PLS 170C1 Lecture Notes - Lecture 5: Meristem, Herbaceous Plant, Protoplast
30 Jan 2017
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Document Summary
Display leaves for maximum interception of sunlight (photosynthesis). Conduct water, mineral nutrients and food molecules (carbohydrates) throughout the plant body. Support owers for maximum pollination and display fruits to promote seed dispersal. Store carbohydrates for later use in growth and reproduction. Develop buds that produce new leaves and reproductive structures. Internodes- regions of the stem between nodes. Cells in herbaceous stems are produced by the apical meristem and arranged to form the three primary tissues (dermal, vascular, and ground). Vascular tissues form bundles of xylem and phloem called vascular bundles. Xylem: elongated cells, thick, 2 walls, lignin-containing, no protoplast at maturity. Xylem cells connect with one another in a continuous system of hollow dead cells (long, thin vessel elements) forming microscopic tubes throughout the plant for water and mineral transport. Phloem: elongated living cells, conducts dissolved food (carbohydrates) throughout the plant body. Sieve-tube elements are long, thin cells that have no nucleus when mature.
