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Abstract

This research focuses on the biodiversity and the evolutionary history of the world-wide medicinal plant genus, Dracaena, and the plant genus Pleomele. The debate concerning the relationship between Dracaena and Pleomele has continued till date -some botanists continue to include Pleomele within Dracaena but others claimed to separate the two genera. Dracaena is a genus comprising of about 40-100 species world wide, mainly in tropics and subtropics, with the exception of America. Pleomele is a genus that has been circumscribed consisting of 10-50 species in Asia. Till date, its center of biodiversity is unknown. Pleomele is only classified well in Hawaii, but confused with Dracaena in the other parts of Asia. Phylogenetic relationship among the 33 taxa within the Dracaena and Pleomele were reconstructed. DNA sequences from the chloroplast DNA intergenic spacer, trnL-trnF and trnH-psbA were analyzed. A phylogeny was reconstructed using neighbor-joining, maximum parsimony in PAUP*, and likelihood criteria in RAxML, and Bayesian inference in MrBayes. The phylogeny with Agave missionum and Agave attenuata as outgroup taxa indicates that Pleomele is mixed with Dracaena. This study provides the first phylogenetic reconstruction with taxonomic sampling of the Dracaena and Pleomele to resolve their questionable placement. The relationships of the climate change adaptation, biogeography, and conservation with the two plant genera will be further discussed in this study. Some suggestions for the benefits of the biodiversity and natural resource conservation in Himalaya regions will be addressed. One significant contribution of this research will be in promoting molecular taxonomy to solve problems in systematics especially in cases when the classification is in debate.
Research
Phylogenetics of the plant genera Dracaena and Pleomele
(Asparagaceae)
Pei-Luen Lu* and Clifford Morden
Department of Botany, University of Hawaii at Manoa, 3190 Maile Way Room 101, Honolulu, Hawaii 96822, USA
Abstract
This research focuses on the biodiversity and the evolutionary history of the world-wide medicinal plant genus,
Dracaena, and the plant genus Pleomele. The debate concerning the relationship between Dracaena and
Pleomele has continued till date - some botanists continue to include Pleomele within Dracaena but others
claimed to separate the two genera. Dracaena is a genus comprising of about 40-100 species world wide,
mainly in tropics and subtropics, with the exception of America. Pleomele is a genus that has been circumscribed
consisting of 10-50 species in Asia. Till date, its center of biodiversity is unknown. Pleomele is only classified
well in Hawaii, but confused with Dracaena in the other parts of Asia. Phylogenetic relationship among the 33
taxa within the Dracaena and Pleomele were reconstructed. DNA sequences from the chloroplast DNA intergenic
spacer, trnL-trnF and trnH-psbA were analyzed. A phylogeny was reconstructed using neighbor-joining, maximum
parsimony in PAUP*, and likelihood criteria in RAxML, and Bayesian inference in MrBayes. The phylogeny with
Agave missionum and Agave attenuata as outgroup taxa indicates that Pleomele is mixed with Dracaena. This
study provides the first phylogenetic reconstruction with taxonomic sampling of the Dracaena and Pleomele to
resolve their questionable placement. The relationships of the climate change adaptation, biogeography, and
conservation with the two plant genera will be further discussed in this study. Some suggestions for the benefits
of the biodiversity and natural resource conservation in Himalaya regions will be addressed. One significant
contribution of this research will be in promoting molecular taxonomy to solve problems in systematics especially
in cases when the classification is in debate.
Key-words: Phylogeny, chloroplast DNA, Asparagaceae, Dracaena, Pleomele.
Introduction
The two plant genera Dracaena Vand. and Pleomele Salisb.
are important genera in the world not only because of their
application in horticulture, medicine, agriculture, and
worshiping in ceremonies by diverse cultures across different
countries, but also in systematics, the two genera may provide
the good evidence to give more stable classification for solving
their unstable family placement from Liliaceae to current
Asparagaceae (Brown 1914; Lee 1975; Wagner et al. 1990;
Staples and Herbst 2005; Judd et al. 2007; APG 2009;
Anonymous 2010). There are several problems about the
two genera, such as unclear systematics, little research in
their biogeography and evolution, conservational issues, and
the using the species among different cultures. Therefore, the
purpose of this study is to clarify their status of classification,
to understand their evolution and biogeography, and to
increase its application in conservation biology, horticulture
and medicine.
Dracaena had been placed within in the family Liliaceae
(Brown 1914). Among the characteristics that support this
includes a superior ovary; leaves that are not twisted at base;
bulbs present; fruits being fleshy, etc (Brown 1914; Bos 1980;
Waterhouse 1987). However, this classification is no longer
used because Dracaena species are woody and flowers have
six stamens, unlike the typical herbaceous Liliaceae. Others
*Corresponding author, e-mail address: peiluen@hawaii.edu
Botanica Orientalis – Journal of Plant Science (2010) 7: 64–72 ISSN 1726-6858
© 2010 Central Department of Botany, Tribhuvan University
http://www.cdbtu.edu.np/botanica-orientalis
have classified Dracaena in the family Agavaceae based on
the features of flowers with 6 stamens, paniculate
inflorescences, and plants with rosettes of fleshy fibrous leaves
(Hutchinson 1973; Huang 1993; Staples and Herbst 2005).
However, the ovary in Dracaena is superior, unlike other
Agavaceae, and this classification is also no longer used.
Dracaena has been classified within the family Ruscaceae
since 2003 (APGII 2003; Judd et al. 2007). Monophyly of
Dracaena is supported by molecular analysis of 18S rDNA,
rbcL, atpB, and matK, and morphologically by the presence
of resin canals in their leaves and bark (APG 2003; Hilu et al.
2003; Judd 2003; Judd et al. 2007). Other key characters for
Ruscaceae include superior ovary; fruits are fleshy and a berry;
leaves are photosynthetic, and stems are cylindrical, green to
brown, but not the major photosynthetic organ of the plant
(Judd et al. 2007). However, currently, Ruscaceae is combined
into the larger family Asparagaceae based on Angiosperm
Phylogeny Group III system (APG 2009) because the research
group’s conclusion of uniting those confusing families into
the same family when they do not show too much distinct
from each other in the molecular data. Thus, Dracaena and
Pleomele are replaced into the family Asparagaceae.
Furthermore, due to morphology though similar to the
characteristics of Ruscaceae, several botanists claimed
Dracaena within the family Dracaenaceae, the family of only
one genus, Dracaena or two genera Dracaena and Sansevieria
(Bos et al. 1992; Brummitt 1992; Watson and Dallwitz 1992;
Kubitzi 1998; Marrero et al. 1998).
Dracaena was first described in 1768 by Vandelli (Brown
1914). The genus Dracaena comprises about 40-100 species
world-wide, mainly in tropics and subtropics, with the
exception of South America (Bos et al. 1992; Kubitzi 1998;
Staples and Herbst 2005; Judd et al. 2007). Several species
have been investigated for their medicinal and horticultural
value (Lee 1975; Bos 1980, 1984; Bos et al. 1992; Chun
1994; Kubitzi 1998; Edward et al. 2001; Milburn, 1984;
Staples and Herbst 2005). Africa is the center of diversity of
Dracaena with some species distributed in Madagascar, Asia,
Socotra, Mediterranean regions, Central America, Cuba,
Macronesia, Northern Australia, and Pacific islands (Gwyne
1966; Kubitzi 1998; Marrero et al. 1998; Staples and Herbst
2005). Two extinct Dracaena species from the Neogene (23.03
± 0.05 million years ago) have been identified based on the
analysis of pollen (Van Campo and Sivak 1976). They are
Dracaena saportae, recorded in Bohemia, Czech Republic,
and Dracaena guinetii, recorded in Tunis, Tunisia Republic
(Van Campo and Sivak 1976; Bonde 2005). The stomata of
leaves are present and anomocytic (Kubitzi 1998).
