全 文 ：ABA 对黑黄檀种子萌发的抑制作用以及其他
植物激素对 ABA 的拮抗作用
?
邓志军1 ,2 , 宋松泉3
??
(1 中国科学院西双版纳热带植物园 , 云南 勐腊 666303 ; 2 中国科学院研究生院 , 北京 100049;
3 中国科学院植物研究所 , 北京 100093 )
摘要 : 以云南特有濒危树种黑黄檀 ( Dalbergia fusca) 的种子为材料 , 研究了脱落酸 (ABA) 对种子萌发的
抑制作用 , 以及种子萌发过程中吲哚乙酸 ( IAA)、赤霉酸 (GA3 )、6-苄基腺嘌呤 (6-BA) 和乙烯利对 ABA
的拮抗作用。黑黄檀种子萌发的适宜温度为 30℃。交替光照 (14 h光照和 10 h黑暗 ) 以及黑暗对种子萌发
没有明显的影响。0 .001～0 .1 mmol?L ABA 不影响种子的萌发率 , 但降低种子的萌发进程 ; 1 mmol?L 和 2 .5
mmol?L ABA 显著地抑制种子的萌发率和萌发进程。种子的萌发率不被 0 .0001～ 1 mmol?L IAA 和 GA3 、
0 .0001～0 .1 mmol?L 6-BA、以及 0 .001～10 mmol?L 乙烯利 (乙烯供体) 的影响 , 但被 1 mmol?L 6-BA 抑制。1
mmol?L ABA 对种子萌发的抑制作用能被 0 .01～1 mmol?L IAA、0 .01～1 mmol?L GA3 、0 .001～0 .1 mmol?L 6-BA
和 0 .1～10 mmol?L 乙烯利所拮抗 , 而且这种拮抗作用与植物激素的类型和浓度有关。0.01 mmol?L 6-BA 和
0 .1 mmol?L 乙烯利对 1 mmol?L ABA 抑制作用的拮抗不能被添加 0 .001 mmol?L IAA 或者 0 .001 mmol?L GA3 加
成。但 0 .1 mmol?L 乙烯利对 1 mmol?L ABA 抑制作用的拮抗能够被添加 0 .01 mmol?L 6-BA 或者 0 .1 mmol?L 6-
BA 加成 , 导致更高的萌发率和幼苗生长。
关键词 : 脱落酸 ; 黑黄檀 ; 乙烯利 ; 植物激素的相互作用 ; 种子萌发
中图分类号 : Q 945 文献标识码 : A 文章编号 : 0253 - 2700 (2008) 04 - 440 - 07
Inhibitory Effect of ABA on Seed Germination of Dalbergia fusca
(Leguminosae) and Antagonism of Other Phytohormones to ABA
DENG Zhi-J un1 , 2 , SONG Song-Quan3 **
(1 Xishuangbanna Tropical Botanical Garden, ChineseAcademy of Sciences, Mengla 666303 , China;
2 Graduate University of Chinese Academy of Science, Beijing 100049 , China;
3 Instituteof Botany, Chinese Academy of Sciences, Beijing 100093 , China)
Abstract : Seeds of Dalbergia fusca, an endangered tree species endemic to Yunnan province of Chinawere used to study
the inhibitory effects of abscisic acid (ABA) and the antagonism of IAA , GA3 , 6-BA and ethephon to ABA in the seed
germination . Theoptimumtemperature for the seed germination was about 30℃ . Therewas no different effects of alternat-
ing photoperiod ( 14 h light and 10 h dark) and darkness onthe seed germination . After treated by 0 .01 - 0.1 mol?L ABA ,
the seed germinationpercentagewas not affected, but thetimecourseof germinationwas decreased, while those levelswere
dramatically inhibited by 1 mmol?L and 2 .5 mmol?L ABA . The seed germination percentage was not affected by 0 .0001 -
1 mmol?L indole-3-acetic acid ( IAA) , gibberellic acid (GA3 ) , 0 . 0001 - 0 .1 mmol?L 6-benzyladenine ( 6-BA) , and0 .001
- 10 mmol?L ethephon ( the ethylenedonor) , but wasinhibited by 1 mmol?L 6-BA . The inhibition effect of 1 mmol?L ABA
on seedgermination was antagonized by 0 .01 - 1 mmol?L IAA , 0 . 01 - 1 mmol?L GA3 , 0. 001 - 0 .1 mmol?L 6-BA , and 0 .1
云 南 植 物 研 究 2008 , 30 (4) : 440～446
Acta Botanica Yunnanica DOI : 10 .3724?SP. J . 1143 .2008.07233
?
