La paléochimiotaxonomie

expérimentale :

Un nouvel outil pour le traçage des

changements paléofloristiques et

paléoclimatiques.

Présentation et application aux

conifères fossiles.Y. Hautevelle, R. Michels, B. Farre, F. Lannuzel, F. Malartre

Botanical chemotaxonomyIntro-duction

Conclusions

II. Methodologydevelopment

Introduction

IV. Palaeochemo-taxonomyof conifers

I. Experimentaland analyticalmethodology

III. Example ofAraucariaceae

Terpenoids have a chemotaxonomic value and are

thus specific of some taxa

Molecular composition :- lignin- carbohydrates- lipids, e.g. terpenoids

conifers

Abietic acid

angio-sperms

lupeol

From bioterpenoids to geoterpenoidsIntro-duction

BIOSPHERE

GEOSPHERE

Sedimentary basin

transport

sediment

bioterpenoids

Geoterpenoids can keeptheir initial

chemotaxonomic value

conifers

angio-sperms

Geoterpenoids ormolecular biomarkers

Diagenetic

transformations

angio-sperms

conifers

Conclusions

II. Methodologydevelopment

Introduction

IV. Palaeochemo-taxonomyof conifers

I. Experimentaland analyticalmethodology

III. Example ofAraucariaceae

Distribution of plantbiomarkers

Palaeofloristic compositionon emerged lands

Intro-duction Palaeofloristic and palaeoclimatic reconstructions

The distribution of plant biomarkers reflect the palaeofloristic composition during the deposition

cypres

fern

Interpretation in terms of palaeofloristic composition

pine pineangio-

sperms

sequoia

Conclusions

II. Methodologydevelopment

Introduction

IV. Palaeochemo-taxonomyof conifers

I. Experimentaland analyticalmethodology

III. Example ofAraucariaceae

Intro-duction

desertic climate

temperate climate

tropical climate

polar climate flora ↔ climate

Relations between floras and climates

Conclusions

II. Methodologydevelopment

Introduction

IV. Palaeochemo-taxonomyof conifers

I. Experimentaland analyticalmethodology

III. Example ofAraucariaceae

Chemostratigraphy of vascular plant biomarkersIntro-duction

stratigraphicrecord

palaeobiodiversity

palaeoflora

palaeoclimate

T°, humidity

desertic climate

Geolo

gic

al ti

mes

tropical climate

temperate climate

Molecular facies

Conclusions

II. Methodologydevelopment

Introduction

IV. Palaeochemo-taxonomyof conifers

I. Experimentaland analyticalmethodology

III. Example ofAraucariaceae

Advantages of palaeochemotaxonomy

but fossils are scarse

Improved approaches for palaeofloristic

and palaeoclimatic reconstruction

PALAEOBOTANIC(fossil plants)

PALYNOLOGY(spore & pollen)

but spores & pollen are not easily related to plant taxa

BOTANICAL PALEOCHEMOTAXONOMY (plant biomarkers)

-widespread in the sedimentary record

- related to plant taxa when they have a palaeochemotaxonical value

however plant biomarkers are :

BUT, presently molecular databases contain many gaps

Intro-duction

Conclusions

II. Methodologydevelopment

Introduction

IV. Palaeochemo-taxonomyof conifers

I. Experimentaland analyticalmethodology

III. Example ofAraucariaceae

Aims of experimental palaeochemotaxonomy

plantbiomarkers

palaeofloristic and palaeoclimatic proxies

➜ new technic of artificial maturation of fresh plants (confined pyrolysis).

➜ experimental "simulation" of the plant diagenesis & fossilisation (at the molecular scale).

➜ Aim :

Molecularsystematic

Botanicalsystematic

Intro-duction

Conclusions

II. Methodologydevelopment

Introduction

IV. Palaeochemo-taxonomyof conifers

I. Experimentaland analyticalmethodology

III. Example ofAraucariaceae

I.01 Experimental and analytical procedures

Fresh plant Sealed gold tubes Confinedpyrolysis

Solubilisation ofterpenoids (CH2Cl2)

Molecular analysis(GC-MS)

Aliphatic

Aromatic

Polar

FractionationConclusions

II. Methodologydevelopment

Introduction

IV. Palaeochemo-taxonomyof conifers

I. Experimentaland analyticalmethodology

III. Example ofAraucariaceae

Composition of fresh Abies pinsapoII.01

Fresh Abies pinsapoMethylated total fraction

Retention time

Diagenetic evolution of abietanoic acids

Fresh Abies pinsapo contain large amounts

of abietanoic acids

Conclusions

II. Methodologydevelopment

Introduction

IV. Palaeochemo-taxonomyof conifers

I. Experimentaland analyticalmethodology

III. Example ofAraucariaceae

II.02

150°C

200°C

250°C

280°C

300°C

Other pyrolysis parameters :duration : 24 h ;pressure : 700 bars.