Additionally, the huge uncertain species numbers of
Dracaena are mainly due to be classified mixed with several
other genera, such as Sansevieria, Cordyline, Yucca, and
Pleomele. Similar situation is seen in Pleomele. Many juvenile
and mature Dracaena often looked very different in
morphology and the both stages can produce flowers and
fruits. That makes the taxonomist to have difficult time to
give really proper classification. Thus, clarifying the taxonomy
and give proper genus based on phylogenetics becomes urgent.
The genus Pleomele was first described by Salisbury in
1796 (Brown 1914). Wagner recognized Pleomele in the family
Agavaceae in 1990 and then in the family Ruscaceae in 2003
with no explanation (Wagner et al. 1990; Wagner and Herbst
2003). Pleomele has been circumscribed as a genus consisting
of 40-50 species world-wide (Wagner et al. 1990; Wagner and
Herbst 2003) and there are six endemic Pleomele species
currently recognized in the Hawaiian Islands (Wagner et al.
1990; Wagner and Herbst 2003). St. John (1985) had classified
nine Pleomele species in Hawaii and described their
morphological features. However, Wagner et al. (1990)
reclassified St. John’s nine species into six and addressed
morphology of all six Pleomele species endemic to Hawaiian
flora (Wagner et al. 1990; Wagner and Herbst 2003).
Taxonomic ambiguity regarding the uncertain
relationship of Dracaena and Pleomele has existed for a long
time. Some species of Pleomele had been described as part of
the larger genus, Dracaena. Brown (1914) separated Pleomele
from Dracaena based on the difference of flowers. Dracaena
has a very short perianth tube with tepals divided to the base
of the flower and thickened staminal filaments near the middle.
In contrast, the perianth tube of Pleomele has tepals connate
for at least one-third of their length (Wagner et al. 1990). St.
John (1985) and Wagner et al. (1990) agreed with this
placement. However, in recent studies, Pleomele was used as
a synonym of Dracaena based on similar morphological
characteristics (Stevens 2001; Staples and Herbst 2005;
Anonymous 2010). Stevens (2001) also combined Pleomele
into Dracaena. Carlquist (1970) addressed Pleomele as an
endemic Hawaiian genus. Wagner et al. (1990) stated Pleomele
is a worldwide genus. However, those are only based on
morphological classification. Because of the lack of
phylogenetic evidence, the monophyletic status of Pleomele
is not affirmed, although it has been regarded as monophyletic
based on several morphological treatments (Brown 1914; Bos
P.-L. Lu and C. Morden / Phylogenetics of Dracaena and Pleomele 65
© 2010 Central Department of Botany, Tribhuvan University, Botanica Orientalis (2010) 7: 64–72
1980; St. John 1985; Wagner et al. 1990; Kubitzi 1998; Staples
and Herbst 2005). Therefore, the purpose of this study is to
provide molecular phylogenetic evidence for the classification
of Dracaena and Pleomele and resolve the systematic
problems between Pleomele and Dracaena at the genetic level.
Materials and Methods
SAMPLE COLLECTION
Leaf tissues from species of Dracaena and Pleomele were
collected from living material and the DNA extracted from
fresh tissue as much as possible or from silica dried tissue
when necessary. Two chloroplastic gene regions were used to
examine these species. The trnH-psbA intergenic spacer (APG
2003; Shaw et al. 2005, 2007) was examined for 18 species
with Agave missionum used for outgroup comparison. The
trnL-trnF intergeic spacer (APG 2003; Shaw et al. 2005, 2007)
was examined with 33 species, and both A. missionum and A.
attenuate were used for outgroup comparison.
DNA EXTRACTION AND AMPLIFICATION
DNA was extracted from leaves using the CTAB as previously
described (Morden et al. 1996; Randall and Morden 1999).
DNA amplification by polymerase chain reaction (PCR), and
template purifications was performed with Taq PCR Core
Kit. Finally, PCR products were purified by EXOSAP method.
DNA products were used for the following experiments. The
trnL-F region was amplified by the primer pairs trnL-tabE
(GGT TCA AGT CCC TCT ATC CC) and trnF (ATT TGA
ACT GGT GAC ACG AG) (Taberlet et al. 1991) with the
parameters 80°C for 5 min; 29 X (94°C for 1 min, 60°C for 1
min, 72°C for 2 min); 72°C for 5 min (Shaw et al. 2005). The
psbA-trnH region was amplified by the primer pairs psbA
(GGTATG CAT GAA CGT AAT GCT C) (Sang et al. 1997)
and trnH (CGC GCA TGG TGG ATT CAC AAT CC) (Tate
and Simpson 2003) with the parameters 80°C for 5 min; 35 X
(94°C for 30 s, 57°C for 30 s, 72°C for 1 min); 72°C for 10
min (Shaw et al. 2005).
PHYLOGENETIC ANALYSIS
After DNA extraction and sequencing, sequences were aligned
using Clustal X (Thompson et al. 1997), then edited and
assembled using MEGA (Tamura et al. 2007). DNA sequences
from the chloroplast genes were analyzed. The aligned in and
manual adjustments were made in MEGA and in MacClade
4.0 (Maddison and Maddison 2000). Maximum parsimony
analyses and maximum likelihood were performed in PAUP*
(Swofford 2002) using the same heuristic search strategy. All
characters were equally weighted, and gaps were treated as
missing data. A Bayesian phylogenetic approach was used to
generate a set of phylogenetic trees with estimated branch
lengths that could then be converted to time in a rate analysis.
MrBayes version 3.1 (Huelsenbeck and Ronquist 2001) were
used to search tree parameter space. The general time reversible
model (GTR+I+Ã) was selected for Bayesian analysis with
intervals of 10,000 generations. Nonparametric bootstrap
values (Felsenstein 1985), decay indices (Bremer 1988;
Sorenson 1999), and Bayesian posterior probabilities were
calculated for the phylogenetic reconstructions to estimate
internal branch support.
Results
The length of the trnL-F sequences among the 33 taxa varied
from 393 bases in D. goldiena to 438 bases in outgroup Agave
missionum and Agave attenuata. The aligned trnL-F matrix is
621 bp long, and has 104 variable characters of which 155 are
parsimony informative. The maximum likelihood search of
the trnL-F of 33 taxa data set retained 550945 trees with
Length (L)=621 (CI=0.564, and RI=0.568; both CI and RI
were calculated including parsimony uninformative
characters). Strict consensus tree obtained from 10 retained
trees. Some nodes have no similar patterns on DI, PP, and BP.
The node of D. steudneri, D. multiflora, and D. umbraculifera
have very strong decay index 14 and Bayesian PP 100, but
not strong in bootstrap percentages 70 (Fig. 1). The node of
D. serrulata and D. augustifolia have very strong decay index
12 and good Bayesian PP 94, but not strong in bootstrap
percentages 64 (Fig. 1). The node of P. forbesii and P. fernaldii
has strong Bayesian PP 100, but has weak decay index 1 and
bootstrap percentages 68 (Fig. 1). Some nodes have no similar
patterns on DI, PP, and BP such as the node between P.
fernaldii and the clade of P. aurea, P forbesii, D. cemcina has
high PP 100 and low BP 68 (Fig. 2).
The length of the psbA-trnH sequences of 19 taxa varied
from 542 bases in all of the ingroup taxa to 597 bases in
outgroup Agave missionum. The maximum likelihood search
of the psbA-trnH data set retained 2026821 trees with L=84
66 P.-L. Lu and C. Morden / Phylogenetics of Dracaena and Pleomele
© 2010 Central Department of Botany, Tribhuvan University, Botanica Orientalis (2010) 7: 64–72
Pleomele halapepe
Pleomele fernaldii
Pleomele forbesii
Pleomele aurea
Pleomele auhawaiiensis
Dracaena marginata
Pleomele hawaiiensis
Pleomele borneensis
Dracaena deremensis
Dracaena cemcina
Dracaena floribunda
Dracaena sanderiana
Dracaena goldiea
Dracaena aubryana
Dracaena cantleyi
Dracaena reflexa
Dracaena refuxa
Dracaena rikki
Dracaena draco
Dracaena serrulata
Dracaena augustifolia
Dracaena lourieri
Dracaena yuccaefolia
Dracaena fragrans
Dracaena massefane
Dracaena sanduana
Dracaena multiflora
Dracaena steudneri
Dracaena umbraculifera
Dracaena tarzen
Dracaena ensifolia
Agave missionum
Agave attenuata
100/100
100/86
9
2
82/80
75/80
2
2
2
2
2
2
2
2
1
1
12
1
7
1
1
5
1
14
6
112
94/70
100/70
94/82
70/50 93/64
82/50
52/50
54/63
80/76
2
52/50
75/50
75/50
75/50
75/50
75/50
75/52
100/68
100/66
52/50
Figure 1. Strict consensus of the maximum parsimony tree with 33 taxa resolved using trnL-trnF sequence data. Posterior
probability values/ Bootstrap percentages > 50% are above branches and decay indices are below branches.
Pleomele halapepe
Pleomele hawaiiensis
Pleomele fernaldii
Pleomele forbesii
Pleomele aurea
Dracaena cemcina
Pleomele auhawaiiensis
Dracaena marginata Pleomele borneensis
Dracaena deremensis
Dracaena cantleyi
Dracaena goldiea
Dracaena aubryana
Dracaena floribunda
Dracaena sanderiana
Dracaena reflexa
Dracaena refuxa
Dracaena rikki
Dracaena draco
Dracaena serrulata
Dracaena augustifolia
Dracaena lourieri
Dracaena yuccaefolia
Dracaena fragrans
Dracaena massefane
Dracaena sanduana Dracaena multiflora Dracaena steudneri
Dracaena umbraculifera
Dracaena tarzen
Dracaena ensifolia
Agave missionum
Agave attenuata
0.01 substitutions/site
100/68
100/ 66
76/ 80
60/ 50
75/ 80
82/ 80
100/ 80
100/100
94/70 54/ 63
93/ 64
Figure 2. Maximum-likelihood tree of 33 taxa resolved using trnL-trnF sequence
data. Posterior probability values/ Bootstrap percentages > 50% are above branches.
P.-L. Lu and C. Morden / Phylogenetics of Dracaena and Pleomele 67
© 2010 Central Department of Botany, Tribhuvan University, Botanica Orientalis (2010) 7: 64–72
(CI=0.905, and RI=0.818; both CI and RI were calculated
including parsimony uninformative characters). Strict
consensus tree obtained from 1359 retained trees. All of the
nodes have similar patterns on DI, PP, and BP (data not
shown). Some of the nodes have no similar patterns on DI,
PP, and BP such as the node of D. multiflora and the clade of
the most of Pleomele and Dracaena taxa has high PP 100 and
low PB 61 (Fig. 3).
The length of the combined psbA-trnH and trnL-F
sequences of 19 taxa varied from 935 bases in all of the ingroup
Dracaena floribunda
Dracaena serrulata
Drcaena sanderiana
Pleomele auhawaiensis
Pleomele forbesii
Pleomele hawaiiensis
Pleomele halapepe
Pleomele aurea
Dracaena fragrans
Dracaena reflexa
Dracaena goldiena
Dracaena refuxa
Dracaena cemcina
Dracaena marginata
Dracaena augustifolia
Dracaena multiflora
Dracaena cantleyi
Dracaena umbraculifera
Agave missionum
0.005 substitutions/site
100/100
100/81
100/72
100/61
100/86
100/87
80/57
Figure 3. Maximum-likelihood tree of 19 taxa resolved using psbA-trnH sequence data. Posterior probability values/ Bootstrap
percentages > 50% are above branches.
Dracaena floribunda
Dracaena marginata Dracaena serrulata
Dracaena augustifolia
Dracaena goldiena Dracaena multiflora
Dracaena fragrans
Dracaena cemcina
Dracaena sanderiana
Dracaena reflexa
Dracaena refuxa
Pleomele auhawaiensis
Pleomele hawaiiensis
Pleomele halapepe
Pleomele forbesii
Pleom ele aurea
Dracaena cantleyi Dracaena umbraculifera
Agave missionum
0.01 substitutions/site
100/100
86/ 52
99/61
100/81
100/83
71/52
Figure 4. Maximum-likelihood tree of 19 taxa resolved using combined psbA-trnH and trnL-trnF sequence data. Posterior
probability values/ Bootstrap percentages >50% are above branches.
68 P.-L. Lu and C. Morden / Phylogenetics of Dracaena and Pleomele
© 2010 Central Department of Botany, Tribhuvan University, Botanica Orientalis (2010) 7: 64–72
taxa to 1035 bases in outgroup Agave missionum. The
maximum likelihood search of the combined data set retained
335021 trees with L=430 (CI=0.744, and RI=0.476; both CI
and RI were calculated including parsimony uninformative
characters). Strict consensus tree obtained from 153 retained
trees. Some nodes have no similar patterns on DI, PP, and BP
such as the node of D. multiflora and D. goldiena have low
BP 50 and PP 50 but has high decay index 6 (data not shown).
On the combined data set all of the nodes have similar patterns
on DI, PP and BP (Fig. 4).
Analyses of all datasets supported a monophyletic clade
containing both of the genera Pleomele and Dracaena (Fig. 1-
4). The strict consensus trees also recovered a polyphyletic
Pleomele with Dracaena on those data analyses (parsimony
and Bayesian) (Fig. 1, 2). The trnL-F of 33 taxa data set in
maximum parsimony tree shows that all of the Hawaiian
Pleomele group together and are closely aligned with a
Dracaena species, D. marginata, but the support for this
relationship is not strong [Bayesian posterior probabilities
(PP): 75, bootstrap percentages (BP): 52, decay index (DI):
2] (Fig. 2). Either of the separated data set of 19 taxa of psbA-
trnH and trnL-F does not have good resolution. The psbA-
trnH of 19 taxa data set in maximum parsimony tree shows
that the polytomy of Dracaena and Pleomele with the
exception of D. cantleyi and D. umbraculifera (Fig. 3). The
two trees are not incompatible in their basic structure.
Therefore a combined analysis using the 19 species that were
sequenced in both analyses was undertaken (Fig. 4). The
combined data set in maximum parsimony tree shows all of
the Hawaiian Pleomele nested together without D. marginata
(PP: 100, BP: 86, DI: 2) (Fig 4). The placement of D. cantleyi
and D. multiflora are different in the phylogenetic trees of
trnL-F and psbA-trnH. Dracaena multiflora is on the more
basal position based on trnL-F analysis and its support is
good (PP: 100, BP: 80) based on psbA-trnH analysis. On the
other hand, D. cantleyi is on the related basal position based
on the psbA-trnH analysis and its support is strong (PP: 100,
BP: 81) based on trnL-F analysis though it has the situation
of a long branch attraction.
Discussion
This is the first time that Pleomele has been included in a
phylogenetic analysis, and the results indicate that it is nested
within Dracaena. The differentiation between Dracaena and
Pleomele was uncertain from the time that Vandelli described
the genus Dracaena (in 1768) and Salisbury named the genus
Pleomele (in 1796). It remained confused until Brown (1914)
separated them by more clear morphological characteristics
based on the difference of flower structure. However, the
debate between the relationship between Dracaena and
Pleomele has never stopped. Bos (1992), Stevens (2001),
and Staples and Herbst (2005) had recently placed the genus
Pleomele into the genus Dracaena but without explanation.
In contrast, Degener (1980), St. John (1985) and Wagner (1990)
agreed that Pleomele should be separated from Dracaena.
This study provides clear evidenced that Pleomele is not
monophyletic and should be combined into Dracaena based
on phylogenetic analysis.
The two Dracaena species, D. tarzen and D. ensifolia,
are the basal clade with high support on the node, and for a
sister group to the other Dracaena and Pleomele species. The
second basal group with high support on the node is included
the three species, D. steudneri, D. multiflora, and D.
umbraculifera. It is formed sister group with the remaining
Dracaena and Pleomele taxa. According to the species
distribution of historical biogeography, we cannot have any
further interpretation. Thus, the examination of morphological
characteristics is needed to discover the patterns.
The combined data sets did not resolve the relationships
among the species Hawaiian Pleomele. It is uncertain which
species first colonized in the Hawaiian Islands or the direction
of the radiation from island to island. Therefore, searching for
faster evolving genetic markers is crucial.
In the analysis of trnL-F, the three species, D. steudneri,
D. multiflora and D. umbraculifera may have the problem of
long branch attraction or be truly evolved in a higher rate of
base substitution at a faster rate. However, in the analysis of
psbA-trnH, the situation does not exist perhaps because psbA-
trnH is relatively slower evolving cpDNA marker compare to
trnL-F for the genus Dracaena and Pleomele. Adding more
non-terminal related taxa on the branches may break up the
long branch or be evolving in a faster rate. Further examination
is necessary.
On the data set of trnL-F, the CI value is not high enough
and has related higher homoplasy. The data set of psbA-trnH
and the combined data set had high CI values and thus their
phylogenies can have more confidence to be trusted. However,
the combined data set has low RI and RC value. The
phylogeny of the data set of combined trnL-F and psbA-trnH
has few synapomoprhy characters. Therefore, the evoluti-
P.-L. Lu and C. Morden / Phylogenetics of Dracaena and Pleomele 69
© 2010 Central Department of Botany, Tribhuvan University, Botanica Orientalis (2010) 7: 64–72
onary tree is not robust. The reasons of inconsistent nodes
support the strict consensus of parsimony trees and ML
trees should be due to the total characteristics are not long
enough (461 bp) because the parsimony informative
characteristics have 33% of the total characters. The reason
for the inconsistent nodes supports of the strict consensus of
parsimony trees and ML trees on the data set of combined
trnL-F and psbA-trnH should be due to too few parsimony
informative characters (10% of total characters) not due to
short sequences.
From the current biogeography literature, it is still not
clear how Pleomele genus emerged from Dracaena or how
Dracaena dispersal from the Africa-Arabic Peninsula to the
South Asia and Southeast Asia. In the previous study, no
geographical barrier was seen between mainland Southeast
Asia and the western part of Malesia until the Pliocene (Hall
1998), and the southern Yunnan, mainland Southeast Asia,
and the western part of Malesia during the Tertiary when it
formed a landmass (Morley 1998). It shows that the flora in
southern Yunnan, China should have been derived from
tropical Asia due to climatic warming after Tertiary when the
Himalaya started to uplift and monsoon forming began (Zhu
2008). Several Dracaena and Pleomele species are native or
endemic to Yunnan and to Myanmar (Kurz 1974; Xinqi and
Turland 2000). The Eastern Himalaya could be the northern
barrier for the Dracaena and Pleomele migration due to cooler
climate but also could be undertaken into the southern Yunnan
flora model to include the species of these two genera in the
near future according the climate change evidence and its theory.
Dracaena and Pleomele belong to tropical and subtropical
plants. If in one location, some species belonging to both
genera exist then this location can be interpreted as “warm”
area. Therefore, these plants can be used as an index for climate
change in the specific location and broader area. For example,
these plants should not occur in the Himalaya regions. But if
they begin to appear in Himalaya regions either by direct
introduction or cultivated methods, it can be assumed the
plants are adapting into the region’s warming climate. Eastern
Himalaya is one of the 25 biodiversity hotspots (Myers et al.
2000), but its flora data is not complete yet. According to
Dracaena/Pleomele’s biological information, it is possible to
find those species in the Eastern Himalaya in the subtropical
area. Further plant identification and survey in this area should
be done. Once the database is set up, the related strategies for
conservation can be carried out.
Conclusion
This study shows that Pleomele is not monophyletic and
could be placed into Dracaena. It can be concluded that
Pleomele and Dracaena as circumscribed are both paraphyletic
groups. Even though Pleomele is resolved to be nested within
Dracaena, the support for this relationship remains not strong
enough. Pleomele is still possible to form a monophyletic
group only in Hawaii (become endemic to the Hawaii
Archipelago) and the remaining species under this genus should
be replaced into Dracaena in other places in the world.
Further work should include more taxa of Dracaena and
Pleomele and focus on other genetic regions to investigate
better resolution and statistic supports of phylogeny for
establishing a robust evolutionary relationship within and
between the genera Dracaena and Pleomele.
Acknowledgements
I wish to express my gratefulness to The Charles H.
Lamoureux Fellowship Award, University of Hawaii at Manoa
and East-West Center Degree Fellowship for supporting me
for this study. I would also like to thank all members of Dr.
Morden’s lab for giving me useful comments on this research
and Mr. Asheshwor Man Shrestha for editing this paper.
References
70 P.-L. Lu and C. Morden / Phylogenetics of Dracaena and Pleomele
© 2010 Central Department of Botany, Tribhuvan University, Botanica Orientalis (2010) 7: 64–72
Anonymous. 2010. Dracaena. In: Wikipedia, The Free
Encyclopedia. [online] URL: http://en.wikipedia.org/wiki/
Dracaena_(plant) (assessed 03.10.2010).
APG (Angiosperm Phylogeny Group). 2003. An update of the
Angiosperm Phylogeny Group classification for the orders
and families of flowering plants: APG II. Botanical Journal
of the Linnean Society 141: 399–436.
