James McDaniel, 2012 graduate of Lynchburg College, presents on Rosa palustris at the Spring 2012 Student Scholar Showcase.

1. Rosa palustris, a Model Species
for Fragrance Investigations
James McDaniel and Nancy Cowden, Ph.D., Biology Department and
Priscilla Gannicott, Ph.D., Chemistry Department and DeAnne Moore
Lynchburg College, 1501 Lakeside Drive, Lynchburg, VA 24501

2. ABSTRACT
• The flowering plants Rosa palustris and Rosa palustris var. scandens have
distinguishing characteristics such as their habitat and floral anatomy that
set them apart. With a five-petaled bloom, R. palustris thrives in swamps
or bogs while R. palustris var. scandens is a double-petaled hybrid
cultivated for gardening purposes. From June 2010 to June 2011, we
investigated the fragrance composition of these flowering plants. A total
of 16 samples were collected from R. palustris and R. palustris var.
scandens flowers, using solid-phase microextraction (SPME). Total ion
chromatograms were produced by a Thermo electron-focus GC/DSQ MS
and XCalibur 1.4 software. Mass spectra were obtained from these
chromatograms using NIST MS Search 2.0, which allowed us to identify the
volatile organic compounds found in these roses. The most abundant
compounds found in R. palustris were 1-(R)-alpha-pinene, phenylethyl
alcohol, geraniol acetate, trans-geraniol, and cis-geraniol. Those found in
R. palustris var. scandens were phenylethyl alcohol, nonanal, 1-(R)-alpha-
pinene, and cis-geraniol. Ultimately, characterizing their fragrance
signatures is important because it has the potential to aid in selecting
fragrant varieties for new hybridizing endeavors in the future.

3. INTRODUCTION
• The genus Rosa includes approximately 200 species as well as more than 18,000
cultivated varieties (Guterman, 2002). Species roses, such as Rosa palustris, have
been cultivated for centuries to produce hybrid varieties. In the garden setting,
hybrid varieties known as cultivars are selectively propagated for desirable
characteristics. Some of these desirable characteristics include the following: long
vase life, flower shape, color, and “scent” (Shalit, 2003). In the field, it is visually
evident that the garden cultivar Rosa palustris var. scandens is propagated for its
flower shape because it has more petals than R. palustris and no prickles whereas
the native rose, R. palustris, has only a single bloom and curved prickles (Figs. 1
and 2). It is not quite clear, however, whether or not R. palustris var. scandens is
propagated for its “scent” because its fragrance composition has not been
characterized previously. “Scent” is important because it is an ancient connection
among flowering plants, their pollinators, and enemies (Raguso, 2008).
• We not only investigated the fragrance composition of the native wetland species,
R. palustris, but also that of the garden cultivar R. palustris var. scandens as a
means of comparison. This summer, we plan to further examine the relationship
between the fragrance of R. palustris and R. palustris var. scandens as well as their
pollinators. By examining this relationship, pollination efficiency can be examined
over time, which can be dependent upon visitor abundance, visitor activity, and
pollen loads deposited on receptive stigmas and seed set (Yeboah Gyan, 1987).
Determination of pollination efficiency coupled with the characterization of the
fragrance of each rose could aid in selecting fragrant varieties for new hybridizing
endeavors in the future.

4. INTRODUCTION
Figure 1. Rosa palustris in a wetland, Figure 2. Rosa palustris var.
Bedford Co., VA. scandens in the Antique Rose
Emporium, Brenham, TX.

5. MATERIALS AND METHODS
• In 2010 and 2011, the month of June provided us with the opportunity to collect a
total of 15 floral fragrance samples from Rosa palustris at the Claytor Nature Study
Center, Bedford Co., Virginia. Additionally, one floral fragrance sample of Rosa
palustris var. scandens was obtained in June of 2011 at the Old City Cemetery,
Lynchburg, Virginia. All of the samples were collected using static-headspace,
solid-phase microextraction (SPME) via 50/30 mm DVB/carboxen fibers (SUPELCO
Analytical, Bellefonte, Pa.). To collect the samples, theSPME fibers were placed
above the floral headspace of each individually bagged bloom (Figure 3). Over the
course of an hour, the SPME fibers absorbed the volatile organic fragrance
compounds emitted from each rose bloom. After an hour had passed, these fibers
were retracted back into their protective casings and transported to Lynchburg
College for further analysis on the same day that the samples were obtained.
• At Lynchburg College, desorption of the volatile organic compounds was achieved
in the laboratory by inserting the individual samples into the injection port of a
Thermo-Scientific Focus GC/DSQ MS set at 250°C. Total ion chromatograms were
analyzed to confirm the identity of each volatile organic compound by comparing
mass spectra to a NIST MS Search 2.0 database.

