290 likes | 310 Views
Module 3 Exchange and transport. 9.1 Transport in dicotyledonous plants. Starter. On your plain piece of A4 paper you have 3 minutes to draw a diagram of a plant and label everything you know from KS4 on plant transport. Learning Objectives . Success Criteria.
E N D
Module 3Exchange and transport 9.1 Transport in dicotyledonous plants
Starter • On your plain piece of A4 paper you have 3 minutes to draw a diagram of a plant and label everything you know from KS4 on plant transport
Learning Objectives Success Criteria Draw the structure of xylem and phloem tissues in dicotyledonous plants (Grade D – C) Describe the distribution of xylem and phloem tissues in dicotyledonous plants (Grade C –B) Explain the importance of plant transport systems(Grade B – A) • Describe the distribution of xylem and phloem tissues in herbaceous dicotyledonous plants, with aid of diagrams and photographs
Dicotyledon • Di = Two • Cotyledon = Seed leaf • Used to classify flowering plants
Monocotyledon Dicotyledon
Task • Explain the need for transport systems in multicellular plants in terms of size and surface area to volume ratio. • Use page 68 – OCR book to help Explain the importance of plant transport systems(Grade B – A
Why do plants need transport systems? Some small or primitive plants, such as mosses, absorb all the nutrients they need directly from their environment. • Three reasons why multicellular plants need transport systems • Size – Many perennial plants are large • Metabolic demands – mineral ions and hormones need to be transported. Internal and underground parts of the plant don’t photosynthesise so oxygen and glucose need to be transported to them and waste products of cell metabolism removed • Surface area : volume ratio – Relatively small, so can’t rely on diffusion alone. Some parts of the plants are adapted to have a large SA:V ratio. Plants that have specialized transport systems are known as vascular plants.
Vascular Tissue • Mainly xylem and phloem • Also includes cambium and possibly other tissues for support
Vascular Bundle in Root • Large central xylem in 3-5 pointed star • Phloem found between arms of ‘star’ • Strength to resist crushing and pulling forces
Vascular Bundle in Shoots • Discrete bundles give strength but also allow flexibility • Xylem is adaxial- closer to centre of stem • Phloem is abaxial- closer to the exterior • Sclerenchyma fibres- Heavily lignified dead cells involved in support and strength • Collenchyma- Unevenly lignified living cells that provide strength and support, they are what make up the resilient strands in celery stalks • Parenchyma- Most common cell, may remain meristematic at maturity
Vascular Bundle in Shoots In older woody plants the vascular bundles are not discrete (they form a continuous ring)
Vascular Bundle in Leaves Vein Make up the midrib and veins of a leaf Midrib
Observing Xylem and Phloem Using Microscope Try to observe the vascular bundles in roots, shoots and leaves Start on the lowest magnification and work up When you have a clear image on the highest magnification possible draw what you can see and label • Draw the structure of xylem and phloem tissues in dicotyledonous plants (Grade D – C)
Past Paper Questions – Answers on whiteboards!!! 1) You are given an outline of a dicotyledonous root. • Sketch in and label the xylem and phloem in the diagram. Individual cells should not be shown [2]
Xylem Phloem 1 Mark for correctly identifying xylem and phloem 1 Mark drawing 3-5 pointed star with phloem between arms
2a) Name the tissues A-C [3] b) Describe how the distribution of B and C would differ in a dicotyledonous root [2] • Describe the distribution of xylem and phloem tissues in dicotyledonous plants (Grade C –B)
2a) A- Epidermis B- Phloem accept phloem etc C- Xylem b) 1- Central 2- Star-shaped/3-5 arms/AW/ xylem 3- No pith/hole/AW 4- Phloem between xylem/ on different radii/AW Accept points on a diagram (xylem and phloem need to be labelled)
Vertical section through part of a leaf of a dicotyledonous plant 3) Identify A, B and C [3]
3) A- Xylem/Xylem vessel(s)/ tube/ element/ lumen of xylem (vessel) B- Guard Cell(s) C- Phloem/ sieve tube(s)/ sieve plate(s)/sieve element(s)
4a) Name this organ [1] b) State in which of the tissues, A-D, xylem vessel elements are found [1]
4a) Root b) D
Plenary • Label each photograph with it’s structure