?? ?Author for correspondence; E-mail : sqsong@ ibcas. ac. cn; Tel : 010 - 62836484
Received date: 2007 - 10 - 10 , Accepted date: 2008 - 04 - 21
作者简介 : 邓志军 (1980 - ) 男 , 在读博士研究生 , 主要从事种子生物学研究。 ?
Foundation item: Knowledge Innovation Program of the Chinese Academy of Sciences ( KSCX2-SW-117 , KSCX2-YW-Z-058)
-10 mmol?L ethephon, which were phytohormone type- and concentration-dependent . The antagonistic actions of 0 .01
mmol?L 6-BA and0 .1 mmol?L ethephon to 1 mmol?L ABA inhibition could not be increased by addition of 0 .001 mmol?L
IAA or 0 .001 mmol?L GA3 . The antagonistic actionof 0 .1 mmol?L ethephonto1 mmol?L ABA inhibition, however, could
be increased by addition of 0 .01 mmol?L 6-BA or 0.1 mmol?L 6-BA , which resulting in higher germination percentageand
enhancing seedling growth .
Key words: Abscisic acid; Dalbergia fusca; Ethephon; Phytohormone interaction; Seed germination
The process of germination begins with the uptake
of water by thedry seed, followedby the expansive em-
bryo growth . This usually culminates in rupture of the
covering layers and the emergenceof the radicle, which
is generallyconsidered to be thecompletionof thegerm-
ination . It has been reported that phytohormones regu-
lategermination and dormancy of seeds . GA3 , at high
concentration, can break the dormancy of positive pho-
toblastic seeds such as Lactuca scariola, negativephoto-
blastic seeds such as Phacelia tanacetifolia, and non-
photoblastic seeds which require stratification, such as
Avena fatua ( Berrie, 1984) . Kinetin can inducegermi-
nation inphotosensitive lettuce seeds, and likeGA , but
a high concentration is needed ( Berrie, 1984) .
ABA is known as a positive regulator of seed
dormancy and a negative regulator of seed germination
(Hilhorst and Downie, 1995; Bewley, 1997; Kooen-
neef et al. , 2002) . ABA treatment of non-endosper-
mic, non-dormant Brassica napus seeds has no effect
on the kinetics of testa rupture, but inhibits the post-
germination extension growth of the radicle ( Schopfer
and Plachy, 1985 ) . ABA does not inhibit the initial
imbibitionof water (water uptakephase1 and 2) need-
ed for the initial extension growth of the embryo, but
inhibits the transition to the seedlinggrowthphase (wa-
ter uptake phase 3 ) after radicle emergence ( Lopez-
Molina et al. , 2001) .
In many species, ethylene stimulates germination
of seeds that may or may not be dormant . Ethylene is
effective in breaking the primary dormancy imposed by
seed coat in cocklebur, subterranean clover and Rumex
crispus seeds, and the embryo dormancy of apple and
sunflower seeds . It can also overcome the thermo-
dormancy in lettuce seeds and the secondary dormancy
in cocklebur seeds (Corbineau and C?me, 1995) .
Dalbergia fusca Pierre ex Prain (family Fabaceae)
is avaluable timber tree endemic toYunnan Provinceof
China . It is considered to be an endangered species and
has been given protection by the Chinese government
(State Environmental Protection Administration of China
and Instituteof Botany of ChineseAcademyof Sciences,
1987) . To our knowledge, the factors affecting theger-
mination of D. fusca seed, including temperature, light
and phytohormones, have not been reported . In this
study, the inhibitory effects of ABA on the germination
of D. fusca seed and the antagonism of IAA , GA3 , 6-
BA and ethephon to ABA were investigated .
