全 文 ：濒危植物杜鹃红山茶的细胞学研究
?
王 霜1 ,2 , 王仲朗1
??
, 梁 静1 , 管开云1
( 1 中国科学院昆明植物研究所 , 云南 昆明 650204; 2 中国科学院研究生院 , 北京 100049 )
摘要 : 报道了杜鹃红山茶 ( Camellia azalea) 的细胞学资料。其间期核为球形前染色体型 , 有丝分裂前期染
色体为中间型。核型公式为 2n = 2x= 30 = 28m (1SAT ) + 2sm, 核型类型属于 Stebbins的 1B 型。第 3、4、9、
10、11、12 条染色体的长臂上具有次缢痕 , 第 15 条染色体的短臂上具随体。细胞学证据支持杜鹃红山茶
在山茶组中较为原始的推断 , 并为人工杂交育种时亲本的选择提出了一些建议。
关键词 : 杜鹃红山茶 ; 核型 ; 育种
中图分类号 : Q 942 文献标识码 : A 文章编号 : 0253 - 2700 (2007) 06 - 655 - 04
Karyological Study on the Endangered Species
Camellia azalea (Theaceae) *
WANG Shuang
1 , 2
, WANG Zhong-Lang
1 **
, LIANG J ing
1
, GUAN Kai-Yun
1
(1 Kunming Instituteof Botany, ChineseAcademy of Sciences, Kunming 650204 , China;
2 GraduateUniversity of Chinese Academy of Sciences, Beijing 100049 , China)
Abstract: The chromosome number and karyotype of Camellia azalea were reported here for the first time . The species
showed in somatic cells theround prochromosometypeof the interphasenuclei andthe interstitial typeof the prophasechro-
mosomes . It was a diploid, and the karyotype could be formulated as 2n= 2x= 30 = 28m (1SAT ) + 2sm, belonging to
Stebbins’1B type . The third, fourth, ninth, tenth, eleventh and twelfth chromosomes had secondary constriction respec-
tively, and one satellite had been found on the fifteenth chromosome . Thecytological results supported the suggestion that
C. azalea was primitive species in Sect . Camellia of the genus Camellia . A clue on selecting parents was also proposed
due to the chromosome numbers and the position in Sect . Camellia .
Key words: Camellia azalea; Karyotype; Breeding
Camellia azalea C . F . Wei was firstly discovered
and published by Wei ( 1986 ) . The next year, Ye
(1987) published this species under the name of Ca-
mellia changii and now as a synonym . It is naturally
distributed in E’huangzhang Natural Reserved Areaof
Yangchun County in Guangdong Province, China . It is
an endangeredspecies andhas avery limited geograph-
ic distribution, now only about 1000 individuals in the
wild and has been classified as one of first class pro-
tected plants in China . Luo et al . ( 2005) investigat-
ed the genetic diversity of three endemic and endan-
gered species of the family Theaceae in Guangdong,
China and showed that C. azalea had very low genetic
diversity . Studies of propagation and breeding on this
species have achieved progress in China in recent years
(Zhang and Liang, 2003; Li et al . 2004) . In 2006 ,
two new cultivars have been developed and registered
from the cultivated plants by Fu ( 2006 ) and Li
( 2006 ) . The chromosome number and karyotype of
C. azalea were firstly studied in this paper, so as to
云 南 植 物 研 究 2007 , 29 (6) : 655～658
Acta Botanica Yunnanica

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?? ?Author for correspondence . E-mail : wang@ mail. kib. ac. cn; Tel .: 0871 - 5223702 ; Fax .: 0871 - 5150227
Received date: 2007 - 07 - 13 , Accepted date: 2007 - 09 - 05
作者简介 : 王霜 ( 1982 - ) 女 , 在读硕士研究生 , 主要从事山茶的育种与繁殖研究。 ?
Foundation item: This paper was supported by Natural Sciences Foundation of Yunnan Province (2001C0010Z)
give some cytological evidences on its studiesof taxono-
my, and to reveal genetic background of chromosomes
on cross-breeding program .
Materials and methods
Materials Cuttings of C. azalea were collected fromYun-
feng CamelliaGarden inZhejiang in August 2005 , then propagat-
ed in Kunming Botanical Garden . The growing root tips were
used for chromosome research . The voucher specimen ( Wang
Zhonglang05 - 081 ) was collected from the same plant which
cuttings were taken, and were deposited in the Herbarium of
Kunming Institute of Botany (KUN) .
