PRINCIPALS OF FLOWERING PLANTS TAXONOMY

BOT 222

Dr. Najat Abdulwahab Bukhari

Lecture 2

University Vision and Mission

Vision:

To be a world-class university and a leader in developing Saudi Arabia’s knowledge economy

Mission:

To provide students with a quality education, conduct valuable research, serve the national and international societies and contribute to Saudi Arabia’s knowledge economy through learning, creativity, the use of current and developing technologies and effective international partnership.

Vision:

upgrading the academic and research to keep pace with scientific progress and requirements of society.

 

Mission:

Development of Academic process and develop scientific research through strategic planning and a clear vision for science and technology at the country level. As well as training of national cadres, and the introduction of a methodology developed to meet the different needs of society, and to serve the various research and developmental projects in the community

Botany department Vision and Mission

Course Description Topics to be Covered

Topic No ofWeeks

Contact hours

- Historical review of plant taxonomy (industrial , natural, evolution)

1 2

- Nomenclature 1 2- Classic taxonomy (morphological taxonomy of vegetation and floral characters – Fruits and seed characters.

5 2

- Key to taxonomical unites. 1 2- Fertilization and seed formation 2 2- The different kinds of fruits 2 2- The sexual differentiations of flowers and their fertilization

2 2

14 14

seed

See d is a fertilized mature egg , it contain of the following parts:

1) The sporophyte embryo, which is either monocots, or dicots

2) Endosperm, food for the embryo

3) Seed coat ( inner and outer), protective coat.

function of the seed:1) Reproduction2) The spread of the plant3) Hybridization, because the seed is an

embryo containing the different genes of the parents.

Often during seed formation the ovary turns into the fruit but there are some cases where the fruits grow without fertilization such as: bananas

The number of seeds in the fruit is different ( 10-10000 (ten thousand). Number of seeds is usually less than the number of eggs due to lack of fertilization of all eggs.

Different types of seeds: There are types of seeds that do not contain

the embryo, for example, bananas grow by a sterile process of fertilization occurs. There may be more than one embryo.

Type of food and quality of "endosperm“, it may contain carbohydrate such as wheat (80% carbohydrate). Or protein such as beans, or oily seeds such as sesame and castor.

Anatomy of the outer coat , as in some seeds the coat have bristles and some have hooks to help spreading and getting to animals. Some seeds are smooth or have hair or nipples. Some have feathery extensions .

Thickness and structure of the seed coat is different . In addition the structure and order of cells and tissues is due to the deposition of some materials such as lignin.

Seeds come in different sizes and shapes is differ (large ,small)

Seeds colors (red, black, brown, and yellow) The structure of the outer seed coat (smooth,

hairy…) Anatomy of the seed. Monocots, dicots seeds. Shape of cotyledons inside the seed

Non- endosperm : as some seeds do not contain any Endosperm , the embryo grows rapidly and absorb all the food the endosperm is almost degraded , for example beans and peas ( non endospermic seeds).

Endospermic seeds are seeds whereby the endosperm is present in the mature seed and serves as food storage organ of the seed reserves endosperm for a long time

Different number of coats in the seed. Small or large embryo, ( different embryo

shape such as straight , coiled and curved). Seed is very important in plant

classifications. It has many classification characters.

Fruit

During the development of the embryo sac the fruit form. The fruit may contain seeds or has no seeds as in banana.

Deference between seed and fruit: The seed has one scar (hilum) which is the

point of attachment to the funiculus. The fruit has two scars (hilum) and filament remains

Fruit consist of ovary and ovary wall which gives the fruits coat (pericarp)

Seed has one outer coat which develops from the nucleus tissue, while fruit has two the ovary wall is another coat.

True fruit is fruit formed of the flower ovary (tomatoes and beans. False fruit is when other flower parts formed the fruit. Such as apples the ovary wall fuse to form the apple skin.

In pineapple and figs flower raceme and inflorescence forms the fruit

Fruit function:

1. Carrying and feeding seeds .

2. Help to spread seeds, especially when the fleman is hook shape in some types (GEUM) of the rose family. Or can be covered hairs to spreading by winds (clematis) of the ranunculaceae family. Or can be as in geraniaceae family.

3. Fruit varies a lot, but it is a vital character of plant classification .

Fruit types:

1) Simple fruit

develops from a single flower.

