Plant Structure Development I Lecture 10 LIFE103 von Fischer Main Sections Anatomy Structures Cells Growth Tissues cells Fig 35 2 3 main plant organs Root Roots anchors the plant in place absorb minerals water store carbohydrates Taproot main vertical root present in most gymnosperms eudicots deeply penetrates Lateral roots branch off taproot Root hairs grow off lateral roots Finer roots access water nutrients Have very high surface area 3 main plant organs Stem Stalk upon which leaves grow Shoot system leaves stem Nodes point on stem where leaves are attached Internodes stem segments b w nodes Axillary bud structure that can form a lateral shoot Growth inhibited by proximity to apical bud Apical terminal bud elongation point of a growing shoot Composed of developing leaves nodes internodes 3 main plant organs Leaf Main photosynthetic organ Blade flattened structure lamina Petiole small leaf stem that joins the leaf to the stem the node Anatomy terms to learn on your own Roots Stems Leaves Prop roots support the tall top heavy trees Ex Hala Trees storage roots store food water Ex Beets Rhizomes horizontal shoot that grows just below the surface bulbs vertical underground shoots consisting of bases of leaves that store foods Stolons horizontal shoots runners that grow along the surface enable plant to reproduce asexually tubers enlarged ends of rhizomes stolons specialized for storing food Simple a undivided blade w one segment compound a blade w multiple segments leaflets doubly compound leaflets divided into smaller leaflets Tendrils modified leaves stems that uses a coil to bring plant closer to a support spines prickly modified leaves bracts modified leaves that surround a group of flowers mistaken as petals Fig 35 8 3 Tissue systems Dermal tissue Epidermis outer protective layer Cuticle waxy coating over epidermis Example root hair extended epidermal cells Vascular tissue long distance transport of materials b w roots shoots Xylem conducts water minerals from roots to shoot Phloem transport sugars Stele pillar vascular tissue collectively of stem or root 3 Tissue systems Ground tissue in b w the dermal vascular tissue layers Pith inside of internal vascular tissue in the stem Cortex outside of external vascular tissue Plant development Differentiation developmental changes in a cell s cytoplasm organelles and or cell wall during development special tissue cells making up the ground tissue system functions storage support metabolic processes a Parenchyma performs most of metabolism synthesizes and stores organic products thin walled ability to divide b Collenchyma unevenly thickened walled support young growing parts of the plant c Sclerenchyma thick lignified walls support mature non growing parts of plant fibers sclereids Meristems Meristem cell division tissue that s perpetually embryonic Apical meristem located apical bud of shoots roots Allows Primary Growth 1 in length Lateral meristem allows Secondary Growth 2 stem thickening in woody plants Vascular cambium adds layers of 2ndary xylem wood phloem producing vascular tissue laterally Cork cambium replaces epidermis 1 growth w tough periderm 2 growth producing dermal tissue laterally Fig 35 11 Shoot tip shoot apical meristem and young leaves Axillary bud Meristem Root apical meristems Primary growth in stems Epidermis Cortex Primary Phloem Primary Xylem Lateral meristems Vascular cambium Cork cambium Secondary growth in stems Pith Periderm Cork Cambium Cortex Primary Phloem 2ndary Phloem Pith Primary Xylem 2ndary Xylem Vascular Cambium Fig 35 12 Review Questions If a sugar molecule is in the apoplastic space how does it back into the symplasm Which of the following places is a meristem NOT found ANSWER Root Hair Where are meristems found ANSWER root tip shoot tip cork cambium vascular cambium ANSWER cotransported w protons H Where is the force generated that moves water from the soil into the roots ANSWER microfibrils in the mesophyll ANSWER Potassium ions K are pumped out of guard cells water follows by osmosis ANSWER Transduction What determines the germination of moistened lettuce seeds ANSWER color of light the seeds are last exposed to last exposed to Red Light Stomata close under draught stress How does this happen This process signals a hormone to bind to a receptor Cortex Vascular cylinder Epidermis Root Hair Zone of Differentiation Dermal Ground Vascular Apical meristem Root cap Zone of Elongation Zone of Cell Division