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Effects of low temperature on formation of spikelets and grain filling of indica inbred rice during panicle initiation in early-season.

籼型常规早稻穗分化期低温对颖花形成和籽粒充实的影响


以籼型常规早稻中嘉早17为材料,于盆栽条件下采用人工气候箱控温,在水稻穗分化一次枝梗原基分化期(Ⅱ)与花粉母细胞减数分裂期(Ⅵ)进行17和20 ℃的低温胁迫处理,研究不同低温对水稻枝梗、颖花分化与退化及籽粒充实的影响.结果表明: 与对照相比,不同低温处理均显著降低每穗枝梗及颖花分化数和现存数,颖花现存数降幅为7.2%~12.4%,同时增加了枝梗和颖花的退化数,影响了花粉活性、花药开裂等花器官发育,导致籽粒充实不良,以17 ℃低温胁迫效应更明显.穗分化Ⅵ期低温处理总枝梗和颖花分化数与现存数低于穗分化Ⅱ期,但二次枝梗和颖花退化数较多,颖花退化数较穗分化Ⅱ期高11.6%;穗分化Ⅱ期低温处理穗部籽粒结实率显著低于穗分化Ⅵ期,降幅达3.7%,主要与花粉粒活性、柱头花粉散落数、花药开裂系数和籽粒充实度受低温影响较大有关.另外,穗分化Ⅱ、Ⅵ两时期受17 ℃低温胁迫效应大于20 ℃.综合穗分化两时期低温胁迫效应的差异,生产中需加强相应栽培措施的调控.
 

A pot experiment in phytotron with controlled temperature was conducted to examine the effects of low temperature (LT) on differentiation and retrogression of branches and spikelets and grain filling of rice during panicle initiation (PI). In this study, indica inbred rice called Zhongjiazao17 was planted and treated at 17 and 20 ℃ of LT during primary branches anlage differentiation (Ⅱ) and pollen mother cell meiosis stage (Ⅵ) of PI. The results showed that the numbers of differentiated and survived branches per panicle were significantly reduced under LT treatment compared with control, and the number of survived spikelets was significantly decreased by 7.2%-12.4%, but the numbers of retrograded branches and spikelets were increased. Moreover, LT affected significantly the development of floral organ such as pollen activity and anther dehiscence, and caused harmful grain filling, particularly at 17 ℃. The numbers of total differentiated and survived branches and spikelets were lower during Ⅵ (PI) than during Ⅱ (PI) under LT stress, but more retrograded secondary branches and spikelets (increased by 11.6%) were found during Ⅵ (PI) compared with Ⅱ (PI). Meanwhile, in contrast to Ⅱ (PI), the seed setting rate was significantly lowered by 3.7% during Ⅵ (PI), which was attributed to reductions in pollen activity, pollen grains on stigma, anther dehiscence coefficient and grain filling rate. LT stress impact on rice panicles was higher at 17 ℃ than at 20 ℃ during Ⅱ and Ⅵ (PI). The cultivation measure could be correspondingly strengthened and improved in practice.

 


全 文 :籼型常规早稻穗分化期低温对颖花形成
和籽粒充实的影响∗
曾研华1,2  张玉屏2  向  镜2  王亚梁2  陈惠哲2  朱德峰2∗∗
( 1南京农业大学农学院, 南京 210095; 2中国水稻研究所水稻生物学国家重点实验室, 杭州 311400)
摘  要  以籼型常规早稻中嘉早 17为材料,于盆栽条件下采用人工气候箱控温,在水稻穗分
化一次枝梗原基分化期(Ⅱ)与花粉母细胞减数分裂期(Ⅵ)进行 17和 20 ℃的低温胁迫处理,
研究不同低温对水稻枝梗、颖花分化与退化及籽粒充实的影响.结果表明: 与对照相比,不同
低温处理均显著降低每穗枝梗及颖花分化数和现存数,颖花现存数降幅为 7.2% ~ 12.4%,同
时增加了枝梗和颖花的退化数,影响了花粉活性、花药开裂等花器官发育,导致籽粒充实不
良,以 17 ℃低温胁迫效应更明显.穗分化Ⅵ期低温处理总枝梗和颖花分化数与现存数低于穗
分化Ⅱ期,但二次枝梗和颖花退化数较多,颖花退化数较穗分化Ⅱ期高 11.6%;穗分化Ⅱ期低
温处理穗部籽粒结实率显著低于穗分化Ⅵ期,降幅达 3.7%,主要与花粉粒活性、柱头花粉散
落数、花药开裂系数和籽粒充实度受低温影响较大有关.另外,穗分化Ⅱ、Ⅵ两时期受 17 ℃低
温胁迫效应大于 20 ℃ .综合穗分化两时期低温胁迫效应的差异,生产中需加强相应栽培措施
的调控.
