全 文 ：第 16 卷
第 6 期

Vol. 16
No . 6
草
地
学
报
ACTA AGRESTIA SINICA


2008 年
11 月

Nov.
2008
Analysis of Cell Wall Components and Ultra-structure
for Brittleness Mutation Rice
SU Yan-jing1 , YAN Chang- jie2 , WANG Xiao-shan1 , ZHAO Guo-qi1*
( 1. College of An imal S cien ce an d T echnology, Yangzhou U nivers ity, Yangzhou, Jiangsu Province 225009, China;
2. Key Laboratory of Plant Fun ct ional Gen om ics, M inis t ry of Edu cat ion and Yangzh ou Un iversity; Jiangsu Key Laboratory of
Crop Genet ics an d Phys iology, Yangzhou, Jiangsu Province 225009, China)
Abstract: The cell wall component and ult ra- structure of plant w ere compared betw een britt leness mut ation ( BM ) r ice obtained
by seed gamma- ray (
) treatment and its w ild t ype from j ap onica var iety Zhonghua-11 in t his study. The cellulose content in
leaf, stem, and ro ot of BM- r ice significantly decr eased (P < 0. 01) by 18. 99% , 37. 29% and 23. 34% com pared w ith those o f
wild type, r espectively, while the hem-i cellulose content in leaf , stem and root for BM- rice significantly increased ( P < 0. 01)
by 46. 07% , 85. 26% and 61. 96% , respect ively. The leaf parenchyma of BM- rice w as much lar ger t han that of w ild t ype rice
by the observ ation of SEM . For t he BM-r ice, the scler enchyma of leaves w as shrunken, vascular bundle o f leaves w as r educed,
the str umae o f outer epidermis of stem w as sparse and the link o f phloem of r oo t was loosed and dispersed. The hiberarchy o f
sclerenchyma cell wa ll of BM- r ice leaf was not obvious by the observat ion o f TEM . Besides, the ar rangement o f parenchyma
cells of BM- rice stem was diso rdered and t he ex terio r of parenchyma cell w all of BM- rice ro ot was knaggy. In conclusion, BM-
rice has po tential advantages in utilization as a fodder- rice.
Key words: Br ittleness mutation rice; Cell w all component; U lt ra- structure; F odder- rice
脆性突变水稻细胞壁成分及其超微结构的分析
苏衍菁1, 严长杰2 , 王小山1 , 赵国琦1*
( 1. 扬州大学动物科学与技术学院, 扬州
225009;
2.扬州大学植物功能基因组学教育部重点实验室, 江苏省作物遗传生理重点实验室, 扬州
225009)
摘要: 以通过伽马射线选育的脆性突变水稻( brit tleness mutationr ice, BM )和对照亲本中花 11( Zhonghua11)为研究对象, 分析
突变基因对水稻细胞壁成分以及细胞超微结构的影响。结果表明: ( 1)脆性突变水稻细胞壁纤维组分含量发生了变化。其中,
与对照亲本相比,脆性突变水稻叶、茎、根纤维素含量分别极显著下降了 18. 99%、37. 29%和 23. 34% ( P< 0. 01) ; 半纤维素的
含量分别极显著提高了46. 07%、85. 26%和 61. 90%( P< 0. 01)。( 2)通过扫描电镜观察, 脆性突变水稻的组织结构发生了较
大变化:叶片薄壁组织扩张, 厚壁组织收缩, 维管束数目减少;茎杆外表皮硅质瘤状结构分布稀疏; 根中柱韧皮部组织排列稀
疏,连接松散。( 3)通过透射电镜观察,脆性突变水稻的细胞和细胞壁结构也有较大变化: 叶片厚壁组织细胞细胞壁分层不明
显;茎杆薄壁组织细胞形状不规则, 大小不均一;根薄壁组织细胞细胞壁表面凹凸不平, 形体膨松胀大。鉴于以上特征, 脆性
突变水稻具有作为饲料稻的潜在优势。
关键词: 脆性突变水稻; 细胞壁组分; 超微结构; 饲料稻
中图分类号: Q944. 672




文献标识码: A




文章编号: 1007-0435( 2008) 05-0594-06
Introduction
The plant cell w all, mainly composed of cellu-
lose, hem-i cel lulo ses and lignin, has certain elas-
t icity and hardness. As the natural defensive par-
close of cell and the fr amew or k of plant , it plays a
signif icant role in disease and lodg ing resistance of
plants. How ever, it s peculiar str ucture, composed
收稿日期: 2008-02-19; 修回日期: 2008-07-14
作者简介:苏衍菁( 1986- ) ,男,江苏南通人,硕士,研究方向为牧草种质资源研究和育种, E-mail: syjyzedu@ 163. com ; * 通讯作者 Auth or
for correspondence, E- mail : js zhaoguoqi@ sohu. com
第 6期 苏衍菁等: 脆性突变水稻细胞壁成分及其超微结构的分析
by chain mutually betw een the t riple, great ly lim-
