BIOL 240W 1st Edition Lecture 5 Outline of Last LectureI. Plant Structure and GrowthII. Three Basic Plant OrgansIII. Dermal Tissue, Vascular Tissue, Ground TissueIV. Differences Between Plant and Animal CellsV. Three Major Types of Plant CellsVI. XylemVII. PhloemOutline of Current LectureI. Multicellular Developmenta. Determinate Growthb. Indeterminate Growthc. MeristemsII. Primary Growth in Rootsa. Three Zones of Cell Divisionb. AnatomyIII. Primary Growth in ShootsCurrent LectureI. Multicellular Developmenta. Determinate growth-animals (and some plant organs) stop growing after they reach a certain size (ex: we reach a maximum height)b. Indeterminate growth-displayed in plants. They have organs in different stages of development that continue to grow.c. Meristems- particular tissues that are undifferentiated (unspecialized) and have indeterminate growth. They are able to respond to environmental conditionsi. These cells are actively dividing, considered “stem” cells, small, and can differentiate when necessary or remain meristematic.ii. Apical Meristems1. Generate primary growth in the length of plant2. Dominant over other growing parts of plantiii. Root apical meristems increase root lengthThese notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.iv. Axillary bud meristems- Subordinate, are not active unless they are signaledII. Primary Growth in rootsa. Three Zones of Cell Divisioni. Cell division zone- root apical meristem at the core of rootii. Elongation zone- cells elongate in this zone. This is responsible for most root growth. Only changing size of cells; not dividingiii. Differentiation zone- where cells take on their final form and become specializedb. Anatomyi. Root cap- protects apical meristemii. Root hairs- facilitate mineral and water uptake. Consist of specialized epidermal cellsiii. Structure of root1. Endodermis- surrounds vascular tissue in root. Regulates water movement in cell2. Pericycle- outermost later of cells in vascular bundle of root. Lateral roots emerge from the pericycle to ensure connections of vascular tissues.III. Primary growth in shootsa. Leaf primordia protect shoot apical meristems. These cells are smallb. Size increase in shoots is the result of cell expansion (not division, similar to root growth)c. Intercalary meristems- present at leaf bases (ex: grasses)i. Why mowing the lawn works; the upper part of the blades can be removed and regrownd. Adaxial (“upper”)i. Top of leafii. Densely packed mesophyll cellsiii. High density of chloroplasts. Optimized for photosynthesise. Abaxial (“lower”)i. High density of stomataii. Important for gas exchangeiii. Loosely packed spongy mesophyll cellsf. Guard cellsi. Associated with stomataii. Inflate/deflate to regulate size of stomatal pore to regulate gas exchange and water lossg. *Bundle sheath cells will be discussed in depth in the futureh. Eudicot and monocot stem organizationi. Eudicot1. Vascular bundles arranged in rings2. Ground tissue separated into cortex and pithii. Monocot1. Vascular bundles scattered2. Ground tissue not separated **NO CONTENT ON SECONDARY GROWTH WITH BE COVERED FOR EXAM
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