Methods Thefresh root tipsof 5 mmlongwerecut off from
rooted cuttings, pretreated with 0 .002 mol?L 8-hydroxyquinoline
solutionat roomtemperaturefor 5 h, thenfixed with Carnoy′sfluid
(absolutealcohol∶glacial acetic acid= 3∶1) at 5℃ overnight . The
fixed root tipsweremacerated inamixtureof 1 mol?L hydrochloric
acid and45% glacial acetic acid (1∶1) at 60℃ for 6 min, imme-
diately rinsed with distilled water at room temperature for 3 - 5
min, then stainedand squashedwithCarbol Fuchsin . Thecytolog-
ical classification of the interphase and mitotic prophase followed
Tanaka (1971; 1977) . Chromosomes of more than 20 cells were
counted . The parameters of the chromosomes were based on the
measurements of 5 cells . Theuseof symbols for the description of
chromosomes followed Levan et al . (1964) and the classification
of karyotype symmetry followed Stebbins (1971) .
Results
At mitotic interphase ( Fig . 1 : B ) , the nuclei
was characterized by some deeply stained, round
prochromosomes of almost equal size with numerous
minute grains distributed in the nucleus, and could be
categorized as the round prochromosome type . At mi-
totic prophase ( Fig . 1 : D) , heterochromatic and eu-
chromatic segments were distinguishable but without
clear boundaries between them, and theheterochromat-
ic segments were distributed in thedistal and interstitial
regions as well as the proximal regions . This corre-
sponded to the interstitial type . The above characteris-
tics have been shown in all theobserved species in the
genus Camellia without any exception ( Kondo et al .
1986; Li and Liang 1990; Gu and Sun 1997; Zhang
and Min, 1999; Min, 2000 ) .
Fig . 1 Theplant and cytological observation of Camellia azalea
Flower and leaves ( A ) , Interphase nuclei ( B) , Metaphase chromosomes (C) , Mitotic prophase (D) , karyotype ( E ) , Bar = 4μm