关键词  水稻; 低温; 穗分化期; 颖花; 花器官; 籽粒充实
文章编号  1001-9332(2015)07-2007-08  中图分类号  S511  文献标识码  A
Effects of low temperature on formation of spikelets and grain filling of indica inbred rice
during panicle initiation in early⁃season. ZENG Yan⁃hua1,2, ZHANG Yu⁃ping2, XIANG Jing2,
WANG Ya⁃liang2, CHEN Hui⁃zhe2, ZHU De⁃feng2 ( 1College of Agronomy, Nanjing Agricultural
University, Nanjing 210095, China; 2State Key Laboratory of Rice Biology, China National Rice
Research Institute, Hangzhou 311400, China) . ⁃Chin. J. Appl. Ecol., 2015, 26(7): 2007-2014.
Abstract: A pot experiment in phytotron with controlled temperature was conducted to examine the
effects of low temperature (LT) on differentiation and retrogression of branches and spikelets and
grain filling of rice during panicle initiation (PI). In this study, indica inbred rice called Zhong⁃
jiazao17 was planted and treated at 17 and 20 ℃ of LT during primary branches anlage differentia⁃
tion (Ⅱ) and pollen mother cell meiosis stage (Ⅵ) of PI. The results showed that the numbers of
differentiated and survived branches per panicle were significantly reduced under LT treatment com⁃
pared with control, and the number of survived spikelets was significantly decreased by 7. 2% -
12.4%, but the numbers of retrograded branches and spikelets were increased. Moreover, LT affect⁃
ed significantly the development of floral organ such as pollen activity and anther dehiscence, and
caused harmful grain filling, particularly at 17 ℃ . The numbers of total differentiated and survived
branches and spikelets were lower during Ⅵ (PI) than during Ⅱ (PI) under LT stress, but more
retrograded secondary branches and spikelets ( increased by 11.6%) were found during Ⅵ (PI)
compared with Ⅱ (PI). Meanwhile, in contrast to Ⅱ (PI), the seed setting rate was significantly
lowered by 3. 7% during Ⅵ (PI), which was attributed to reductions in pollen activity, pollen
grains on stigma, anther dehiscence coefficient and grain filling rate. LT stress impact on rice pani⁃
cles was higher at 17 ℃ than at 20 ℃ during Ⅱ and Ⅵ (PI). The cultivation measure could be
correspondingly strengthened and improved in practice.
Key words: rice; low temperature; panicle initiation; spikelets; floral organ; grain filling.
∗浙江省自然科学基金项目(Y13C130013)、中国农业科学院院所基金项目(2012RG004⁃2)和国家现代农业产业技术体系建设专项(CARS⁃01⁃
09B)资助.
∗∗通讯作者. E⁃mail: cnrice@ qq.com
2014⁃07⁃10收稿,2015⁃05⁃20接受.
应 用 生 态 学 报  2015年 7月  第 26卷  第 7期                                                         
Chinese Journal of Applied Ecology, Jul. 2015, 26(7): 2007-2014
    水稻为喜温作物,对温度非常敏感,但目前全球
极端冷害天气气候事件频频发生[1],对其造成了严
重的危害.低温冷害是影响水稻生产和产量的主要
灾害之一,在我国所有稻区均有发生,一般 4 ~ 5 年
就会发生一次较强的低温冷害,在大的灾害年可使
稻谷损失达 50~ 100 亿 kg[2] .低温冷害对水稻的影
响已成为近年来研究的热点问题[3-4],水稻幼穗形
成期一般需经历 30 d 左右,早稻此时所处月份(5
月)的温度波动较大,易形成“小满寒” (五月寒)气
候,对穗分化不同时期易造成不同程度的影响[5-6] .
低温冷害对孕穗期的影响已有较多报道.耿立清
等[7]认为,水稻孕穗开花期对低温非常敏感,此期
若遇低温,易造成枝梗及颖花分化不良;杨仕华
等[8]指出,孕穗期低温使每穗粒数减少,结实率大
幅度下降,最终导致水稻减产;曲辉辉等[9]研究表
明,日均温为 15 ℃时,孕穗期低温持续天数对水稻
障碍型冷害的形成有重要影响;姜丽霞等[10]研究认
为,在黑龙江省稻区,水稻实际单产与孕穗期障碍型
冷害期间的平均温度呈极显著正相关,与低温持续
时间呈极显著负相关.以上研究主要集中于花粉母
细胞减数分裂期,而一次枝梗原基分化期对稻穗最
终枝梗及颖花数的形成有重要影响,其受低温胁迫
后影响如何,相关研究不多,特别是低温对两时期的
枝梗和颖花分化与退化及籽粒充实的影响鲜有报
道.本文基于穗分化一次枝梗原基分化期和花粉母
细胞减数分裂期两时期,以籼型常规早稻中嘉早 17
为试验材料,研究低温对枝梗和颖花分化与退化、花
粉性状及籽粒充实的影响,旨在揭示低温对穗分化
不同时期冷害的影响规律,为水稻抗逆栽培和育种
提供理论依据.
