全 文 ：园 　艺 　学 　报 　2007, 34 (3) : 683 - 687
Acta Horticulturae Sinica
Rece ived: 2006 - 10 - 18; Accepted: 2007 - 03 - 143 Author for correspondence ( E2mail: liuzhengan@ ibcas1ac1cn)
Rela tion sh ip Between the Types of Flower2bud D ifferentia tion
and Forc ing Successive Secondary Flower ing of Tree Peon ies
J IANG Zhuo, L IU Zheng2an3 , WANG L iang2sheng, and SHU Q ing2yan
(B eijing B otanical Garden, Institu te of B otany, the Chinese A cadem y of Sciences, B eijing 100093, Ch ina)
Abstract: The types of flower2bud differentiation in 135 cultivars of tree peonies ( Paeo2
n ia suffru ticosa) were identified and grouped as few (3 - 4) , medium (5 - 7) or many (8 -
10) in number of flower2buds and small, medium or large in flower2bud differentiation gradi2
ent. Ten rep resentative cultivars were chosen and investigated for their behavior in forcing suc2
cessive secondary flowering. The results indicated that the flower2bud number and differentia2
tion gradient were directly related with secondary flowering. The cultivars with fewer flower2
buds and large differentiation gradient could not be forced for successive secondary flowering in
the same p lant, while the cultivars with medium2numbered or many flower2buds and small dif2
ferentiation gradient flowered successively from January to Ap ril 2006 in the same p lant by forc2
ing. Among the latter, Paeon ia‘Ru Hua Si Yu’had a secondary flowering percentage of 75%
and p roduced good quality flowers during the p rimary and secondary flowering.
Key words: Paeon ia suffru ticosa; Flower2bud differentiation; Successive secondary flow2
ering
牡丹花芽分化类型与促成连续二次开花
姜　卓 , 刘政安 3 , 王亮生 , 舒庆艳
(中国科学院植物研究所北京植物园 , 北京 100093)
摘 　要 : 以 135个牡丹品种为试材 , 归纳了花芽分化数量和梯度类型 , 将同枝条的芽数聚类为少 (3～
4)、中等 (5～7)、多 (8～10) 3类 ; 花芽分化梯度为小、中、大 3种类型。选取 10个代表品种进行促成
连续二次开花研究。结果表明 , 花芽分化数量的多少及梯度的大小直接影响着开花次数 , 花芽分化数量少、
梯度大的品种不能同株促成连续二次开花 ; 花芽分化数量中等或多、梯度小的品种可以同株促成连续二次
开花 , 其中 ‘如花似玉 ’二次开花率达 75% , 且两次开花品质均优良。
关键词 : 牡丹 ; 花芽分化 ; 连续二次开花
中图分类号 : S 685111　　文献标识码 : A　　文章编号 : 05132353X (2007) 0320683205
Tree peony ( Paeon ia suffru ticosa Andr. ) p lants growing in the open flower only once a year with short
and concentrated flowering period, which is a p roblem that needs solution in the Paeoniaceae. P. suffru ticosa
var. h ibern iflora Makino was published in Japan in 1961 (Hagiya, 1961). Zhang Xiu2xin reported in 2004
that the flowering mechanism of autumn2flowering tree peonies. A lthough most p lants of P. suffru ticosa var.
h ibern if lora occasionally bloom twice a year, the flower quality are poor and the flowering period are not stable
(Hashida, 1995; Zhang, 2004). A t p resent, the technology of forcing culture of tree peonies is well devel2
© 1994-2009 China Academic Journal Electronic Publishing House. All rights reserved. http://www.cnki.net
Acta Horticulturae Sinica Vol. 34
oped (Cheng et al. , 2001; L iu et al. , 2002, 2003) . However, each forced p lant can flower only once. L iu
Zheng2an (2003) found that a few cultivars could be forced for successive secondary flowering and inferred
that the phenomenon is closely related with the number of flower2buds differentiated and the type of differentia2
tion gradient. This paper aim s at clarifying their relationship s and solving the p roblem of shortness of flowering
period and the lack of successive secondary flowering.
1　M a ter ia ls and M ethods
111　M a ter ia ls
The experimentwas carried out from November 2005 to Ap ril 2006. Flower2buds from 62year2old p lants of
135 tree peony cultivars commonly found inside and outside China were observed. Ten rep resentative culti2
vars, namely Ru Hua Si Yu, H igh Noon (American cultivar) , J ing Yu, Guan Qun Fang, Feng Dan, Luoyang
Hong, W u Long Peng Sheng, Hu Hong, Zhao Fen, and Kaoh (Japanese cultivar) , were chosen and investi2
gated for their behavior in forcing successive secondary flowering. Flowers from 2 - 4 strong branches on each
of 10 rep licate 32year2old grafted p lants of each cultivar were investigated. A ll the materials were taken from
the Baihua Yuan Garden in Heze, Shandong p rovince.
