PLANT ORGAN – FLOWERS, SEEDS, FRUITS
Hay Fever/Allergic Rhinitis
• This is caused by inhalation of the pollen grains of certain wind-pollinated plants, that
is, plants that rely on wind to transfer their pollen grains from one flower to another.
• When inhaled, the pollen grains stimulate the body to release histamine and other
substances, which cause inflammation and other symptoms of allergy.
• Wind-pollinated plants must produce vast amounts of tiny pollen grains to ensure
that at least some of them will land on flowers of the same species and result in
successful reproduction.
• Not all pollen grains of wind-pollinated plants cause allergic reactions, however. Pines,
for example, are wind pollinated, yet allergies to pine pollen are rare.
Reproductive Flexibility
• One reason for the success of flowering plants, or angiosperms, is that they
reproduce both sexually and asexually.
• The biological function of flowers, however, is sexual reproduction.
• Their varied colors, shapes, and fragrances are adaptations (evolutionary
modifications) that increase the likelihood that pollen grains will be carried from plant
to plant.
• Sexual reproduction entails the fusion of reproductive cells, collectively called
gametes.
• The union of gametes, which is called fertilization, occurs within the flower’s ovary.
• Offspring of plants that reproduce sexually show considerable genetic variation.
• Sexual reproduction offers the advantage of new combinations of genes not found in
either parent.
• These new gene combinations may make an individual plant better suited to its
environment.
• Asexual reproduction does not involve the formation of flowers, seeds and fruits.
• Instead, offspring, generally form asexually when a vegetative structure of an existing
plant expands, grows and the becomes separated from the rest of the plant, often by
the death of tissues.
• The offspring of asexual reproduction are virtually genetically identical to each other
and to the parent plant from which they came.
Flowers
• A flower is a reproductive shoot usually consisting of four kinds of organs—sepals,
petals, stamens, and carpels—arranged in whorls (circles) on the end of a flower stalk,
or peduncle.
• Peduncle is at the end of a flower stalk that may terminate in a single flower or a
cluster of flowers known as an inflorescence.
• Receptacle forms when the tip of the peduncle enlarges that bears some or all of the
flower parts.
• Stamens and Carpels participate directly in sexual reproduction.
PHBIOSC201 – Pharm. Botany w/ Taxonomy Lecture
Rody Rica B. Agdipa, RPh
, • Sepals constitute the outermost and lowest whorl on a floral shoot, are leaflike in
shape and form and are often green.
• Calyx is the collective term for all the sepals of a flower.
• Petals are whorls just inside and above the sepals which are broad, flat and thin, but
tremendously varied in shape and frequently brightly colored, which attracts
pollinators.
• Corolla is the collective term for all petals
• Each stamen has a thin stalk called a filament, at the top of which is an anther, a
saclike structure in which pollen grains form.
• Needs to be transferred from the anther to the carpel for the sexual reproduction to
occur.
• At first, each consists of two cells surrounded by a tough outer wall.
• One cell generates two male gametes, known as sperm cells, and, the other produces
a pollen tube through which the sperm cells travel to reach the ovule.
Carpels
• May be separate or fused into a single structure
• A single carpel or a group of fused carpels is sometimes called a pistil. A pistil may
consist of a single carpel or a group of fused carpels.
• In most flowers, each carpel or group of fused carpels has three sections.
• Stigma is where pollen grains land.
• Style is a neck-like structure through which the pollen tube grows.
• Ovary is a jug-like structure that contains one or more ovules and can be develop into
a fruit.
Ovary
PHBIOSC201 – Pharm. Botany w/ Taxonomy Lecture
Rody Rica B. Agdipa, RPh
Hay Fever/Allergic Rhinitis
• This is caused by inhalation of the pollen grains of certain wind-pollinated plants, that
is, plants that rely on wind to transfer their pollen grains from one flower to another.
• When inhaled, the pollen grains stimulate the body to release histamine and other
substances, which cause inflammation and other symptoms of allergy.
• Wind-pollinated plants must produce vast amounts of tiny pollen grains to ensure
that at least some of them will land on flowers of the same species and result in
successful reproduction.
• Not all pollen grains of wind-pollinated plants cause allergic reactions, however. Pines,
for example, are wind pollinated, yet allergies to pine pollen are rare.
Reproductive Flexibility
• One reason for the success of flowering plants, or angiosperms, is that they
reproduce both sexually and asexually.
• The biological function of flowers, however, is sexual reproduction.
• Their varied colors, shapes, and fragrances are adaptations (evolutionary
modifications) that increase the likelihood that pollen grains will be carried from plant
to plant.
• Sexual reproduction entails the fusion of reproductive cells, collectively called
gametes.
• The union of gametes, which is called fertilization, occurs within the flower’s ovary.
• Offspring of plants that reproduce sexually show considerable genetic variation.
• Sexual reproduction offers the advantage of new combinations of genes not found in
either parent.
• These new gene combinations may make an individual plant better suited to its
environment.
• Asexual reproduction does not involve the formation of flowers, seeds and fruits.
• Instead, offspring, generally form asexually when a vegetative structure of an existing
plant expands, grows and the becomes separated from the rest of the plant, often by
the death of tissues.
• The offspring of asexual reproduction are virtually genetically identical to each other
and to the parent plant from which they came.
Flowers
• A flower is a reproductive shoot usually consisting of four kinds of organs—sepals,
petals, stamens, and carpels—arranged in whorls (circles) on the end of a flower stalk,
or peduncle.
• Peduncle is at the end of a flower stalk that may terminate in a single flower or a
cluster of flowers known as an inflorescence.
• Receptacle forms when the tip of the peduncle enlarges that bears some or all of the
flower parts.
• Stamens and Carpels participate directly in sexual reproduction.
PHBIOSC201 – Pharm. Botany w/ Taxonomy Lecture
Rody Rica B. Agdipa, RPh
, • Sepals constitute the outermost and lowest whorl on a floral shoot, are leaflike in
shape and form and are often green.
• Calyx is the collective term for all the sepals of a flower.
• Petals are whorls just inside and above the sepals which are broad, flat and thin, but
tremendously varied in shape and frequently brightly colored, which attracts
pollinators.
• Corolla is the collective term for all petals
• Each stamen has a thin stalk called a filament, at the top of which is an anther, a
saclike structure in which pollen grains form.
• Needs to be transferred from the anther to the carpel for the sexual reproduction to
occur.
• At first, each consists of two cells surrounded by a tough outer wall.
• One cell generates two male gametes, known as sperm cells, and, the other produces
a pollen tube through which the sperm cells travel to reach the ovule.
Carpels
• May be separate or fused into a single structure
• A single carpel or a group of fused carpels is sometimes called a pistil. A pistil may
consist of a single carpel or a group of fused carpels.
• In most flowers, each carpel or group of fused carpels has three sections.
• Stigma is where pollen grains land.
• Style is a neck-like structure through which the pollen tube grows.
• Ovary is a jug-like structure that contains one or more ovules and can be develop into
a fruit.
Ovary
PHBIOSC201 – Pharm. Botany w/ Taxonomy Lecture
Rody Rica B. Agdipa, RPh