its the dig est ibility by domest ic animals[ 1, 2] . A-l
though several scholars put forw ard many schemes
to incr ease dig est ibility to some extent about the
high-eff iciency ut ilizat ion of the rice st raw , such as
microbe ferment t reatment, ammoniated t reat-
ment , steam treatment and so on [ 3, 4] . How ever,
such pre- treatments undoubtedly increase labor in-
put and feeding cost for farmers. T herefore, cult-i
v at ing a kind of rice w ith high st raw dig estibility is
obviously po sit ive to animal husbandry.
Brit t leness mutat ion ( BM ) rice, selected
through
60
Co ( gamma ray) and inherited stably, is
a kind of mutated r ice fr om j ap onica var iety Zhon-
ghua-11. In rice, at least 6 brit t le mutants have
been r eported and assigned to dif ferent chromo-
somes by classic or mo lecular methods[ 5] . Fo r the
mutant used in this study, the sequence analy sis
show ed that there w ere 7 base pair sdelet ion of ce-l
lulose synthase catalyt ic subunit ( CesA) in chro-
mosome 1, w hich induced that this mutant exhib-i
ted fr ag ile culm and leaf w ith no rmal seed set and
plant height ( data pr epared to subm it ) g iving the
clue to develop the cel lulo se decreased var iet ies as
animal feed. This study aimed at pr oviding certain
theoret ical basis fo r study ing the deg radation ef f-i
ciency of BM-rice st raw , by contrast ing and analy-
zing the differ ence of cell w all components and u-l
t ra-st ructure betw een BM-rice and its w ild type.
Materials and Methods
Sample collection and treatment
BM-rice and its w ild type ( CK-rice ) w er e
planted in the experimental farm of Ag ricultural
Co llege, Yangzhou University in the grow ing sea-
son fr om June to September in 2006, w ith the same
and accustomed management and technolog y.
All samples in this study w ere co llected at
boot ing stage.
Analysis of cel l wall components
Samples fo r analysis w ere the w hole plants,
including leaves, stems, and shoots. T hey w er e
dried in 65
fo r 48h, then smashed and ground
through 0. 425mm scr een. Analysis of cellulose,
hem-i cel lulo se, ADL ( Acid deterg ent lignin) , and
AIA ( Acid inso luble ash) w ere carried out accord-
ing to pr inciples out lined by van Soest
[ 6]
.
Microscopic analysis by SEM and TEM
Samples for scanning elect ron m icroscope
( SEM ) and transmission electron m icroscope
( TEM ) w er e the excised leaves, stems, and shoo ts
f rom cultur es w ith the same developed dur at ion
and fix ed in 3% g lutaraldehyde and 50mM cacody-
late buf fer ( pH= 7. 0) . Only fully expanded leaves
w ere examined in this study.
All tissues w er e sto red at 4
fo r approx-i
mately one month befo re post- fix ation in 1. 5%
OsO 4 . Af ter several rinses, the materials w er e de-
hydrated in an ethanol series and then embedded in
low viscosity resin. Thin sect ions ( 60 to 100nm)
w ere cut w ith a diamond knife, co llected on copper
g rids and stained w ith 1% aqueous urany lacetate
for 15min follow ed by 15min in Reynold
s lead cit-
rate
[ 7]
. T he sect ions w ere examined in a t ransmis-
sion elect ron micro scope ( T EM ; Phillips Tecnai
12, Ho lland) .
Samples taken from the fix ativ e w ere cut w ith
a r azor blade to expose a g land fo r SEM analy sis.