APG (Angiosperm Phylogeny Group). 2009. An update of the
Angiosperm Phylogeny Group classification for the orders
and families of flowering plants: APG III. Botanical Journal
of the Linnean Society 141: 399–436.
Bonde S.D. 2005. Eriospermocormus indicus gen. et sp. nov.
(Liliales: Eriospermaceae): first record of a
monocotyledonous corm from the Deccan Intertrappean beds
of India. Cretaceous Research 26: 197–205.
Bos J J. 1980. Dracaena surculosa Lindl. Miscellaneous Papers
19: 6579.
Bos J.J. 1984. Dracaena in West Africa. Ph.D. Thesis, Agricultural
University Wageningen, Netherlands.
Bos J.J. 1992. Wild and cultivated Dracaena fragrans.
Edinburgh Journal of Botany 49: 311-331.
P.-L. Lu and C. Morden / Phylogenetics of Dracaena and Pleomele 71
© 2010 Central Department of Botany, Tribhuvan University, Botanica Orientalis (2010) 7: 64–72
Bos J.J., Graven P., Hetterscheid W.L.A. and Van De Wege J.J.
1992. Wild and cultivated Dracaena fragrans. Edinburgh
Journal of Botany 49: 311–331.
Bremer K. 1988. The limits of amino acid sequence data in
angiosperm phylogenetic reconstruction. Evolution 42: 427–
803.
Brown N.E. 1914. Notes on the genera Cordyline, Dracaena,
Pleomele, Sansevieria and Taetsia. Kew Bulletin 273–279.
Brummitt R.K. 1992. Vascular Plant: Families and Genera.
Royal Botanical Gardens, Kew, UK.
Carlquist S. 1970. Hawaii: A Natural History. Published for the
American Museum of Natural History, The Natural History
Press, Garden City, New York, USA.
Chun M.N. 1994. Native Hawaiian Medicine. First People’s
Production, Honolulu, Hawaii, USA.
Degener O. and Degener I. 1980. Flora Hawaiiensis, fam. 68.
Pleomele hawaiiensis. Publ. privately, 2 pp.
Edward H.G.M., Olveira L.F.C.D. and Quye A. 2001. Raman
spectroscopy of coloured resins used in antiquity: dragon’s
blood and related substances. Spectrochimica Acta Part A 57:
2831–2842.
Felsenstein J. 1985. Confidence limits on phylogenies: an
approach using bootstrap. Evolution 39: 783–791.
Gwyne M.D. 1966. Conservation of Plant Association on
Socotra. East Africa Agriculture and Forestry Research
Organization, Nairobi, Africa.
Hall R. 1998. The plate tectonics of Cenozoic SE Asia and the
distribution of land and sea. In: Biogeography and Geological
Evolution of SE Asia (R. Hall and J.D. Holloway, eds.), pp.
99–131. Backhuys Publishers, Leiden, The Netherlands.
Hilu K.W., Borsch T., Müller K., Soltis D.E., Soltis P.S., Savolainen
V., Chase M.W., Powell M.P., Alice L.A., Evans R., Sauquet H.,
Neinhuis C., Slotta T.A.B., Rohwer J.G., Campbell C.S. and Chatrou
L.W. 2003. Angiosperm phylogeny based on matk sequence
information. American Journal of Botany 90: 1758–1776.
Huang T.C. 1993. Plant Taxonomy: Families of Taiwan Vascular
Plants. SMC Publishing Inc., Taipei, Taiwan.
Huelsenbeck J.P. and Ronquist F. 2001. MRBAYES: Bayesian
inference of phylogeny. Bioinformatics 17: 754755.
Hutchinson J. 1973. The Families of Flowering Plants. Oxford
University Press, third edition. ELY House, London, UK.
Judd W.S. 2003. The genera of Ruscaceae in the southeastern
United States. Harvard Papers in Botany 7: 93149.
Judd W.S., Campbell C.S., Kellogg E.A., Stevens P.F. and
Donoghue M.J. 2007. Plant Systematics: A Phylogenetic
Approach (Third edition). Sinauer Associates, Inc. Sunderland,
Massachusetts, USA.
Kubitzi K. 1998. The Families and Genera of Vascular Plants,
Vol III. Floweing Plants. Monocotyledons: Lilianae. Springer,
Berlin Heidelberg, New York, USA.
Kurz S. 1974. Forest Floras of British Burma. Bishen Singh
Mahendra Pal Singh and Periodical Experts, Dehra Dun, India.
Lee S.J. 1975. Ben cao gang mu. Ren min wei sheng chu ban she.
Beijing. V3, pp. 1959–1960. The peoples’ republic of China
(Original work was published in 1578).
Maddison D.R. and Maddison W. 2000. MacClade 4: Analysis
of Phylogeny and Character Evolution. Sinauer Associates,
Inc., Sunderland, Massachusetts, USA.
Marrero A., Almeida R.S. and Gonzalez-Martin M. 1998. A new
species of the wild dragon tree, Draceana (Dracaenaceae)
from Gran Canaria and its taxonomic and biogeographic
implications. Botanical Journal of the Linnean Society 128:
291–314.
Morden C.W., Caraway V., Motley and Timothy J. 1996.
Development of a DNA library for native Hawaiian plants.
Pacific Science 50: 324–335.
Morley J.R. 1998. Palynological evidence for Tertiary plant
dispersals in the SE Asian region in relation to plate tectonics
and climate. In: Biogeography and Geological Evolution of
SE Asia (R. Hall and J.D. Holloway, eds.), pp 221–234.
Backhuys Publishers, Leiden, The Netherlands.
Myers N., Mittermeier R.A., Mittermeier C.G., da Fonseca
G.A.B. and Kent J. 2000. Biodiversity hotspots for
conservation priorities. Nature 403: 853–858.
Randell R.A. and Morden C.W. 1999. Hawaiian plant DNA
library II: endemic, indigenous, and introduced species. Pacific
science 53: 401–417.
Sang T.D., Grawford D.J. and Stuessy T.F. 1997. Chloroplast
DNA phylogeny, reticulate evolution and biogeography of
Paeonia (Paleoniaceae). American Journal of Botany 84:
1120–1136.
Shaw J., Lickey E.B., Beck J.T., Farmer S.B., Liu W., Miller J.,
Siripun K.C., Winder C.T., Schilling E.E. and Small R.L. 2005.
The tortoise and the hare II. Relative utility of 21 noncoding
chloroplast DNA sequences for phylogenetic analysis.
American Journal of Botany 94: 275–288.
Shaw J., Lickey E.B., Beck J.T., Farmer S.B., Liu W., Miller J.,
Siripun K.C., Winder C.T., Schilling E.E. and Small R.L. 2007.
Comparison of whole chloroplast genome sequences to choose
noncoding regions for phylogenetic studies in angiosperms:
The tortoise and the hare III. American Journal of Botany
94: 275–288.
Sorenson M.D. 1999. TreeRot, Version 2. Boston University,
Boston, MA, USA.
St. John. H. 1985. Monograph of Hawaiian species of Pleomele
(Liliaceae). Hawaiian plant studies 103. Pacific Science 39:
171–190.
Staples G.W. and Herbst D.R. 2005. A Tropical Garden Flora.
Bishop Museum Press, Honolulu, Hawaii, USA.
Stevens P.F. 2001 onwards. Angiosperm Phylogeny Website.
Version 9, June 2008 [and more or less continuously updated
since]. [online] URL: http://www.mobot.org/MOBOT/
research/APweb/.
Swofford D. 2002. PAUP*: Phylogenetic Analysis Using
Parsimony (*and Other Methods), Version 4.0 Beta 10.
Sinauer Associates, Inc., Sunderland, Massachusetts, USA.
Taberlet P., Gielly L., Pautou G. and Bouvet J. 1991. Universal
primers for amplification of three non-coding regions of
chloroplast DNA. Plant Molecular Biology 17: 1105–1109.
Tamura K, Dudley J., Nei M. and Kumar S. 2007. MEGA4:
Molecular Evolutionary Genetics Analysis (MEGA) software
version 4.0. Molecular Biology and Evolution 24: 1596–
1599.
Tate J.A. and Simpson B.B. 2003. Paraphyly of Tarasa
(Malvaceae) and diverse origins of the polyploidy species.
Systematic Botany 28: 723–737.
72 P.-L. Lu and C. Morden / Phylogenetics of Dracaena and Pleomele
© 2010 Central Department of Botany, Tribhuvan University, Botanica Orientalis (2010) 7: 64–72
Thompson J.D., Gibson T.J., Plewniak F., Jeanmougin F. and
Higgins D.G. 1997. The ClustalX windows interface: flexible
strategies for multiple sequence alignment aided by quality
analysis tools. Nucleic Acids Research 24: 4876–4882.
Van Campo E. and Sivak J. 1976. Presence de pollens de
dracaenas dans le Neogene mediterraneen. Revue de
Micropaleontologie 18: 264–268.
Wagner W.L. and Herbst D.R. 2003. Electronic supplement to
the manual of flowering plants of Hawaii, Version 3.1.
December 12, 2003. [online] URL: http://rathbun.si.edu/
botany/pacificislandbiodiversity/hawaiianflora/
supplement.htm.
Wagner W.L., Herbst D.R. and Sohmer S.H. 1990. Manual of
the Flowering Plants of Hawaii. 2 vols, Bishop Museum
Special Publication 83. pp. 1351–1354. University of Hawaii
Press and Bishop Museum Press, Honolulu, Hawaii, USA.
Waterhouse J.T. 1987. The phylogenetic significance of
Dracaena-type growth. Proceedings of the Linnean Society
of New South Wales 109: 129–314.
Watson L. and Dallwitz M.J. 1992. The families of flowering
plants: descriptions, illustrations, identification, and
information retrieval. Version 14th. [online] URL: http://
delta-intkey.com.
Xinqi C. and Turland N.J. 2000. Dracaena Vand. ex L.. Flora of
China 24: 215–217.
Zhu H. 2008. The tropical flora of southern Yunnan, China,
and its biogeographic affinities. Annals of the Missouri
Botanical Garden 95: 661680.
... L.; dragon tree) had been changing frequently within the past. Their unstable family placement varied from Dracaenaceae, Liliaceae, Agavaceae, Convallariaceae and Ruscaceae, to now Asparagaceae and the subfamily Nolinoideae (APG 1998, APG II 2003, APG III 2009, Baker 1875, Bos 1998, Brown 1914, Cronquist 1968, 1981, Dahlgren et al. 1985, Lu and Morden 2010, Rudall 2000, Salisbury 1866). In addition, the systematic relationship of the three monophyletic dracaenoid genera Dracaena, Pleomele (Salisb.) and Sansevieria (Thunb.) ...
... remained unclear. This is reflected by strongly varying species numbers found in literature (40-170;Bos et al. 1992, Lu and Morden 2010, Marrero et al. 1998, Stevens, P.F. 2001. ...
... Lu and Morden (2014) suggest that the origin of dracaenoid species is located in South-or Southeast Asia and their worldwide distribution (with exception of South America) occurred via three consecutive, bird-mediated dispersal steps: (1) from Southeast Asia to the Pacific Islands, (2) from Southeast Asia or Hawaiian Islands to Central America and (3) from Southeast Asia over the Arabian Peninsula to Africa. Africa is now the center of diversity of Dracaena (Bos 1984, Bos 1998, Marrero et al. 1998, Lu and Morden 2010. ...
Thesis
The present thesis introduces a new methodological approach based on magnetic resonance imaging (MRI) which allows for analyzing the development and load-adapted strategy of plant structures. Thus, the application of MRI could be extended to the fields of functional morphology, biomechanics and biomimetics of plants. MRI allows for repetitive non- destructive and non-invasive in vivo imaging of plant structures and entire plant organisms, while simultaneously enabling a combined spatial analysis of the functional anatomy, biomechanics and the development of plants. By this, it became possible to reveal the unique development and load-adapted strategy of branch-stem-attachments of dragon trees (Dracaena marginata). Three-dimensional MR images of the unloaded and mechanically loaded condition of a branch- stem-attachment were qualitatively and quantitatively analyzed to understand the complex three-dimensional displacements of the outer surface and inner tissues of the plant structure. The in vivo biomechanical experiments revealed a load-adapted placement of the mechanically relevant vascular bundles with sclerenchymatic fiber caps in the branch-stem junction of D. marginata. Furthermore, the soft (visco-elastic) parenchyma matrix dissipates compressive stresses and strains while simultaneously allowing for a load-induced reorientation of the vascular bundles along the course of occurring stress trajectories. This results in a high tensile resistance of the structure. In addition, the complex branch ontogeny could be simplified to seven chronological ontogenetic stages that give unique three-dimensional insights into the development of the load-adapted strategy of D. marginata. The load-adapted strategy and development of lateral organs of dragon trees and arborescent monocotyledons in general has not been fully understood up to date. Magnetic resonance imaging has proven to be a powerful method with great potential in the field of functional morphology, biomechanics and biomimetics of plants and its wide range of possible applications can be extended far beyond the framework of the present dissertation.
... Many species have been commercialised and are sold for use in landscaping and as indoor plants, particularly the widely cultivated ornamental mother-in-law's tongue or snake plant (various species and cultivars of Sansevieria). These genera also have broad uses in traditional medicine (e.g., Bos 1984, Chhabra et al. 1987, Neuwinger 2000, Mwachala & Mbugua 2007, Lu & Morden 2010, Takawira-Nyenya & Stedje 2011Despite their economic and social value, the taxonomy and classification of the dracaenoid genera have remained controversial. The dracaenoids have a complex taxonomic history. ...
... The first phylogenetic study explicitly focused on relationships within the dracaenoids was that of Lu & Morden (2010), who sampled 24 species of Dracaena and six species previously included in Pleomele and confirmed that Pleomele (narrowly defined by the authors as dracaenoid species endemic to Hawaii) formed a clade embedded within Dracaena. They did not include any sample of Sansevieria at that time. ...
... Lu & Morden (2014), in a substantially larger analysis, sampled 95 species representing all three dracaenoid genera and used four combined chloroplast intergenic spacer DNA regions (trnL-trnF, ndhF-rpl32, trnQ-rps16, and rpl32-trnL). They concluded that Sansevieria was monophyletic and nested inside a paraphyletic grade comprising intermixed species of Dracaena and Pleomele, thus corroborating the decision by Bos (1984Bos ( , 1998, Jankalski (2008) and Lu & Morden (2010 to sink Pleomele into Dracaena, based on both morphological and molecular evidence, and rejecting the decisions by Degener & Degener (1980), St. John (1985 and Wagner (1990), who argued that Pleomele and Dracaena should be treated as separate genera. Jankalski (2008) identified a distinct group of Dracaena taxa that consisted of endemic Hawaiian species with large, yellow, bird-pollinated flowers (formerly included in Pleomele) and erected Dracaena subg. ...