2) Compound fruit

is one that develops from several ovaries in either a single flower or multiple flowers

3) Aggregate fruit

. A fruit, such as the raspberry, consisting of many individual small fruits derived from separate ovaries within a single flower

Simple fruits:

Simple fruit isormed from one ovary, it is divided into two:

Dry simple fruitsThe fruit coat is dry may be thick or rugged.

Succulent simple fruitsFruit wall is soft not dry, consist of

three layers (outer, middle and inner)

Dry simple fruit can be divided into according to is the opening, at maturity:

Indehiscent fruits

1) Nut

2) Achen

3) Caryopsis

4) Cypsela

5) Urticle

6) samara

dehiscent fruits

1) Follicle

2) Legume

3) Siliqua

4) Silicula

5) Capsule

These are the fruits that does not open to discharge seeds, that is they will not open in any way and are shed as a fruit for dispersal. These indehiscent dry fruits come in different types that include (walnut, hazelnut)

Indehiscent fruits

Types of Indehiscent fruits

1) Nut Large, one-seeded fruit with hard peri carp, the ovary wall

is tough and woody. The coat is developed from the ovary wall after fertilization

Consist of upper or lower ovary, (walnuts develop from lower ovary of a three carpal flower, fused)

The examples of the type are walnuts and pecans.

2) Achen contains a single seed .Seed coat is not

merged with ovary wall. The matured ovary wall is also thin, generally produced in clusters. At maturity the pericarp is dry and not attached to the internal seed, except at the placental attachment. (Rosa, Ranunculus)

3) Caryopsis A very small, one-seeded , develpes from

one carbla upper ovary. The actual seed coat is completely merged to the ovary wall or pericarp . ( as in geramineae Corn (maize), wheat, rice, rye, barley, oats )

4) Cypsela one-seeded , develops from two fused carpels

of lower ovary. The actual seed coat is completely merged to the ovary wall. The fruit has pappus which help spreading (Sonchus ،Helianthus annuus)

5) Urticle one-seeded, nut like. Not opened. The

floral part surrounds the fruit as in (polygonaceae chenopdiaceae)

6) Samaradry fruit in which a flattened "wing" of fibrous,

papery tissue is produced from the ovary wall. A samara is bi-carpellate (two carpels) and indehiscent (not opening along a seam) type. The shape of a samara allows the wind to carry the seed from the parent tree. Terminalia , Machaerium

1) Follicle develops from a single

ripened ovary with one carpel. The fruit split only once to release their seeds. The split is always lengthwise ventral suture . ( as in Delphinum )

2 -Dehiscent fruits

2) Legume The legume fruits are derived from a simple

ovary that has one carpel with two rows of ovules. Split open when ripe at Ventral suture and dorsal suture.

Peas, beans and peanuts are the examples of legume type.

A peanut is not a nut in the botanical sense it is one of the indehiscent legumes that will not split open when ripe.

3) Siliqua The siliqua fruits are derived

from one ovary that has two fused carpels. It has two lparietalies placinta between them a thin tissue called (relplum). The fruit is elongate thin, when it open ripe the two carpels open from bottom upper but remain connected at the top (as in cruciferae and manthiola)

4) SiliculaSimilar to the siliqua fruits but it is short

and broad (as in Capsella).

5) Capsule

The capsule is composed of more than one carpel. which splits apart (dehisce) to release the seeds, at maturity. In some capsules, the split happens between carpels, and in others each carpel splits open. In some others, seeds are discharged through openings or pores that form in the capsule.

According to the opening method, the capsule is divided to :

1) Loculicidal Longitudinally dehiscent along the

capsule wall between the partitions of the locule,( as in the fruits of irises and lilies, gossypium, viola)

2) Septicidal Splitting open, or dehiscent, down the

middle of the partitions uniting carpels , (as in colchicum, Liliaceae family)

3) Septifragal

The capsule break open in which the valves of a pod break away from the partitions and these remain attached to the common axis (as in Datura)

4) Circumscissile The fruit splitting or opening along a

circumference with the top coming off as a lid, the capsule is called (pyxidium) ( as in potulaca and Anagallis)

5) Teeth

Partial separation of carpala as a result ot cracking the top of the capsul. Where upper teeth is formed ( as in Caryophyllaceae family)

6) Doricidal “pors” In the capsule box appear at the carpal

apex number of pores. The fruit open out of these pores ( as in Papaver).