Identification and Gene Mapping of White Stripe Leaf and White Panicle Mutant wlp6 in Rice

doi:10.16819/j.1001-7216.2018.7144

Abstract

Abstract:

【Objective】Leaf color mutants are important materials for studying the regulation of photosynthesis, chlorophyll biosynthesis and genetic development in rice. The discovery of leaf color mutants is an important genetic basis for functional genomics research in rice. 【Method】 A mutant of white stripe leaf and white panicle was found in Changhui 121, which could be inherited stably to successive generations, and temporarily termed wlp6 (white striped leaf and panicle 6). wlp6 and wild-type seeds were seeded in the early, middle and late seasons in Nanchang, Jiangxi Province and the agronomic traits of the middle and late rice were investigated. Chlorophyll contents in leaf and glume at the 3-leaf stage, tillering stage and heading stage were tested. The development of mesophyll cells at the heading stage was observed with a electron microscopy. Temperature and light sensitive experiments were carried out in an illumination incubator. The phenotype of reciprocal F₁between wlp6 and Changhui 121, 02428 was observed and chi-square test was conducted on F₂ segregating population to analyze the genetic pattern of the mutant. The F₂ population derived from wlp6/02428 was used as material, and the mapping was carried out by the BSA method. 【Result】 From 1-leaf stage to mature stage, all leaves of wlp6 showed white stripes. At the heading stage, glumes and branches were albino, and the panicle turned green under high temperature. The plant height, number of effective panicles and number of grains per panicle of the mutant were significantly lower than those of its wild type in the two seasons, and the seed-setting rate and 1000-grain weight of wlp6 in late season were also significantly lower. The leaf chlorophyll contents of wlp6 were significantly lower than those of the wild type at all growth stages. The husk chlorophyll contents of wlp6 were significantly lower than those of the wild type in early and late season. In wlp6, the number of chloroplasts decreased, the volume became smaller, and there was no obvious lamellar structure. Leaf chlorophyll contents increased with the temperature and sunshine duration increase. Genetic analysis showed that the trait was controlled by recessive nuclear genes. WLP6 was located in the interval InDel markers R-7-R-8(physical distance 137 kb), on the short arm of chromosome 6. In this interval, 21 candidate genes were predicted. Through the analysis of candidate genes and sequencing, we found that LOC_Os06g14620 encodes a small chain of RNA reductase, 142nd and 158th base of the coding region carried a substitution from T to C, and the base A was inserted at the 288th position. The insertion of the base leads to termination of the gene translation. Therefore, it is speculated that LOC_Os06g14620 is the candidate gene for WLP6.【Conclusion】LOC_Os06g14620 is the candidate gene of the cloned white stripe gene St1. WLP6 is the allele of St1, with different mutation sites and phenotypes.

Key words: rice, white stripe and white panicle, chlorophyll, temperature and light sensitive, gene mapping

摘要：

目的叶色突变体是研究水稻光合作用,叶绿素生物合成和遗传发育调控机理的重要材料。发掘水稻叶色突变体,是水稻功能基因组学研究的重要遗传基础。方法在昌恢121中发现了一份白条纹叶及抽穗期白穗突变体,经过连续多代自交能稳定遗传,暂命名为wlp6(white striped leaf and white panicle 6)。在南昌分早、中和晚3季播种wlp6与野生型种子,考查了中稻与晚稻的部分农艺性状;测定3叶期、分蘖期、抽穗期叶片及颖壳的叶绿素含量;通过电镜观察抽穗期叶肉细胞发育情况。在光照培养箱中进行温光敏感实验;将wlp6与昌恢121及02428正反交,观察F₁植株表型,对F₂分离群体进行卡方测验,分析突变体遗传规律;以wlp6/02428衍生的F₂群体为材料,利用BSA法进行基因定位。结果 wlp6自第1片叶到成熟,叶片均呈白条纹,抽穗期颖壳及枝梗失绿,高温天气穗转绿。突变体株高、有效穗数和每穗粒数在早稻季和中稻季均显著低于野生型,晚稻季wlp6的结实率和千粒重也显著低降低。叶绿素含量测定表明,wlp6叶片叶绿素含量在不同生育期及不同季均显著低于野生型,早稻和晚稻季种植的wlp6颖壳叶绿素含量也比野生型低。电镜观察抽穗期的叶肉细胞发现,wlp6叶绿体数目减少,体积变小,没有分化出明显的片层结构。温光敏感实验表明,突变体对光照强弱钝感,叶色受温度和日照长短影响,随着温度升高和日照时间变长突变体叶绿素含量有上升趋势。遗传分析表明,该性状受隐性核基因控制,利用wlp6/02428得到的616个F₂单株将WLP6定位于第6染色体短臂InDel标记R-7与R-8间,物理距离137 kb,此区间预测了21个候选基因。经候选基因分析及测序发现,其中LOC_Os06g14620编码一个核糖核酸还原酶小亚基,编码区第142和158位碱基由T替换为C,第288位插入了碱基A,碱基的插入导致翻译提前终止,因此推测LOC_Os06g14620是WLP6的候选基因。结论 LOC_Os06g14620是已经克隆的白条纹叶基因St1的候选基因,推测WLP6与St1等位,但突变位点不同,且表型也有差异。