Materials and methods
Plant material Fruits of Dalbergia fuscawerecollected at
maturity inDecember , 2004 fromtrees growing in Xishuangbanna
Tropical Botanical Garden (101°25′E , 21°41′N; altitude 600 -
700 m) , Menglun, Mengla, Yunnan, China . After removal from
fruits, the seedsweredriedfor 14 days at 15±1℃ in50% rela-
tive humidity ( RH ) to a moisture content of 0 .092± 0 .004 g
H2 O g
- 1 dryweight (DW) and then kept at 15℃ beforethedif-
ferent experimental treatments .
Moisture content determinations The moisture content
of the seeds is expressed on a dry weight basis ( g H2 O g- 1 DW,
g g- 1 ) andwas determined by weighing5 replicates of 100 seeds
each after the seedswere dried for 48 h at 80℃ .
Germination testing Four replicatesof 50 seeds each were
germinated on two pieces of filter paper moistened with 7 ml of
distilled water or of a water solution of phytohormone of indicated
concentration in closed 9-cm diameter Petri dishes subjecting to
different light andtemperatureregimes . Seedsshowing2-mmradi-
cleemergence were counted as germinated . The germination rate
is expressed on a timecourse of germinationand?or thenumber of
days taken to reach the 50% germination stage (T50 ) .
Statistical analysis The effects of temperature, light and
phytohormones on seed germination were analyzed using a one-
way ANOVA model from the SPSS 11 .5 package for Windows
(SPSS Inc .) .
Results
Effects of temperature and light on seed germination
1444 期 DENG and SONG: Inhibitory Effect of ABA on Seed Germination of Dalbergia fusca and Antagonism . . .
The weight of 1000 seeds of D. fusca was 46 .05
±0 .73 g . When the seeds were germinated in dark-
ness at15 , 20 , 25 , 30 , 35 and 40℃ respectively, the
germination percentage and germination rate of seeds
were markedly affected by temperature, the time
required for 50% germination of seeds (T50 ) was about
80 h at 15℃ , 40 h at 20℃ , 29 h at 25℃ , 25 h at
30℃ , 27 h at 35℃ and 62 h at 40℃ ( Fig . 1 : a) .
The optimumtemperature for final germination percent-
age and T50 was about 30℃ , and for seedling growth,
about 35℃ (Fig . 1 : b) .
The alternating photoperiod [14 h light (12μmol
m
- 2
s
- 1 ) and 10 h dark] and darkness had no effect
on the final germination percentage and T50 at 30℃
(Fig . 1 : c) . The fresh weight of seedlings produced
by germinating seeds in the alternatingphotoperiod was
a little lower than in darkness (Fig . 1 : d) .
Inhibitory effects of abscisic acid on seed germination
0 .001 - 0 .1 mmol?L ABA did not affect the seed
germination percentage, but decreased the time course
of germination; 1 and 2 .5 mmol?L ABA dramatically
inhibited seed germination and decreased the time
courseof germination (Fig . 2 : a) . Except that0 .0001
mmol?L ABA slightly stimulated seedling growth ( data
not shown) , 0 . 001 - 1 mmol?L ABA inhibited seedling
growth (Fig . 2 : b) .
Effects of IAA , GA3 , 6-BA and ethephon on seed
germination
At 30℃ , thegermination percentageof seeds was
not affected by 0 .0001 - 1 mmol?L IAA , 0 . 0001 - 1
mmol?L GA3 , 0 .0001 - 0 .1 mmol?L 6-BA , and 0 .001
- 10 mmol?L ethephon ( the ethylene donor) , but was
inhibited by 1 mmol?L 6-BA (Table 1) .
The fresh weight of the seedlings produced by ger-
minating seeds was increased by 0.0001 mmol?L and
0.001 mmol?L IAA , 0. 0001 - 0.1 mmol?L GA3 , 0. 0001
Fig . 1 Effects of temperature and light on germination percentage and rateof D. fusca seeds
a . seeds were germinated at 15 , 20 , 25 , 30 , 35 and 40℃ , respectively, and in darkness for 5 d; b . Fresh weight of seedlings produced by
germinating seeds (excluding cotyledons) ; c . seeds weregerminated at 30℃ and alternating photoperiod (14 h light?10 h dark) or darkness for
5 d; d . Fresh weight of seedlings produced by germinating seeds ( excluding cotyledons) at 30℃ with alternating photoperiod or darkness .
Seeds showing radicle emergencefor 2 mmwere scored as germiated . All values are means±SD of four replicates of 50 seeds each .
