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Apical bud. Plants: photosynthetic multicellular autotrophs with cellulosic cell walls Growing points Meristems. Sunlight. Node. Internode. Node. Plant traits:. CO 2. Shoot system. Leaves. Axillary bud. Branch. Stem. Lateral roots. Water. Root system. Nutrients
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Apical bud Plants: photosynthetic multicellular autotrophs with cellulosic cell walls Growing points Meristems Sunlight Node Internode Node Plant traits: CO2 Shoot system Leaves Axillary bud Branch Stem Lateral roots Water Root system Nutrients (such as N, P, K) Taproot
longitudinal section of stem apex longitudinal section of root tip
Cross sections: Meristematic tissue Leaf Shoot system Dermal tissue system (brown) Ground tissue system (gray) Stem Vascular tissue system (red) Dermal tissue system (brown) Root system Root Ground tissue system (gray) Meristematic tissue Vascular tissue system (red)
Plant cells have unique organelles: cell walls, vacuoles, and chloroplasts; and other organelles in common with animal cells: (b) Adjacent plant cells are connected by plasmodesmata. Cell 2 Smooth ER Cell wall Plasmodesma Plasma membrane Plasma membrane Cell 1 Cell wall Cell wall Vacuole Plasma membrane Rough endoplasmic reticulum Chloroplast Smooth endoplasmic reticulum Mitochondrion Golgi apparatus
Plant cells are bounded by a cellulosic cell wall. Most cells have only primary (1st) walls: Woody cells have secondary walls: cellulose, hemicellulose, pectin, proteins including lignin, and many layers of cellulose microfibrils Side view Top view Cellulose microfibrils Cross-links Primary cell wall Pectin Plasma membrane 1 m 50 nm Functions of cell walls: