第六节 植物运动——植物生理学课件PPT

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• 根的向重力性 • 根冠与淀粉粒 • 向重力性的PIN模型
The amyloplast act as a Statolith
Proposed model for the redistribution of auxin during gravitropism
Mechanism of Gravitropism
• Amyloplasts (organelles containing starch grains) settle by gravity to the bottom of cells in the root tip.
• The amyloplasts may be attached to actin filaments which are also attached to vesicles containing PIN proteins.
第六节 植物的运动 plant movement
http://.darwin200.org/
http://.nature./news/spec ials/darwin/index.html#d arwin200
植物运动的分类
• 向性运动(tropic movement) • 感性运动(nastic movement) • 生长运动(growth movement) • 膨压运动(turgor movement)
Model of effects of TIBA and
NPA on PIN cycling
and auxin efflux
Auxin transport inhibitors block PIN1
Control
Brefeldin A (BFA)
2h washout of BFA
BFA washout with cyotchalasin D
PIN proteins have 10 to 12 transmembrane regions
Model of Experiments That Have Examined the Mechanisms of the Control of PIN1 Protein Localization. (A) Vesicle-dependent transport of the PIN1
protein to the basal membrane appears to be along actin tracks. A high-affinity NPA binding protein has been found to interact with actin and may act as a bridge between these transport vesicles and the actin tracks and/or may serve to localize PIN1-containing IAA efflux plexes to the basal membrane. (B) Treatment with cytochalasin leads to a random PIN1 protein distribution and reduces polar auxin transport.
• This INHIBITS root cell elongation. • So the cells at the top surface of the root elongate,
causing the root to grow down.
Arabidopsis PIN mutant
WT
PIN2
AUX1
AUX1 = Auxin permease: promotes ac百度文库opetal (i.e. toward the tip) movement of auxin from phloem to root apex
A. Schematic representation of an Arabidopsis root marking tissues for gravity perception (magenta), gravity signal transmission (blue) and gravi response (green). B. A confocal image showing PIN2 (green) localisation in the Arabidopsis root apex. C. Close up of PIN2 localisation in epidermal cells. D. Close up of PIN2 localisation in LRC cells (indicated by arrows). E. A confocal image showing AUX1 (red) localisation in the Arabidopsis root apex. F. Close up of AUX1 localisation in epidermal cells. G. Close up of AUX1 localisation in LRC cells.
植物向性运动
tropic movement
• 向光性(phototropism) • 向重力性(gravititropism) • 向水性(hydrotropism) • 向化性(chemotropism) • 向触性(thigmotropism)
Cholodny-Went Model
植物向重力性生长 gravitropism
BFA washout with TIBA
Brefeldin A
Protophloem cells
Immunolocalisation studies revealed AUX1 appears
asymmetrically localised in root protophloem pole cells
• Tethered to amyloplasts, PIN proteins are inserted in the plasma membrane on the underside of pericycle cells causing auxin to accumulate on the under side of the root.
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