Sixty-five leaf samples in sect. Oleifera H. T. Chang, sect. Paracamellia Sealy, sect. Camellia, and sect. Thea (L.) Dyer of genus Camellia L. were discriminated directly with an OMNI-sampler accessory on the basis of biochemical profiles and a hierarchical dendrogram was finally constructed. The results showed that the infrared spectra of Camellia were fingerprint-like patterns which were highly typical for different taxa. The hierarchical dendrogram based on principal component analysis of Fourier Transform Infrared (FTIR) data confirmed most of morphological classifications of the four sections proposed in previous works. Infrared spectra of leaves are of taxonomic value in genus Camellia, and this technique can be widely used for identification and classification of other taxa when standard spectra are available. The relationships between sect. Oleifera and sect. Paracamellia, subsect. Lucidissima H. T. Chang and subsect. Reticulata H. T. Chang in sect. Camellia, and the species/varieties were also discussed, as many dissensions about the classification exist between Chang’s and Ming’s system.
全 文 :Journal of Systematics and Evolution 46 (2): 194–204 (2008) doi: 10.3724/SP.J.1002.2008.07125
(formerly Acta Phytotaxonomica Sinica) http://www.plantsystematics.com
FTIR spectra of Camellia sect. Oleifera, sect. Paracamellia, and sect.
Camellia (Theaceae) with reference to their taxonomic significance
1Jin-Bo SHEN 1,2Hong-Fei LÜ* 1Qiu-Fa PENG 3Ju-Fang ZHENG 1Yu-Mei TIAN
1(College of Chemistry and Life Science, Zhejiang Normal University, Jinhua 321004, China)
2(Key Laboratory of Photosynthesis and Environmental Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China)
3(Zhejiang Key Laboratory for Reactive Chemistry on Solid Surfaces, Institute of Physical Chemistry, Zhejiang Normal University, Jinhua 321004, China)
Abstract Sixty-five leaf samples in sect. Oleifera H. T. Chang, sect. Paracamellia Sealy, sect. Camellia, and
sect. Thea (L.) Dyer of genus Camellia L. were discriminated directly with an OMNI-sampler accessory on the
basis of biochemical profiles and a hierarchical dendrogram was finally constructed. The results showed that the
infrared spectra of Camellia were fingerprint-like patterns which were highly typical for different taxa. The hier-
archical dendrogram based on principal component analysis of Fourier Transform Infrared (FTIR) data confirmed
most of morphological classifications of the four sections proposed in previous works. Infrared spectra of leaves
are of taxonomic value in genus Camellia, and this technique can be widely used for identification and classifica-
tion of other taxa when standard spectra are available. The relationships between sect. Oleifera and sect. Para-
camellia, subsect. Lucidissima H. T. Chang and subsect. Reticulata H. T. Chang in sect. Camellia, and the spe-
cies/varieties were also discussed, as many dissensions about the classification exist between Chang’s and Ming’s
system.
Key words Camellia, cluster analysis, infrared spectra, taxonomic significance.
The genus Camellia L., containing many impor-
tant economic plants, is endemic to eastern and
southeastern Asia (Ming, 2000; Gao et al., 2005).
Now it is estimated that more than 400 Camellia
species have been named and published (Gao et al.,
2005). Although the species discovered in this genus
have been sorted out, classified and revised many
times during generic revision (Sealy, 1958; Chang &
Bartholomew, 1984; Chang, 1998; Ming, 2000), there
is much disagreement concerning combination and
species number, with the number varying from 119 to
280, depending on the taxonomic authority (Gao et al.,
2005). Hence, it is necessary to further investigate the
classification of the species using other technologies.
Chemotaxonomy has strongly influenced the en-
tire field of biology, which is also useful for plant
systematics. Fourier Transform Infrared (FTIR) Spec-
troscopy is a rapid, noninvasive, high-resolution ana-
lytical tool for identifying types of chemical bonds in a
molecule by producing an infrared absorption spectrum
that is like a molecular “fingerprint”. This technology
allows detecting the whole range of infrared spectrum
in measurements of biological specimens (Griffiths &
de Haseth, 1986). Thus, these “fingerprints” are made
up of the vibrational features of all the cell components,
i.e., DNA, RNA, proteins, and membrane and cell-wall
components. The biochemical profiles of FTIR from
whole cell samples are extremely high density data sets
and, consequently, FTIR data must be analyzed by
means of multivariate analysis when multiple samples
are compared. FTIR has been shown to be a valuable
tool for differentiating, classifying and discriminating
closely related microbial strains (Naumann et al., 1991;
Lamprell et al., 2006; Rebuffo et al., 2006). In plant
classification, Kim et al. (2004) have proposed this
approach is robust in chemotaxonomic classification of
flowering plants, and we previously have used this
method to identify the species in Hypericum L. and
Triadenum Raf. (Lü et al., 2004). All these previous
studies show that this approach is valid representations
of phylogenetic relationships between plant taxa even
closely related.
In this paper we followed Chang’s treatment and
selected 63 closely related species and 2 varieties of
Camellia (Table 1) with the main objectives to (i)
illustrate the relationships of these closely related
species based on leaf chemical characteristics by FTIR
technique in conjunction with previous reported
morphology characteristics, and (ii) introduce the
potential usability of Camellia species in order to
effectively understand and use them.
1 Material and methods
1.1 Materials
A total of 63 species and 2 varieties in 4 sections
———————————
Received: 21 September 2007 Accepted: 21 November 2007
* Author for correspondence. E-mail: luhongfei0164@sina.com; Tel.:
86-579-82282284.
