BISC 101 Lecture Notes - Lecture 10: Cell Wall, Vascular Plant, Primary Cell
14 Mar 2016
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Shoot system(stems and leaves: absorb light and co2, photosynthetic(green) 3. reproductive shoots bear flowers for sexual reproduction. Root system: absorbs water and nutrients from soil(root hairs, non-photosynthetic, anchors vascular plant in soil, storage organ: Prop roots and buttress roots (holds tree up from unstable ground) Tap roots grow vertically; lateral roots grow horizontally; fibrous roots are dense. Stoma(pores) + guard cells: regulate gas exchange (and water loss). Strands that support parts of plant shoots. Tracheids: long, slender, with tapering ends, and pits(primary cell wall) through which water can pass. Vessels: shorter, wider, thinner walled tubes stacked end-to-end with perforations between adjacent cells through which water passes. Sieve-tube: contain sieve plates(pores) between adjacent cells. Lack nucleus, ribosomes, vacuole, cytoskeleton- allows phloem sap to pass through more easily. Companion: connected to sieve-tubes by many plasmodesmata. Provides metabolic support for itself and adjacent sieve-tube. Detects gravity (determines direction of growth) and cork cambium) increase diameter of shoots and roots:
