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欣欣向榮-植物的生長與發育

Plant Growth and Development

清華大學生命科學系

林彩雲

November 17, 2007

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草本

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木本

http://en.wikipedia.org/wiki/Image:Araucaria_heterophylla_01.jpg

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木本

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Genome Sizes (haploid)

Base pairs Genes NotesPhi-X 174 5,386 10 virus of E. coli

Human mitochondrion 16,569 37

E. coli 4,639,221 4,377 4,290 of these genes encode proteins; the rest RNAs

Arabidopsis thaliana 115,409,949 25,498

Humans 3.3 x 109 ~25,000

Rice 4.3 x 108 ~60,000

Psilotum nudum 2.5 x 1011

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Photosynthesis

RespirationTranspiration

光合作用

呼吸作用蒸散作用

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PhotosynthesisCarbon dioxide + Water + Sunlight = Sugar + Oxygen

6 CO2 + 6 H2O + Energy => C6H12O6 + 6 O2

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Photosynthetic organismsLeaves from higher plants flanked by colonies of photosynthetic purple bacteria (left) and cyanobacteria (right)

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Photosynthesis 光合作用

http://en.wikipedia.org/wiki/Photosynthesis

http://upload.wikimedia.org/wikipedia/commons/0/0c/Simple_photosynthesis_overview.svg

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Photosynthesis

光合作用

Electron transfer in the Photosynthetic Membrane from Robert Carpentier's web site

http://www.uqtr.ca/labcarpentier/eng/home_frames.htm

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固定CO2

再生RuBP 還原反應

http://en.wikipedia.org/wiki/Photosynthesis

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Increasing CO2 levelsThe light reactions of photosynthesis stop when the sun goes down

However, CO2 fixation can continue as long as ATP and NADPH is available

In cacti and other succulents CO2 uptake by the plant occurs primarily at night

PhotosynthesisCarbon dioxide + Water + Sunlight = Sugar + Oxygen

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C4 and C3 photosynthesis and CAM

In hot and dry conditions, plants will close their stomata to prevent loss of water.

These conditions will cause an increase of photorespiration by the oxygenase activity of ribulose-1,5-bisphosphate carboxylase/oxygenaseand decrease in carbon fixation.

http://upload.wikimedia.org/wikipedia/commons/f/f9/HatchSlackpathway.png

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RespirationC6H12O6 + 6 O2 => 6 CO2 + 6 H2O + Energy

GlycolysisTCA cycleElectron transport chain

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http://upload.wikimedia.org/wikipedia/commons/7/74/CellRespiration.svg

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Glycolysis, breakdown glucose to pyruvic acid in cytosol

Oxidation of pyruvic acid to CO2 and H2O in mitochondria

NADH dehydrogenase

succinatedehydrogenase

cytochrome c reductase(cytochrome b-c1 complex)

cytochrome c oxidase

ATP synthase

Outer membrane

Intermembranespace

Inner membrane Cristae

Matrix

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NADH dehydrogenase

succinatedehydrogenase

cytochrome c reductase(cytochrome b-c1 complex)

cytochromec oxidase

ATP synthase

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Comparison of respiration and photosynthesis

Respiration PhotosynthesisEnergy Released Stored

Reactants Glucose CO2 and H2O

Products CO2 and H2O Glucose

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Comparison of respiration and photosynthesis

Respiration PhotosynthesisSource Glucose Light

Types NAD NADP

Carriers of energy rich electrons

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Comparison of respiration and photosynthesis

Products of electron transport

Respiration Photosynthesis

ATP ATP + NADPH

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Comparison of respiration and photosynthesis

ATP synthesis

Respiration PhotosynthesisETC Yes YesPump proton Yes YesProton gradient Yes YesATP synthase Yes Yes

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Evaporation

Condensation Precipitation

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TranspirationTransporting minerals from the soil throughout the plant

Cooling the plant through evaporation

Moving sugars and plant chemicals

Maintaining turgor pressure

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Eduard Strasburger′s On construction and function of the conduits in plants, 1891.

Woody stems with their lower end immersed in concentrated solutions of copper sulfate or picric acid and severed by a cut made below the surface of the liquid, will readily suck the solution up.

Immediately upon contact, the poisonous fluid kills all living cells in its way, but the copper or the acid arrive in the transpiring leaves and kill them as well. The uptake of the solution and the loss of water from the dead leaves may continue for several weeks, and new solutions of a different color may be lifted in a dead stem.

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Science 23 September 2005:Vol. 309. no. 5743, p. 1993DOI: 10.1126/science.309.5743.1993

How does a garden grow?

Transpiration

From water absorption through a plant's roots to water vapor lost through its leaves, Tracy Sterling of New Mexico State University and animator Matt Byrnes created a friendly, interactive activity with a playful design.

The animation teaches plant biology basics and offers numerous interactive features, such as changes to environmental conditions that can impact the speed of water movement.