SHEN et al.: FTIR spectra of Camellia sect. Oleifera, sect. Paracamellia, and sect. Camellia
195
(5 species in sect. Oleifera H. T. Chang, 16 species in
sect. Paracamellia Sealy, 37 species and 2 varieties in
sect. Camellia and 5 species in sect. Thea (L.) Dyer,
mainly according to Chang, 1998) of Camellia were
included in this study (details of the plant species are
given in Table 1). The five species in sect. Thea were
used to illustrate the power of this technology for
taxonomic classification, because these species have
some unique chemical composition, especially the
caffeine and theobromine (Chang et al., 1996). The
third mature leaves fully exposed to sunlight on the
two-year-old branches of three to four different plants
in the International Camellia Species Garden in Jinhua
city, Zhejiang, China (29°7′ N and 119°35′ E) were
taken for FTIR analysis in April 2006. Leaves were
picked from plants and then immediately freeze-dried.
The samples were then pulverized by slight grinding
in an agate mortar and the ground samples were then
stored at –20 ℃.
1.2 FTIR spectroscopy
All spectra were obtained with the aid of an
OMNI-sampler attenuated total reflectance (ATR)
accessory on a Nicolet FTIR spectrophotometer
(Nicolet Nexus 870, American) followed the methods
of Ellis et al. (2002) and Lü et al. (2004) with some
modifications. A small amount of powdered leaves
was respectively placed directly on the germanium
piece of the infrared spectrometer with constant
pressure applied and data of infrared absorbance,
collected over the wavenumber ranged from 4000
cm–1 to 675 cm–1, were computerized for analyses by
using the Omnic software (version 5.2). The reference
spectra were acquired from the cleaned blank crystal
prior to the presentation of each sample replicate. All
spectra were collected with a resolution of 4 cm-1, and
to improve the signal-to-noise ratio, 256 scans were
co-added and averaged. Samples were run in tripli-
cate, and all of them were undertaken within a day
period.
1.3 Data normalization and statistical analysis
Before data analysis, regions in the spectra that
are dominated by CO2 (2403.21–2272.06 cm–1 and
682.77–675.00 cm–1) were filtered out to follow the
spectral trend of neighboring data points. Procedures
were then implemented to minimize problems arising
from baseline shifts. Spectra were first subjected to
path-length correction, and then the spectra were
baseline corrected and normalized so that the smallest
Table 1 Source of materials*
Taxon Voucher
Camellia sect. Thea (L.) Dyer (茶组)
C. atrothea H. T. Chang & H. S. Wang (老黑茶) J. B. Shen & J. L. Fu (沈锦波, 傅佳丽) 2006111119101
C. taliensis (W. W. Sm.) Melchior (大理茶) J. B. Shen & J. L. Fu (沈锦波, 傅佳丽) 2006111119401
C. assamica (Mast.) H. T. Chang (普洱茶) J. B. Shen & Q. F. Peng (沈锦波, 彭秋发) 2006111118301
C. sinensis (L.) Ktze. (茶) J. B. Shen & J. L. Fu (沈锦波, 傅佳丽) 2006111120501
C. leptophylla S. Y. Liang ex H. T. Chang (膜叶茶) J. B. Shen & J. L. Fu (沈锦波, 傅佳丽) 2006111119601
Sect. Oleifera H. T. Chang (油茶组)
C. gauchowensis H. T. Chang (高州油茶) J. B. Shen (沈锦波) 200612230401
C. oleifera Abel (油茶) J. B. Shen (沈锦波) 200612230802
C. vietnamensis T. C. Huang ex Hu (越南油茶) X. Y. Lin (林秀艳) 200701280701
C. sasanqua Thunb. (茶梅) J. B. Shen (沈锦波) 200612230601
C. lanceoleosa H. T. Chang & J. S. Chiu (狭叶油茶) J. B. Shen (沈锦波) 200612230501
Sect. Paracamellia Sealy (短柱茶组)
C. fluviatilis Hand.-Mazz. (窄叶短柱茶) X. Y. Lin (林秀艳) 200701282401
C. grijsii Hance (长瓣短柱茶) J. B. Shen (沈锦波) 200701122001
C. yuhsienensis Hu (攸县油茶) J. B. Shen (沈锦波) 200701122102
C. odorata L. S. Xie & Z. Y. Zhang (芳香短柱茶) X. Y. Lin (林秀艳) 200701283502
C. shensiensis H. T. Chang (陕西短柱茶) J. B. Shen (沈锦波) 200701122901
C. confusa Craib (小果短柱茶) J. B. Shen (沈锦波) 200612232201
C. kissi Wall. (落瓣短柱茶) J. B. Shen (沈锦波) 200701122302
C. tenii Sealy (大姚短柱茶) X. Y. Lin (林秀艳) 200701283102
C. hiemalis Nakai (冬红短柱茶) J. B. Shen (沈锦波) 200612232602
C. miyagii (Koidz.) Makino & Nemoto (琉球短柱茶) J. B. Shen (沈锦波) 200701123001
C. brevistyla (Hayata) Coh. Stuart (短柱茶) J. B. Shen (沈锦波) 200612232501
Journal of Systematics and Evolution Vol. 46 No. 2 2008 196