244 云 南 植 物 研 究 30 卷
Table 1 Effects of phytohormones on germination of Dalbergia fusca
seeds . Seeds weregerminated at indicated concentrations of
phytohormones for 5 d ( dark, 30℃ ) . Seeds showing radicle
emergencefor 2 mmwere scored as germinated . All values
are means±SD of four replicates of 50 seeds each
Concentration
( mmol?L )
Phytohormone
IAA GA 6 ?-BA Ethephon
0 w100 ?. 0±0 .0 99 .5±0 K. 5 100 _. 0±0 . 0 99 ?. 5±0 .5
0 ?. 0001 99 .5±0 .5 100 .0±0 ]. 0 99 M. 0±1 .0 —
0 -. 001 99 ?. 0±1 .0 99 .5±0 K. 5 99 M. 0±0 ?. 5 100 . 0±0 .0
0 ?. 01 98 .5±1 .0 100 .0±0 ]. 0 99 M. 0±0 .5 100 . 0±0 .0
0 R. 1 98 ?. 5±1 .0 99 .0±1 K. 0 99 M. 0±0 ?. 5 100 . 0±0 .0
1 w99 ?±1 c. 0 99 .5±0 K. 5 71 M. 3±6 ?. 4 100 . 0±0 .0
10 ?— — — 100 . 0±0 .0
- 0. 01 mmol?L 6-BA , and 0 .001 mmol?L and 0 .01
mmol?L ethephon, but was inhibited by 0 .1 mmol?L
and 1 mmol?L IAA , 1 mmol?L GA3 , 0 . 1 mmol?L and 1
mmol?L 6-BA , and 1 mmol?L and 10 mmol?L ethephon
(Table 2 ) .
Antagonism of IAA , GA3 , 6-BA and ethephon to
ABA during seed germination
The germination percentage, the time course of
germination and the seedlinggrowth were significantly in-
hibited by 1 mmol?L ABA (Fig . 2 and 3a) , which could
be antagonized by 0.01 - 1 mmol?L IAA, 0. 01 - 1 mmol?L
GA3 (Fig . 3: a) , 0.001 - 0.1 mmol?L 6-BA and 0.1 - 10
mmol?L ethephon (Fig . 3 : b) . In these antagonisms to
ABA , the effect of ethephon was the largest, GA3 and
6-BA , the medium, and IAA , the smallest . Theopti-
mumantagonistic concentration to 1 mmol?L ABA was
Table 2 Effects of phytohormones on fresh weight ( mg?plant) of seedlings
produced by germinating Dalbergia fusca seeds . Seeds were germinated
at indicated concentrations of phytohormones for 5 d ( dark, 30℃ ) .
Fresh weight of seedling does not include cotyledons . All values
are means±SD of four replicates of 50 seeds each
Concentration
( mmol?L )
Phytohormone
IAA GA 6 5-BA Ethephon
0 +42 b. 78±4 4.20 43 %. 95±3.01 42 .93±2 .12 44.62±1 }.03
0 .0001 44 b. 83±2 4.13 44 %. 21±6.01 43 .13±2 .77 44.10±3 }.16
0 .001 45 b. 16±3 4.33 48 %. 05±3.18 46 .00±3 .15 45.85±3 }.20
0 . 01 42 b. 53±4 4.72 53 %. 88±4.09 48 .73±1 .41 51.16±3 }.36
0 .1 39 b. 55±5 4.26 51 %. 21±3.51 40 .33±1 .45 44.74±1 }.93
1 +26 b. 73±2 4.88 43 %. 74±4.13 4.84±0 .13 42.70±1 }.08
10 =— — — 26.30±0 }.79
0 .01 mmol?L for IAA and GA3 , 0. 1 mmol?L for 6-BA ,
and 10 mmol?L for ethephon (Fig . 3 : a and b) .
It was noted that 0 .01 - 0 .1 mmol?L IAA, 0 . 01
- 0 .1 mmol?L GA3 , and 0 .001 - 0 .1 mmol?L 6-BA in-
creased, and 0 .01 - 1 mmol?L ethephon markedly in-
creased, the fresh weight of seedlings in antagonismto
ABA ( datanot shown) .
