Biology 2217A/B Lecture Notes - Lecture 3: Meristem, Cork Cambium, Vascular Cambium
4 Feb 2019
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Plant body two systems: root system, normally underground, dark, moist, woody. Illuminated, relatively dry: herbaceous (does not develop woody parts) Plant body three categories: annuals, herbaceous, grow, reproduce and die in one year. Biennials: 2 years to complete life cycle, perennials, woody or herbaceous that live more than 2 years. Dermal tissues: protects the soft tissues of plants and controls interactions with the plants" surroundings. It secretes a waxy layer called the cuticle that inhibits water loss. In plant parts that become woody the epidermis is replaced by a new surface layer, the periderm. Ground tissue: parenchyma, collenchyma, sclerenchyma, bulk of nonwoody, herbaceous plants, distinguished by cell wall structure, growing cell secretes a primary cell wall, some cells later secrete a secondary cell wall between primary wall and plasma membrane. Figure a) parenchyma, b) collenchyma, c) sclerenchyma. Parenchyma: undifferentiated precursors of all cells, versatile, capable of performing many different functions.