1  材料与方法
1􀆰 1  试验材料与种植方法
供试品种(组合)为籼型常规超级早稻中嘉早
17,为大面积生产的主推品种,主茎叶片数 13 片,生
育期 114.3 d.在 2012年预备试验的基础上,于 2013
年在中国水稻研究所人工气候箱内进行,采用盆栽
种植,土壤基础肥力为: pH 5. 93、有机质 28􀆰 26
g·kg-1、全 氮 1. 50 g · kg-1、 碱 解 氮 128􀆰 24
mg·kg-1、全磷 0.87 g·kg-1、有效磷 44.8 mg·kg-1、
全钾 25􀆰 27 g·kg-1、速效钾 13 mg·kg-1 .
采用塑盘基质育秧,3 月 26 日播种,4 月 26 日
水稻秧苗为 3叶 1心时移栽至装有过筛均匀的田间
细土的塑料盆中(长×宽×高为 22.6 cm×18􀆰 7 cm×
22􀆰 2 cm),每盆装过筛均匀干土 10 kg,每盆种植生
长一致的秧苗 2穴,每穴 2苗,每处理 10盆,每盆作
为 1个重复样本.每盆施尿素、过磷酸钙和氯化钾分
别为 1.489、1.868、0.934 g,氮肥按基肥 ∶ 分蘖肥 ∶
穗肥= 5 ∶ 3 ∶ 2施用,磷、钾肥全部用作基肥.其余管
理措施与高产栽培一致.
1􀆰 2  试验设计与处理
从移栽期开始,每隔 3 d标记主茎叶龄,以准确
掌握水稻生育进程.将生长发育基本一致的稻株单
穗(以主茎穗为主,含部分分蘖穗)进行挂牌标记,
以保持各单穗花期基本一致.当水稻穗分化为一次
枝梗原基分化期(Ⅱ:叶龄余数为 3.0 叶,S1)和花粉
母细胞减数分裂期(Ⅵ:叶龄余数为 0.5 叶,叶枕距
为 0 cm,S2)时进行不同低温处理,处理温度设置根
据长江中下游地区早稻生产上遭遇“五月寒”天气
出现的频次,日平均温度分别设为 17 ℃(T1)、20 ℃
(T2),以 23 ℃(CK)为对照.均采用人工气候箱自动
控温处理,具体温度处理时段设置见表 1.自然光照,
空气相对湿度为 80.0%,水稻穗分化各时期连续处
理 3 d后,将处理盆栽移到室外让其自然生长,直至
成熟.试验期间及试验前后富阳地区逐日温度变化
见图 1,温度较为适宜水稻生长.穗分化 S1处理日期
为 5月 29 日—6 月 1 日,S2处理日期为 6 月 6—9
日,各处理期间室外日均温分别为 22.1 和 23.3 ℃,
与 CK处理较为一致.
1􀆰 3  测定项目与方法
1􀆰 3􀆰 1颖花分化与退化   于始穗期每处理取样 3
盆,在放大镜下按松岛省三方法[11]观察每穗一次、
二次枝梗和颖花现存数及退化数.将直接着生在一
次枝梗上的颖花简称为一次颖花,直接着生在二次
枝梗上的颖花简称二次颖花.每穗一次、二次枝梗
(颖花)分化数为其现存数和退化数的总和.
1􀆰 3􀆰 2花药开裂、花粉活性及柱头花粉数   在开花
期 9:00—11:00,每处理 3 盆取稻穗上、中、下部位
枝梗上的颖花 20 个,观察花粉粒活性、花药开裂与
柱头花粉散落数目.
表 1  水稻穗分化期温度处理
Table 1   Temperature treatment during panicle initiation
of rice (℃)
处理温度
Treatment
temperature (℃)
时间 Time
07:00—
10:00
10:00—
15:00
15:00—
17:00
17:00—
07:00
17 18.0 21.0 19.5 15.0
20 21.0 24.0 22.5 18.0
23 24.0 27.0 25.5 21.0
8002 应  用  生  态  学  报                                      26卷
图 1  2013年水稻幼穗分化期温度变化(富阳市)
Fig.1  Changes of air temperature during panicle initiation of rice in 2013 (Fuyang City).