112　Flower2bud d ifferen tia tion num bers and grad ien t types
The p rocedure of flower2bud differentiation was finished on November 15, 2005 (W ang, 1986; L iu et
al. , 2002) . W e selected ten shoots from each of the 135 cultivars, recorded the bud numbers on each shoot.
Then we selected another five shoots of each cultivar, divided the shoots into three equal parts ( top , m iddle
and basal) , observed the flower2bud differentiation characteristics of every position ( flower2bud, leaf2bud)
with SMZ800 stereom icroscope (N ikon, Japan) , and calculated the flower2bud differentiation percentage of
every position, identified the differentiation gradient types of flower2buds of each cultivar as follows: when the
differentiation percentage of the flower2buds of the top , m iddle and basal parts are all 100% , it is regarded as
the small2gradient type ( Plate, 1 - 5) ; when the differentiation percentage of the flower2buds of the top part is
100% , that of the m iddle part is greater than 50% , and that of the basal part is greater than 20% , it is regar2
ded as the medium 2gradient type; when the differentiation percentage of the flower2buds of the top part is
100% , that of the m iddle part is less than 50% , and that of the basal part is less than 20% , it is regarded as
the large2gradient type ( Plate, 6 - 10).
113　Forc ing of successive culture
On November 20, 2006, the ten rep resentative forcing cultivars were kep t at 2 - 4℃ in cold storage for
two weeks. On December 4, we p lanted them in pots, and forced them to flower for the first time. After the
first flowering, some shootswere p runed above the unsp routed flower2buds, forced the flower2buds at the lower
part of the shoots for secondary flowering. During the forcing, the average day light was eight hours, and the
temperature was 19 - 28℃ during the day, with a hum idity of 26% - 54% , while the temperature at nightwas
10 - 15℃, with a hum idity of 50% - 69%.
114　Eva lua tion of flower ing qua lity
By determ ining the stalk length, leaf width, flower diameter, petal number, flower color and leaf area,
we evaluated the quality of twice flowering. Flower color was determ ined by colorimeter NF333 ( two chromatic
components: a3 and b3 , flower chroma c3 = a3 2 + b3 2 ) and Royal Horticultural Society Color Chart (pet2
al color zone).
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No. 3 J IANG Zhuo et al. : Relationship Between the Types of Flower2bud D ifferentiation and Forcing Successive ⋯
2　Results and Ana lysis
211　Flower2bud d ifferen tia tion num bers and grad ien t types
W e analyzed the data of bud numbers through SPSS layered2clustering method and classified the cultivars
into three types. Type Ⅰ ( Few2flowered type) had 3 - 4 buds, which includes 67 cultivars, accounting for
50% of the total number. Type Ⅱ (Medium2numbered2flowered type) had 5 - 7 buds, which includes 59 cul2
tivars, accounting for 44% of the total number. Type Ⅲ (Many2flowered type) had 8 - 10 buds, which in2
cludes 9 cultivars, accounting for 6% of the total number.
The results of investigation of the 135 cultivars indicated that, in type Ⅰ, 12 cultivars belonged to small2
gradient type, 24 belonged to medium2gradient type, and 31 belonged to large2gradient type; in type Ⅱ, 8
cultivars belonged to small2gradient type, 28 belonged to medium2gradient type, and 23 belonged to large2gra2
dient type; in type Ⅲ, 3 cultivar belonged to small2gradient type, 1 belonged to medium2gradient type, and 5
belonged to large2gradient type. Overall, few of the cultivars were of the small2gradient type. For bud number
types and flower2bud differentiation gradient types ( TypeⅠ2small gradient: W u Long Peng Sheng, TypeⅠ2
medium gradient: Feng Dan, TypeⅠ2large gradient: Luoyang Hong; Type Ⅱ2small gradient: Ru Hua Si Yu,
Type Ⅱ2medium gradient: J ing Yu, Type Ⅱ2large gradient: Zhao Fen; Type Ⅲ2small gradient: H igh Noon,
Type Ⅲ2medium gradient: A lice Harding, Type Ⅲ2large gradient: Hakuhō) .
212　Budbreak percen tage and flower ing percen tage
Excep t that the buds of Kaoh did break dormancy, the first budbreak percentage of the top bud of the oth2
er nine cultivars reached 100%. The p rimary and secondary flowering percentages were different for different
cultivars ( Table 1) . For Hu Hong and W u Long Peng Sheng, whose p rimary flowering percentages were low2
er than 30% , the secondary flowering percentage was 0% ; For Luoyang Hong, whose p rimary flowering per2
centage was 10% , the secondary flowering percentage was 10% ; For Zhao Fen, whose p rimary flowering per2
centage was 100% , since most of the buds had already broken and flowered, the secondary flowering percent2
age was 0%. Budbreak time, budbreak percentage and flowering percentage of the buds in every position on
the same shoot were different for different cultivars. Ru Hua Si Yu and H igh Noon, cultivars of small flower2
bud differentiation gradient type, could be forced for successive secondary flowering in the same p lant, with
the secondary flowering percentage above 75% ; while Feng Dan , J ing Yu and Guan Qun Fang had secondary
flowering percentages of 44% - 60%.