T he tissue was po st- f ixed in OsO4 , dehydr ated as
above; crit ical point dr ied in CO2 , spurted w ith
gold and examined in a scanning elect ron micro-
scope
[ 8]
( SEM ; PHILIPS XL-30E, Holland) .
Statistical Analysis of Data
Dif ferences betw een contents of cell w all com-
ponent w er e tested for significance by T-test using
SPSS softw are and signif icance w as declared at P<
0. 05.
Results
Analysis of cell wal l components for BM-rice
Dif ferences betw een BM- rice and CK-r ice in
cel l w all components w ere show ed in T able 1. The
results show that the cellulo se content based on
DM ( dry matter) in CK-rice leaf, stem and root were
35. 02%, 41. 62% and 41. 39%, respectively; w hile
595
草
地
学
报 第 16卷
for BM-rice w ere 28. 37%, 26. 10% and 31. 73%,
respectively. Stat ist ical analysis indicated that
there w er e significant dif ferences in cellulose con-
tent betw een the tw o kinds of rice ( P< 0. 01) . T he
hem-i cellulose content in CK-rice leaf , stem and
root were 29. 41%, 17. 93% and 26. 35%, respec-
t ively; w hile fo r BM-rice w ere 42. 96% , 33. 22%
and 42. 66% , respect iv ely . T here w ere signif icant
dif ferences in hem-i cellulose content betw een the
tw o kinds of rice ( P< 0. 01) , too . Besides that ,
the ADL content in CK-rice leaf and stem w ere 4.
21% and 4. 71% , w hile in BM- rice leaf and stem
w ere 5. 49% and 6. 60%. T here w er e signif icant
dif ferences in ADL content in leaf ( P< 0. 01) and
stem ( P< 0. 05) betw een the tw o kinds of rice,
but the ADL content in r oot have no dif ference be-
tw een the tw o ( P> 0. 05) .
To sum up, in comparison with CK-rice, cellu-
lose content in BM-rice leaf , stem and root sepa-
r ately dropped by 18. 99%, 37. 29%, and 23. 34%,
the hem-i cellulose content separately enhanced by
46. 07% , 85. 26% and 61. 90% , and the ADL content
of BM-rice leaf and stem separately increased by
30. 22% and 40. 13%, but r oot ADL decreased by
10. 93%. A long w ith a ser ies of change in f iber
content , finally the BM rice performed a certain
drop in DM.
Table 1
Differences between BM-rice and CK-rice
in cell wall components
S am ple
Cell wall com pon ent , DM%
Cellulos e H em-i cellu lose ADL AIA
BM-rice leaf 28. 37 42. 96 5. 49 8. 70
CK-rice leaf 35. 02 29. 41 4. 21 6. 89
T-tes t ** ** ** **
BM-rice stem 26. 10 33. 22 6. 60 4. 06
CK-rice stem 41. 62 17. 93 4. 71 6. 26
T-tes t ** ** * *
BM-rice root 31. 73 42. 66 6. 66 3. 63
CK-rice root 41. 39 26. 35 7. 48 2. 59
T-tes t ** ** NS **


Note: NS indicates n o signif icant dif f erence ( P > 0. 05) ; * and
** indicate signif icant dif feren ce ( P< 0. 05) and ext reme-signi ficant
di ff erence ( P< 0. 01) , respectively
Analysis of Ultra-structure for BM-rice
Observation by SEM
Transverse sect ion of leaf w as composed o f
epidermis, basic t issues ( contained sclerenchyma
and par enchyma) , and vascular tissue ( contained
vascular bundle and phlo em ) from outside to in-
side. All these tissues of CK-rice w ere show ed in-
teg rally in Fig. 1A. Compar ed w ith it s w ild type,
these t issues of BM-r ice leaf displayed g reat chan-
ges ( F ig. 1B) show ing that the parenchyma ( PAR)
w as enlarg ed and the sclerenchyma ( S ) w as
shr unken. Besides, the number of v ascular bundle
also reduced from three to tw o.
T he outer epidermis of stem w as composed of
str umae, mastoid process and seta, w hich w ere
showed integrally in Fig. 1C. Compared w ith its
w ild type, these st ructures o f BM-rice stem dis-
played g reat changes ( Fig . 1D) represented by the
sparse dist ribut ion o f st rumae.