Tmax: 最高温 Maximum temperature; Tmean: 均温 Average temperature; Tmin: 最低温 Minmium temperature.
1􀆰 3􀆰 3籽粒结实率   在成熟期取 4 盆考种,用于籽
粒结实率等指标测定,将整穗一次枝梗分成上部、中
部和下部,分别考查饱满粒、秕粒(籽粒充实不足 1 /
3)和空粒(未受精籽粒).各穗位划分标准参考张卫
星等[12]的方法.
1􀆰 3􀆰 4参数计算  受精率 = (饱粒数+秕粒数) / (空
粒数+饱粒数+秕粒数) ×100%;花药开裂系数 = (完
全开裂花药数+部分开裂花药数) /镜检花药总数×
100%;最大库容量=总颖花数×千粒重;库容有效充
实度=实际充实量 /最大库容量×100%.
1􀆰 4  数据处理
用 Excel 2003软件进行数据处理,SPSS 16.0 软
件作统计分析,采用 Duncan 法进行差异显著性检
验,显著性水平设为 α= 0.05.
2  结果与分析
2􀆰 1  水稻穗分化期低温对枝梗和颖花数的影响
稻穗由一次、二次枝梗及枝梗上的颖花等组成,
一次枝梗是颖花形成的基础,其颖花数与二次枝梗
数密切相关.由图 2 可知,无论是 S1时期,还是 S2时
期,T1、T2低温处理每穗总枝梗和颖花现存数均显著
低于对照,降幅分别为 12. 2% ~ 23. 3%和 7. 2% ~
12􀆰 4%,而一次、二次枝梗和颖花现存数低温处理亦
显著低于对照(表 2).一次、二次枝梗和颖花现存数
为 S1>S2,且二次枝梗现存数差异显著,S1较 S2时期
高 3.6%.对处理温度和时期而言,低温处理间各指
标为 S1>S2,以 T1低温处理差异较明显,总枝梗和颖
花现存数 S2时期受低温的影响高于 S1时期.
2􀆰 2  水稻穗分化期低温对枝梗和颖花分化与退化
的影响
2􀆰 2􀆰 1枝梗和颖花分化  枝梗和颖花分化是稻穗形
成的重要基础.由图 3 可知,与对照相比,17 ℃与
20 ℃的低温处理均显著降低了总枝梗和颖花分化
数,降幅分别达到 4.8% ~ 8.5%和 6.0% ~ 9.9%,一
次、二次枝梗与颖花分化数也显著低于对照(表 3),
17 ℃低温处理总枝梗和颖花分化数以及二次枝梗
与颖花分化数显著低于 20 ℃低温处理.就处理时期
而言,各指标均表现为S1 >S2 ,且二次枝梗分化数
图 2  水稻穗分化期低温对总枝梗和颖花现存数的影响
Fig. 2   Effects of low temperature on survived branches and
spikelets during panicle initiation of rice.
T1: 17 ℃; T2: 20 ℃; CK: 23 ℃ . S1: 穗分化一次枝梗原基分化期
Differentiated primary branches anlage stage; S2: 花粉母细胞减数分裂
期 Pollen mother cell meiosis stage. 不同小写字母表示处理间差异显
著(P < 0. 05) Different small letters meant significant difference among
treatments at 0.05 level.下同 The same below.
90027期                    曾研华等: 籼型常规早稻穗分化期低温对颖花形成和籽粒充实的影响           
表 2  水稻穗分化期低温对枝梗和颖花现存数的影响
Table 2  Effects of low temperature on survived branches
and spikelets during panicle initiation of rice
处理
Treat⁃
ment
一次枝
梗现存数
SPB
二次枝
梗现存数
SSB
一次颖
花现存数
SSPB
二次颖
花现存数
SSSB
T1S1 8.1c 30.6d 41.6c 108.7bc
T1S2 8.0d 28.0e 38.3d 105.7c
T2S1 8.3b 35.0b 44.6b 113.6b
T2S2 8.2c 34.0c 43.0bc 110.6b
CKS1 8.9a 39.9a 49.0a 119.3a
CKS2 8.8a 39.8a 48.9a 118.9a
T1 8.1b 29.3c 40.0c 107.2c
T2 8.3b 34.5b 43.8b 112.1b
CK 8.8a 39.8a 48.9a 119.1a
S1 8.4a 35.2a 45.1a 113.9a
S2 8.3a 33.9b 43.4a 111.7a
T1: 17 ℃; T2: 20 ℃; CK: 23 ℃ . S1: 穗分化一次枝梗原基分化期
Differentiated primary branches anlage stage; S2: 花粉母细胞减数分裂
期 Pollen mother cell meiosis stage. SPB: Survived primary branches;
SSB: Survived secondary branches; SSPB: Survived spikelets on primary
branches; SSSB: Survived spikelets on secondary branches. 同列不同小
写字母表示处理间差异显著(P< 0. 05) Different small letters in the
same column meant significant difference among treatments at 0.05 level.
