllous when
attached to the perianth as in the flowers of lily. The stamens in a
flower may either remain free (polyandrous) or may be united in
varying degrees. The stamens may be united into one bunch or
one bundle (monoadelphous) as in china rose, or two bundles
(diadelphous) as in pea, or into more than two bundles
(polyadelphous) as in citrus. There may be a variation in the length
of filaments within a flower, as in Salvia and mustard.
explain gynoecium and structure of 1 carpel
Gynoecium is the female reproductive part of the flower and is made
up of one or more carpels. A carpel consists of three parts namely
stigma, style and ovary. Ovary is the enlarged basal part, on which
lies the elongated tube, the style. The style connects the ovary to the
stigma. The stigma is usually at the tip of the style and is the
receptive surface for pollen grains.
different ways in which carpels exist in flower
When more
than one carpel is present, they may be free (as in lotus and rose)
and are called apocarpous. They are termed syncarpous when
carpels are fused, as in mustard and tomato. After fertilisation, the
ovules develop into seeds and the ovary matures into a fruit.
wht is placenta? what is placentation
Each ovary bears one or more
ovules attached to a flattened, cushion-like placenta
The arrangement of ovules within the ovary is known
as placentation. The placentation are of different types namely,
marginal, axile, parietal, basal, central and free central
types of placentation
In marginal placentation the placenta forms a ridge along the
ventral suture of the ovary and the ovules are borne on this ridge
forming two rows, as in pea.
When the placenta is axial and the
ovules are attached to it in a multilocular ovary, the placentaion is
said to be axile, as in china rose, tomato and lemon.
In parietal
placentation, the ovules develop on the inner wall of the ovary or
on peripheral part. Ovary is one-chambered but it becomes twochambered due to the formation of the false septum, e.g., mustard
and Argemone.
When the ovules are borne on central axis and
septa are absent, as in Dianthus and Primrose the placentation iscalled free central.
In basal placentation, the placenta develops at the
base of ovary and a single ovule is attached to it, as in sunflower, marigold.
what is the fruit
The fruit is a characteristic feature of the flowering plants. It is a mature
or ripened ovary, developed after fertilisation. If a fruit is formed without
fertilisation of the ovary, it is called a parthenocarpic fruit.
what are the parts of fruit
Generally, the fruit consists of a wall or pericarp and seeds. The
pericarp may be dry or fleshy. When pericarp is thick and fleshy, it is
differentiated into the outer epicarp, the middle mesocarp and the inner
endocarp.
mango and coconut are drupe fruits. what are their parts
In mango and coconut, the fruit is known as a drupe (Figure 5.17).
They develop from monocarpellary superior ovaries and are one seeded.
In mango the pericarp is well differentiated into an outer thin epicarp, a
middle fleshy edible mesocarp and an inner stony hard endocarp. In
coconut which is also a drupe, the mesocarp is fibrous.
what is a seed
The ovules after fertilisation, develop into seeds. A seed is made up of a
seed coat and an embryo. The embryo is made up of a radicle, an embryonal
axis and one (as in wheat, maize) or two cotyledons (as in gram and pea).
what is dicot seed
The outermost covering of a seed is the seed coat. The seed coat has two
layers, the outer testa and the inner tegmen. The hilum is a scar on the
seed coat through which the developing seeds were attached to the fruit.
Above the hilum is a small pore called the
micropyle. Within the seed coat is the embryo,
consisting of an embryonal axis and two
cotyledons. The cotyledons are often fleshy and
full of reserve food materials. At the two ends of
the embryonal axis are present the radicle and
the plumule (Figure 5.14). In some seeds such
as castor the endosperm formed as a result of
double fertilisation, is a food storing tissue and
called endospermic seeds. In plants such as
bean, gram and pea, the endosperm is not
present in mature seeds and such seeds are
called non-endospermous
monocot seed
Generally, monocotyledonous seeds are endospermic but some as in
orchids are non-endospermic. In the seeds of cereals such as maize the
seed coat is membranous and generally fused with the fruit wall. The
endosperm is bulky and stores food. The outer covering of endosperm
separates the embryo by a proteinous layer called aleurone layer. The
embryo is small and situated in a groove at one end of the endosperm. It
consists of one large and shield shaped cotyledon known as scutellum
and a short axis with a plumule and a radicle. The plumule and radicle
are enclosed in sheaths which are called coleoptile and coleorhiza
respectively
describe solanaceae
It is a large family, commonly called as the ‘potato family’. It is widely
distributed in tropics, subtropics and even temperate zones.
what are the vegative characters
Plants mostly herbs, shrubs and rarely small trees
Stem: herbaceous rarely woody, aerial; erect, cylindrical, branched, solid
or hollow, hairy or glabrous(smooth), underground stem in potato (Solanum
tuberosum)
Leaves: alternate, simple, rarely pinnately compound, exstipulate;
venation reticulate
floral chatcers if solanceae
Inflorescence : Solitary, axillary or cymose as in Solanum
Flower: bisexual, actinomorphic,pentamerous,hypogynous
Calyx: sepals five, united, persistent, valvate aestivation
Corolla: petals five, united; valvate aestivation
Androecium: stamens five, epipetalous
Gynoecium: bicarpellary obligately placed, syncarpous; ovary superior,
bilocular, placenta swollen with many ovules, axile
Fruits: berry or capsule
Seeds: many, endospermous