Interaction among phytohormones during seed ger-
mination
ABA inhibition for seed germination ( Fig . 4 ) ,
thetime courseof germination andseedlinggrowth ( da-
ta not shown) was notably antagonized by 0 .01 mmol?L
6-BA and 0 .1 mmol?L ethephon, which could not be
increased by addition of 0 .001 mmol?L IAA or GA3 ,
but could be increased by addition of 6-BA ( 0 . 01 or
0 .1 mmol?L ) or ethephon (0 . 1 mmol?L) (Fig . 4 ) .
Fig . 2 Effects of ABA on germination percentage (a) and fresh weight of seedling (b) of D. fusca seeds . Seeds were germinated
at indicated concentrations of ABA for 5 d (dark, 30℃ ) . Seeds showing radicle emergence for 2 mmwere scored as germinated .
Freshweight of seedling does not include cotyledons . a, 0 mmol?L ABA ; b, 0 . 001 mmol?L ABA ; c, 0 . 01 mmol?L ABA ;
d, 0 . 1 mmol?L ABA ; e, 1 mmol?L ABA ; All values are means±SD of four replicates of 50 seeds each
3444 期 DENG and SONG: Inhibitory Effect of ABA on Seed Germination of Dalbergia fusca and Antagonism . . .
Fig . 3 Antagonism of IAA , GA3 , 6-BA and ethephon to ABA . Seeds of D. fusca weregerminated at different treatments, respectively,
for 5 d ( dark, 30℃ ) . Seeds showingradicle emergencefor 2 mmwerescored asgerminated . a and h, 1 mmol?L ABA ; b, 1 mmol?L ABA
+ 0 .01 mmol?L IAA ; c, 1 mmol?L ABA + 0 .1 mmol?L IAA ; d, 1 mmol?L ABA + 1 mmol?L IAA ; e, 1 mmol?L ABA + 0 . 01 mmol?L
GA3 ; f , 1 mmol?L ABA + 0 .1 mmol?L GA3 ; g, 1 mmol?L ABA + 1 mmol?L GA3 ; i , 1 mmol?L ABA + 0 .001 mmol?L 6-BA ; j , 1 mmol?
L ABA + 0 .01 mmol?L 6-BA ; k, 1 mmol?L ABA + 0 . 1 mmol?L 6-BA; l , 1 mmol?L ABA + 0 .1 mmol?L ethephon; m, 1 mmol?L ABA +
1 mmol?L ethephon; n, 1 mmol?L ABA + 10 mmol?L ethephon . All values are means±SD of four replicates of 50 seeds each
Fig . 4 Interaction among phytohormones during germination of D. fusca
seeds . Seeds weregerminated at different treatments, respectively, for 5 d
( dark, 30℃ ) . Seeds showing radicle emergencefor 2 mmwere scored as
germinated . a, 1 mmol?L ABA ; b, 1 mmol?L ABA + 0 .01 mmol?L 6-BA ;
c, 1 mmol?L ABA + 0 .01 mmol?L 6-BA + 0 .001 mmol?L IAA ; d, 1
mmol?L ABA + 0 .01 mmol?L 6-BA + 0 .001 mmol?L GA3 ; e, 1 mmol?L
ABA + 0 .1 mmol?L ethephon; f , 1 mmol?L ABA + 0 .1 mmol?L ethephon
+ 0 .001 mmol?L IAA; g, 1 mmol?L ABA + 0 .1 mmol?L ethephon +
0 .001 mmol?L GA3 ; h, 1 mmol?L ABA + 0 .1 mmol?L ethephon + 0 .01
mmol?L 6-BA ; i , 1 mmol?L ABA + 0 .1 mmol?L ethephon + 0 .1 mmol?L
6-BA . All values are means±SD of four replicates of 50 seeds each
Discussion
Among the several environmental factors which af-
fect germination, temperature is the singlemost impor-
tant factor governing both the maximum germination
percentage and the germination rate ( Heydecker,
1977; Huang et al. , 2003) . Temperature affects both
the capacity for germination and the rateof germination
( Bewley and Black, 1994 ) . T50 for D. fusca seed was
about 80 h at 15℃ , 40 h at 20℃ , 29 h at 25℃ , 25 h
at 30℃ , 27 h at35℃ and 62 h at 40℃ (Fig . 1 : a) .