Table 1 (continued)
Taxon Voucher
C. obtusifolia H. T. Chang (钝叶短柱茶) J. B. Shen (沈锦波) 200701122701
C. puniceiflora H. T. Chang (粉红短柱茶) J. B. Shen (沈锦波) 200701123001
C. microphylla (Merr.) Chien (细叶短柱茶) X. Y. Lin (林秀艳) 200701283202
C. maliflora Lindl. (樱花短柱茶) J. B. Shen (沈锦波) 200701122802
C. phaeoclada H. T. Chang (褐枝短柱茶) J. B. Shen (沈锦波) 200701123602
Sect. Camellia (红山茶组)
C. jinshajiangica H. T. Chang & S. L. Lee (金沙江红山茶) Q. F. Peng (彭秋发) 200603601
C. omeiensis H. T. Chang (峨眉红山茶) Q. F. Peng (彭秋发) 200603611
C. lanosituba H. T. Chang (绵管红山茶) Q. F. Peng (彭秋发) 200603631
C. longigyna H. T. Chang (长蕊红山茶) Q. F. Peng (彭秋发) 200603641
C. lapidea Y. C. Wu (石果红山茶) Q. F. Peng (彭秋发) 200603651
C. phelloderma H. T. Chang, Liu & Zhang (栓皮红山茶) Q. F. Peng (彭秋发) 200603661
C. mairei (Lévl.) Melchior (毛蕊红山茶) Q. F. Peng (彭秋发) 200603671
C. trichosperma H. T. Chang (毛籽红山茶) Q. F. Peng & X. Y. Lin (彭秋发, 林秀艳) 200604691
C. semiserrata C. W. Chi (南山茶) Q. F. Peng & X. Y. Lin (彭秋发, 林秀艳) 200604701
C. semiserrata var. albiflora Hu & T. C. Huang (白花南山茶) Q. F. Peng & X. Y. Lin (彭秋发, 林秀艳) 200604721
C. reticulata Lindl. (滇山茶) Q. F. Peng (彭秋发) 200603711
C. phellocapsa H. T. Chang & B. K. Lee (栓壳红山茶) Q. F. Peng (彭秋发) 200603742
C. compressa H. T. Chang & X. K. Wen ex H. T. Chang (扁果红山茶) Q. F. Peng (彭秋发) 200603751
C. magniflora H. T. Chang (大花红山茶) Q. F. Peng (彭秋发) 200603761
C. lungshenensis H. T. Chang (龙胜红山茶) Q. F. Peng & B. Jiang (彭秋发, 姜波) 200610771
C. brevicolumna H. T. Chang, H. S. Liu & Y. Z. Zhang (短轴红山茶) Q. F. Peng (彭秋发) 200603781
C. pitardii Coh. Stuart (西南红山茶) Q. F. Peng & B. Jiang (彭秋发, 姜波) 200610801
C. pitardii var. yunnanica Sealy (窄叶西南红山茶) Q. F. Peng (彭秋发) 200603821
C. cryptoneura H. T. Chang (隐脉红山茶) Q. F. Peng (彭秋发) 200603851
C. brachygyna H. T. Chang (短蕊红山茶) Q. F. Peng (彭秋发) 200603871
C. tunganica H. T. Chang & B. K. Lee (东安红山茶) Q. F. Peng (彭秋发) 200603881
C. bambusifolia H. T. Chang, H. S. Liu & Y. Z. Zhang (竹叶红山茶) Q. F. Peng (彭秋发) 200603891
C. albo-sericea H. T. Chang (白丝毛红山茶) Q. F. Peng (彭秋发) 200603911
C. bailinshanica H. T. Chang, H. S. Liu & G. X. Xiong (白灵山红山茶) Q. F. Peng (彭秋发) 200603921
C. oligophlebia H. T. Chang (寡脉红山茶) Q. F. Peng (彭秋发) 200603931
C. edithae Hance (尖萼红山茶) Q. F. Peng & B. Jiang (彭秋发, 姜波) 200610961
C. paucipetala H. T. Chang (寡瓣红山茶) Q. F. Peng (彭秋发) 200603971
C. boreali-yunnanica H. T. Chang (滇北红山茶) Q. F. Peng (彭秋发) 200603991
C. hunanica H. T. Chang & L. L. Qi (湖南山茶) Q. F. Peng & B. Jiang (彭秋发, 姜波) 2006101051
C. magnocarpa (Hu & T. C. Huang) H. T. Chang (大果红山茶) Q. F. Peng & X. Y. Lin (彭秋发, 林秀艳) 2006041081
C. liberistamina H. T. Chang & J. S. Chiu (离蕊红山茶) Q. F. Peng & X. Y. Lin (彭秋发, 林秀艳) 2006041091
C. lucidissima H. T. Chang (闪光红山茶) Q. F. Peng (彭秋发) 2006031101
C. chekiangoleosa Hu (浙江红山茶) Q. F. Peng & B. Jiang (彭秋发, 姜波) 2006101111
C. mongshanica H. T. Chang & C. X. Ye (莽山红山茶) Q. F. Peng (彭秋发) 2006031121
C. japonica L. (山茶) Q. F. Peng & B. Jiang (彭秋发, 姜波) 2006101131
C. rusticana Honda (雪山茶) Q. F. Peng & B. Jiang (彭秋发, 姜波) 2006101141
C. changii C. X. Ye (假大头茶) Q. F. Peng & B. Jiang (彭秋发, 姜波) 2006101151
C. subintegra T. C. Huang ex H. T. Chang (全缘红山茶) Q. F. Peng & X. Y. Lin (彭秋发, 林秀艳) 2006041161
C. crassissima H. T. Chang & W. J. Shi (厚叶红山茶) Q. F. Peng & X. Y. Lin (彭秋发, 林秀艳) 2006041181
* All plant materials were collected from plants in the International Camellia Species Garden in Jinhua, Zhejiang, China. Voucher specimens were
kept in the Herbarium of Zhejiang Normal University.
SHEN et al.: FTIR spectra of Camellia sect. Oleifera, sect. Paracamellia, and sect. Camellia
197
absorbance was equal to 0 and the highest to 1 for
each spectrum. The smoothed first derivatives of these
normalized spectra were calculated using the
Savitzky-Golay algorithm (Savitzky & Golay, 1964)
with five-point smoothing. These data were then
subjected to multivariate analysis. Finally, a hierar-
chical dendrogram was constructed from principal
component analysis (PCA) of FTIR data by the
Ward’s method (Anderberg, 1973) with a Euclidean
distance measure using the Palaeontological Statistics
package (PAST, version 1.68).