Transpiration: Water Movement Through Plants

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A balancing act

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Environmental Factors Affecting Growth

Light

Temperature

Water

Humidity

Nutrition

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Temperature effects

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Nutrition effects

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Plants in communitiesPlant or landscape ecologySuccessionAvailable light and moisture Competitive weeds thrive AllelopathyRelationships between plants and pollinators, animals, birds, pests, predators

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black walnuts

Plants guard their “personal space" with poisons

Allelopathy

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Plant hormones and growth regulators

Auxin

Gibberellin (GA)

Cytokinin

Ethylene

Abscisic acid (ABA)

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Auxin caused responsesBending toward a light source (phototropism) Downward root growth in response to gravity (geotropism) Promotion of apical dominanceFlower formation Fruit set and growth Formation of adventitious roots

http://en.wikipedia.org/wiki/Image:IAAII.pnghttp://upload.wikimedia.org/wikipedia/en/f/f7/Redtip9845.jpghttp://upload.wikimedia.org/wikipedia/commons/d/d6/Plastids_types.svghttp://upload.wikimedia.org/wikipedia/commons/6/6f/Arabidopsis_thaliana.jpg

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GibberellinsStimulate cell division and stem elongation

Break seed dormancy

Speed germination

Promote flowering and sex expression

Promote enzyme induction

Enhance leaf and fruit senescence

http://upload.wikimedia.org/wikipedia/commons/a/ac/Gibberellic_acid.svg

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CytokininsStimulate cell division

Affect shoot and root morphogenesis

Involved in chloroplast maturation

Affect cell enlargement and auxiliary bud release

Cytokinins also are used to delay aging and death (senescence)

http://upload.wikimedia.org/wikipedia/commons/b/bb/Zeatin.png

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EthyleneInduces ripening

Causes leaves to droop (epinasty) and drop (abscission)

Promotes senescence

http://upload.wikimedia.org/wikipedia/commons/e/e9/Ethene_structural.svghttp://upload.wikimedia.org/wikipedia/commons/d/d5/Yang-cycle.png

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Abscisic acid (ABA) A general plant-growth inhibitor

Induces dormancy and prevents seeds from germinating

Causes abscission of leaves, fruits, and flowers

Causes stomata to close

http://en.wikipedia.org/wiki/Image:Abscisic_acid_structure.png

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Phytochrome

Pr Pfr Response666 nm

730 nm

Dark reversionDegradation

Regulate the time of flowering based on the photoperiodismand to set circadian rhythms.

Regulates the germination of seeds, elongation of seedlings, the size, shape and number of leaves, the synthesis of chlorophyll, and the straightening of the epicotyl or hypocotylhook of dicot seedlings.

http://upload.wikimedia.org/wikipedia/commons/a/a5/Flower_poster_2.jpg

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Critical Terms Used to Describe Circadian Rhythms

(A) Sleep movements of Phaseoluscoccineus. Position of the primary leaves of a seedling at night (left) and during the day (right).

(B) Circadian rhythm of leaf movements of P. coccineusentrained to light/dark cycles and monitored in continuous light. The peaks of the curve represent the night time leaf position.

http://www.plantcell.org/content/vol18/issue4/images/large/pc040980F01_LW.jpeghttp://www.plantcell.org/content/vol18/issue4/images/large/pc040980F02_HT.jpeg

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horizontal above-ground stems (stolons) of the strawberry

leavesornamental plant Bryophyllum

of the common

Grafting

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Flowering: conversion of apical meristem into a floral meristem

TemperatureMany annual plants and biennial plants have their time of flowering delayed unless they have undergone a preceding period of wintertime cold (vernalization)

The buds of many species of woody angiosperms found in temperate climates, also need a preceding period of cold weather before they develop into flowers

PhotoperiodPhotoperiod is detected in the leaves

Leaves produce a chemical signal that is transmitted to the apical meristems to start their conversion into floral meristems.

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Structure of the Flower

The ABC Model of Flower Development

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A for the sepals

A, B and E for the petals

B, C and E for the stamens

C and E for the carpels

C, D and E for the ovules

Except for the A function, which is carried out at least partially by members of the APETALA2 transcription factor family, all regulatory functions are performed by the MADS-box family of transcription factors.

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Rationale for stimulating beveragesflavor, feeling of alertness

Caffeine is chemically related to purine bases in DNA

Desirable effects: stimulation of central nervous system, faster heartbeat, constriction of blood vessels, increased respiration rate, suppression of appetite, diuresis

Undesirable effects: headaches on withdrawal, infertility, birth defects, insomnia

http://upload.wikimedia.org/wikipedia/commons/d/d8/Caffeine.svg

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Tea (Camellia sinensis)Processing: Green tea: leaves are steamed, rolled to break cells and release aroma, dried

Black tea: leaves are withered, rolled, fermented(non-alcoholic), dried

Aroma and flavor from essential oils, additional taste from tannins; stimulating effect from caffeine and theophylline

Caffeine levels vary with the type of tea, black most, oolong intermediate, green tea least; also length of brewing will determine the amount of caffeine in a cup of tea

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Stimulating effect from theobromine, chemically related to caffeine

Theobroma cacao

http://www.botanical.com/botanical/mgmh/c/cacao-02-l.jpghttp://www.botanical.com/botanical/mgmh/c/cacao-02a-l.jpg

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