T ransverse sect ion of duramen of roo t w as
composed of parenchyma and vascular t issue ( con-
tained vascular bundle and phloem ) , w hich w ere
showed integr ally in Fig. 1E. Compared w ith its
w ild type, these t issues of BM-rice root display ed
g reat changes ( F ig. 1F) r epresented by the loosed
and disper sed link o f phloem ( P) .
Observation by TEM
Hiberarchy of cell w all could be divided into
m iddle lamella ( ML ) , primar y w all ( PW ) , and
secondary w all ( SW) from outside to inside, w hich
w ere show ed integ rally in Fig. 2A. According to
F ig. 2B, those t issues of BM-rice leaf perform
g reat changes represented by the unobv ious hiber-
archy of cel l w all, especially betw een primary w all
and secondary wall. Furthermore, the cell w all
thickness o f BM-r ice w as thinner than that of CK-
rice acco rding to the tw o f igures.
In view of F ig. 2C, it show ed that the sizes of
par enchyma cells o f CK-rice stem w ere homogene-
ous; their shapes w ere ordered and the gaps among
dif ferent cells w ere smal l. But the parenchyma cell
of BM-r ice stem displayed some changes w ith the
dif ferent sizes, disordered shapes and the large gap
among dif ferent cells according to Fig. 2D.
Accor ding to F ig . 2E and Fig. 2F , compar ed
w ith the parenchyma cell of CK-rice root , BM-rice
per formed an obvious change that the exterior of
cel l w all w as knaggy and the shape o f cell w al l w as
expansible.
596
第 6期 苏衍菁等: 脆性突变水稻细胞壁成分及其超微结构的分析
Fig. 1
Diff erences between BM-rice and CK-rice in leaf tissue, outer epidermis of stem, and duramen of root


A. CK- rice leaf, show ing that epidermis ( E) , sclerenchyma (S ) , phloem ( P) , parenchyma ( PAR) , and xylem ( X) of vascular t issu e are
integrally exi sted. B. BM- rice leaf ( SEM
500) . C. CK- rice, show ing that st rumae, mastoid proess, and seta are integral ly existed. D. Outer
epidermis of BM-rice s tem ( SEM
1000) . E. CK-rice, s howin g that phloem ( P) , parenchyma ( PAR) , and vascu lar bundle are integrally exis-
ted. F. Duramen of BM-rice root ( SEM
1000)
Discussion and Conclusion
Appearance characters of BM-rice
According to Sundatol et al . and Doyle et al . ,
the mechanical processing such as cut t ing, smash-
ing, pr essing, sof tening and so on, to some ex-
tent, extends the contact surface area betw een the
st raw and the r umen micr oorg anism and it is go od
fo r the rumen micro organism
s fermentat ion and
degenerat ion, and enhances the st raw
s palatable-
ness, it s intake and ut ilization [ 9, 10] . Because of the
inf luence by the mutant g ene, the BM-rice has the
character s such as brit tleness, lodg ing, and so ft-
ness; these natural character s w ould play a vital
role in enhancing the str aw
s ut ilization.
Cell wall components of BM-rice
T he dif ference betw een BM-r ice and CK-rice
w as mainly caused by the gene mutat ion, w hich in-
duces the block o f cel lulo se synthesis. In order to
make up the drop of cellulose content, cult ivar
w ould synthesis more hem-i cellulo se to complete
the funct ion w hich the cel l w all should have. But
w ith the change of these components, it w ill bring
the change of cell w all inter nal st ructur e w hich is
the foundat ion of the str aw
s ef ficient ut ilizat ion.
Ookaw a et al .
[ 11]
repo rted that , the cellulo se
content each stem contains direct ly determines
w hether it s t issues and or gans are w el-l developed
or not . T he mor e cellulose it contains, the t ighter
it s linking st ructure w il l be, vice verse. Compar ed
597
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地
学
报 第 16卷
w ith its w ild type, the signif icant decrease o f cellu-
lose content of BM-rice has indicated its loo se link-
ing st ructure, w hich w ould make it easier for the
rumen micro organism to absorb the surface and d-i
r ect ly secrete the degener at ion enzyme which is
benef it to degrade the str aw cellulose and hemice-l
luloses bet ter and faster.