Article
The evolutionary history of the dracaenoid genera Dracaena and Sansevieria (Asparagaceae, Nolinoideae) remains poorly resolved, despite long-recognised issues with their generic boundaries and increased attention paid by both horticulturalists and taxonomists. In this study we aim to: (1) elucidate evolutionary relationships within and between Dracaena and Sansevieria using molecular phylogenetic inference of both nuclear (nDNA) and plastid (cpDNA) markers, (2) examine the infrageneric classifications of each genus, and (3) revise the circumscription of the dracaenoids in light of morphological and phylogenetic evidence. In total, we sampled 21 accessions of Dracaena (ca. 19 species), 27 accessions of Sansevieria (ca. 26 species), and six outgroup taxa. Phylogenetic analyses were based on nucleotide sequences of two non-coding plastid DNA regions, the trnL-F region (trnL intron and trnL-trnF intergenic spacer) and rps16 intron, and the low-copy nuclear region At103. Phylogenetic hypotheses were constructed using maximum parsimony, maximum likelihood, and Bayesian inference. Individual datasets were analysed separately and, after testing for congruence, as combined datasets. We recovered instances of soft incongruence between nDNA and cpDNA datasets in Sansevieria, but general trends in the dracaenoids were congruent, although often poorly supported or resolved. The dracaenoids constitute a strongly supported monophyletic group. Dracaena was resolved as a paraphyletic grade embedded with two clades of Sansevieria, a primary clade comprising most species, and a secondary clade including S. sambiranensis, a distinctive species from Madagascar. The backbone of our phylogeny was only resolved in nDNA analyses, but combined analyses recovered strongly supported species groups. None of the previous infrageneric classifications were supported by our phylogeny, and biogeographic groupings were frequently more significant than morphology. More work is needed to resolve internal relationships in the dracaenoids, but we support a recent proposal to recognise a broadened circumscription of Dracaena that includes Sansevieria. We provide a generic description for the recircumscribed Dracaena and new combinations for several species of Sansevieria in Dracaena.
... Plant extracts and isolated compounds could constitute an alternative solution to this problem because some of them are used in traditional medicine to treat several ailments, including microbial infections. The genus Dracaena (Dracaenaceae) contains approximately 100 species of shrubs and trees spread in tropical and subtropical regions of the world [2,3]. Dracaena steudneri Engl. is distributed in the DR Congo, Ethiopia, and East to southern African countries. ...
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Microbial infections are leading causes of death and morbidity all over the world due to the development of the resistance to antibiotics by certain microorganisms. In this study, the chemical exploration of the ethanol (EtOH) extract of the aerial part of Dracaena stedneuri (Dracaenaceae) led to the isolation of one previously unreported chalcone derivative, i.e., 2′,4′-dihydroxy-2,3′-dimethoxychalcone (1), together with 12 known compounds: 8-(C)-methylquercetagetin-3,6,3′-trimethyl ether (2), methylgalangine (3), quercetin (4), kaempferol (5), 6,8-dimethylchrysin (6), ombuine-3-O-rutinoside (4ʹ,7-dimethylquercetin-3-O-α-L-rhamnopyranosyl-(1 → 6) -β-D-glucopyranoside) (7), alliospiroside A (8), β-sitosterol 3-O-glucopyranoside (9), ishigoside (10), betulinic acid (11), oleanolic acid (12), and lupeol (13). The structures were determined by spectroscopic and spectrometric analysis including 1- and 2-Dimensional Nuclear Magnetic Resonance (1D- and 2D-NMR), High-Resolution Electrospray Ionization Mass Spectrometry (HRESIMS), and comparison with literature data. The isolated secondary metabolites and crude extract displayed antibacterial activity against some multidrug-resistant strains with minimal inhibitory concentration (MIC) values ranging from 32 to 256 μg/mL. The antibacterial activity of compound 13 against Enterobacter aerogenes ATCC13048 (MIC value: 32 μg/mL) was higher than that of chloramphenicol used as the reference drug (MIC = 64 μg/mL).
... Зокрема досліджень у галузі філогенії та еволюції квітки [11,12]. Роди Dracaena та Sansevieria є спорідненими [2, 18], раніше їх відносили до родини Agavaceae [1, 18], Convallariaceaea [13], Dracaenaceae [2, 16], Ruscaceae [6] і за сучасною молекулярно-філогенетичною систематикою ці роди відносяться до великої гетерогенної родини Asparagaceae sensu lato [8,9, 17]. Пола Рудал з групою науковців [13] -здійснили кладистичний аналіз деяких представників порядку Asparagales на основі молекулярних даних та морфологічних ознак квітки, включивши деякі ознаки гінецею. ...
... In contrast to the works cited above, very few genetic studies have been performed on D. draco. Moreover, these studies were not very extensive and focused on a small number of DNA regions (mainly barcodes) [1,4,33,34]. So far, there are no more comprehensive genomic data on D. draco. ...
Article
Full-text available
Dracaena draco, which belongs to the genus Dracaena, is an endemic succulent of the Canary Islands. Although it is one of the most popular and widely grown ornamental plants in the world, little is known about its genomic variability. Next generation sequencing, especially in combination with advanced bioinformatics analysis, is a new standard in taxonomic and phylogenetic research. Therefore, in this study, the complete D. draco chloroplast genome (cp) was sequenced and analyzed in order to provide new genomic information and to elucidate phylogenetic relationships, particularly within the genus Dracaena. The D. draco chloroplast genome is 155,422 bp, total guanine-cytosine (GC) content is 37.6%, and it has a typical quadripartite plastid genome structure with four separate regions, including one large single copy region of 83,942 bp length and one small single copy region of 18,472 bp length, separated by two inverted repeat regions, each 26,504 bp in length. One hundred and thirty-two genes were identified, 86 of which are protein-coding genes, 38 are transfer RNAs, and eight are ribosomal RNAs. Seventy-seven simple sequence repeats were also detected. Comparative analysis of the sequence data of various members of Asparagales revealed mutational hotspots potentially useful for their genetic identification. Phylogenetic inference based on 16 complete chloroplast genomes of Asparagales strongly suggested that Dracaena species form one monophyletic group, and that close relationships exist between D. draco, D. cochinchinensis and D. cambodiana. This study provides new and valuable data for further taxonomic, evolutionary and phylogenetic studies within the Dracaena genus.
... ex L. is placed in the family Asparagaceae subfamily Nolinoideae [33,34]. It is considered to be monophyletic based on molecular studies [35], and it comprises 190 species [3]. ...
Article
Full-text available
This article is a broad review focused on dragon trees—one of the most famous groups of trees in the world, well known from ancient times. These tertiary relicts are severely endangered in most of the area where they grow. The characteristic features of the dragon tree group are described and the species belonging to this group are listed. This review gathers together current knowledge regarding the taxonomy, evolution, anatomy and morphology, physiology, and ontogeny of arborescent dragon tree species. Attention is also paid to the composition, harvesting, medicinal, and ethnobotanical use of the resin (dragons’ blood). An evaluation of population structure, distribution, ecology, threats, and nature conservation forms the final part of the review. In the conclusions we recommend further avenues of research that will be needed to effectively protect all dragon tree species.