下同 The same below.
差异达显著水平.在处理温度和时期的互作效应中,
低温处理间,各指标均为 S1 >S2,在 17 ℃低温处理
下各指标差异显著,20 ℃低温处理下一次枝梗分化
数差异显著;另外,S2时期的各指标受温度影响差异
大于 S1时期,说明在花粉母细胞减数分裂期水稻对
低温的敏感性较强.
2􀆰 2􀆰 2枝梗和颖花退化  温度对枝梗和颖花退化有
重要影响.由表 3 可知,一次、二次枝梗和颖花退化
数及退化率均表现 T1>T2>CK,低温处理(T1、T2)的
一次枝梗退化数显著高于CK处理,而二次枝梗和
图 3  水稻穗分化期低温对总枝梗和颖花分化数的影响
Fig.3  Effects of low temperature on differentiated branches and
spikelets during panicle initiation of rice.
颖花退化数各温度处理间差异显著.就处理时期而
言,S2时期的颖花退化数显著高于 S1时期,比 S1时
期高 11.6%,二次枝梗退化数以 S2略高于 S1,因此,
低温处理降低了 S2时期颖花和二次枝梗的现存数,
导致总分化数降低.在处理温度和时期的互作效应
中,各温度处理的二次枝梗和颖花退化数以 S2>S1,
T1低温处理下颖花退化数差异显著,而低温处理 S2
时期的一次枝梗退化数稍低于 S1时期.颖花退化数
以 T1S2处理显著高于其他温度处理.总体上,低温处
理增加了 S2时期的二次枝梗和颖花退化程度.
表 3  水稻穗分化期低温对枝梗和颖花分化数与退化数的影响
Table 3  Effects of low temperature on differentiated and retrograded branches and spikelets during panicle initiation of rice
处理
Treat⁃
ment
一次枝梗 Primary branches
分化数
DPB
退化数
RPB
退化率
RPBP (%)
二次枝梗 Secondary branches
分化数
DSB
退化数
RSB
退化率
RSBP (%)
颖花数 Spikelets
一次颖花分
化数 DSPB
二次颖花分
化数 DSSB
退化数
RS
退化率
RSP (%)
T1S1 9.2b 1.1a 11.7a 43.4c 12.9a 29.6b 44.3b 118.1b 12.1b 7.5b
T1S2 8.9d 0.9a 10.5b 41.0d 13.0a 31.7a 42.0c 116.3c 14.3a 9.1a
T2S1 9.3b 1.0a 10.5b 45.9b 10.9b 23.7d 46.4b 122.3ab 10.6c 6.3b
T2S2 9.1c 0.9a 10.2b 45.3b 11.3b 24.9c 45.3b 119.7b 11.4bc 6.9b
CKS1 9.7a 0.8b 8.3c 49.3a 9.4c 19.1e 49.8a 125.6a 7.0d 4.0c
CKS2 9.6a 0.8b 8.6c 49.3a 9.5c 19.3e 49.8a 125.4a 7.4d 4.2c
T1 9.1c 1.0a 11.1a 42.2c 12.9a 30.7a 43.1c 117.2c 13.2a 8.3a
T2 9.2bc 1.0a 10.3b 45.6b 11.1b 24.3b 45.9bc 121.0b 11.0b 6.6b
CK 9.6a 0.8b 8.5c 49.3a 9.5c 19.2c 49.8a 125.5a 7.2c 4.1c
S1 9.4a 1.0a 10.2a 46.2a 11.1a 24.1b 46.8a 122.0a 9.9b 5.9a
S2 9.2a 0.9a 9.7a 45.2b 11.3a 25.3a 45.7a 120.5a 11.1a 6.7a
DPB: Differentiated primary branches; RPB: Retrograded primary branches; RPBP: Retrograded primary branches percentage; DSB: Differentiated
secondary branches; RSB: Retrograded secondary branches; RSBP: Retrograded secondary branches percentage; DSPB: Differentiated spikelets on pri⁃
mary branches; DSSB: Differentiated spikelets on secondary branches; RS: Differentiated spikelets; RSP: Retrograded spikelets percentage.
0102 应  用  生  态  学  报                                      26卷
    综合枝梗和颖花数来看,低温处理 S2时期的每
穗枝梗与颖花分化数和现存数均低于 S1时期,推测
其原因与 S2时期的枝梗和颖花退化数较高以及两
时期稻穗发育进程受低温胁迫效应不同有关.