Diagenetic evolution of abietic acid

280°C Presence ofaromatic diterpanes

Pyrolysed Abies pinsapoTotal fractionm/z 219, 223, 237, 239, 241

Conclusions

II. Methodologydevelopment

Introduction

IV. Palaeochemo-taxonomyof conifers

I. Experimentaland analyticalmethodology

III. Example ofAraucariaceae

Calibration of the pyrolysis temperature

II.03

phytene

280°C

280°C presence of diterpanesclassically detected

in the geosphereLiAlH4

Unsaturated abietanes

not satisfying

Pyrolysis with LiAlH4

Pyrolysed Abies pinsapoAliphatic fraction TIC

280°CSaturatedabietanes

labdanes

Diterpane diagenesis

Pyrolysed Abies pinsapoAliphatic fraction TIC

Conclusions

II. Methodologydevelopment

Introduction

IV. Palaeochemo-taxonomyof conifers

I. Experimentaland analyticalmethodology

III. Example ofAraucariaceae

Generation of saturated diterpanes

II.04Pyrolysed Abies pinsapoAliphatic fraction TIC

Pyrolysed Abies pinsapoAromatic fraction TIC

pyrolysed Abies pinsapoPolar fraction TIC

with LiAlH4

280°C

WithoutLiAlH4

280°C

withoutLiAlH4

280°C

Conclusions

II. Methodologydevelopment

Introduction

IV. Palaeochemo-taxonomyof conifers

I. Experimentaland analyticalmethodology

III. Example ofAraucariaceae

Palaeochemotaxonomy of a virtual fossil Abies pinsapo

Typical molecular signature of fossil

Pinaceae

II.05

Aliphatic fractionTime : 24 h, pressure : 700 bar, temperature : 280°C, WITH LiAlH4

Aromatic fractionTime : 24 h, pressure : 700 bar, temperature : 280°C, WITHOUT LiAlH4

Polar fractionTime : 24 h, pressure : 700 bar, temperature : 280°C, WITHOUT LiAlH4

Determination/prediction of the fossil molecular signature

of the pyrolysed plant

The reproduction of this procedure on a great number of plant taxa will considerably increase our knowledge in palaeochemotaxonomy and contribute

to the reconstruction of ancient floraConclusions

II. Methodologydevelopment

Introduction

IV. Palaeochemo-taxonomyof conifers

I. Experimentaland analyticalmethodology

III. Example ofAraucariaceae

Summary of the experimental procedure

Conifers currently studied

Coniferal order is composed of 7 familiesAraucariaceae

3 Agathis, 8 Araucaria & 1 Wollemia

Cupressaceae1 Calocedrus, 4 Chamaecyparis, 2 Cupressus, 5 Juniperus,

1 Microbiota, 3 Thuja & 1 Thujopsis

Pinaceae 4 Abies, 3 Cedrus, 4 Larix, 5 Picea, 4 Pinus, 1 Pseudotsuga &

1 Tsuga

Podocarpaceae4 Podocarpus

Sciadopityaceae1 Sciadopitys

Taxaceae2 Taxus, 2 Cephalotaxus, 1 Torreya

Taxodiaceae 1 Cryptomeria, 2 Cunninghamia, 1 Sequoiadendron, 1 Meta-

sequoia, 1 Sequoia & 2 Taxodium

69 species studied forexperimental palaeochemotaxonomy

III.01

Conclusions

II. Methodologydevelopment

Introduction

IV. Palaeochemo-taxonomyof conifers

I. Experimentaland analyticalmethodology

III. Example ofAraucariaceae

Example of Araucariaceae (sesquiterpenoids)

Araucariaangustifolia

Araucariaaraucana

Araucarialaubenfelsii

n-C14 n-C15

Aliphatic fraction Aromatic fraction

farnesane

bisabolanes cadalanescadalenepentaMedi

hydroindenes

chamazulene ?

curcumenes

III.02

Conclusions

II. Methodologydevelopment

Introduction

IV. Palaeochemo-taxonomyof conifers

I. Experimentaland analyticalmethodology

III. Example ofAraucariaceae

III.03

Araucariaangustifolia

Araucariaaraucana

Araucarialaubenfelsii

labdanes

(iso)pimaranes

MonoaromaticLabdane ?

Monoaromatictetracyclic diterpane

Aromaticabietanes

Aliphatic fraction Aromatic fraction

Example of Araucariaceae (diterpenoids)

béyérane

phyllocladaneskauranes

phyllocladanes

Conclusions

II. Methodologydevelopment

Introduction

IV. Palaeochemo-taxonomyof conifers

I. Experimentaland analyticalmethodology

III. Example ofAraucariaceae

Results for the whole Coniferale orderIV.01

AraucariaceaeHigh abundance of tetracyclic diterpanes

Low abundance of tricyclic diterpanes

CupressaceaeHigh diversity between the different genera

Cuparene, cedrane and totaranes seem specific

Systematic occurrence of ferruginol and occasional occurrence of tetracylic diterpanes

Conclusions

II. Methodologydevelopment

Introduction

IV. Palaeochemotaxonomyof conifers

I. Experimentaland analyticalmethodology

III. Example ofAraucariaceae

IV.02

PinaceaeSystematic presence of dehydroabietic acid and dehydroabietol

Some fonctionnalised compouds seem to be specific for some genera

TaxodiaceaeHigh diversity between the different genera

Presence of ferruginol & sugiol

Occasional occurrence of tetracyclic diterpanes

Results for the whole Coniferale order

Conclusions

II. Methodologydevelopment

Introduction

IV. Palaeochemotaxonomyof conifers

I. Experimentaland analyticalmethodology

III. Example ofAraucariaceae

ConclusionsConclusion

Experimental Palaeochemotaxonomy ➜ pertinent and innovative approach

investigate the molecular composition of fossil plants from their present

representatives

BOTANICAL PALAEOCHEMOTAXONOMY(plant biomarkers)

PALEOBOTANIC(fossil plants)

PALYNOLOGY(spore & pollen)

Molecularsystematic

Botanicalsystematic

Conclusions

II. Methodologydevelopment

Introduction

IV. Palaeochemotaxonomyof conifers

I. Experimentaland analyticalmethodology

III. Example ofAraucariaceae

Y. HautevelleR. Michels, F. Malartre, B. Farre, F. Lannuzel, F. Malartre

La paléochimiotaxonomie

expérimentale :

Un nouvel outil pour le traçage des

changements paléofloristiques et

paléoclimatiques.

Présentation et application aux conifères fossiles.