... ex L. belongs to the family Asparagaceae (APG III, 2009). It is considered to be monophyletic based on molecular studies (Lu & Morden, 2010) and comprises approximately 116 species (Govaerts et al. 2018). Dracaena is distributed in subtropical and tropical regions of the world. ...
Article
Full-text available
Forest undergrowth plants are tightly connected with the shady and humid conditions that occur under the canopy of tropical forests. However, projected climatic changes, such as decreasing precipitation and increasing temperature, negatively affect understory environments by promoting light‐demanding and drought‐tolerant species. Therefore, we aimed to quantify the influence of climate change on the spatial distribution of three selected forest undergrowth plants, Dracaena Vand. ex L. species, D. afromontana Mildbr., D. camerooniana Baker, and D. surculosa Lindl., simultaneously creating the most comprehensive location database for these species to date. A total of 1,223 herbarium records originating from tropical Africa and derived from 93 herbarium collections worldwide have been gathered, validated, and entered into a database. Species‐specific Maxent species distribution models (SDMs) based on 11 bioclimatic variables from the WorldClim database were developed for the species. HadGEM2‐ES projections of bioclimatic variables in two contrasting representative concentration pathways (RCPs), RCP2.6 and RCP8.5, were used to quantify the changes in future potential species distribution. D. afromontana is mostly sensitive to temperature in the wettest month, and its potential geographical range is predicted to decrease (up to −63.7% at RCP8.5). Optimum conditions for D. camerooniana are low diurnal temperature range (6–8°C) and precipitation in the wettest season exceeding 750 mm. The extent of this species will also decrease, but not as drastically as that of D. afromontana. D. surculosa prefers high precipitation in the coldest months. Its potential habitat area is predicted to increase in the future and to expand toward the east. This study developed SDMs and estimated current and future (year 2050) potential distributions of the forest undergrowth Dracaena species. D. afromontana, naturally associated with mountainous plant communities, was the most sensitive to predicted climate warming. In contrast, D. surculosa was predicted to extend its geographical range, regardless of the climate change scenario.
Article
Background Leukemia is the most common type of childhood cancer. Numerous flavonoids isolated from plants have been reported as potential chemotherapeutic agents against malignant growth while taking care of healthy cells. Purpose To discover new anticancer agents from the seeds of Dracaena steudneri Engl for their potential uses as candidate compounds against leukemia cell lines. Methods A panel of chromatography techniques (CC, Sephadex LH-20 and semi-preparative HPLC) were used to isolate these compounds from the MeOH/CH2Cl2 (1:1) crude extract of the seeds of D. steudneri. Their structure elucidation was achieved based on spectral evidence (UV, NMR and HRESIMS). Resazurin reduction assays were performed to assess the cytotoxicity of the crude extract and isolates. Results From the seeds of D. steudneri 8 compounds were isolated (1 – 8). Quercetin derivatives: 3,3′-di-O-methylquercetin-4′-O-β-D-glucoside (5) and 3,3′-di-O-methylquercetin (7) displayed significant cytotoxicity against the two leukemia cell lines tested with IC50 < 10 µM. Doxorubicin (reference drug) exhibited strong cytotoxic potency; IC50 of 0.01 µM (against CCRF-CEM cells) and moderate activity; IC50 of 26.78 µM (towards CEM/ADR5000 cells). To the best of our knowledge, this is the first report of flavonoids glycosides from the genus Dracaena. Conclusion The results obtained in this study showed that flavonoids isolated from Dracaena steudneri are promising candidates for cancer chemotherapy. The mode of action and the cytotoxicity of the most active compounds (5 and 7) should be further investigated.
Article
The leaves of Dracaena steudneri yielded 6 new flavonoids–3,5,7-trihydroxy-6-methyl-3′,4′-methylenedioxyflavone (1), 5,7-dihydroxy-3-methoxy-6-methyl-3′,4′-methylenedioxyflavone (2), 3,5,7-trihydroxy-6-methoxy-3′,4′-methylenedioxyflavone (3), (2S,3S)-3,7-dihydroxy-6-methoxy-3′,4′-methylenedioxyflavanone (4), 4′,5,7-trihydroxy-3,3′,8-trimethoxy-6-methylflavone (5), (2R) 7-hydroxy-2′,8-dimethoxyflavanone (6)–together with 13 known congeners. Their structures were established using spectroscopic and spectrometric methods including NMR, CD, and HRMSn measurements. The compounds were evaluated for their anti-inflammatory potential through measurement of the levels of cytokines IL-1β, IL-2, GM-CSF, and TNF-α in the supernatant of human peripheral blood mononuclear cells stimulated by lipopolysaccharide. Flavones derivatives 1–4 with a C-3′/4′ methylenedioxy substituent led to a substantial increase in the production of IL-1β and GM-CSF out of 4 pro-inflammatory cytokines relative to LPS control. Quercetin derivatives 5, 11, and 13 with a hydroxyl group at C-4′ inhibited the production of IL-2, GM-CSF, and TNF-α. The presence of a C-2/C-3 double bond in 14 was pivotal to the significantly stronger (0.4 to 27.5% of LPS control) inhibitory effect compared to its dihydro derivative 8 (36.2 to 262.7% of LPS control) against all tested cytokines. It is important to note that the inhibitory activity of 14 was substantially higher than that of the standard drug used, ibuprofen.
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A Tropical Garden Flora sets a new standard for reference manuals about cultivated garden plants. More than a decade in preparation, this book will be indispensable for gardeners in the Hawaiian Islands and similar climate areas around the world. It describes more than 2,100 species of tropical and subtropical plants, provides brief descriptions and keys for identification, and weaves together the origins, uses, biology, landscape properties, and practical tips for propagating and growing each species. The rigorous taxonomic research that underpins A Tropical Garden Flora assures that each species is correctly identified and reconciles many discrepancies between the botanical taxonomic literature and the horticultural names known to gardeners, as well as correcting errors in naming that have been repeated in other, less authoritative manuals. Thus, this new book will be the reference about tropical garden plants for decades to come.
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The recently-developed statistical method known as the "bootstrap" can be used to place confidence intervals on phylogenies. It involves resampling points from one's own data, with replacement, to create a series of bootstrap samples of the same size as the original data. Each of these is analyzed, and the variation among the resulting estimates taken to indicate the size of the error involved in making estimates from the original data. In the case of phylogenies, it is argued that the proper method of resampling is to keep all of the original species while sampling characters with replacement, under the assumption that the characters have been independently drawn by the systematist and have evolved independently. Majority-rule consensus trees can be used to construct a phylogeny showing all of the inferred monophyletic groups that occurred in a majority of the bootstrap samples. If a group shows up 95% of the time or more, the evidence for it is taken to be statistically significant. Existing computer programs can be used to analyze different bootstrap samples by using weights on the characters, the weight of a character being how many times it was drawn in bootstrap sampling. When all characters are perfectly compatible, as envisioned by Hennig, bootstrap sampling becomes unnecessary; the bootstrap method would show significant evidence for a group if it is defined by three or more characters.
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