关键词: 水稻, 白条纹叶及白穗, 叶绿素, 温光敏感, 基因定位

CLC Number:

Lingfeng LI, Yuyi XIONG, Linjuan OUYANG, Xiaosong PENG, Xiaorong CHEN, Xiaopeng HE, Junru FU, Jianmin BIAN, Lifang HU, Jie XU, Haohua HE, Xiaotang SUN, Changlan ZHU. Identification and Gene Mapping of White Stripe Leaf and White Panicle Mutant wlp6 in Rice[J]. Chinese Journal OF Rice Science, 2018, 32(6): 538-548.

李玲锋, 熊玉毅, 欧阳林娟, 彭小松, 陈小荣, 贺晓鹏, 傅军如, 边建民, 胡丽芳, 徐杰, 贺浩华, 孙晓棠, 朱昌兰. 水稻白条纹叶及白穗突变体wlp6的鉴定与基因定位[J]. 中国水稻科学, 2018, 32(6): 538-548.

Figures/Tables 11

Table 1 Part agronomic traits of wlp6 and its wild type(WT).

农艺性状 Agronomic trait	中季 Middle season			晚季Late season
农艺性状 Agronomic trait	突变体Mutant	野生型WT		突变型Mutant	野生型WT
生育期 Growth duration / d	116.0±3.7	121.0	±1.6	135.0±2.3	132.0	±3.6
株高 Plant height / cm	137.4±6.6	149.2	±5.2^*	118.0±4.7	134.6	±3.0^**
剑叶长 Length of flag leaf / cm	28.2±1.4	36.6	±3.3^**	31.1±3.9	34.8	±2.2
剑叶宽 Width of flag leaf / cm	1.8±0.1	2.0	±0.0	1.8±0.2	1.9	±0.1
有效穗数 No.of Effective panicle per plant	7.6±1.1	10.2	±2.4^*	7.4±0.9	10.8	±1.6^**
穗长 Panicle length / cm	26.2±1.8	27.7	±1.0	24.2±0.5	27.2	±1.2^**
穗粒数 Grain number per panicle	147.1±19.9	190.9	±13.7^*	142.8±5.9	204.4	±20.8^**
结实率 Seed-setting rate / %	89.0±4.7	89.3	±2.8	60.7±1.1	74.1	±5.9^**
千粒重 1000-grain weight / g	24.3±0.3	23.6	±0.3	22.1±1.6	24.5	±1.1^**

Fig. 1. Phenotype of wlp6 and its wild type. ^ A, 3-leaf stage; B, Tillering stage; C, Heading stage; D, Panicle color; E, Flag leaf at heading; F, Mature grains.

Fig. 2. Comparison of chlorophyll contents of the leaves and glume between wlp6 and wild-type in early, middle and late seasons at the three-leaf stage, tillering stage and heading stage.^ **Difference between the mutant and WT was significant at 0.01 level, respectively(two-tailed t test).

Fig. 3. Ultrastructure of mesophyll cells in wlp6 and its wild type. ^ A and B represent mesophyll cells of wlp6; C and D represent wild-type mesophyll cells.