Mor eover , Fleming et al . repo rted that the
silicate par ticipated in format ion of cell w all and its
connect iv e form w as [ S-i O-C] , w hich is the base o f
cell w all st ructur e
[ 12, 13]
. Therefor e, the decrease
of the AIA content o f BM rice ( T able 1) w ould
change its cell w al l str ucture and facilitate the
st raw
s utilizat ion, too.
Fig. 2
Differences between BM-rice and CK-rice in cell
wall of sclerenchyma cell in leaf , parenchyma cell in stem,
and cell wall of parenchyma cell in root
A. CK- rice, sh ow in g that middle lamel la ( ML ) , primary w all
( PW ) , and secondary w all ( SW) are integral ly existed. B. Cel l w all
of clerenchym a cell of BM-rice leaf ( TEM
26500) . C. CK-rice,
show ing that the cells arrangemen ts are order. D. BM- rice, show ing
th e cel l s izes are variant and the cell arrangements are dis ord er
( TEM
5800) . E. Cell w all of parenchym a cel l of CK-rice root . F.
Paren chyma cel l w all of BM- rice root ( TEM
23000)
Ultra-structure of BM-rice
Wilson et al .
[ 14, 15]
believ ed that , compared
w ith o ther t issues, the ex ter io r epidermis, scleren-
chyma and vascular tissue ar e al l dif ficult to de-
gr ade. How ever, the phloem, inner epidermis and
par enchyma are all easy to degrade by the r umen
m icroor ganism. Because of the inf luence of mutant
g ene, the BM- rice ow ns the char acters such as en-
larging parenchyma and shrinking scler enchyma,
w hich w ould promo te the str aw
s ut ilization.
Akin and Hart ley[ 16] and Engels et al . [ 17] be-
liev ed that , along w ith the lengthening of r umen
dig est ion t ime, the par enchyma o f st raw can be de-
gr aded completely by the rumen m icrobial, but the
secondary wall could only be deg raded under the
normal condition because of cell w all
s delamina-
t ion of the sclerenchyma and the differ ent lignif ied
deg ree, w hile the lignified m iddle lamella and pr-i
mary w all are very dif ficult to do so by the r umen
m icroor ganism. Because of the inf luence of mutant
g ene, BM-rice per forms the variance in the hiber-
archy and the thickness of cell w all display ing the
super io rity in the st raw
s ut ilization and the deg ra-
dat ion eff iciency.
Applied foreground and significance of BM-rice
Fodder-rice, one of the new feedstuf f re-
sources, has the dif ferent r equest in use and eff-i
ciency in comparison w ith the or dinary edible r ice.
Such quest ions as it s quality and economical coeff-i
ciency may not be under the consideration. But in
or der to be digested w ell by the animal, it should
enhance the content of its CP and the ut ilizat ion of
DM . Because o f the threshold of fodder-rice re-
search and the insuf ficiency o f basic r esearch deve-l
opment , especial ly the inadequacy of the idio-
plasmic resources, it st ill did no t form the scale in
the specia-l purpo se variety o f fodder-rice breeding
and its applicat ion. Ow ing to the BM-rice
s po ten-
t ial advantag es in it s utilizat ion, it may not only be
used as the fodder-rice dir ect ly, but also taken as
the idioplasmic resources of breeding.
Because the lack of coarse fodder resources
has greatly limited the cow breeding indust ry
s de-
velopment in South China, the development of
coarse fodder r esources w ith lo cal characteristics is
imperat ive. A cco rding to many resear ches, it is
598
第 6期 苏衍菁等: 脆性突变水稻细胞壁成分及其超微结构的分析
feasible to use the entire ensilage rice or ensile the
fresh wet st raw in cow feeding
[ 18, 19, 20]
. Therefore,
in this w ay, cult ivation of the BM-r ice as the fod-
der r esource may not only display the pr edom-i
nance of rice cult ivat ing in South China, but also
be surely benefit to the development o f cow breed-
ing indust ry in these areas.
Acknowledgments
The authors w ould like to thank Yang zhou U-
niversity Test Center for their assistance with the
experimental w orks. Furthermore, Y. Xu w as
thanked for his useful advice and valuable assis-
tance.
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