2 Results
2.1 FTIR spectra of Camellia species
FTIR detected all compounds, including poly-
mers and low-molecular weight compounds in whole
cell samples, subsequently providing biochemical
profiles of extremely high-density data sets.
Representative baseline-corrected and normalized
FTIR spectra for C. sinensis, C. oleifera, and C.
japonica are shown in Fig. 1. Absorption bands in the
range of 4000–1500 cm–1 are typically due to func-
tional groups (e.g., –OH, C=O, N–H, CH3, etc.), while
the region 1500–675 cm–1 is referred to as the finger-
print region, which is highly specific for each taxon.
To quantitatively distinguish the changes of caf-
feine in the three species, difference spectra were
generated by digital subtraction of the spectra of C.
japonica and C. oleifera from the spectra of C. sinen-
sis, respectively (Fig. 2). Based on the structure
characteristics of caffein, 1551 cm–1 had been
assigned to a C-N stretch of O=C2N, 1659 cm–1 to the
C=O stretching vibration, the doublet at 1600 and
1551 cm–1 to the C=C and C=N bonds of the caffeine,
745 cm–1 to the C-H deformation vibration of the
aromatic ring, and the 1404, 1426, and 1485 cm–1 peak
to the C-H deformation vibration of CH3-N. Together,
all peaks in these wavenumbers of difference spec-
trum were consistent with the presence of caffeine in
C. sinensis.
2.2 Cluster analysis
Although on closer inspection quantitative dif-
ferences may be observed in Fig. 1, such complicated
spectra readily illustrate the need to use multivariate
statistical techniques in the analysis of FTIR data.
Therefore, we then investigated a perspicuous way of
viewing the relationships between these taxa using
hierarchical cluster analyses. Based on the Euclidean
distances calculated using the first 20 PCs (84.7%), a
dendrogram as shown in Fig. 3 was constructed using
the Ward clustering algorithm.
The dendrogram divided 63 species and 2 varie-
ties into two main clusters: cluster 1 (C1) was a rather
loose cluster which included all the species in sect.
Oleifera, sect. Paracamellia, sect. Thea and two
species in sect. Camellia (C. tunganica and C. subin-
tegra); cluster 2 (C2) comprised all the remaining
species in sect. Camellia. On closer inspection, C1 can
be seen to contain three subclusters: subcluster 1a
(SC1a) comprised the 5 species in sect. Thea; sub-
cluster 1b (SC1b) contained all species in sect. Oleif-
era (except C. sasanqua Thunb.) and one species in
sect. Paracamellia (C. fluviatilis); finally, the remain-
ing 15 species in sect. Paracamellia, one species in
sect. Oleifera (C. sasanqua) and two species in sect.
Camellia (C. tunganica and C. subintegra) clustered
subcluster 1c (SC1c). The species in C2 were subse-
quently divided into two groups: subcluster 2a (SC2a)
contained the species in subsect. Reticulata H. T.
Chang, while the subcluster 2b (SC2b) comprised the
subsect. Lucidissima H. T. Chang, and the remaining
14 species in subsect. Reticulata.
3 Discussion
3.1 FTIR spectroscopy and multivariate analysis
Fourier transform infrared (FTIR) spectroscopy
allows detecting the whole range of infrared spectrum
simultaneously providing speed and accuracy in
measurements of biological specimens (Griffiths & de
Haseth, 1986). With this technique, Sheng et al.
(2006) reported the effect of MG132 on the change of
FTIR spectra of cell wall during pollen germination
and pollen tube growth, and Wu et al. (2003) studied
the chemical characterization of casparian strip in
needles of Pinus bungeana. The application of a
combination with numerical methodologies, FTIR is
recommended and has many advantages. This tech-
nique has been successfully exploited for classifying
of normal and aged soybean seeds (Kusama et al.,
1997) and distinguishing cell walls mutants from
wild-type Arabidopsis (Chen et al., 1998; Mouille et
al., 2003). These studies, including determination of
the fruit content in processed foods (Wilson et al.,
1993) and discrimination of the genuineness of Chi-
nese medicines (Hong et al., 2006), have also been
conducted. In plant taxonomic classification related
studies, Séné et al. (1994) showed differences in the
plant cell walls of five angiosperms. Further, Kim et
al. (2004) proposed that FTIR was an excellent
method for determining phylogenetic relationships
between flowering plants, and Lü et al. (2004) used
Journal of Systematics and Evolution Vol. 46 No. 2 2008 198
Fig. 1. Representative normalized and baseline-corrected FTIR spectra in the range 4000–675 cm–1 obtained from leaves of Camellia sinensis, C.
oleifera and C. japonica. Absorption bands in the range of 4000–1500 cm–1 are typically due to functional groups, while the region between
1500–675 cm–1 is referred to as the fingerprint region.
Fig. 2. Difference spectra obtained by digital subtraction from C. sinensis spectrum, respectively, of C. oleifera and C. japonica spectrum. Peaks of
interest regarding to the caffein are marked.
SHEN et al.: FTIR spectra of Camellia sect. Oleifera, sect. Paracamellia, and sect. Camellia
199
Fig. 3. Dendrogram obtained by hierarchical cluster analysis of 63 species and 2 varieties based on their FTIR spectra. C1 and C2 are the clusters
discussed in the text, while SC1a–SC1c are the subclusters of C1 and SC2a and SC2b are the subclusters of C2. Cluster analysis was carried out using
the Ward clustering algorithm.
Journal of Systematics and Evolution Vol. 46 No. 2 2008 200
this method to identify the species in Hypericum and
Triadenum.
In our experiments, the difference spectra (Fig. 2)
could detect the presence of caffeine in C. sinensis,
and also the dendrogram showed all the 5 species in
sect. Thea were clustered in SC1a at the similarity
level of –0.48. According to the morphological char-
acteristics, sect. Oleifera, sect. Paracamellia, and sect.
