STRUCTURE & FUNCTION OF PLANT TISSUE International Class – SMAN 1 Yogyakarta Third Semester – XI Class

INTRODUCTION Tissue Systems : In all multicellular organisms, there is a hierarchy to organizing cells. Cells that are similar form tissues. Tissues that work together form organs. Organs that work together form organisms. Animals and Plants have this hierarchy

PLANT TISSUES AND ORGANS All plant tissues can be divided in one of two categories: Permanent tissue (more mature, differentiated without active cell division) Meristematic tissue (undifferentiated, but actively mitotic cells; is the zone of the plant which doesn’t ever stop growing) Apical meristem Lateral meristem Primary meristem Dermal tissue system Vascular tissue system Ground tissue system

Meristematic tissue : APICAL meristem (involved in increasing length; continued division – primary growth; located in root tips and shoot tips; RAM is at the tip of the root & grows down; SAM is at the tip of a shoot/stem & grows up) LATERAL meristem (involved in increasing girth; cylinders of dividing cells that extend the width of roots and stems) PRIMARY meristem (derived from apical meristem in roots and shoots)

Examples : Lateral Meristem : Primary Meristem : Vascular Cambium Cork Cambium Primary Meristem : Procambium - Vascular Tissue System Ground Meristem - Ground Tissue System Protoderm - Dermal Tissue System

Cork tissue Epidermis Cork cambium Lenticels

Permanent tissue : DERMAL tissue system (outer covering) VASCULAR tissue system (including : Xylem and Phloem) GROUND tissue system (strength and storage of sugar; including : Parenchyma, Colenchyma, & Sclerenchyma) EPIDERMIS (covering primary stems, primary roots, leaves) PERIDERM (covering woody stems, woody roots)

Dermal Tissue of a Leaf Stomata Is the outer covering of the leaf, root, and primary stems (not bark) Has a waxy coating called the cuticle which is waterproof. Dermal Tissue of a Leaf Stomata

Dermal tissue : The dermal tissue system consists of the EPIDERMIS and the PERIDERM. The epidermis is a single layer of closely packed cells. It both COVERS and PROTECTS the plant. It can be thought of as the plant's "skin." Depending on the part of the plant that it covers, the dermal tissue system can be specialized to a certain extent. For instance, the epidermis of a plant's leaves secretes a coating called the cuticle that helps the plant retain water (waterproof).

The periderm, also called BARK, replaces the epidermis in plants that undergo secondary growth. The periderm consists of cork cells and protects the plant from pathogens, prevents excessive water loss and provides insulation for the plant.

Vascular Tissue : Xylem : Tracheids are long and narrow and connect to one another Vessel Elements are wider and shorter. Transport water & minerals from root to leaves. Vessel Members: Water & mineral transport and support (Mostly in advanced angiosperms) Tracheids: Water & mineral transport and support (Mostly in gymnosperms and lower angiosperms). Sclerenchyma Cells: Fibers & Sclereids: support, protection Xylem Parenchyma Cells: storage, short distance transport Laticifers: secretion, storage of secondary metabolites Resin & Gum Duct Epithelial Cells: secretion

Vascular Tissue : Phloem : Sieve Tube Members & Companion Cells are the long phloem cells : transport of sugars, organic nitrogen compounds, and growth regulators in angiosperms They are separated by porous sieve tube plates. Taking care of the cellular functions are the companion cells. Sieve cells, Albuminous Cells: transport of sugars, organic nitrogen compounds, and growth Sclerenchyma Cell: Fibers, Sclereids: support, protection Phloem Parenchyma Cells: storage and short-distance transport Laticifers: secretion and storage of secondary metabolites Resin & Gum Duct Epithelial Cells: secretion

Xylem and Phloem Transport water & minerals from root to leaves transport of sugars, organic nitrogen compounds, & growth regulators Xylem and Phloem Transport water & minerals from root to leaves

Ground Tissue : The ground tissue system synthesizes organic compounds, supports the plant and provides storage for the plant. It is mostly made up of : PARENCHYMA cells, but can also include some COLLENCHYMA, and SCLERENCHYMA cells as well.

Living, thin walled cells. Variable in shape. Lack chloroplasts. PARENCHYMA CELLS PARENCHYMA Cells:  Living, thin walled cells.  Variable in shape.  Lack chloroplasts.  These cells cover the outside surface of herbaceous plants.    Little gas exchange occurs through these cells, due to a thick covering of a lipid compound call cutin.

Parenchyma cells that have developed secondary cell walls. SCLERENCHYMA CELLS SCLERENCHYMA Cells:  Parenchyma cells that have developed secondary cell walls.  Nonelastic secondary cell walls and are dead at maturity. There are two main types:  fibers and sclereids (sel batu).   Fibers are long and narrow.  They protect and support other tissues due to their thick-lignified cell walls. Lack of protoplasm.

Collenchyma cells have uneven thickenings in their primary cell walls. Collenchyma cells differentiate from parenchyma cells & are alive at maturity.   Collenchyma cells have uneven thickenings in their primary cell walls.   Are important for support of the growing regions of shoots, (rare in) roots, & leaves (are found in expanded leaves, petioles, & near the apex of stems). 

PLANTS AND PLANT STRUCTURES GYMNOSPERMS : ANGIOSPERMS : Monocots : Grasses, Grains, Palms, Orchids and Lilies (Family of Gramineae). Dicots : Peanut, Beans, etc. (Family of Leguminoceae)

DIFFERENCES BETWEEN MONOCOTS & DICOTS

OVERVIEW OF PLANT GROWTH Most plants exhibit indeterminate growth. There’re 2 types of growth : Primary growth – increase in length : Initiated by apical meristems Apical meristems give rise to primary meristematic tissues Primary meristematic tissues give rise to 3 tissue types Secondary growth – increase in girth : Due to lateral meristems Cork cambium produces secondary dermal tissues (periderm) which replace epidermis Vascular cambium produces new layers of vascular tissues

The plant organs are : Root, Shoot (or Stem), & Leaf Each organ has all 3 types of tissues.