656 云 南 植 物 研 究 29 卷
Table 1 Karyomorphological parameters of Camellia azalea
No . Relative length Ratio Type No . Relative length Ratio Type
1 E2 ?. 74 + 2 . 00 = 4 . 74 1 .37 m 16 1 +. 95 + 1 ?. 45 = 3 .40 1 .34 m
2 E2 ?. 60 + 2 . 06 = 4 . 66 1 .26 m 17 1 +. 87 + 1 ?. 37 = 3 .24 1 .36 m
3 E2 ?. 09 + 2 . 06 = 4 . 15 1 .01
mSC 18 1 +. 77 + 1 ?. 38 = 3 .15 1 .28 m
4 E2 ?. 11 + 1 . 99 = 4 . 10 1 .06
mSC 19 1 +. 52 + 1 ?. 49 = 3 .01 1 .02 m
5 E2 ?. 10 + 1 . 99 = 4 . 09 1 .06 m 20 1 +. 59 + 1 ?. 38 = 2 .97 1 .15 m
6 E2 ?. 10 + 1 . 74 = 3 . 84 1 .21 m 21 1 +. 58 + 1 ?. 35 = 2 .93 1 .17 m
7 E1 ?. 88 + 1 . 87 = 3 . 75 1 .01 m 22 1 +. 58 + 1 ?. 27 = 2 .85 1 .24 m
8 E1 ?. 84 + 1 . 82 = 3 . 66 1 .01 m 23 1 +. 52 + 1 ?. 26 = 2 .78 1 .21 m
9 E2 ?. 36 + 1 . 24 = 3 . 60 1 .90
smSC 24 1 +. 51 + 1 ?. 27 = 2 .78 1 .19 m
10 X2 ?. 37 + 1 . 22 = 3 . 59 1 .94
smSC 25 1 +. 40 + 1 ?. 38 = 2 .78 1 .01 m
11 X1 ?. 89 + 1 . 62 = 3 . 51 1 .17
mSC 26 1 +. 38 + 1 ?. 35 = 2 .73 1 .02 m
12 X1 ?. 84 + 1 . 67 = 3 . 51 1 .10
mSC 27 1 +. 44 + 1 ?. 17 = 2 .61 1 .23 m
13 X2 ?. 16 + 1 . 34 = 3 . 50 1 .61 m 28 1 +. 42 + 1 ?. 16 = 2 .58 1 .22 m
14 X1 ?. 98 + 1 . 52 = 3 . 50 1 .30 m 29 1 +. 19 + 1 ?. 17 = 2 .36 1 .02 m
15 X2 ?. 14 + 1 . 34 = 3 . 48 1 .60 mS 30 1 +. 12 + 1 ?. 01 = 2 .13 1 .11 m
S
: chromosome with satellite; SC : chromosome with secondary constriction
At mitotic metaphase, the chromosome number of
C. azalea was determined to be 2n= 30 (Fig . 1 : C) .
Absolute chromosome lengths ranged from 1 .8 to 3 .8
μm and therefore could be classified as the small chro-
mosome type . The size of chromosomes within each
complement varied continuously and was formulated as
2n= 2x = 30 = 28m ( 1SAT ) + 2sm (Fig . 1 : E ; Table
1) . Six chromosomes displayed secondary constriction
on the long arms of the 3rd , 4th , 9th , 10th , 11th and
12th chromosomes . The 15th chromosome had a satellite
on the short arm . The relative length of chromosomes
ranged from 2 .13 to 4 .74 . The mean arm ratio was
1 .25 . The ratio of longest chromosome to shortest one
was 2 .23 . No chromosome had an arm ratio more than
2 .0 . Thus the karyotype asymmetry was classified as
type 1B .
Discussion
The phylogeny status of Camellia azalea
The genus Camellia is distributed in East Asia
and contained a lot of important economic plants . Ac-
cording to the latest revision on this genus, there are
about 120 species throughout the world (Min 2000 ) .
Nearly half of total species in Camellia had chromo-
some reports already (Zhang and Min, 1999 ) . C. a-
zalea was placed in Sect . Camellia in this genus (Min
and Brtholomew, 2007; Gao et al . 2005; Min 2000) .
Zhang and Min (1998) had ever summarized the chro-
mosome reports on this section, and indicated that
there was a clear direction in Sect . Camellia, namely
the karyotype was from symmetry to asymmetry, and
the chromosome number was from diploid to polyploid .
They also showed that there were only two kinds of
karyotype, 2A and 2B, in Sect . Camellia in the pre-
vious studies . The chromosomes observed in this study
displayed that C. azalea was a diploid and had rela-
tively high symmetrical 1B karyotype, much primitive
compared to those in the same section . Wu et al .
(2003 ) suggested that two widely cultivated groups of
Camellia recitulata and Camellia japonica were proba-
bly derived from primitive species, C . azalea and Ca-
mellia semiserrata which were distributed in the north
margin of tropical zone . The cytological results of
C. azalea supported the above suggestion .
Breeding significance
Camellia azalea has avery special flowering sea-
son . Most species of the genus Camellia bloom from
December to February, while C. azalea is in full
bloommostly from May to October in the wild . Some
plants of C . azalea can even bloom all the year round
under cultivation . Its flowers are bright red, nearly
distinct, obovate to longobovate (Fig . 1 : A ) . Its leaf
is very unique as well with entiremargin, glabrous sur-
faces, obovate to obcordate-laneolate ( Min and Bar-
tholomew, 2007) . Thereforeit is avery precious breed-
ingmaterial to breed new cultivars with long flower sea-
son andwithspecial leaves . Control pollination isoneof
the most important methods in camellia breeding, but
7566 期 WANG Shuang et al .: Karyological Study on the Endangered Species Camellia azalea (Theaceae)
interspecific hybridization is commonly limited by com-
patibility . Cytological research could give a clue on se-
lecting parents . After more than 20-year experiments on
artificial hybridization, Xia (2003) concluded that the
combination between species in the same section had
higher compatibility, and it was easier to cross between
diploid and polyploidy, if the combination was among
different sections . C. azalea was a diploid, and was
placed in the sect . Camellia, so it is better to select
those in the same section, or polyploid camellia if in
different section, soas to improvethe cross-compatibili-
ty . If C . azalea is selected as pollen parent, some ex-
periments on thestorageof pollens should bedone first,
becauseboth parents have different flower seasons .
Acknowledgements : Special thanks to Mr . WANG Jia-yun, the
director of Yunfeng Camellia Garden in Zhejiang, for sending us
thematerials . The authors thank Dr . Greg DAVIS, the president
of International Camellia Society, for his comments to this study
and detailed reviews of the English manuscript . The authors
would also liketo express their thanks to Dr . YANG Shixiong for
his valuable suggestions .
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