Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Cell growth wikipedia , lookup
Cytokinesis wikipedia , lookup
Cytoplasmic streaming wikipedia , lookup
Extracellular matrix wikipedia , lookup
Cellular differentiation wikipedia , lookup
Cell encapsulation wikipedia , lookup
Cell culture wikipedia , lookup
List of types of proteins wikipedia , lookup
Vascular Tissue -- Xylem and Phloem Ground Tissue -forms the bulk of the plant. -thin-walled and capable of photosynthesis when they contain chloroplasts. -have thicker walls for flexible support (celery strands). -are hollow, nonliving support cells with secondary walls. Plant Ground Tissues • Thin cell wall • Storage & photosynthesis PARENCHYMA • Uneven cell wall • Flexible support COLLENCHYMA • Thick cell wall • Strength and support SCLERENCHYMA Two Kinds of Plant Vascular Tissue • Xylem - Carries H2O, dissolved nutrients. - Upward movement. - Dead at maturity. - Vessel Elements- pitted cell wall. Water pipeline - Tracheids - pitted • Phloem - Carries products of photosynthsis.-Sieve tube - perforated - Up and downward movement. end walls - Alive at maturity Sieve-tube - transport sugar Vessels Tracheid - Companion Cells- swirl cytoplasm to push sugar up or down Companion cells Vascular Tissue • Two types of vascular (transport) tissue: • Xylem transports water and minerals from roots to leaves and contains two types of conducting cells: tracheids and vessel elements. • Phloem transports organic nutrients from leaves to roots and has sieve-tube elements with companion cells, sieve plates. Xylem structure Xylem transports water and minerals from roots to leaves Contains two types of conducting cells: tracheids and vessel elements. Water Leaves Roots Tracheids lie along side other tracheids, over-lapping extensively, so that water can flow out of the pits of one cell into an adjacent cell. This allows long range transfer of water and solutes, although (since the cells are dead) the flow has to be passive, pulled by an external force. Water Flow (passive flow) The driving force for this flow is hydrostatic pressure, coming partly from root pressure (pushing up wards) but mainly from the suction pressure created by water being evaporated from leaves. Passive water flow in plants is upwards. Softwoods (conifers) – tracheids only Hardwoods – note the larger bore of the vessel elements In Angiosperms - Vessel elements, idealised Vessel element, here with a open end (simple perforation plate). A perforated (scalariform) perforation plate Tracheids Phloem structure Transports organic nutrients from leaves to roots Has sieve-tube elements with companion cells cells at sieve plates. Organic nutrients Leaves Roots