Fig. 4. wlp6(left) and its wild type(right) at different temperatures. ^ A, B, C, D and E represent the 2-leaf stage seedlings at 20℃, 25℃, 28℃, 30℃ and 32℃, respectively.

Fig. 5. Leaf chlorophyll contents at various temperatures.^ **Difference between the mutant and WT was significant at 0.01 level, respectively(two-tailed t test).

Fig. 6. Chlorophyll contents of seedlings grown under different photoperiods.^ **Difference between the mutant and WT was significant at 0.01 level, respectively(two-tailed t test).

Fig. 7. Plant height, soluble sugar content, chlorophyll contents and chlorophyll a/b ratio of wlp6 and wild-type seedlings under different light intensities.^ **Difference between the mutant and WT was significant at 0.01 level, respectively(two-tailed t test).

Table 2 ．Separation ratio of white stripe and normal plants in two F2 populations.

杂交组合 Cross-combination	白条纹 White striped plants	正常株 Normal plants	分离比 Ratio of segregation	卡方值 χ²
wlp6/昌恢121 wlp6/Changhui 121	838	2 546	1∶3.04	0.09
wlp6/02428	457	1 412	1∶3.09	0.27

Table 3 Some important primers used for gene mapping.

标记 Marker	正向引物序列 Forward primer	反向引物序列 Reverse primer	物理距离 Physical distance / kb
RM19715	CCAATCTAAATTACGCCGCTAGG	GCCAGCTGTTGTTTGTAGTTTCG	7 869
RM19765	GCTCCACAGAAAAGCAAAGC	TGCAACAGTAGCTGTAGCCG	8 931
R-9	TTTTCATATGGCGACCAAGC	CATAAAATTTGGCTCAGTACAGC	8 363
R-8	CTCGGAGTAAGCCCAAATCA	CTGGTTGGCTTTTGCTGTG	8 325
R-7	GCTGATTTGTTTGGTCCGGG	TCTTTCCGGCATCCCATGTC	8 188
R-6	GTTTAGGCTGTCAGCAAGGC	TCAGTGACGACTCGCTCTTC	8 180

Fig. 8. Location of WLP6(A, B) and mutation site(C).^ A, The initial location of WLP6; B, Fine mapping of WLP6; C, Candidate gene, thick arrow indicating location of mutation.

