Introduction-to-botany.docx

INTRODUCTION TO BOTANY Botany

Botany is the branch of biology concerned with the scientific study of plants. Traditionally, botanists studied all organisms that were not generally regarded as animal. However, advances in our knowledge about the myriad forms of life, especially microbes (viruses and bacteria), have led to spinning off from Botany the specialized field called Microbiology. Still, the microbes are usually covered in introductory Botany courses, although their status as neither animal nor plant is firmly established. It was alluded to in the opening definition that Botany is a science. Just what makes Botany, or anything else a science? It is important to acquire a grasp of the fundamentals of science itself to fully appreciate both how botanical knowledge of was gained as well as how it can be used. It is usually quickly disinteresting to acquire facts simply for the sake of knowing. Humans do not just appreciate mountains because they are there, they climb them because they are there!

Plants

Is a living things typically green possecing green pigment called chlorophyll (green pigment of the plant responsible to absorb energy from the sun) and by means of this pigment, a part of the energy coming from the sun is absorb and by means of this energy carbon dioxide and water are combine forming carbohydrate food which is a food of a plant, since the raw materials, carbon dioxide and water are found everywhere, the plant does not have to have the power of locomotion. Since the plant cannot move,the plant can protect itself by means of the rigid walls of cellulose (Is a substance found in the cellwalls of plant cells that is characterized as hard, colorless, non-motile, and most of all resistant to many environmental condition).

Uses of Plants

There can be no disputing the fundamental significance of plants to the ecology of our planet. Photosynthetic plants utilize energy arriving from the sun to create complex organic molecules from inorganic substances, and by this process contribute oxygen to the atmosphere. Advanced animal life is very much dependent upon this source of oxygen. However, humans utilize plants in many other ways, especially as sources of pleasure, food, and material for shelter and more. Consider here the role plants play in our everyday lives and in our economy.

TERMS COMMONLY USED IN THE STUDY OF PLANT LIFE DURATION OF PLANT LIFE – life span of the plants  Annuals – plants that live for only one year season of single season. Examples: sugar cane, rice, etc.

 

Biennials – plnats that live during the favorable growing period of two years. Examples: carrots, cabbage, turnips. Perrenials – plants that live frm year to year. Examples: tropical trees, fruit bearing trees, etc.

HABITS OF PLANTS – refers to the formof growth of plants.  Trees – these are erect plants, perrenials, with large singlewoody stem five meters ormore in height. Example is coconut.  Shrubs – with one single woody stem, perennials, smaller than trees with several branches arising or at near the ground. Examples coffee, mango, citrus and ramabutan.  Herbs – the stem of herbs develop only very little woody tissues and can live for only a year or two. Examples are banana, sugar cane, corn and pandan.  Vines – plants with slender stem either soft or hard and climbing over other plants or object. These plants are provided of organ for support calle tendrils. Examples are upo, calabasa and sitaw.  Scandent shrubs – woody vines sprawling over other plants or objects commonly no special organ for climbing. Examples are bougainvillea and sampaguita. HABITAT OF PLANTS – the kind of environment in which the plant grow.  Terrestrials – plant that grow on the ground or in the soil. Examples are all land plants.  Aquatic – plant the grow in water. Example watyer lily.  Hydrophytes –on decaying plant that grow under very wet condition. Example is palay.  Epiphytes / Aerial – air plants, grown on another plants but do not take nourishment form it. Example is orchids  Parasite – grow on another plant and take nourishment form it. Examples are rust and molds.  Saprophytes – plant that do not posses chlorophyll and grow on decaying organic matter. Example is mushroom.  Xerophytes – grow under very dry habitat. Example is cactus.  Mesophytes – plants that are not specialized to grow in either very dry or very wet habitat. Example is lansones.  Halophytes – growing on saline or salty conditon. Examples are mangrove and seaweeds.  Glycophytes – Plants grow in non-saline of not salty condition. Example is hydrilla. DISTINGUISHING CHARACTERISTICS OF MONOCOTS, DICOTS AND GYMNOSPERMS Division

Spermatophyta - seed bearing plants

Subdivision

Angiosperms (Angiospermae) (flowering plants with seeds enclosed)

Gymnosperms (Gymnospermae) (cones with naked seeds)

Class

Monocots (Monocotyledoneae) (means 1 cotyledon)

Seeds

1 cotyledon; endosperm often present

2 cotyledons; endosperm often lacking

1 to many cotyledons; no endosperm; female gametophyte tissue present

Flowers

Flower parts in multiples of 3

Flower parts in multiples of 4 or 5

No true flowers

Leaves

Linear; leaf base or petiole (if present) Broad; petiole present; net venation Needle-like or scale-like sheathing; parallel venation

Vascular System of Stem

Scattered vascular bundles; no cambium or secondary growth

Ring of vascular bundles in primary Ring of vascular bundles in primary growth; cambium present; may have growth; cambium present; may have woody secondary growth woody secondary growth

Growth Habit

Herbaceous to wood-like (ex. palm), but no true wood (secondary xylem)

Herbaceous or woody

General Appearance

Dicots (Dicotyledoneae) (means 2 cotyledons)

Herbaceous or woody

PLANT HISTOLOGY Tissues

Is group of cells of similar structure like shape, size and arrangement having a common origin which together performing a specific function. Most plant cells are specialized to a greater or lesser degree, and arranged together in tissues. A plant tissue can be simple or complex depending upon whether it is composed of one or more than one type of cell. The simplest tissue found in plants is called parenchyma. The cells are not very specialized, more or less rounded or angular where packed together, and thin-walled. A type of parenchyma called chlorenchyma because the cells contain chloroplasts forms tissue (usually in the leaves) responsible for photosynthesis occurring in the plant. Note that in simple tissues at least (tissues comprised mostly of one cell type), the tissue name follows from the cell type. However, tissues may also have unique anatomical names related to where in the plant they occur. The principal tissues of the plants are:

Meristematic Tissues

Found at the tip of the roots and branches,composed of cells that are actively dividing characterized as long or elongated with thin cell walls and with big nucleus. Tissues comprised of cells that remain undifferentiated and supply, by their divisions, cells to form new tissues and organs, are called meristems. Meristem tissue occurs in places that allow for a very orderly pattern of growth. Meristematic tissues are:   

Apical Meristem – located just behind the root cap and the apex of the stem and responsible forgrowth of the root and the stem. Lateral Meristem – located outside the cylinder of the wood and responsible for the thickness of the stem. Intercallary Meristem – found just above the node and at the face of the leaf sheath.