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Plant anatomy (植物解剖学)

Mount Usu / Sarobetsu post-mined peatland
From left: Crater basin in 1986 and 2006. Cottongrass / Daylily

[morphology, seed]

Tissue system (組織系)

1868, 1875 Sachs (Plant physiologist)
1884 van Tieghen

they proposed "tissue system"

1884 Haberlaudt

dermal tissue, mechanical tissue, absorptive tissue, assimilating tissue, conductive tissue, storage tissue, aerenchyma tissue, secretary tissue, locomotive tissue, sensitive tissue, stimulus conducting tissue


Flower ()

Process of corolla formation
A) flower arrangement
Magnoliaceae = spiral arrangement → [semi-] → cyclic arrangement = Fabaceae
1: spiral arrangement: primitive unspecialized perianth

Ex. Magnoliaceae, Calycanthaceae, Himanthandraceae, Nymphaeceae
Corolla arrangement - spiral
Stamen, carpel (pistil) - many

2: cyclic arrangement: monocyclic arrangement, dicyclic arrangement, tricyclic arrangement, etc.
3: semi-cyclic arrangement
B) modified stamens
a) Se | P → St
b) Se → P-St

Vascular bundle system (維管束系, VBS)

= (fibro)vascular bundle system = phloem (師部)+ xylem (木部, cell wall only)
Vascular plants, having the conducting tissues, xylem and phloem, have come to dominate terrestrial habitats, so much so, in fact, that they are sometimes spoken of as “the land plants” a designation that quite overlooks may algae, fungi, liverworts and mosses that share this same habitat. Pteridophyta (ferns), seed plants


Ex. ferns: inner endodermis = stele, central cylinder

Parenchyma (柔組織): tissue composed of living-walled cells, most often functioning in photosynthesis or storage
Fig. Elements of the xylem
Fig. Elements of the phloem

Microscopic observation of vascular bandle system

Objectives: understanding the structures of vascular bandles, based on the comparisons between monocotyledons and dicotylenons
Materials (often used for training): Cucurbita moschata var. Toonas (or Cucurbita maxima) = dicotyledonae, and Zea mays = monocotyledonae
  1. Slice thinnly the stems of pumpkins and corns by a razor blade or other sharp blade.
  2. Soak into 50% Et-OH mixed with 1% safranin for 1 hr
  3. Soak into 50% Et-OH for ca 10 sec
  4. Soak into 75% Et-OH for ca 10 sec
  5. Soak into 85% Et-OH for ca 10 sec
  6. Soak into 95% Et-OH for ca 10 sec
  1. Soak into 100% Et-OH for ca 10 sec
  2. Soak into 100% Et-OH mixed with 1% light green for ca 30-120 sec
  3. Soak into 95% Et-OH for ca 10 sec
  4. Soak into 100% Et-OH for ca 10 sec
  5. Soak into 100% Et-OH for ca 10 sec
  6. Soak into the solution made of Et-OH:xylene = 1:1 for ca 10 sec
  7. Soak into 100% xylene for ca 10 sec
  8. Soak into 100% xylene for ca 10 sec
  9. Mount by Canada balsam
  10. Observation under a microscope

Xylem (木部)

Water transport from roots
Vessel (導管)

lost cell wall and made single tube
xylemscalariform xylemspiral

Tracheid (仮導管)

lost cell wall and made single tube

Fibrous tissue (繊維細胞)
Xylem parenchyma (木部柔組織)

Phloem (師部)

→ nutrient transport
a) sieve tube (→ sieve plate: cell wall of phloem forms into a sheet)
b) companion cell
c) phloem fiber
d) phloem parenchyma
e) fibrous tissue
f) resin canal


Alternate pit
Bordered pit
Half-bordered pit
Simple pit: ramiform pit
Vestured pit

pit pit pit
_________bordered pit_____simple________◎: pit

Stele (中心柱)

= central cylinder, vascular cylinder
= vascular or vessel bundle tissue + its related tissues
Morphologically-various steles

seed plants → a few types
ferns → diverse steles used for taxonomical key

Evolutionary relationship
amphipholic siphonostele (両篩管状中心柱) → dictyostele (網状中心柱)
ectophloic siphonostele (多篩管状中心柱) → eustele (真生中心柱)
A. protosteles (原生中心柱):
are the simplest, and are often considered to be the most primitive, type of stele. Protosteles occur in Psitophyta and Microphyllophyta and in the juvenile stems of other groups (in many roots as well).

A0: concentric vascular bundle (包囲維管束): fossil records only
A1: haplostele (単一中心柱)
A'. actinostele (放射中心柱)
= radical vascular bundle (放射維管束)

Ex. Psilotum
Ex. all the vascular plants

sweet potato = root ↔ potato = (underground) stem

A''. plectostele (背腹中心柱)

Ex. Lycopodium


e: endodermis, p: phloem, x: xylem

B. ectophloic siphonostele (solenostele) (外部管状中心柱)

B'. amphipholic siphonostele (両節管状中心柱)

C. dictyostele (網状中心柱)
stele In siphonostelic stems with short internodes, overlapping of the nodal leaf gaps results in disection of the stele. As seen in transection, the stele appears as discrete strands or bundles, each surrounded by endodermis and the phloem surrounding the xylem. A siphonostele thus disected is called a dicotyostele. This type of stele characterizes many ferns.
D. eustele (真正中心柱)
stele = collateral vascular bundle
Where the xylem and phloem occur in discrete collateral or bicollateral strands or bundles, the arrangement is called a eustele. A eustele occurs in the internodes of Equisetum and in many gymnosperms and flowering plants. Certain of the strands pass into the leaves as traces.

bicollateral vascular bundle (複並立維管束)

E. atactostele (不整中心柱)

Leaf ()

Fig. Sectoin of leaf


Root ()