References 45

[1]	von Caemmerer S, Quick W P, Furbank R T. The development of C4 rice: Current progress and future challenges.Science, 2012, 336(6089): 1671-1672.
[2]	Leister D.Chloroplast research in the genomic age.Trends Genet, 2003, 19(1): 47-56.
[3]	张洪征, 程治军, 万建民. 水稻白化突变体研究进展. 生物技术通报, 2013, 1(11): 1-7.
	Zhang H Z, Cheng Z J, Wan J M.Progresses on the studying of rice leaf albino.Biotechnol Bull, 2013, 1(11): 1-7. (in Chinese with English abstract)
[4]	Awan M A, Konzak C F, Rutger J N, Nilan R A.Mutagenic effect of sodium azide in rice.Crop Sci, 1980, 20(5): 663-668.
[5]	孙亚利, 李万昌, 姬生栋. 水稻苗期叶色失绿基因的研究概况. 湖北农业科学, 2015, 54(11): 2564-2568.
	Sun W J, Li W C, Ji S D.Research overview on the rice seeding leaf chlorosis genes.Hubei Agric Sci, 2015, 54(11): 2564-2568. (in Chinese)
[6]	陈叶平, 翟哲, 杨文君, 孙健, 舒小丽, 吴殿星. 水稻条白叶和白穗突变基因St-wp的遗传分析与精细定位. 核农学报, 2015, 29(7): 1246-1252.
	Chen Y P, Zhai Z, Yang W J, Sun J, Shu X L, Wu D X.Genetic analysis and fine mapping of St-wp gene in mutant rice with stripe white leaf and white panicle. J Nucl Agric Sci, 2015, 29(7): 1246-1252. (in Chinese with English abstract)
[7]	Kusumi K, Mizutani A, Nishimura M, Lba K.A virescent gene V1 determines the expression timing of plastid genes for transcription/translation apparatus during early leaf development in rice. Plant J, 1997, 12(6): 1241-1250.
[8]	孙林鹤. 水稻白化转绿突变体v13的表型分析及精细定位. 南京: 南京农业大学, 2011.
	Sun L H.Phenotypic analysis of a rice virescent mutant v13 and fine mapping of the gene causing mutation. Nanjing: Nanjing Agricultural University, 2011. (in Chinese with English abstract)
[9]	Sanchez A C, Khush G S.Chromosomal location of some marker genes in rice using the primary trisomics.J Hered, 1994, 85(4): 297-300.
[10]	李红昌, 钱前, 王赟, 李晓波, 朱丽煌, 徐吉臣. 水稻白穗突变体基因的鉴定和染色体定位. 科学通报, 2003, 25(3): 461-466.
	Li H C, Qian Q, Wang Y, Li X B, Zhu L H, Xu J C.Identification and chromosomal localization of rice white panicle.Chin Sci Bull, 2003, 25(3): 461-466. (in Chinese with English abstract)
[11]	朱小燕, 徐芳芳, 桑贤春, 蒋钰东, 代高猛, 王楠, 张长伟, 何光华. 水稻叶脉白化突变体wpsm的遗传分析与基因定位. 作物学报, 2013, 39(8): 1409-1415.
	Zhu X Y, Xu F F, Sang X C, JiangY D, Dai G M, Wang N, Zhang C W, He G H. Genetic analysis and gene mapping of a rice white midrib mutantwpsm. Acta Agron Sin, 2013, 39(8): 1409-1415. (in Chinese with English abstract)
[12]	李娜, 储黄伟, 文铁桥, 张大兵. 水稻白色中脉Oswm突变体的遗传分析与基因定位. 上海农业学报, 2007, 23(1): 1-4.
	Li N, Chu H W, Wen T Q, Zhang D B.Genetic analysis and mapping of the rice white midrib mutantOswm. Acta Agric Shanghai, 2007, 23(1): 1-4. (in Chinese with English abstract)
[13]	胡景涛, 张甲, 李园园, 付宠允, 郑静, 陈家彬, 胡燕, 李仕贵. 水稻白色中脉Oswm2的遗传分析与分子标记定位. 遗传, 2008, 30(9): 1201-1206.
	Hu J T, Zhang J, Li Y Y, Fu C Y, Zheng J, Chen J B, Hu Y, Li S G.Genetic analysis and mapping of a rice white midrib mutantOswm2. Hereditas, 2008, 31(9): 1201-1206. (in Chinese with English abstract)
[14]	金怡, 刘合芹, 汪得凯, 陶跃之. 一个水稻苗期白条纹叶及抽穗期白穗突变体的鉴定和基因定位. 中国水稻科学, 2011, 25(5): 461-466.
	Jin Y, Liu H Q, Wang D K, Tao Y Z.Genetic analysis and gene mapping of a white striped leaf and white panicle mutant.Chin J Rice Sci, 2011, 25(5): 161-166. (in Chinese with English abstract)
