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Questions and answersAnatomy of stem
Introduction to Botany. Lecture 11
Alexey Shipunov
Minot State University
September 21st, 2011
Shipunov BIOL 154.11
Questions and answersAnatomy of stem
Outline
1 Questions and answers
2 Anatomy of stemAnatomy of mature stemStructure of wood
Shipunov BIOL 154.11
Questions and answersAnatomy of stem
Outline
1 Questions and answers
2 Anatomy of stemAnatomy of mature stemStructure of wood
Shipunov BIOL 154.11
Questions and answersAnatomy of stem
Previous final question: the answer
What is ataktostele?
Dispersed (scattered) vascular bundles of monocots
Shipunov BIOL 154.11
Questions and answersAnatomy of stem
Previous final question: the answer
What is ataktostele?
Dispersed (scattered) vascular bundles of monocots
Shipunov BIOL 154.11
Questions and answersAnatomy of stem
Anatomy of mature stemStructure of wood
Primary structure of stem
Shipunov BIOL 154.11
Questions and answersAnatomy of stem
Anatomy of mature stemStructure of wood
Cork cambium and origin of bark
Bark is everything outside vascular cambium, therefore,bark = secondary phloem + peridermEach year new layer of cork cambium appear fromparenchyma cells of secondary phloemConsequently, bark consists of multiple and mostly unevenlayers
Shipunov BIOL 154.11
Questions and answersAnatomy of stem
Anatomy of mature stemStructure of wood
Bark, cork, periderm and wood
Bark = secondary phloem + peridermPeriderm = phellem + cork cambium + fellodermCork = phellemWood = trunk − bark, or simply secondary xylem
Shipunov BIOL 154.11
Questions and answersAnatomy of stem
Anatomy of mature stemStructure of wood
Bark and wood
Bark = 1 + 2, wood is 5 (heartwood) and 6 (sapwood)
Shipunov BIOL 154.11
Questions and answersAnatomy of stem
Anatomy of mature stemStructure of wood
Renewal of bark in sea buckthorn (Hippophaërhamnoides)
Shipunov BIOL 154.11
Questions and answersAnatomy of stem
Anatomy of mature stemStructure of wood
Secondary phloem
Forms outside vascular cambiumRich of fibersDoes not form annual ringsHas rays of parenchyma cells, sometimes wedge-shaped(dilated)
Shipunov BIOL 154.11
Questions and answersAnatomy of stem
Anatomy of mature stemStructure of wood
Dilated rays of beech (Fagus sp.)
Shipunov BIOL 154.11
Questions and answersAnatomy of stem
Anatomy of mature stemStructure of wood
Periderm
Periderm is the product of cork cambium99% of periderm is a phellem (cork), thick outside layerPhelloderm is a tiny layer of living cells inside of corkcambium
Shipunov BIOL 154.11
Questions and answersAnatomy of stem
Anatomy of mature stemStructure of wood
Formation of bark zone in medlar (Mespilusgermanica)
Shipunov BIOL 154.11
Questions and answersAnatomy of stem
Anatomy of mature stemStructure of wood
Lenticels
Lenticels are specialized regions of periderm; they supplystem cells with oxygenIn order to produce lenticel, some cells of cork cambiumdivide and grow much faster than others
Shipunov BIOL 154.11
Questions and answersAnatomy of stem
Anatomy of mature stemStructure of wood
Lenticel of elderberry (Sambucus sp.)
Shipunov BIOL 154.11
Questions and answersAnatomy of stem
Anatomy of mature stemStructure of wood
How cambium is working
Shipunov BIOL 154.11
Questions and answersAnatomy of stem
Anatomy of mature stemStructure of wood
Secondary structure of stem (scheme)
Shipunov BIOL 154.11
Questions and answersAnatomy of stem
Anatomy of mature stemStructure of wood
Secondary structure of stem (photo and explanations)
Shipunov BIOL 154.11
Questions and answersAnatomy of stem
Anatomy of mature stemStructure of wood
Secondary xylem and rays
Secondary xylem, or wood, is the product of vascularcambiumSome cambium cells are fusiform initials; they form axialvessel elementsOther cambium cells are ray initials; they form rays(parenchyma + tracheids)Rays provide horizontal transport of water; axial systemprovide vertical transport
Shipunov BIOL 154.11
Questions and answersAnatomy of stem
Anatomy of mature stemStructure of wood
Fusiform and ray initials
Shipunov BIOL 154.11
Questions and answersAnatomy of stem
Anatomy of mature stemStructure of wood
Three planes of view
Transverse* (cross-section)Radial (longitudinal section from center to periphery andperpendicular to stem surface)Tangential (longitudinal section parallel to stem surface)
Shipunov BIOL 154.11
Questions and answersAnatomy of stem
Anatomy of mature stemStructure of wood
Three plains of maple (Acer sp.) wood
Shipunov BIOL 154.11
Questions and answersAnatomy of stem
Anatomy of mature stemStructure of wood
Three plains again (the scheme)
Shipunov BIOL 154.11
Questions and answersAnatomy of stem
Anatomy of mature stemStructure of wood
Earlywood and latewood
Earlywood (springwood) contains more parenchyma andoften have larger vessel elementsLatewood (summerwood) often have small vesselelements and looks darker
Shipunov BIOL 154.11
Questions and answersAnatomy of stem
Anatomy of mature stemStructure of wood
Diffuse and ring porous wood
In ring porous wood (like in red oak) bigger vesselelements concentrate in earlywoodIn diffuse porous wood larger vessel elements spreadacross early- and latewood (American elm)
Shipunov BIOL 154.11
Questions and answersAnatomy of stem
Anatomy of mature stemStructure of wood
Diffuse and ring porous wood in two species ofcinquefoil (Potentilla spp.)