2􀆰 3  水稻穗分化期低温对花器官的影响
由图 4可知,无论是 S1时期,还是 S2时期,水稻
花粉粒活性与柱头花粉散落数均表现为 T1<T2<CK,
且差异达显著水平,而各低温处理的花粉粒活性与柱
头花粉散落数 S2时期显著高于 S1时期,两者分别增
加 3.6%~10.2%和 5.3~6.0个散落花粉粒,由此说明
S2时期花粉受低温胁迫的效应低于 S1时期.
    水稻花药开裂程度受温度影响的趋势与前者基
本一致(图 5),与对照相比,低温处理两时期主要通
过降低花药完全开裂数,提高花药部分开裂数和花药
未开裂数来降低花药开裂系数.低温处理的花药完全
开裂数和花药开裂系数均为 S2>S1,而花药部分开裂
数和未开裂数为 S2<S1,且在 T1处理下差异显著,说
明 S1时期花药开裂受低温的影响大于 S2时期.
2􀆰 4  水稻穗分化期低温对籽粒充实的影响
籽粒充实程度决定籽粒的最终产量,而温度影
响籽粒的发育与充实.最大库容量反映颖花发育与
籽粒充实的协调程度.由表 4 可知,低温处理显著降
低了总颖花量、千粒重、最大库容量、实际充实量和
库有效充实度,且两低温处理间差异显著;最大库容
图 4  水稻穗分化期低温对花粉性状的影响
Fig.4   Effects of low temperature on pollen characters during
panicle initiation of rice.
量和单穗颖花量 S1时期显著高于 S2时期,库有效充
实度与之相反,与较高的实际充实量有关.对处理温
度和时期而言,低温处理下单穗颖花量、籽粒最大库
容和千粒重均为 S1>S2,而库实际充实量与之相反,因
此,库有效充实度 S2时期显著高于 S1时期,说明低温
处理对 S1时期籽粒充实的胁迫效应大于 S2时期.
    结实率影响籽粒的最终产量,受精率为籽粒充
实奠定基础.由表 5可知,每穗各部位籽粒受精率和
结实率均为 T1 <T2 <CK,且在穗下部和中部各温度
处理间差异显著,全穗受精率和结实率低温处理显
图 5  水稻穗分化期低温对花药开裂的影响
Fig.5  Effects of low temperature on anther dehiscence during
panicle initiation of rice.
AFD: 花药完全开裂 Anther full dehiscence; APD: 花药部分开裂 An⁃
ther part dehiscence; AFID: 花药未开裂 Anther full indehiscence;
ADC: 花药开裂系数 Anther dehiscence coefficient.
11027期                    曾研华等: 籼型常规早稻穗分化期低温对颖花形成和籽粒充实的影响           
表 4  水稻穗分化期低温对籽粒库容充实的影响
Table 4  Effects of low temperature on grain sink capacity
filling during panicle initiation of rice
处理
Treat⁃
ment
单穗颖
花量
Spikelets
per panicle
千粒重
1000⁃
grain mass
(g)
最大库
容量
Peak sink
(g)
实际充
实量
Actual
filling of
sink
(g)
库有效
充实度
Effective
filling rate
of sink
(%)
T1S1 150.3c 25.90bc 3.89bc 2.18c 56.0d
T1S2 144.0d 25.87c 3.73c 2.20c 59.1c
T2S1 158.1b 26.32ab 4.16b 2.52b 60.5c
T2S2 153.6c 26.21b 4.03b 2.56b 63.6b
CKS1 168.3a 26.57a 4.47a 2.96a 66.2a
CKS2 167.7a 26.44a 4.43a 2.98a 67.2a
T1 147.1c 25.89c 3.81c 2.19c 57.5c
T2 155.9b 26.27b 4.09b 2.54b 62.1b
CK 168.0a 26.51a 4.45a 2.97a 66.7a
S1 158.9a 26.26a 4.18a 2.55a 60.9b
S2 155.1b 26.17a 4.06b 2.58a 63.3a
著低于对照,T1、T2低温处理结实率分别降低 18.0%
和 6.3%.就处理时期而言,S2时期每穗各部位籽粒
受精率和结实率均显著高于 S1时期,S2时期全穗结
实率比 S1时期高 3.8%.在处理温度和时期的互作效
应中,两低温处理穗各部位和全穗籽粒受精率与结
实率均为 S2>S1,T1处理下差异均达显著水平,T2处
理下以弱势粒位差异显著.
2􀆰 5  枝梗、颖花和花器官特征与籽粒充实的关系
相关分析表明(表 6),枝梗、颖花现存数和花药
开裂系数、花粉活性、柱头花粉粒数与受精率及结实
率均呈显著或极显著正相关,枝梗和颖花退化数与
受精率和结实率呈显著或极显著负相关.说明枝梗
与颖花现存数能表征籽粒充实状况,而良好的花器
官发育能反映籽粒的充实程度,也间接表明低温处
理不利于籽粒的充实.
