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Section Two Stems. Definition: important vegetative organ . Physiological function conduction supporting function preservation breeding Medicinal value. Cortex Eucommiae. Herba Ephedrae. Medulla Tetrapanacis. Lignum Aquilariae Resinatum. 一、 Morphological Features and types
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Section Two Stems Definition: importantvegetative organ. Physiological function conduction supporting function preservation breeding Medicinal value
Cortex Eucommiae HerbaEphedrae Medulla Tetrapanacis Lignum Aquilariae Resinatum
一、Morphological Features and types of Stem 1. ☆morphological features Definition: node , internode , shoot
☆ buds In fact it is meristem or immature structure of developing organs. According to the growth location of buds • Normal bud : terminal bud,axillary bud,accesory bud • Adventitious bud
The outer form of stem 1.terminal bud 2.Lateral bud 3.node 4.Leaf scar 5.internode 6.lenticel
According to the nature of the development of buds • Leaf bud • Flower bud • Mixed bud • According to the activity of buds • Active bud • Dormant bud
According to bud scales with or without • Naked bud Scaly bud
Way branching stems 1.Monopodial branching 2.Sympodial branching 3.Dichotomous branching 4.False dichotomous branching
☆2.Stem types woody stem: tree, shrub, subshrub, woody vine herbaceous stem: annual herb, biennial herb, perennial herb, herbaceous vine succulent stem
erect stem twining stem climbing stem screeping stem
☆3.Stem Modifications ①upper terraneous stem Leafy stem Shoot thorn Hook-like stem Stem tendril Tubercle,bulblet False bulb
Abnormal aerial stem 1.Leafy shoot 2.leafy stem 3.hook-like stem 4.Shoot thorn 5.stem tendril 6.Tubercle 7.bulblet
Anomalous aerial stem 1.Leafy shoot(天门冬)2. leafy stem(仙人掌)3. hook-like stem(钩藤) 4.Shoot thorn(皂荚)5. stem tendril(葡萄)6. tubercle(示珠芽)
②Subterraneous stem Rhizome Tuber Corm bulb
abnormal subterraneous stem Ⅰ.rhizome Ⅱ.rhizome Ⅲ.tuber Ⅳ.corm Ⅴ.bulb 1.scaly leaf 2.terminal bud 3.bulb plate 4.adventitious root Ⅵ. bulb
The abnormal subterraneous stem 1.rhizome(姜)2. tuber(半夏)3. corm(荸荠) 4.bulb(洋葱)5.lognitudinal onion 6.bulb(百合)
二、Inner Structure of Stem ①Structure of Stem Apex meristematic zone elongation zone maturation zone
②Primary Structure of Dicot Stems epidermis(trichome and stoma) cortex vascular cylinder Definition : endarch: The order of differentiation and maturation of primary xylem of stem is from the inside to outside, and is known as endarch.
Primary structure of Dicot stems 1、epidermis 2、cortex 3、vascular cylinder 4、collenchyma 5、parenchyma 6、phloem fiber 7、primary phloem 8、fascicular cambium 9、primary xylem 10、pith rays 11、pith
Transverse section of sunflower 1、epidermis 2、collenchyma 3、resin canal 4、cortex 5、phloem fiber 6、pith rays 7、primary phloem 8、sieve tube 9、fascicular cambium 10、vessel 11、xylem fiber 12、xylem parenchyma 13、pith
③Secondary Structure of Dicot Stems A. Woody Dicot Stems Fascicular cambium , Interfascicular cambium , secondary xylem , secondary phloem Definition:annual ring , early wood , late wood , sap wood , heart wood , rhytidome
1.Epidermis 2.Periderm ①phellem ②phellogen③phelloderm 3.Cortex 4.Phloem fibre 5.Vascular bundle ①phloem ②cambium ③xylem 6.pith
transverse section radial ~ tangential~
Ⅰ.transverse section Ⅱ.radial section Ⅲ.tangential section 4.Secondary xylem 5.ray 6.Annual ring 7.Sap wood 8.Heart wood
Early wood and late wood Sap wood and Heart wood
B. Herbaceous Dicot Stems The model sketch of herbaceous stem 1.non-glandular hair 2.Glandular scale 3.Collenchyma 4.Epidermis 5. glandular hair 6.Endodermis 7.Fibre 8.Phloem 9.stone cell 10.xylem
c. Rhizome of Dicot Stems 一、Normal Structure of Rhizoma Transverse section of huanglian rhizoma 1、phellem 2、cortex 3、stone cell group 4、5、rays 6、phloem 7、xylem 8、pith
Transverse section of the rhizome of Huanglian 1.cork 2.cortex 3.Stone cells 4.Pericyclic fibre bundles 5.cambium 6.phloem 7.Pith ray 8.xylem 9.pith
二、Anomalous Structure ofRhizome of Dicot Stems (1)Anomalous structure of rhubarb rhizoma Up,1、phloem 2、cambium 3、xylem rays 4、star dots Down,1、vessel 2、cambium 3、phloem 4、grume cavity 5、rays
Transverse section of rhizome of Dahuang 1.xylem 2.pith 3.Allotype vascular bundle
(3)Transverse section of spikenard Rhizoma 1、phellem 2、phloem 3、xylem 4、pith 5、cranny
④Structure of Monocot Stems ①Without cambium and phellogen ②Closed collateral vascular bundle or amphivasal bundle ③No pith endodermis
⑤Gymnosperm Stems Like Woody Dicot Stems , but different parts is that it has tracheid ,rays , xylem parenchyma without xylem fiber. Meanwhile secondary phloem is simple.
Transverse Section of Gymnosperm 1、epidermis 2、phellem 3、phellogen 4、cortex basic meristem 5、epithelia 6、phloem 7、cambium 8、xylem rays 9、resin canal 10、secondary xylem 11、pith rays 12、metaxylem 13、protoxylem 14、pith
Review Questions 一.Definition node , internode , exarch , endarch , annual ring , early wood , late wood , sap wood , heart wood 二.simple answer 1.what is the difference of the stem of Monocotyledoneae and Dicotyledoneae? 2.what is the function of the stem? 3.How about the secondary structure of the woody stem?