6. MATERIALS AND METHODS
Figure 3. Static-headspace SPME field
sampling technique.

7. RESULTS
• When comparing the Rosa palustris samples, it became evident that
some of them not only differed in the number of volatile organic
compounds that were present, but also by the relative percentages
(percent area and percent height) of each compound.
• Although other compounds were identified using the NIST MS
search 2.0 database, we consistently identified 1-(R)-alpha-pinene,
phenylethyl alcohol, cis-geraniol, trans-geraniol, and geraniol
acetate as the volatile, organic fragrance compounds that
constituted the greatest relative percentages out of all of the
fragrance compounds found in R. palustris (Figs. 4 and 5). In
addition, the NIST MS search 2.0 database determined that 1-(R)-
alpha-pinene, nonanal, phenylethyl alcohol and cis-geraniol
constituted the greatest relative percentages out of all of the
fragrance compounds found in R. palustris var. scandens (Figs. 6 and
7).

8. RESULTS
RT: 8.00 - 18.00
12.69 NL:
100 5.20E8
95 14.70 TIC F: MS
90 rcarolina628
10mix1
85 Phenylethyl alcohol
80
75 Trans-geraniol
70
65
60 Cis-geraniol
16.42
55
50
14.33
45
40
35
30
Geraniol acetate
25
20
15 14.95
10 13.77
15.18
10.40 11.40 17.18
5 8.62 9.43 13.20 15.27
9.59
0
8 9 10 11 12 13 14 15 16 17 18
Time (min)
Figure 4. A representative total ion chromatogram Figure 5. Relative percentages of all fragrance
of a Rosa palustris SPME sample (6/28/2010). compounds found in a fresh Rosa palustris
bloom (6/28/2010).

9. RESULTS
RT: 8.00 - 18.00
13.63 NL:
100 1.16E8
Phenylethyl alcohol
95 TIC F: MS
90 PalustrisSca
ndens06032
85 011mixedpg
13.32 1
80
75
70
65
60
55
50 Nonanal
45
40 Cis-geraniol
35
30 16.26
(R)-alpha-pinene
25 14.78
20
13.93 15.74 17.57
15 10.44 12.40 17.19
10 9.51 11.28 12.72 15.29
5 8.53 9.71 16.40
0
8 9 10 11 12 13 14 15 16 17 18
Time (min)
Figure 6. A representative total ion chromatogram of a Figure 7. Relative percentages of all
Rosa palustris var. scandens SPME sample (6/3/2011). fragrance compounds found in a fresh Rosa
palustris var. scandens bloom (6/3/2011).

10. DISCUSSION
• More than 400 volatile, organic compounds are known to be related to rose scent
(Shalit, 2003). Among these are alcohols described as having a “rose like” odor
that are frequently found in rose species (Chemicalland21.com, 2010). Phenylethyl
alcohol, cis-geraniol, and trans-geraniol are all alcohols which appeared in mass
spectra in 13, 12, and 11 samples, respectively, out of 15 total Rosa palustris
samples. The ester, geraniol acetate, which is described as having a “floral or
fruity” rose aroma (Chemicalland21.com, 2010), appeared in mass spectra in ten
out of 15 R. palustris samples. (R)-alpha pinene, which is a bridged hydrocarbon,
appeared in all 15 R. palustris samples and is also described as a volatile rose
compound. For Rosa palustris var. scandens, the alcohols phenylethyl alcohol and
cis-geraniol appeared in the mass spectrum obtained. Also present were the
aldehyde nonanal, which is described as having a strong “floral or fruity” aroma,
and (R)-alpha-pinene. Combined, our work represents the first known analysis of
the volatile organic fragrance compounds found in R. palustris and R. palustris var.
scandens.
• Future research will allow us to correlate each rose with its pollinators and to
examine how fragrance signatures affect insect visitors’ responses to the scents
produced.

11. SELECTED LITERATURE
AroKor Holdings, Inc. 2000 – 2010. Chemicalland21.com. Retrieved April 7, 2012, from:
http://www.chemicalland21.com
The Taunton Press, Inc. 2012. Fine Gardening. Retrieved April 7, 2012, from:
http://www.finegardening.com/plantguide/rosa-palustris-var-scandens-swamp-rose.aspx
Guterman, I., M. Shalit, N. Menda, D. Piestun, M. Dafny-Yelin, G. Shalev, E. Bar, O. Davydov, M.
Ovadis, M. Emanuel, et al. 2002. Rose Scent: Genomics Approach to Discovering Novel Floral
Fragrance-Related Genes. The Plant Cell 14: 2325-2338.
Raguso, R. A. 2008. Wake Up and Smell the Roses: The Ecology and Evolution of Floral Scent. Annual
Review of Ecology, Evolution, and Systematics 39: 549-569.
Shalit, M., et al. 2003. Volatile Ester Formation in Roses. Identification of Acetyl-Coenzyme A.
Geraniol / Citronellol Acetyltransferase in Developing Rose Petals. Plant Physiology 131: 1868-1876.
Yeboah Gyan, K., S. R. J. Woodell. 1987. Analysis of insect pollen loads and pollination
efficiency of some common insect visitors of four species of woody Rosaceae.
Functional Ecology 1: 269-274.