Table 1　Budbreak and flower ing percen tage of d ifferen t cultivars after forc ing ( % )
Cultivar
Once
Budbreak percentage Flowering percentage
Secondary
Budbreak percentage Flowering percentage
Luoyang Hong 100a 10b 100a 10b
H igh Noon 100a 90a 88a 80a
Ru Hua Si Yu 100a 80a 100a 75a
J ingyu 100a 90a 100a 60ab
Feng Dan 100a 90a 90a 60ab
Guan Qun Fang 100a 67a 100a 44ab
　　Note: D ifferent letters in the same column indicate significance at level of 5%.
213　Flower ing qua lity
Compared with the quality of the p rimary flowering, the secondary flowering of H igh Noon had the flower
diameter reduced, the value of flower chroma c3 decreased, and the stalk length increased. The secondary
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© 1994-2009 China Academic Journal Electronic Publishing House. All rights reserved. http://www.cnki.net
Acta Horticulturae Sinica Vol. 34
flowering of Ru Hua Si Yu had petal number reduced, the flower diameter, stalk length and leaf area in2
creased, and the flower color was slightly different to become red purp le (75C) in stead of p rimary blue pur2
p le (76B ) in p rimary flowering; and in J ing Yu, Feng Dan and Guan Qun Fang, petal numbers reduced in
secondary flowering but leaf characters were good ( Table 2).
Table 2　Com par ison of flower qua lity of d ifferen t cultivars dur ing pr imary and secondary flower ing
Cultivar Flower
times
Cut2flower
Stalk length ( cm) Leaf width ( cm) Flower diameter( cm)
Flower
Petal number Flower chroma c3 RHSCC Leaf area( cm2 )
H igh Noon 1 2618b 3410a 1218a 3919a 3111a 3C 11915a
2 3212a 3412a 1113b 3314a 2416b 2C 13315a
Ru Hua Si Yu 1 3018b 4212a 1218a 7416a 1115a 76B 5710b
2 3616a 4413a 1410a 5319b 1310a 75C 16111a
J ing Yu 1 2611b 1010b 1215a 7013a 313a 56D 　415b
2 3612a 2713a 1318a 5318a 314a 56D 6913a
Feng Dan 1 2418a 1912a 1216a 1219a 119a 56D 2411b
2 2911a 2913a 1116a 1110b 217a 56D 6518a
Guan Qun Fang 1 2318b 2516b 1212b 23313a 4019a 72A 3115b
2 3111a 3819a 1319a 15315a 3011a 71A 11014a
Luoyang Hong3 3 1 2215 3315 2118 9410 3712 77C 7111
2 3110 3312 1215 8910 4211 71C 17418
　　Note: D ifferent letters in the same column indicate significance at level of 5%. A, B , C and D indicate colour zone. 3 3 : Just one flower,
not taken into account in statistics.
3　D iscussion s
To realize forcing for successive secondary flowering, it is fundamental to choose cultivars of app rop riate
flower2bud differentiation numbers and gradient types. W hen first flowering is over, it is necessary to p rune the
shoots on time and break the ap ical dom inance. The types which have many flower2buds and small differentia2
tion gradient, such as Ru Hua Si Yu and H igh Noon, can be forced for successive secondary flowering in the
same p lant from January to Ap ril, w ith the secondary flowering percentage of more than 75% , so they possess
high commercial and ornamental values. The types which have few flower2buds and large differentiation gradi2
ent, such as Luoyang Hong, are not suitable for successive secondary flowering. The types which have medi2
um 2numbered flower2buds and medium differentiation gradient, such as Guan Qun Fang, could have the dif2
ferentiation percentage of the flower2buds in the m iddle and lower parts of the shoots increased by taking suit2
able measures to raise the secondary flowering percentage. The high successive secondary flowering percentage
of cultivars such as Ru Hua Si Yu and H igh Noon may be due to the wild species from which the cultivars de2
rived (L i, 1998) and the endogenous phytohormone levels of the flower2buds at different positions (Xiao et
al. , 2001) , which isworth further studies in genetic and physiologicalmechanism s of their successive flower2
ing.
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Explana tion of pla tes: 1 - 5: Q ing Xiang Bai Yu Cui (of small flower2bud differentiation gradient type) with five buds, of which all are flower2
buds ( FB). Flower2bud differentiation percentage: 100% on top, 100% in the m iddle, 100% at base. 6 - 10: Pu JüZhao Shui (of large flower2
bud differentiation gradient type) with five buds, showing flower2buds ( FB ) in 6 - 8 and leaf2buds (LB ) in 9 - 10. Flower2bud differentiation
percentage: 100% on top, 17% in the m iddle, 0 at base.
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