Camellia belong to subgen. Camellia, while sect.
Thea belongs to the subgen. Thea (L.) H. T. Chang.
However, our dendrogram implies that sect. Oleifera
(SC1b) and sect. Paracamellia (SC1c) have closer
relationships with sect. Thea (SC1a) than sect. Camel-
lia (C2). This result is not consistent with the Chang’s
(1998) or Ming’s (2000) phylogenesis of genus Ca-
mellia. The difference appears to have some relation-
ship with the small number of sections (4 sections) we
studied. Indeed, within the 65 tested samples, species
that were morphologically indistinguishable could be
distinguished based on their spectra (Fig. 3).
Moreover, the power of this approach is its completely
unsupervised nature, because PCA, an unsupervised
learning method, was used to reduce the dimensional-
ity of the FTIR data, and then led to construction of a
dendrogram that provided hierarchical levels of
species groupings. Hence, the taxonomic classification
using FTIR for Camellia species and varieties in our
study is reliable. Our classification results (Figs. 1, 2)
have demonstrated that FTIR spectroscopy can be
used not only to identify (Lü et al., 2004) but also to
classify species in the same genus. Thus, it is capable
using this technology to further analyze the relation-
ship between sect. Oleifera and sect. Paracamellia,
subsect. Lucidissima and subsect. Reticulata, and the
species/varieties which are still in debate at present.
3.2 Relationship between sect. Oleifera and sect.
Paracamellia
The species in sect. Oleifera and sect. Para-
camellia share many morphological characteristics.
The flowers of the species are usually white and
slightly fragrant, which usually bloom in autumn to
early winter, and the perules drop at flowering. Sealy
(1958) firstly listed 6 species and 2 varieties in sect.
Paracamellia. Ming (2000) followed Sealy and listed
7 species (C. grijsii, C. fluviatilis, C. gauchowensis, C.
oleifera, C. sasanqua, C. kissi, and C. brevistyla) and
8 varieties. However, Chang & Ren (1998) divided
Sealy’s system into sect. Oleifera and sect. Para-
camellia, because plants of sect. Oleifera have longer
styles and androecium and higher seed oil content than
of sect. Paracamellia.
In the SC1b of the hierarchical dendrogram we
constructed, 5 species in sect. Oleifera (except C.
sasanqua) were separated at the top level (Similarity
–0.38) from other species in sect. Paracamellia,
indicates that the sect. Oleifera is distinguishable from
the sect. Paracamellia in FTIR fingerprint-like spec-
tra. Leaf micro-morphologies also revealed that sect.
Oleifera could differ from sect. Paracamellia. Section
Oleifera shares the same pattern of anticlinical cells
and the same size between adaxial and abaxial epi-
dermal cell, no red secretory on the abaxial epidermis,
and long ovate stomatal shape; but in sect. Para-
camellia, different pattern of anticlinical cells and
different size between adaxial and abaxial epidermal
cells, having red secretory on the abaxial epidermis
(Lin et al., 2007), and shuttle stomatal shape in sect.
Oleifera (Ao et al., 2002). Moreover, the unanimous
morphology of pollen grains in sect. Paracamellia
also showed this section is a natural group (Ao et al.,
2001). Taken the macro-morphology, micro-morpho-
logy and chemical characteristics together, the mer-
gence of the two sections is quite unnatural.
3.3 Evidence for interspecific relationships in sect.
Oleifera and sect. Paracamellia
The most prominent common characteristic of C.
lanceoleosa and C. fluviatilis is their long narrow
leaves. Ming (2000) described the two species as “leaf
blade lanceolate to narrowly lanceolate, leathery, both
surfaces glabrous; flowers axillary or subterminal,
solitary; outer filament whorl basally connate; ovary
globose, yellow tomentose, 3-loculed”. Because of the
“leaf blade lanceolate to narrowly lanceolate; flowers
5–6 cm in diameter” in C. lanceoleosa, this species
was treated as a variety of C. fluviatilis (C. fluviatilis
var. megalantha (H. T. Chang) T. L. Ming). Lin et al.
(2007) showed that characteristics of the leaf mi-
cro-morphology in the two species, such as stomata,
anticlinal walls shape and size of adaxial and abaxial
epidermal cells, the thickness ratio of palisade paren-
chyma and spongy parenchyma, were similar with no
apparent difference between them. Their close rela-
tions were also demonstrated in the dendrogram of
FTIR data (Fig. 3), in which they showed close rela-
tionship (Similarity –0.03). All of the evidence proves
that Ming’s treatment of the two species is reasonable.
In Ming’s taxonomic treatment, C. obtusifolia H.
T. Chang, C. puniceiflora H. T. Chang were combined
into C. brevistyla based on the similar characteristics
of “leaf blade shape, visible and slight impressed
midvein, and 1-locule with 1 seed”, and C. micro-
phylla (Merr.) Chien was considered to be a variety of
C. brevistyla (Ming, 2000). Our data suggests it is
quite natural to combine C. puniceiflora into C.
SHEN et al.: FTIR spectra of Camellia sect. Oleifera, sect. Paracamellia, and sect. Camellia
201
brevistyla, and treat C. microphylla as C. brevistyla
var. microphylla (Merr.) Ming from FTIR spectra
analysis. Support for this conclusion could also be
found in micro-morphological studies by Lin et al.
