LECTURE 6 Author: Ass.-prof. Shanayda M.I. MORPHOLOGY OF THE REPRODUCTIVE ORGANS OF PLANTS

The reproductive structures are usually specific to a particular group of plants, such as flowers and seeds, fern sori, and moss capsules. Structures such as flowers and fruits are only found in the Angiosperms.flowersseedssorimossflowersfruits

Flowers and fruits are widely used in medicine as medicinal raw material ( flowers chamomile, fructus oliv, raspberry ). They are diagnostic features in systematic of flowering plants.

Flower is the total reproductive structure of an Angiosperm. Its basic parts include the peduncle, receptacle, sepal, petal, stamens and carpels (pistils). The function of a flower is to produce male gametes and female gametes. Peduncle

Parts of flowers: 1)Peduncle ( pedicel in inflorescens ) 2)Receptacle *These parts of the flowers (pedicel and receptacle) structure have common origin with stem. 3 ) Perianth - the outer whorl of floral leaves of a flower; collectively, the calyx and corolla. 4)Androecium 5) Gynoecium

AndroeciumAndroecium Androecium one or two whorls of stamens, each a filament topped by an anther where pollen is produced. Pollen contains the male gametes. Type of androecium: number of stamens, their shape and arrangement. Androeciumstamens filamentantherpollengametes The androecium of sage flower, which consists of two long and two short stamens – it is Two-strong. of cabbage flower Four-strong

Gynoecium Gynoecium Gynoecium (from Greek gynaikos oikia: woman's house): one or more pistils. The female reproductive organ is the carpel:carpel this contains an ovary with ovules (which contain female gametes). In the flower of raspberries, spring adonis pistil (gynoecium) consists of many free carpels, that is apocarpous complex. In the flowers of cherry and pea gynoecium consists of one carpel, that is monocarpous simple. In the flowers of poppy gynoecium consists of many carpels, that grow together – this is cenocarpous.

an ovary In the flowering plants, an ovary is a part of the female reproductive organ of the flower or gynoecium. Specifically, it is the part of the carpel which holds the ovules. The position of the ovary with respect to the other parts of the flower is also variable. Three different positionsof flower exist - I - a hypogynous, II - an epigynousa perigynous I - a hypogynous, II - an epigynous III - a perigynous

A flower possessing sepal, petal, stamens and carpels is defined as a complete flower (cherry, rose). If any one (or more) of the four is absent, the flower is incomplete (tulip, lily, willow).

Sexual structure of plants In the majority of species individual flowers have both pistils and stamens. These flowers are described by botanists as being perfect, bisexual, or hermaphrodite (cherry, rose). However, in some species of plants hermaphrodite the flowers are imperfect or unisexual which having only either male (stamens) or female (pistil) parts (cucumber, maize, willow, poplar). Some plants have asexual flowers (snow-ball tree) Dioecious plants (willow, poplar) have male and female parts on separate ioecious plants. However, where unisexual male and female flowers appear plants. However, where unisexual male and female flowers appear on the same plant, the species is considered on the same plant, the species is considered monoeciousmonoecious (cucumber, maize, birch-tree) monoecious

Flower types (corolla types) cruciform – in Cabbage family, rosaseous – in Rose family, papilionaceous (pea-type) – in Legume family, bilabiate (mint-type) – in Mint family (has upper and lower lips), ligulate – in Sunflower family. pseudoligulate – in Sunflower family tubular – in Sunflower family too funnel form – in Sunflower family too inflate funnel (calcarate – in foxglove). Liliaceous - lily

Symmetry: Symmetry: Some flowers are actinomorphic (radially symmetrical) – in cherry, rose, tulip - and others are zygomorphic (bilaterally symmetrical) – in violet, bean.

Pollination of flower Entomophilous flowers Anemophilous flowers

Fertilisation

INFLORESCENCES Inflorescence is the shoot bearing flowers and no leaves. Also it is a group of flowers attached to a common axis in a specific arrangement. Flower is single when one flower per stem or the flowers are greatly spread-apart as to appear they do not arise from the same branch (poppy).

