Organismal Biology: Plant Structure PDF

ORGANISMAL BIOLOGY STRUCTURE OF PLANT ORGAN SYSTEM INTRODUCTION  The body of any plant or animal consists of hundreds to thousands of trillions of cells.  These cells become organized into tissues, organs and organ systems, each capable of carrying out sp...

ORGANISMAL BIOLOGY STRUCTURE OF PLANT ORGAN SYSTEM INTRODUCTION  The body of any plant or animal consists of hundreds to thousands of trillions of cells.  These cells become organized into tissues, organs and organ systems, each capable of carrying out specialized functions, thus division of labor can be observed among parts of a plant body.  Organs work together in system. Organ systems are joined together to make a complete living thing or organism.  In most flowering plants, the body consists of a root and a shoot system.  The root system is composed of the roots, while the shoot system consists of the stem and leaves.  A typical plant consists of organs that carry out either vegetative or reproductive functions. VEGETATIVE ORGANS  - are those that are concerned with growth and nutrition, such as roots, stems and leaves REPRODUCTIVE ORGANS  -Those involved in reproduction, like flowers, seeds, and fruits. A. ROOTS- grows extensively underground producing many branches that anchor the plant in the soil to give it support,absorbs water and minerals to support its metabolic purposes  Growing from the many branches of the root system are numerous root hairs found in the special zone near the root tip.They greatly increase the absorptive surface of the root.  Plants have three types of root systems: 1.) taproot, with a main taproot that is larger and grows faster than the branch roots; 2.) fibrous, with all roots about the same size; 3.) adventitious, roots that form on any plant part other than the roots TAP ROOT- DICOT PLANT ( Exs. Mahogany,narra) FIBROUS- MONOCOT PLANT(Exs. Corn,grass) The vascular tissue, that transports substances, it arranged differently in monocots and dicots. In monocot root,vascular tissue forms a ring, and in the dicot root, the xylem, which transports water and minerals, is star- shaped; and the phloem which transports organic nutrients, is located between the points of the star  B. STEMS  -The shoot system of a plant consists of the stem, the branches, and the leaves.  It is considered as the main axis of the plant, bears the leaves in a way that will expose them to ample amount of sunlight.  In trees, the shoot consists of the main stem which is commonly called trunk or bole, their main ascending axis, with lateral branches to which smaller branches and branchlets or twigs are attached.  Shrubs,have many upright stems, and the terms trunk or bole are not usually applied.  External parts: Nodes-point from which a new buds/stem or leaves arises  Internodes-area between two nodes  Bud-embryonic stem that gives plant the potential for further growth(leaf, flower or both)  Types of bud:terminal(found on the apex); lateral or axillary buds(side); adventitious buds(maybe formed in internode)  The eyes of the potato is an example of a bud.  Hairs could be present also in the stem  Lenticels(tiny raised pores for gas exchange)  Leaf scars(scars left by a fallen leaf)  Bud scar(scar left by a fallen buds) Buds could be naked( without the covering like in rosas de baybayon); covered(like in gumamela).  Buds could also be active( develops into flower,leaf); dormant(in active)  CROSS SECTION OF A STEM ( MONOCOT AND DICOT)  C. LEAVES  Primarily the food factory of the plant body  Parts: blade/ lamina (expanded green part); petiole( leaf stalk); stipule  The upper acute between the petiole and stem is the leaf axil where the axillary bud is found.  Not all leaves are foliage leaves and they are specialized to protect the buds, attached to objects(tendrils), store foods(bulbs) or even capture insects  Another kind of leaf is cotyledon, seed leaf. It is a part of the embryo within the seed of the plant  Leaf veins- vascular bundles within a leaf. Monocots have parallel, while dicots have net like(pinnate or palmate).  D. FLOWERS  -Specialized reproductive shoots of angiosperm sporophytes. They formed when a lateral bud along the stem develops into a short, modified branch called a receptacle.  The formation of a flower is directed by master genes found inbthe apical meristems of the stem.  Parts: petals (collective term corolla); sepals( calyx); one or more carpels/pistil(female organs). And stamen(male)  Petals for pollination, sepals for photosynthesis and covering  Stigma is a sticky part on the upper part of a carpel specialized to trap pollen grains  Style-supports the stigma on top of it.  Ovary-swollen part containing ovules which contain egg cell undergoing meiosis and develops into haploid female gametophyte.  Stamens-consists of anther producing pollen inside the pollen sac  The pollen consists of sperm cells that fertilized the egg cells in the ovules  VARIATIONS OF FLOWER Regular- symmetrical around their central axis. Pieces are roughly identical Irregular- are not radially symmetrical Singular flower- one flower in one receptacle Inflorescences- clustered flower Complete-if both essential(reproductive) and accessory(petals,sepals) parts could be found Incomplete –if it lacks one Perfect- if both stamen and pistil could be found Imperfect- if one of the reproductive parts is lacking GUMAMELA- a regular,complete and perfect flower  FRUIT  -matured ovary  Types of fruit Drupe - has fleshy fruit and a single seed with a hard endocarp eg peaches, coconut and olives. Berry - has many seeds eg tomatoes, peppers and cucumber but not strawberries! Aggregate fruit - develop from one flower with many pistils eg strawberries. Legumes - split along two sides eg beans, peas. SEED  A seed is an embryonic plant enclosed in a protective outer covering. The formation of the seed is part of the process of reproduction in seed plants, the spermatophytes, including the gymnosperm and angiosperm plants.  The three primary parts of a seed are the embryo, endosperm, and seed coat. The embryo is the young multicellular organism before it emerges from the seed. The endosperm is a source of stored food, consisting primarily of starches. The seed coat consists of one or more protective layers that encase the seed