(2007). However, FTIR spectra data cluster analysis
(Fig. 3) displays distant relationship between C.
obtusifolia and C. brevistyla which indicates that the
combination of C. obtusifolia into C. brevistyla is
unreasonable. Chang (1998) claimed that the two
species were similar, in the exception of the characters
that “perules 10, deciduous at flowering leaving 5–6
scar on the pedicel” in C. obtusifolia and “perules 6–7,
deciduous leaving 2–3 scar on the pedicel” in C.
brevistyla. Moreover, the two species also have
distinct pollen exine sculpture characteristics: C.
brevistyla is foveolate-reticulate, while C. obtusifolia
is rugulate-fossula (Ao et al., 2001). Based on these
above evidence, we consider that the treatment of
combining C. obtusifolia into C. brevistyla lacks
enough evidence. Further studies should be carried out
to treat their taxonomic relationship.
When reconsidering Ming’s combination of C.
yuhsienensis Hu and C. odorata L. S. Xie & Z. Y.
Zhang into C. grijsii, and treating C. shensiensis H. T.
Chang as a variety of C. grijsii, we find some differ-
ences sill exist between his definition and our results.
The dendrogram (Fig. 3) displayed near relationships
(Similarity –0.04) for C. odorata, C. grijsii and C.
shensiensis. To the contrary, C. yuhsienensis showed
distant relationship with C. grijsii. The examinations
of pollen exine sculpture characteristics (Ao et al.,
2001) and leaf micro-morphology (Lin et al., 2007)
also showed that C. grijsii and C. shensiensis shared
many similar characteristics, but the two species had
distinct characteristics with C. yuhsienensis (Lin et al.,
2007). All these mentioned above illuminate that
combination of C. yuhsienensis into C. grijsii lacks
enough evidence and should be examined further.
Therefore, combining of C. grijsii, C. odorata, and C.
shensiensis is considered here to be a reasonable one,
after the evidences from morphology (Chang, 1998;
Ming, 2000), anatomy (Ao et al., 2001; Lin et al.,
2007) and FTIR data are considered together.
Camellia sasanqua belongs to sect. Oleifera, and
C. fluviatilis belongs to sect. Paracamellia in Chang’s
system. In the dendrogram we constructed, however,
C. sasanqua had close relationship with sect. Para-
camellia, while C. fluviatilis belonged to the branch of
SC1b, which had most species in sect. Oleifera. This
difference can be interpreted as that C. fluviatilis seeds
have high oil content, and C. sasanqua is planted only
as ornamental shrub (Gao et al., 2005). Therefore,
according to the chemical bonds in molecules, the
relationships of C. sasanqua and C. fluviatilis in the
dendrogram we constructed seem to be reasonable.
3.4 Relationship between subsect. Reticulata
Chang and subsect. Lucidissima Chang in sect.
Camellia
Section Camellia is characterized by large, usu-
ally red flowers, undifferentiated bracts and sepals
(perules), and basal fusion of the petal. According to
Chang (1998), sect. Camellia contains two subsec-
tions, subsect. Reticulata and subsect. Lucidissima.
Subsect. Reticulata has tomentose ovaries while
subsect. Lucidissima has glabrous ovaries. However,
Ming (2000) considered that the ovary characteristic
(tomentose or glabrous) just illustrated the interspeci-
fic relationships of sect. Camellia, and finally reduced
a large number of species. In our FTIR study, al-
though there was a single group (SC2a) belonging to
subsect. Reticulata, it was shown in SC2b that the
species of subsect. Reticulata could not be separated
from those of subsect. Lucidissima by the “whole-
organism fingerprinting” FTIR. Thus, these results
seem to suggest that the establishing of subsection
based on ovary characteristic is questionable. How-
ever, more evidence still needs to be provided for
illustrating the relationship between the two subsec-
tions.
3.5 Evidences for interspecific relationships in
sect. Camellia
Section Camellia is the largest section in the ge-
nus Camellia with about 60 species, subspecies and
varieties. Sealy (1958) considered that this section
contained 8 distinct species. Chang (1998) included
57 species while Ming (2000) revised it back to 12
species. There is still much confusion on the number
and delimitation of species in this section.
There are similar FTIR spectra between C. ja-
ponica and C. rusticana Honda in our study (Fig. 3).
Ming (2000) pointed out that “the petiole of C. rusti-
cana is somewhat short and pubescent” and thus
regarded it as a variation of C. japonica. Our results
based on leaf chemical composition supported this
treatment. Moreover, C. semiserrata C. W. Chi, C.
trichosperma H. T. Chang, C. semiserrata var. albi-
flora Hu & T. C. Huang and C. magnocarpa (Hu & T.
C. Huang) H. T. Chang share same features including
“leaf blade elliptic to oblong-elliptic, margin entire on
basal half and serrate on apical half; style apically 3–5
parted” (Ming, 2000). Their close relations are also
demonstrated in the dendrogram of cluster analysis
(Fig. 3) in which they show high similarity score
(Similarity close to –0.09). All evidence proves that
Journal of Systematics and Evolution Vol. 46 No. 2 2008 202
Ming’s treatment of C. semiserrata var. albiflora and
C. magnocarpa as varieties of C. semiserrata is
reasonable. However, according to our results, the
mergence of C. phellocapsa and C. mongshanica into
C. semiserrata seems to be unnatural.
The most extensive combination of Ming’s
treatment is the combination of C. albo-sericea, C.
boreali-yunnanica, C. paucipetala, C. jinshajiangica,
C. brachygyna, C. oligophlebia, C. bailinshanica, C.
bambusifolia, and C. brevicolumna into C. reticulata.
These species share the same features as follow:
“bracteoles and sepals caducous after anthesis”, “leaf
blade secondary veins adaxially visible or raised”,
“filaments glabrous or subglabrous”, and “current year
branchlet and abaxial leaf pubescent” (Ming, 2000).