表 5  水稻穗分化期低温对穗部籽粒充实的影响
Table 5  Effects of low temperature on grain filling within a rice panicle during panicle initiation (%)
处理
Treatment
穗上部 Upper panicle
受精率
Fertilization
rate
结实率
Seed setting
rate
穗中部 Middle panicle
受精率
Fertilization
rate
结实率
Seed setting
rate
穗下部 Lower panicle
受精率
Fertilization
rate
结实率
Seed setting
rate
全穗 Whole panicle
受精率
Fertilization
rate
结实率
Seed setting
rate
T1S1 63.5e 61.4e 65.6c 64.4d 65.7c 63.9c 64.9c 63.2c
T1S2 67.7d 66.7d 73.1b 71.9c 71.6b 70.5b 70.8b 69.7b
T2S1 72.8c 71.2c 76.3b 74.4bc 85.1a 83.4a 78.0ab 76.3ab
T2S2 77.4b 77.1b 77.8b 77.2b 85.9a 85.3a 80.4a 79.9a
CKS1 84.1a 83.0a 85.3a 84.5a 84.7a 83.9a 84.7a 83.8a
CKS2 86.2a 85.6a 85.7a 85.3a 84.7a 84.2a 85.5a 85.0a
T1 65.6c 64.0c 69.4c 68.1c 68.7b 67.2b 67.9c 66.4c
T2 75.1b 74.1b 77.1b 75.8b 85.5a 84.3a 79.2b 78.1b
CK 85.2a 84.3a 85.5a 84.9a 84.7a 84.0a 85.1a 84.4a
S1 73.4b 71.9b 75.7b 74.4b 78.5b 77.0b 75.9b 74.4b
S2 77.1a 76.5a 78.9a 78.1a 80.7a 80.0a 78.9a 78.2a
表 6  枝梗、颖花和花器官特征与籽粒充实的相关系数
Table 6   Correlation coefficients between the branches,
spikelet, pollen characters and grain filling
指标
Index
受精率
Fertilization
rate
结实率
Seed
setting rate
枝梗现存数 Survived branches 0.91∗∗ 0.90∗∗
颖花现存数 Survived spikelets 0.86∗ 0.85∗
枝梗退化数 Retrograded branches -0.96∗∗ -0.95∗∗
颖花退化数 Retrograded spikelets -0.84∗ -0.83∗
花药开裂系数 Anther dehiscence coefficient 0.91∗∗ 0.92∗∗
花粉活性 Pollen activity 0.98∗∗ 0.99∗∗
柱头花粉散落数 No. of pollen grain on stigma 0.97∗∗ 0.98∗∗
∗P<0.05; ∗∗P<0.01.
3  讨    论
低温冷害是目前世界水稻生产普遍面临的问
题,已得到各国学者的广泛关注.水稻在生殖生长过
程中,孕穗期对低温的耐受能力最弱[13] .研究表明,
穗分化始期低温冷害影响枝梗及颖花的形成[14] .一
次枝梗原基分化期(Ⅱ期)决定枝梗的形成,而花粉
母细胞减数分裂期(Ⅵ期)影响颖花的最终现存数.
本研究结果表明,低温降低了水稻枝梗和颖花现存
数,但显著提高了枝梗和颖花的退化程度,从而导致
两者总分化数降低,这与前人的研究结果[7]较为相
似.穗分化形成期的临界温度是 17 ℃ [15],试验结果
发现,17 ℃低温处理的二次枝梗和颖花现存数与一
次颖花现存数显著低于 20 ℃低温处理.研究表明,
二次枝梗对颖花的贡献大于一次枝梗[16],每穗颖花
现存数差异主要由二次颖花现存数的变化导致[17] .
Ⅵ期枝梗和颖花分化数与现存数受低温的影响大于
Ⅱ期,以 17 ℃低温差异更明显,主要是因为穗分化
Ⅵ期枝梗和颖花的退化数高于Ⅱ期,且颖花退化数
2102 应  用  生  态  学  报                                      26卷
差异显著;另外,尽管穗分化Ⅵ期的枝梗和颖花分化
已基本完成,但过多的枝梗和颖花退化会相对减少
两者的现存数,最终导致分化数降低,而穗分化Ⅱ期
稻穗枝梗和颖花尽管也同样遭遇低温冷害的影响,
但低温处理结束后稻穗仍处于分化发育中,其自我
恢复能力在一定程度上提高了枝梗和颖花的分化
数,同时减缓了枝梗和颖花的退化程度.至于穗分化
Ⅵ期低温处理后枝梗和颖花的退化数高于Ⅱ期,可
能与两时期稻穗发育进程及受低温影响效应不同有
关,导致两时期枝梗和颖花退化程度的差异,其机理
尚需进一步研究.