The optimum temperature for germination percentage
and T50 was about 30℃ , and for seedling growth,
about 35℃ ( Fig . 1 : b) . These results are in agree-
ment with the viewpoint of Heydecker ( 1977 ) and
Huang et al. (2003) .
The alternating photoperiod (14 h light and 10 h
dark) or darkness had no effectongerminationpercent-
age and T50 at 30℃ (Fig . 1 : c) , and had a little ef-
fect on the fresh weight of the seedlings produced by
germinating seeds (Fig . 1 : d) , showing that the seed
of D. fusca was non-photoblastic .
0 . 001 - 0 .1 mmol?L ABA did not affect thegerm-
ination percentage of theseeds, but it affected the time
courseof thegermination and theseedlinggrowth (Fig .
2) . 1 and 2 .5 mmol?L ABA dramatically inhibited the
germination percentage, the time courseof germination
and the subsequent seedling growth ( Fig . 2 ) . It has
been reported that the addition of exogenous ABA to
themedium during imbibition resembles the effects of
maternal ABA during seed development and residual
444 云 南 植 物 研 究 30 卷
ABA in mature seeds . It has been also reported that
the imbibitionof freshor after-ripened tobaccoseeds in
mediumwith 10μmol?L ABA greatly delays seedgerm-
ination (Leubner-Metzger, 2003) .
The germination percentage of the seeds was not
affected by 0.0001 - 1 mmol?L IAA , 0 .0001 - 1 mmol?L
GA3 , 0. 0001 - 0.1 mmol?L 6-BA , and 0 .001 - 10 mmol?
L ethephon ( Table 1 ) , implying that D. fusca seeds
might have sufficient endogenous IAA , GAs, cytokinins
and ethylene required for germination . The germination
percentageof theseeds was inhibited by 1 mmol?L 6-BA
(Table 1 ) . The seedling growth after germination was
enhanced by 0.0001 mmol?L and 0.001 mmol?L IAA ,
0. 0001 - 0.1 mmol?L GA3 , 0. 0001 - 0.01 mmol?L 6-
BA, and 0 .001 mmol?L and 0 .01 mmol?L ethephon, but
was inhibited by 0.1 mmol?L and 1 mmol?L IAA, 1
mmol?L GA3 , 0. 1 mmol?L and 1 mmol?L 6-BA, and 1
mmol?L and 10 mmol?L ethephon (Table 2) . These re-
sults also indicated that the effects of IAA , GA3 and 6-
BA on theseedgermination and subsequent growth were
phytohormone type- and concentration-dependent . Seed
germinationof theGA-deficient biosynthesis mutant ga1
of Arabidopsis depends on the addition of GA to theme-
dium during imbibition ( Koornneef and Karssen,
1994) . Studies with the GA-deficient gib-1 clearly
showed that GAs control the endospermbreakdown . The
mutant seed only germinated in the presence of GA or
after removal of the covering layers opposing the radicle
(detipping) (Groot et al. , 1987) . The germination of
detipped gib-1 seeds inwater indicated a locationof GA
action in the covering layers surrounding the tip of the
radicle . Measurements of the puncture force required to
break through these layers showed that the major action
of endogenous GA was directed to the weakening of the
mechanical resistance of the endospermcells around the
radicle tip (Groot et al. , 1987) . In wild-type seeds the
endospermweakening occurred in water before radicle
protrusion; in gib-1 seeds it was absolutely dependent
on applied GA4 + 7 . Simultaneously incubation of deem-
bryonated endospermand isolated axes showed that only
wild-type embryos produce a factor that induces endo-
spermweakening, that probably is GA . GA can induce
α-amylasesynthesis, and stimulatemobilizationof stored
reserves ( Bewley and Black, 1994) .
The freshweight of theseedlings produced by ger-
minating seeds was enhanced by 0 .0001 - 0 .01 mmol?L
6-BA ( Table 2 ) , showing that 6-BA could stimulate
growth in an unknown manner . Cytokinins arevery ef-
fective promoters of germination, since early protein
synthesis is anecessary event for seedgermination, and
exogenously applied cytokinin could enhance protein
synthesis ( Berrie, 1984) .