Shipunov BIOL 154.11
Questions and answersAnatomy of stem
Anatomy of mature stemStructure of wood
Annual rings
Interleaving early- and latewood from to sequential yearsform an impression of annual ring“Ring” is just a layer of darker (i.e., smaller) cellsTropical trees do not form annual rings
Shipunov BIOL 154.11
Questions and answersAnatomy of stem
Anatomy of mature stemStructure of wood
Annual rings in juniper (Juniperus sp.)
Shipunov BIOL 154.11
Questions and answersAnatomy of stem
Anatomy of mature stemStructure of wood
Sapwood and heartwood
Sapwood is a peripheral layer of working xylem, it usuallyhas relatively light colorHeartwood is a central, non-functional, old, dark-coloredxylem
Shipunov BIOL 154.11
Questions and answersAnatomy of stem
Anatomy of mature stemStructure of wood
Sapwood and heartwood of European pine (Pinussylvestris)
Shipunov BIOL 154.11
Questions and answersAnatomy of stem
Anatomy of mature stemStructure of wood
Tyloses
Tyloses control the winter functioning of vessels
Shipunov BIOL 154.11
Questions and answersAnatomy of stem
Anatomy of mature stemStructure of wood
Two taxonomic terms
“Gymnosperms” All seed plants except angiosperms =Spermatophyta − Magnoliopsida
“Dicots” All angiosperms except monocots =Magnoliopsida − Liliidae
Shipunov BIOL 154.11
Questions and answersAnatomy of stem
Anatomy of mature stemStructure of wood
Conifer wood
Simpler structure, few cell typesSimple raysSometimes have resin ducts; resin secreted by epithelialcells
Shipunov BIOL 154.11
Questions and answersAnatomy of stem
Anatomy of mature stemStructure of wood
Ginkgo (Ginkgo biloba) wood (not a conifer, butgymnosperm)
Shipunov BIOL 154.11
Questions and answersAnatomy of stem
Anatomy of mature stemStructure of wood
Resin duct in pine wood ( c©BSA)
Shipunov BIOL 154.11
Questions and answersAnatomy of stem
Anatomy of mature stemStructure of wood
Monocot “wood”
Most of monocots do not have lateral meristems andtherefore have no true woodPalms have only primary tissues; their trunk widens frombottom to topSome monocots (dragon trees) have anomaloussecondary growth
Shipunov BIOL 154.11
Questions and answersAnatomy of stem
Anatomy of mature stemStructure of wood
Cross section of palm (Phoenix canariensis) trunk
Shipunov BIOL 154.11
Questions and answersAnatomy of stem
Anatomy of mature stemStructure of wood
Dragon tree (Dracaena draco)
Shipunov BIOL 154.11
Questions and answersAnatomy of stem
Anatomy of mature stemStructure of wood
Anomalous secondary growth in Bougainvillea(Bougainvillea spectabilis)
Shipunov BIOL 154.11
Questions and answersAnatomy of stem
Anatomy of mature stemStructure of wood
Summary
Bark consists of secondary phloem and corkWood is a secondary xylem
Shipunov BIOL 154.11
Questions and answersAnatomy of stem
Anatomy of mature stemStructure of wood
Final question (1 point)
Where is a cambium?
Shipunov BIOL 154.11
Questions and answersAnatomy of stem
Anatomy of mature stemStructure of wood
Final question (1 point)
Where is a cambium?
Shipunov BIOL 154.11
Appendix For Further Reading
For Further Reading
J. E. Bidlack, Sh. H. Jansky.Stern’s introductory plant biology. 12th edition.McGraw-Hill, 2011.Chapter 6.
Th. L. Rost, M. G. Barbour, C. R. Stocking, T. M. Murphy.Plant Biology. 2nd edition.Thomson Brooks/Cole, 2006.Chapter 5.
Shipunov BIOL 154.11