PLB 105 Lecture Notes - Lecture 10: Flowering Plant, Phloem, Pectin
Document Summary
Composed of living parenchyma cells with thin primary cell walls. Meristematic ability, important for the role of regeneration and wound healing: allows plants to produce adventitious roots. May be compact or have extensive spaces between the cells. Makes up the mesophyll of leaves and the cortex (out layers) and pith (innermost layers) of stems and roots: also forms the soft tissues of fruits. Composed of collenchyma cells (from the greek word kolla, meaning glue), unevenly thickened primary cell walls with the carbohydrate pectin. Provides flexible structural support (like a knee brace) Stimulation of collenchyma occurs due to mechanical stress such as wind and rain resulting in more supporting for plant organs. Sclerenchyma tissue - 2 types: sclereids and fibers. hard sclerenchyma cells, both primary and secondary cell walls. Often dead at maturity, but provide structural supports. Found throughout plant body-roots, stems, leaves, seed coats and even in the hulls of peanuts.