[15]	Yoo S C, Cho S H, Sugimoto H, Li J J, Kusumi K, Koh H J, Koh I, Paek N C.Rice virescerrt 3 and stripe l encoding the large and small subunits of ribonucleotide reductase are required for chloroplast biogenesis during early leaf development.Plant Physiol, 2009, 150(1): 388-401.
[16]	Nagao S.Genie analysis and linkage relationship of characters in rice.Adv Genet, 1951, 4(4): 181-212.
[17]	Iwata N, Satoh H, Omura T.Linkage studies in rice new genes belonging to the 11th linkage group.Jpn J Breed, 1979, 29(2): 182-183.
[18]	Maekawa M.Studies on genetical difference between distantly related rice varieties.Mem Facul Agric Hokk Univ, 1982, 13(2): 146-177.
[19]	Maekawa M.A new leaf stripe gene st-5 its linkage with d-2 and the location of gene P in the second linkage group. Rice Genet Newsl, 1988, 5(21): 85-87.
[20]	Maekawa M, Inukai T, Shinbashi N.A new gene for leaf stripe(st-6) found in linkage group 3. Rice Genet Newsl, 1990, 7(11): 108-109.
[21]	Stern D B, Hanson M R, Barkan A.Genetics and genomics of chloroplast biogenesis: Maize as a model system.Trends Plant Sci, 2004, 9(6): 293-301.
[22]	刘少奎, 张启军, 漆庆明,赖东, 廖慧敏, 颜文飞, 张斌, 吕川根. 水稻白条纹新基因st9(t)的初步定位. 江苏农业学报, 2012, 28(5): 928-932.
	Liu S K, Zhang Q J, Qi Q M, Lai D, Liao H M, Yan W F, Zhang B, Lu C G.Mapping a novel rice white stripe gene,st9(t). Jiangsu J Agric Sci, 2012, 28(5): 928-932. (in Chinese with English abstract)
[23]	何颖红, 邹国兴, 饶玉春, 胡江, 刘坚, 高振宇, 郭龙彪, 朱丽, 钱前. 水稻白条叶突变体(st10)的遗传分析与基因定位. 分子植物育种, 2011, 9(2): 136-142.
	He Y H, Zou G X, Rao Y C, Hu J, Liu J, Gao Z Y, Guo L B, Zhu L, Qian Q.Genetic analysis and molecular mapping of a white-stripe leaf mutation in rice.Mol Plant Breed, 2011, 9(2): 136-142. (in Chinese with English abstract)
[24]	成钦淑, 叶邦全, 袁灿, 李伟滔, 尹俊杰, 王静, 贺闽, 汪吉春, 王玉平, 李仕贵, 陈学伟. 水稻白条纹叶突变体st11的遗传分析与基因定位. 中国水稻科学, 2015, 29(01):14-21.
	Cheng Q S, Ye B Q, Yuan C, Li W T, Yin J J, Wang J, He M, Wang J C, Wang Y P, Li S G, Cheng X W.Genetic analysis and gene mapping of white stripe leaf mutantst11 in rice. Chin J Rice Sci, 2015, 29(1): 14-21. (in Chinese with English abstract)
[25]	叶卫军. 水稻白条纹叶突变体st12的精细定位. 金华: 浙江师范大学, 2013.
	Ye W J.Fine mapping of a white stripe leaf mutant st12 in rice. Jinhua: Zhejiang Normal University, 2013. (in Chinese with English abstract)
[26]	桑贤春, 徐芳芳, 凌英华, 赵芳明, 杨正林, 唐彦强, 田晓庆, 李云峰, 何光华. 水稻条斑花叶突变体st(t)的鉴定与遗传定位. 作物学报, 2010, 36(2): 211-216.
	Sang X C, Xu F F, Ling Y H, Zhao F M, Yang Z L, Tang Y Q, Tian X Q, Li Y F, He G H.Identification and molecular mapping of stripe leaf mutantst(t) in rice, 2010, 36(2): 211-216. (in Chinese with English abstract)
[27]	邝小林. 水稻白条纹叶突变体基因st(k)的遗传分析及基因定位. 成都: 四川农业大学, 2013.
	Kuang X L.Genetic analysis and molecular mapping of a white stripe leaf gene st(k) in rice. Chengdu: Sichuan Agricultural University, 2013. (in Chinese with English abstract)
[28]	王新华. 水稻白条纹叶突变体B38的表型分析及突变基因的精细定位. 南京: 南京农业大学, 2013.
	Wang X H.Phenotypic analysis of rice green-white-stripe mutant B38 and fine mapping of the underlying gene. Nanjing: Nanjing Agricultural University, 2013. (in Chinese with English abstract)