The germination percentage, the time course of
germination and the seedling growth were significantly
inhibited by 1 mmol?L ABA ( Fig . 2 and 3a) , which
were markedly antagonized by 0 .01 - 1 mmol?L IAA ,
0 . 01 - 1 mmol?L ( Fig . 3 : a) , 0 . 001 - 0 .1 mmol?L 6-
BA and 0 .1 - 10 mmol?L ethephon (Fig . 3 : b) . How-
ever, the antagonistic effects of IAA, GA3 , 6-BA and
ethephon to ABA were unknown . In these antagonisms
to ABA , the effect of ethephon was the largest, GA3
and 6-BA , themedium, and IAA , the smallest (Fig .
3) , showing that these antagonismswere also phytohor-
mone type- and concentration-dependent . Ethylene is
also known to allow dormant sunflower embryos to ger-
minate inhypoxia (Corbineau andC?me, 1992) , over-
comes the inhibition of germination imposed by osmotic
agents in Amaranthus caudatus seeds (Kepczynski and
Karssen, 1985; Kepczynski , 1986) .β-1 , 3-glucanase
is implicated in the after-ripening-mediated promotion
of tobacco testa and endosperm rupture . Class I β-1 ,
3-glucanase (βGlu I ) is transcriptionally induced in
germinating tobacco seeds just prior to endosperm rup-
ture but after testa rupture ( Leubner-Metzger et al. ,
1995 , 1998) .βGlu I induction is highly localized in
the micropylar endosperm at the site of radicle emer-
gence . Light, GA and ethylene promoteβGlu I expres-
sion and endosperm rupture . ABA inhibitsβGlu I ex-
pression and endosperm rupture of wild-type seeds
(Leubner-Metzger, 2003) . The slow growth rateof the
radicles that emerge from detipped gib-1 seeds indi-
cates GAs also control embryo growth as part of germi-
nation . Probably embryo growth is primarily controlled
at the extensibility of the cell walls ( Schopfer and
Plachy, 1985) . The inhibitory action of applied ABA
on germination has indeed been related to reducing
5444 期 DENG and SONG: Inhibitory Effect of ABA on Seed Germination of Dalbergia fusca and Antagonism . . .
cell-wall extensibility (Karssen, 1995) .
It has been shown that 0 .01 mmol?L 6-BA +
0 .001 mmol?L IAA or + 0 .001 mmol?L GA3 , and 0 .1
mmol?L ethephon + 0 .001 mmol?L IAA or + 0 .001
mmol?L GA3 for antagonism to 1 mmol?L ABA had no
synergic role (Fig . 4 ) , but that 0 .1 mmol?L ethephon
+ 0 .01 mmol?L 6-BA or + 0 .1 mmol?L 6-BA had a
synergic role on antagonismto 1 mmol?L ABA , signifi-
cantly increasing the germination percentage ( Fig . 4)
and the seedlinggrowth ( data not shown) .
To our knowledge, It was first reported that inhi-
bition by ABA for seed germination could be antago-
nized by IAA , GA3 , 6-BA , ethephon, 6-BA + IAA or
+ GA3 , ethephon+ IAA or + GA3 , and ethephon+ 6-
BA ; and that 6-BA + IAA or + GA3 , and ethephon+
IAA or+ GA3 had no synergic role, and that ethephon
+ 6-BA had a synergic role, for antagonism to ABA .
These roles were also phytohormone type- and concen-
tration-dependent . However, these antagonism mecha-
nisms are unknown, and deserve further research . It
might be considered that effects of phytohormones on
seed germination might become a model system for
studying interactions among phytohormones .
Acknowledgements: The authors are grateful to Professor Jin
Xiao-bai (Institute of Botany, Chinese Academy of Sciences) for
revisingthe paper .
