Plant Systems

Plant SystemsREVISETO DOLabel the cross section of the leaf on your worksheet

Chloroplast Stoma Lower epidermisAir SpacesUpper epidermisSpongy MesophyllCuticle Palisade MesophyllGuard cells OxygenCarbon DioxideAUTOTROPHSWhat does this mean?That they can produce there own energyTwo types of plantsProduce seeds eg. Flowering plantsDont produce seeds eg mosses and fernsLand plants require???WaterCarbon dioxideOxygen Sunlight

3Systems in plantsShoot systemorgans above ground: leaves, stems and reproductive organs (flowers and seeds)Root systemorgans below ground: roots and root hairs

Plant tissuesPlants have specialised cells and tissues for particular roles such as:storage, structure, transport, photosynthesis, respiration, growth and reproduction.Important tissues include1. Meristematic tissue2. Dermal tissue including root hairs3. Ground tissue includes all internal cells except vascular tissue4. Vascular tissue

1. Meristematic tissue Cells division by mitosis for growthFound at the root, shoot tips and ring around the inside of stem and branches Cells differentiate into whatever type of cell/tissue is required.Allowing Growth in length and width

2. Dermal tissuesis the outer most layer of cells in plant tissues, eg. eipdermis layerProtects the plant body from cuts, invasion by microorganisms and water loss. Epidermal tissues include: Waxy cuticle on leaves for protectionFine hairs on roots for water absorption

3. Ground tissuesInternal plant cells (under the epidermal cells) other than the vascular tissueStorage starchSupportPhotosynthetic

4. Vascular tissuesTransport of substances throughout plant

Two main types: xylem and phloem

Xylem cellstransports water and nutrients from roots to the rest of the plantin one direction only (roots to leaves)mature cells are dead and have open ends to conduct water tubular skeletons

Phloem cellsTransports sugars (sucrose) and other materials from leaves to other parts of the plantPhloem cells are livingTwo types of phloem cells: sieve cells and companion cellsSieve cellsno nucleusshare cytoplasmpass materials between sieve cells through sieve platesCompanion cellshave a nucleus and cell organelles to control each sieve cell

Sucrose enters phloem throughcompanion cell sieve cell diffusion. Water enters phloem from xylem through osmosis

TO DO:What are the four different types of tissues found in plants?What do each do?Create a table to compare xylem and phloem.Transporting SystemsRoot systemAnchoringUptake of water and nutrientsFine root hairs increase surface area for more effective uptake

Water MovementRoot pressurewater enters roots by osmosis, dissolved minerals (ions) enter roots by diffusion and active transportthe pressure of osmosis, diffusion and active transport forces water and mineral ions into and up the xylem cells

Shoot systemWater moves up through xylem cells, sugars move down through phloem cellsXylem and phloem cells are found together in vascular bundlesVascular bundles are arranged differently in each section of the plant

TranspirationContinuous upwards movement of water is driven by the evaporation of water from the leavesThe constant loss of water by plants through leaves is called transpirationThe upward movement of water is aided by:Adhesion; attraction between water molecules and the inside walls of xylem vesselsCohesion; forces of attraction between individual water molecules

TranslocationThe movement of glucose from where it is synthesised (photosynthesis in leaves) to other parts of the plant

TO DOExplain the forces that enable water in a xylem vessel to reach the top of a tree?Gaseous ExchangeStomata control the movement of carbon dioxide in and water and oxygen out of leaves.

Stomata are tiny pores found mostly in the lower epidermis of leaves

Stoma open when guard cells absorb water and close when they lose water

Stomata open in moist conditionsand close in dry conditions, controlling the amount of evaporation

TO DOThrough what structure does gas exchange occur in plants?What is the function of the stomata?Draw a diagram to show how the stomata open and closeUnder what environmental conditions are stomata most likely to be open?How do stems and roots exchange gases with the environment?Removing wastesDeciduous plants: leaves before autumnInto bark that will peel or drop offDead cells to form lignin (woody centre)Exude resins, fats, waxes or latex