Approaches to subspecies diagnostics in big sagebrush (Artemisia tridentata) using an Electronic Nose

Hector Ortiz, Bryce Richardson

USFS-Rocky Mountain Station, Chicago Botanic Garden

The Chemical Species Profile Discrimination (A Brief Description)

• Smell receptor

• Chemosensors

• Odor sensing,

e-nose applications

• Smell profiles

Camphene Arthole 1,8-Cineole Methy Santolinate Camphor

Methacrolein or methacroldehyde Molecular formula C4H6O

Big Sagebrush Emission of HIPV’s, GLV’s, VOC’s

- High Sensitivity to Light and Temperature - Herbivore Selection Pressure, caused speciation? - Insects

Baldwing et, al. 2006

Aerial interaction of the wild tabacco Nicotiana atenuata and sagebrush Artemisia tridentata.

• Determinate sensitivity to known plant volatiles (methacrolein)

• Develop an standard protocol for volatile

analysis • Assess effectiveness at discriminating

subspecies

Objectives

• Parameterization with pure methacrolein

• Sensor selection

• Train E-Nose with Artemisia samples

PC-Nose Standardization

1. Collect and freeze fresh leaves 2. Crush and elute with water 3. Centrifuge 4. Program the settings of the PC Nose 5. Training and sample analysis

Sample Preparation

Methacroleine 10% 20% 50% 70% 80%

10% 8 0 0 0 0

20% 0 8 0 0 0

50% 0 0 8 0 0

70% 0 0 0 8 0

80% 0 0 0 0 8

Identified As

Trai

ne

d A

s

Correct: 100%

Cross Validation Methacrolein Method

• First analysis shows, how the volatile profiles within and between samples of the same subspecies are related

- These samples were collected from a common garden

• Second analysis shows differences among subspecies (tridentata, vaseyana and wyomingensis)

• Third analysis was a comparison between subspecies within a small geographic range

Results

WAT-1

ORT-3 Putative hybrid

NVT-2

NVT-1

MTT-1 IDT-3

Canonical Projection Plot first analysis—within subspecies and individual

variation, A. tridentata

0.0

5.0

10.0

15.0

20.0

M-

Dis

tan

ce

WAT-1 ORT-3 NVT-2 NVT-1 MTT-1 IDT-3

Potential hybrid

Variation within samples A. tridentata

MTV-1

IDV-4

IDV-3 Putative hybrid

IDV-2

CAW-3

UTV-1

Canonical Projection Plot first analysis—within subspecies and individual

variation, A. vaseyana

M-D

ista

nce

0.0

5.0

10.0

15.0

20.0

25.0

MTV-1 IDV-4 IDV-3 IDV-2 CAW-3 UTV-1

Potential hybrid

Variation within samples A. vaseyana

MTW-3

UTV-2 COW-2

MTW-1

IDW-2

IDW-3

Canonical Projection Plot A. wyominensis

M-D

ista

nce

0.0

5.0

10.0

20.0

25.0

30.0

35.0

MTW-1 UTV-2 COW-2 IDW-2 IDW-3 MTW-1

Variation within samples A. wyomingensis

A. wyomingensis

A. vaseyana

A. tridentata

-10.0 -5.0 0.0 5.0 10.0 15.0 20.0 25.0 30.0

-5.0

0.0

5.0

10.0

Fact

or

2

Factor 1

Second analysis comparison among A. tridentata, A. vaseyana, A. wyomingensis

vaseyana UTV-3

wyomingensis UTW-1

tridentata UTT-1

Factor 1

Fact

or

2

-25.0 -20.0 -15.0 -10.0 -5.0 0.0 5.0 10.0 15.0

-10.0

-5.0

0.0

5.0

10.0

Comparison between subspecies within a small geographic range (<15km)

Location: La Sal, Utah

• Other factors under consideration: • Environment

• Time of year

• Stems, seeds and flower parts?

On Going Work

• The e-nose can detect presence or absence of VOC’s, and different concentrations of methacrolein

• The protocol developed appears to capture the important volatiles involved in distinguishing subspecies

• The e-nose was capable of differentiating subspecies from a common environment

Summary