Viewing the dendrogram we constructed, C. reticulata
and C. jinshajiangica were clustered in different
branches of C2, which indicates their leaf chemical
components may be different. Previous reports
(Chang, 1998) also showed that C. reticulata could be
distinguishable from the C. jinshajiangica in the
presence of villous filaments. Thus, the combination
of the two species in Ming’s system seems to be quite
unreasonable. Moreover, C. brachygyna, C. bailin-
shanica, C. jinshajiangica, and C. changii made up a
single group in SC2b. The combination of them is
worthy being considered. Moreover, the close rela-
tionships of C. reticulata and C. bambusifolia, C.
brachygyna and C. jinshajiangica, and C. bore-
ali-yunnanica and C. oligophlebia indicate the possi-
bility of their mergence. However, it seems to be
unnatural to combine other species, which lies sepa-
rately in other groups.
Camellia tunganica and C. subintegra have pet-
als strongly adnated to androecium, which is the
characteristic of sect. Camellia. In the dendrogram we
constructed, however, the two species clustered with
other species of sect. Paracamellia in branch of SC1c.
Previous systems are based on the macro-morpho-
logical taxonomy, while the relationships of these
species in our classification are investigated on leaf
chemical characteristics. Hence, the difference may
have some relationship with what the characteristics
are studied. However, we still can not exclude the
possibility that the population size in the Camellia
species garden may lead to the discrepancy, since
chemical components may be varied a little in differ-
ent population sizes.
3. 6 Potential usability
Most species in section Thea can be cultivated
for tea production (Chang et al., 1996), while most
species in sect. Oleifera, sect. Paracamellia, and sect.
Camellia are grown for edible oil production and
ornamental shrubs (Gao et al., 2005). Our “whole-
organism fingerprinting” FTIR data show far rela-
tionship between C. sasanqua and other species in
sect. Oleifera. Therefore, it seems unreasonable to use
this species for oil usage, and this conclusion is con-
sistent with current usage of this species as ornamen-
tal shrub. Similarly, C. tenii, C. miyagii, and C. tun-
ganica are not suggested for oil usage as these species
consist of a single group at the similarity level of –0.1.
Although C. fluviatilis belongs to sect. Paracamellia
in Chang’s system, our results show that this species
has close relationship with species that have high seed
oil content, which indicates that this species has
usability potential for oil usage.
In conclusion, the infrared spectra of Camellia
are fingerprint-like patterns which are highly typical
for different taxa. The hierarchical dendrogram based
on principal component analysis (PCA) of FTIR data
shows relationships between species that are in
agreement with most of the previous proposed
morphological classifications. Differences in cell
compositions and structures of the four Camellia
species by infrared spectroscopy thereby can provide
the basis for chemotaxonomy of species. Infrared
spectra of leaves appear to have taxonomic value and
be more useful for discriminating closely related
species or varieties in the genus Camellia, and this
technique can be widely used for identification and
classification of other taxa when standard spectra are
available. In our studies, the sections and the inter-
specific relationships we concluded are based on the
chemical bonds of total mixture of leaf cells, reflect-
ing the interspecific differences on chemical compo-
nents. Therefore, additional evidence, such as DNA
data, is still needed for interpreting the classification
of Camellia.
Acknowledgements The authors thank Dan-Ting
LI (Institute of Physical Chemistry, Zhejiang Normal
University) for her skillful FTIR technical assistance;
Prof. Ji-Yin GAO (Research Institute of Subtropical
Forestry, Chinese Academy of Forestry) and Prof. R.
Parks CLIFFORD (University of North Carolina,
USA) for their assistances in species identification.
We also express our thanks to Mr. Yue-Qiang DU and
Miss Bi-Ying TANG for their kind helps during the
course of specimen collection.
SHEN et al.: FTIR spectra of Camellia sect. Oleifera, sect. Paracamellia, and sect. Camellia
203
References
Anderberg M R. 1973. Cluster analysis for applications. New
York: Academic Press.
Ao C-Q (敖成齐), Chen G-X (陈功锡), Chang H-T (张宏达).
2002. Leaf epidermis morphology of Camellia and its
taxonomic significance. Acta Botanica Yunnanica (云南植
物研究) 24: 68–74.
Ao C-Q (敖成齐), Chen G-X (陈功锡), Xi J-B (席嘉宾),
Zheng Z-W (郑政伟), Zhang H-D (张宏达). 2001. Study
on the pollen morphology of section Paracamellia in
genus Camellia. Journal of South China Agricultural
University (华南农业大学学报) 22: 66–68.
Chang H-T (张宏达 ), Bartholomew B. 1984. Camellias.
Oregon: Timber Press.
Chang H-T (张宏达), Ren S-X (任善湘). 1998. Theaceae. In:
Flora Reipublicae Popularis Sinicae ( 中国植物志 ).
Beijing: Science Press. 49 (3): 1–194.
Chang H-T (张宏达), Zhang R-M (张润梅), Ye C-X (叶创兴).
1996. Diagnosis on the systematic development of
Theaceae VI Revision of the species of sect. Thea,
Camellia. Acta Scientiarum Naturalium Universitatis
Sunyatseni (中山大学学报自然科学版) 35: 11–17.
Chen L, Carpita NC, Reiter WD, Wilson RH, Jeffries C,
McCann MC. 1998. A rapid method to screen for cell-wall
mutants using discriminant analysis of Fourier
transformation infrared spectra. The Plant Journal 16:
385–392.
Ellis DI, Broadhurst D, Kell DB, Rowland JJ, Goodacre R.
2002. Rapid and quantitative detection of the microbial
spoilage of meat by Fourier transform infrared
spectroscopy and machine learning. Applied and
Environmental Microbiology 68: 2822–2828.
Gao J-Y (高继银 ), Parks CR, Du Y-Q (杜跃强 ). 2005.
Collected species of the genus Camellia an illustrated
outline (山茶属植物主要原种彩色图集 ). Hangzhou:
Zhejiang Science and Technology Press.