众多学者认为,孕穗期低温下水稻颖花产生不
育的最敏感时期是Ⅵ期,即剑叶与倒二叶叶枕距为
-4~ +4 cm时,这一时期的低温直接影响小孢子的
分化发育,造成小孢子分化数量减少和已分化的小
孢子发育不良,从而导致花药开裂不良或不能开裂,
受精率降低,结实率下降[18-19] .关于穗分化Ⅱ、Ⅵ期
低温处理对花器官发育影响的研究较少,从本试验
结果来看,低温对水稻花粉育性、柱头花粉散落数和
花药开裂系数的影响均为Ⅵ期低于Ⅱ期,即穗分化
Ⅵ期受低温胁迫的效应较轻.花药开裂系数的增加
主要体现在较多的花药完全开裂数及相对较低的花
药部分开裂数和未开裂数,主要原因可能是低温处
理对穗分化Ⅱ期枝梗分化的影响不利于颖花内花药
的形成,造成花粉过早败育,花粉粒不散落,柱头花
粉萌发少;而穗分化Ⅵ期的颖花和花药已基本成型,
花药已变为黄绿色,花粉也基本成熟,花粉内已积累
一定量的淀粉粒[20],尽管此期稻穗枝梗和颖花受低
温影响严重,但花器官受害程度相对较轻.另外,与
23 ℃对照处理相比,17 ℃低温处理对两时期花器
官的影响程度高于 20 ℃处理,在花粉粒活性和柱头
花粉散落数方面表现尤为显著.
水稻产量在很大程度上取决于结实率,生育中
后期低温冷害显著降低结实率,造成水稻大幅度减
产[21] .障碍型冷害使水稻因空壳率增加而减产,低
温条件下空壳率和产量呈显著负相关[22-23] .此外,
产量的高低取决于产量库容,即单位面积颖花数×
粒重.水稻籽粒充实是指颖花受精后光合产物和茎
鞘贮存物向籽粒运输和积累的过程[24] .耿立清等[25]
研究认为,孕穗-灌浆期低温影响水稻籽粒充实,降
低籽粒最终粒重.本研究也表明,穗分化Ⅱ、Ⅵ期低
温降低籽粒充实和粒重,穗分化Ⅱ期的单穗最大库
容量大于穗分化Ⅵ期,而实际充实量和库有效充实
度与之相反,且库有效充实度差异显著,可能与穗分
化Ⅱ期受低温后源相对不足有关,这从穗分化Ⅵ期
籽粒较高的受精率与结实率上可以得到佐证.与对
照相比,低温处理显著降低了籽粒受精率和结实率,
以 17 ℃低温处理表现尤为明显.相关分析表明,枝
梗与颖花现存数和花药开裂系数、花粉活性、柱头花
粉散落数与受精率和结实率均呈显著或极显著正相
关,而枝梗和颖花退化数与受精率和结实率呈显著
或极显著负相关.
一般而言,日平均气温小于 20 ℃或日最低温度
为 16 ℃,持续 3 d 及以上为“五月寒”,可作为早稻
孕穗期低温冷害评价的指标[5,26] .本试验中,在水稻
一次枝梗原基分化期内,室外夜温出现了短暂的
17 ℃日最低温度,但日平均温度高于 20 ℃,总体较
利于水稻枝梗和颖花的形成[26],而在一次枝梗原基
分化期处理后及花粉母细胞减数分裂期内,温度适
宜水稻生长(图 1);另外,本研究设置 23 ℃的人工
气候箱对照处理,以避免自然环境温度对试验结果
的影响,但室外温度处理的结果与对照处理基本一
致(数据略),对试验结果影响不大,可达到试验
目的.
综合本研究结果来看,穗分化Ⅵ期低温处理降
低了稻穗枝梗和颖花的现存数,提高了枝梗和颖花
的退化程度,但穗分化Ⅱ期低温处理不利于花器官
发育和籽粒结实.因此,在生产中除了选择耐冷性品
种外[27],还应分别针对两时期各自的低温冷害效
应,从水分管理、养分供应和合理确定播种期等方面
来加强相应栽培措施的调控[28-30],以达到水稻高产
稳产的抗逆栽培目的.
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作者简介  曾研华,男,1986年生,博士研究生. 主要从事水
稻高产栽培理论技术与栽培生理研究. E⁃mail: zyh74049501
@ 163.com
责任编辑  张凤丽
4102 应  用  生  态  学  报                                      26卷