BI111 Lecture Notes - Lecture 19: Ground Tissue, Pectin, Hemicellulose
Document Summary
Overview of the plant body: photo auto most plants, shoot and root leaves and stems then roots, dendritic spread in branches, morph that has shown due to selection. Root sys: funcs: below ground, anchors and lets upright part grow tall for light, absorb water and mins store carbs. Sclereids protect , irregular cells fruit and seeds. Fibres support, needle shaped cells, some elasticity: xylem: conduct water and mins, thick, lig secondary walls, dead when func, 2 types of xylem. Tracheids: elong, overlapping ends, hollow, water flow to leaves, lateral connections through pits, reliable against air bubbles. Vessel members: shorter tube columns, connected one on top of other, faster water movement, easily blocked by air bubbles that disrupt water con. Plant cell: general props: cell wall- more like basket, vacuole 30-80% of volume, cellulose in hemicellulose, storage and turgor pressure, buffer in osmotic pressures enviro changes, like channels, plasmodesmata cyto connections b/t adj cells.