Griffiths PR, de Haseth JA. 1986. Fourier transform infrared
spectroscopy. New York: Wiley.
Hong Q-H (洪庆红), Cheng Z-F (成则丰), Cheng C-G (程存
归 ). 2006. Application of FTIR spectroscopy to the
analysis of quality mensuration of Paeonia lactiflora Pall.
from native habitat. Spectroscopy and Spectral Analysis
(光谱学与光谱分析) 26: 1610–1613.
Kim SW, Ban SH, Chung H, Cho S, Chung HJ, Choi PS, Yoo
OJ, Liu JR. 2004. Taxonomic discrimination of flowering
plants by multivariate analysis of Fourier transform
infrared spectroscopy data. Plant Cell Reports 23:
246–250.
Kusama T, Abe H, Kawano S, Iwamoto M. 1997. Classification
of normal and aged soybean seeds by discriminant analysis
using principal component scores of near infrared spectra.
Nippon Shokuhin Kogyo Gakkai-Shi 44: 569–578.
Lamprell H, Mazerolles G, Kodjo A, Chamba JF, Noel Y,
Beuvier E. 2006. Discrimination of Staphylococcus aureus
strains from different species of Staphylococcus using
Fourier transform infrared (FTIR) spectroscopy.
International Journal of Food Microbiology 108: 125–129.
Lin X-Y (林秀艳), Peng Q-F (彭秋发), Lü H-F (吕洪飞), Du
Y-Q (杜跃强), Tang B-Y (汤妣颖). 2008. Leaf anatomy
of Camellia sect. Oleifera and sect. Paracamellia
(Theaceae) with reference to their taxonomic significance.
Journal of Systematics and Evolution (植物分类学报) 46:
183–193.
Lü H-F (吕洪飞), Cheng C-G (程存归), Tang X (唐熙), Hu
Z-H ( 胡正海 ). 2004. Spectrum of Hypericum and
Triadenum with reference to their identification. Acta
Botanica Sinica (植物学报) 46: 401–406.
Ming T-L (闵天禄). 2000. Monograph of the genus Camellia
(世界山茶属的研究). Kunming: Yunnan Science and
Technology Press.
Mouille G, Robin S, Lecomte M, Pagant S, Höfte H. 2003.
Classification and identification of Arabidopsis cell wall
mutants using Fourier-Transform InfraRed (FT-IR)
microspectroscopy. The Plant Journal 35: 393–404.
Naumann D, Helm D, Labischinski H. 1991. Microbiological
characterizations by FT-IR spectroscopy. Nature 351:
81–82.
Rebuffo CA, Schmitt J, Wenning M, von Stetten F, Scherer S.
2006. Reliable and rapid identification of Listeria
monocytogenes and Listeria species by artificial neural
network-based Fourier transform infrared spectroscopy.
Applied and Environmental Microbiology 72: 994–1000.
Savitzky A, Golay MJE. 1964. Smoothing and differentiation of
data by simplified least squares procedures. Analytical
Chemistry 36: 1627–1633.
Sealy JR. 1958. A revision of the genus Camellia. London: The
Royal Horticultural Society.
Sheng X-Y, Hu Z-H, Lü H-F, Wang X-H, Baluska F, Samaj J,
Lin J-X. 2006. Roles of the Ubiquitin/Proteasome pathway
in pollen tube growth with emphasis on mg132-induced
alterations in ultrastructure, cytoskeleton, and cell wall
components. Plant Physiology 141: 1578–1590.
Séné CFB, McCann MC, Wilson RH, Grinter R. 1994. Fourier
transform Raman and Fourier-transform infrared
spectroscopy: an investigation of five higher plant cell
walls and their components. Plant Physiology 106:
1623–1631.
Wilson RH, Slack PT, Appleton GP, Sun L, Belton PS. 1993.
Determination of the fruit content of jam using Fourier
transform infrared spectroscopy. Food Chemistry 47:
303–308.
Wu X-Q, Lin J-X, Zhu J-M, Hu Y-X, Klaus H, Lukas S. 2003.
Casparian strips in needles of Pinus bungeana: isolation
and chemical characterization. Physiologia Plantarum 117:
421–424.
Journal of Systematics and Evolution Vol. 46 No. 2 2008 204
山茶属油茶组、短柱茶组和红山茶组植物叶的
红外光谱分析及其分类学意义
1沈锦波 1,2吕洪飞 1彭秋发 3郑菊芳 1田玉梅
1(浙江师范大学化学与生命科学学院 金华 321004)
2(中国科学院植物研究所 北京 100093)
3(浙江师范大学物理化学研究所浙江省固体表面反应化学重点实验室 金华 321004)
摘要 利用傅立叶红外光谱仪和OMNI采样器直接、迅速、准确地测定山茶属Camellia 4组63种2变种植物叶片的红外光谱, 结
果表明: 各分类群(种)的红外光谱具有高度特异性, 其红外光谱图的变化可以作为山茶属植物属下的分类依据之一。这也暗
示了利用标准红外光谱图库, 可以区分和鉴定出山茶属植物的种类。经主成分分析后的红外光谱数据构建的树型聚类图与先
前的形态分类结果大体一致, 能将油茶组sect. Oleifera和短柱茶组sect. Paracamellia植物明显区分, 并且各组中亲缘关系较近
的种聚在一起。因此支持它们作为两个独立的组处理。但是, 红山茶组sect. Camellia内的滇山茶亚组subsect. Lucidissima和光
果红山茶亚组subsect. Reticulata植物在聚类图上很难区分, 建议将这两个亚组植物进行归并。最后讨论了张宏达和闵天禄系
统中存在分歧的油茶组、短柱茶组和红山茶组内的种间分类关系。
关键词 山茶属; 聚类分析; 红外光谱; 分类学意义