Types of simple monopodial inflorescences ( branching with a main axis and reduced or missing laterals) Raceme Raceme - (lily of the valley, digitalis) Spike Spike - (plantain)

Corymb Corymb - a grouping of flowers where all the flowers are at the same level, the flower stalks of different lengths forming a flat-topped flower cluster (apple). Umbel Umbel - were all the flower stalks rising from the same point of the same length, the flower head is rounded like an umbrella (cherry, onion).

Capitulum Capitulum - the flowers are arranged into a plate composed of many separate unstalked flowers, the in the Daisy (Asteraceae) familyAsteraceae (dandelion, sunflower).

Head Head - the flowers are arranged into a round composed of many separate unstalked flowers (clover). Spadix Spadix – consisting of a single fleshy axis with many small sessile flowers (female inflorescence in corn).

Types of compound monopodial inflorescences Compound umbel Compound umbel - is an umbel where each stalk of the main umbel produces another smaller umbel of flowers (dill, carrot). Compound corymb Compound corymb (rowan- tree). Compound spike Compound spike (wheat, barley). Compound raceme Compound raceme (rice, oat).

Verticillaster Verticillaster - a whorled collection of flowers around the stem, the flowers produced in rings at intervals up the stem. As the stem tip continues to grow more whorls of flowers are produced (gentian, mint, etc). Catkin Catkin is a cluster of flowers (birch- tree)

FRUITS Fruit – is the organ of Angiosperm containing seeds. Fruit a tru is the product of the ovary wall, and the seeds are fertilized ovules. The function of the fruit is to protect the seeds as they develop and to help in their dispersal. Ovary wall after fertilized develop into pericarp (consist from exocarp, mesocarp and endocarp).

Some fruits are fleshy with parts we like to eat, some are dry some are heavy and are designed to be dispersed by falling and rolling away from the parent plant.

Fruits may divided into Fleshy Fruits, and Dry Fruits. Fleshy Fruits can have one seed or several seeds in. Dry Fruits can be divided into those in which the seeds are contained in a seedpod of some sort which opens to release the seeds (called Dehiscent), and those in which there isn't a seedpod which opens (Indehiscent).

There are other types of fleshy fruit which some people classify separately. A Hep is a fleshy fruit containing achenes, as in the Rose (Rosa); a Pepo is a fleshy fruit with a leathery skin, formed from an inferior ovary. This type of fruit is found only in members of the Gourd Family (Cucurbitaceae) - Cucumbers, Water Melon, and Pseudocarp. Pseudocarp - Pseudocarp - is a false fruit, because it does not contain the seeds. The seeds are achenes, on the outside of a fleshy fruit. This is a Strawberry

DRY DEHISCENT FRUITS Follicle Follicle Delphinium, Larkspur. Legume Legume (Fabaceae): Liquorice, Pea, Runner Bean. Silique Silique Cabbage Family : Cabbage, Radish. A silique which is less than twice as long as broad is called a Silicula. A Capsule A Capsule is the most common fruit type. A Capsule is a dry fruit which splits open to release the seeds.

DRY INDEHISCENT FRUITS Achene Achene - Sunflower. Cypsela Cypsela - Dandelion. Other fruits of this type are found in the same plant family, the Daisy Family (Asteraceae). Nut Nut is a large single hardened achene - Chestnut. ther fruits of this type are: Acorn (Quercus), Hazel. Nutlet Nutlet - Mint Family (Lamiaceae) is a very large plant family, Caryopsis Caryopsis is like an achene, but with the seedcoat fused with the fruit coat. This is the fruit of Sweetcorn. Other fruits of this type are all members of the Grass Family (Poaceae): Barley, Oats, Rice, Rye, Wheat.

SEED Seed - the part of a flowering plant that contains the endosperm and embryo. It will develop into a new plant if sown; a fertilized and mature ovule.ovule Embryo is the product of repeated mitotic division of the zygote. Endosperm – food triploid reserve tissue in seed derived from fertilized polar nuclei, is resulting from double fertilization.

In Monocot the embryo produced a single cotyledon (single leaf), in Dicot – two cotyledon.