References:
Berr ?ie AMM , 1984 . Germination and dormancy [ A ] . In: WilkinsM ed:
Advanced Plant Physiology [ M ] . London: Pitman Publishing Ltd,
440—468
Bewl $ey JD, 1997 . Seed germination and dormancy [ J ] . Plant Cell , 9 :
1055—1066
Bewl $ey JD, Black M, 1994 . Seeds . Physiology of Development and Ger-
mination (2nd edition) [M ] . New York: Plenum Press
Corb ?ineau F , C?me D, 1992 . Germination of sunflower seeds and its reg-
ulation by ethylene [ A ] . In: Fu JR , KhanAA eds . Advances in the
Sciences and Technology of Seeds [M ] . Beijing-New York: Sciences
Press, 277—287
Corb ?ineau F , C?me D, 1995 . Control of seed germination and dormancy
by the gaseous environment [ A ] . In: Kigel J , Galili G eds . Seed
Development and Germination [M ] . New York: Marcel Dekker Inc,
397—424
Groo ?t SPC, BruinsmaJ , Karssen CM, 1987 . Theroleof endogenousgib-
berellin in seed and fruit development of tomato: studies with a gib-
berellin-dificient mutant [ J ] . Physiol Plant, 71 : 184—190
Heyd ?ecker W, 1977 . Stress and seed germination: an agronomic view
[A ] . In: Khan A ed . The Physiology and Biochemistry of Seed
Dormancy and Germination [ M ] . Amsterdam: Elsevier?North Hol-
land and Biomedical Press, 237—282
Hilh ?orst HWM , Downie B , 1995 . Primary dormancy in tomato ( Lycoper-
sicon esculentum cv . Moneymaker) : studies with the sittens mutant
[ J ] . J Exp Bot, 47 : 89—97
Huan ?g ZY , Zhang XH , ZhengGH et al. , 2003 . Influenceof light, tem-
perature, salinity and storage on seed germination of Haloxylon am-
modendron [ J ] . J Arid Enviro, 53 : 145—154
Kars ?sen CM , 1995 . Hormonal regulation of seed development, dormancy,
and germination studied by genetic control [ A ] . In: Kigel J , Galili
G eds . Seed Development and Germination [ M] . New York: Marcel
Dekker Inc, 333—350
Kepc ?zynski J , 1986 . Inhibition of Amaranthus caudatus seed germination
by polyethylene glycol-6000 and abscisic acid and its reversal by
ethephon or 1-aminocyclopropane-1- carboxylic acid [ J ] . Physiol
Plant, 67 : 588—591
Kepc ?zynski J , Karssen CM, 1985 . Requirement for the action of endoge-
nous ethylene during germination of non-dormant seeds of Amaran-
thus caudatus [ J ] . Physiol Plant, 63 : 49—52
Koor ?nneeff M , Karssen CM, 1994 . Seed dormancy and germination [A ] .
In: Meyerowitz EM, Somerville CR eds . Arabidopsis [ M ] . New
York: Cold Spring Harbor Laboratory Press, 313—334
Koor ?nneef M, Bentsink L , Hilhorst H , 2002 . Seed dormancy and germi-
nation [ J ] . Curr Opin Plant Biol , 5 : 33—36
Leub ?ner-Metzger G, 2003 . Hormonal and molecular events during seed
dormancy release and germination [ A ] . In: Nicolás G, Bradford
KJ , C?meD et al. eds . The Biology of Seeds . Recent ResearchAd-
vances [M ] . Oxon: CABI Publishing, 101—112
Leub ?ner-Metzger G, Fründt C , V?geli-Lange R et al. , 1995 . Class Iβ-
1 , 3-glucanase in the endosperm of tobacco during germination [ J ] .
Plant Physiol , 109: 751—759
Leubner-Metzger G, Petruzzelli L , Waldvogel R et al. , 1998 . Ethylene-
responsive element binding protein ( EREBP ) expression and the
transcriptional regulation of class Iβ-1 , 3-glucanase during tobacco
seed germination [ J ] . Plant Mol Biol , 38 : 785—795
Lope ?z-MolinaL , Mongrand S, Chua NH , 2001 . Postgermination develop-
mental arrest checkpoint is mediated by abscisic acid and requires
ABI5 transcription factor in Arabidopsis [ J ] . Proc Nat Acad Sci
USA, 98 : 4782—4787
Scho ?pfer P, Plachy C , 1985 . Control of seed germination by abscisic ac-
id . II I . Effect on embryo growth potential ( minimumturgor pressure)
and growth coefficient ( cell wall extensibility) in Brassica napus L
[ J ] . Plant Physiol , 77 : 676—686
Stat ?e Environmental Protection Administration of China, Instituteof Bota-
ny of the Chinese Academy of Sciences, 1987 . Rare, Endangered and
Protective Plant Species in China [ M ] . Beijing: Sciences Press,
45—46 ( in Chinese)
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