[29]	许凤华,程治军,王久林, 吴自明, 孙伟, 张欣, 雷财林, 王洁, 吴赴清, 郭秀平, 刘玲珑, 万建民. 水稻白条纹叶Gws基因的精细定位与遗传分析. 作物学报, 2010, 36(5): 713-720.
	Xu F H, Cheng Z J, Wang J L, Wu Z M, Sun W, Zhang X, Lei C L, Wang J, Wu F Q, Guo X P, Liu L L, Wan J M.Genetic analysis and fine-mapping ofGws gene using green-white-stripe rice mutant. Acta Agron Sin, 2010, 36(5): 713-720. (in Chinese with English abstract)
[30]	辛龙. 水稻白条纹叶突变体wgl58的遗传分析与基因定位. 成都: 四川农业大学, 2013.
	Xin L.Genetic analysis and gene mapping of a White-stripe-leaf mutant wgl58 in rice. Chengdu: Sichuan Agricultural University, 2013. (in Chinese with English abstract)
[31]	廖婷婷. 水稻白化基因AL5942的遗传鉴定及早衰基因D475的图位克隆. 成都: 四川农业大学, 2015.
	Liao T T.Genetic analysis and map-based cloning of the albino mutant al5942 and the early senescence mutant d475 in rice. Chengdu: Sichuan Agricultural University, 2015. (in Chinese with English abstract)
[32]	宋桂云, 徐正进, 苏慧, 王翠花, 宫雅琴, 孙海燕. 不同穗型的两个水稻品种株型的研究. 内蒙古民族大学学报: 自然科学版, 2006, 21(3): 294-299.
	Song G Y, Xu Z J, Su H, Wang C, Gong Y Q, Sun H Y.The study on plant shape of different panicle rice varieties.J Inn Mong Univ Nat, 2006, 21(3): 294-299. (in Chinese with English abstract)
[33]	左维维. 水稻白条纹叶白穗突变体基因WP4的图位克隆. 杭州: 浙江农林大学, 2016.
	Zuo W W.Map-based cloning of a rice utant gene wp4 controlling white stripe leaf and panicle. Hangzhou: Zhejiang A&F University, 2016. (in Chinese with English abstract)
[34]	Wang Y, Wang C, Zheng M, Lyu J, Xu Y, Li X, Niu M, Long W, Wang D, Wang H, Terzaghi W, Wang Y, Wan J.WHITE PANICLE 1, a Val-tRNA synthetase regulating chloroplast ribosome biogenesis in rice, is essential for early chloroplast development.Plant Physiol, 2016, 170(4): 2110.
[35]	王晓雯, 蒋钰东, 廖红香, 杨波, 邹帅宇, 朱小燕, 何光华, 桑贤春. 水稻白穗突变体wp4的鉴定与基因精细定位. 作物学报, 2015, 41(6): 838-844.
	Wang X W, Jiang Y D, Liao H X, Yang B, Zou S Y, Zhu X Y, He G H, Sang X C.Identification and gene fine mapping of white panicle mutantwp4 in Oryza sativa. Acta Agron Sin, 2015, 41(6): 838-844. (in Chinese with English abstract)
[36]	Song J, Wei X, Shao G N, Sheng Z H, Chen D B, Liu C L, Jiao G A, Xie L H, Tang S Q, Hu P S.The rice nuclear gene WLP1 encoding a chloroplast ribosome L13 protein is needed for chloroplast development in rice grown under low temperature conditions. Plant Mol Biol, 2014, 84(3): 301-314.
[37]	陈德西, 李婷, 曲广林, 黄文娟, 何忠全, 李仕贵. 水稻条斑和颖花异常突变体st-fon的鉴定与遗传分析. 中国水稻科学, 2012, 26(6): 677-685.
	Chen D X, Li T, Qu G L, Huang W J, He Z Q, Li S G.Characterization and genetic analysis of a streaked and abnormal glumous flower mutantst-fon. Chin J Rice Sci, 2012, 26(6): 677-685. (in Chinese with English abstract)
[38]	Zhang Z G, Cui X A, Wang Y W, Wu J X, Gu X F, Lu T G.The RNA editing actor WSP1 is essential for chloroplast development in rice. Mol Plant, 2017, 10(1): 86-98.
[39]	宋建. 水稻白叶白穗突变体基因wlpl的图位克隆与功能分析. 北京: 中国农业科学院, 2013.
	Song J.Map-based cloning and functional study of rice mutant gene wlpl gene controlling white leaf and panicle. Beijing: Chinese Academy of Agricultural Sciences, 2013. (in Chinese with English abstract)
[40]	Rogers S O, Bendich A J.Extraction of DNA from plant tissues.Plant Mol Biol Manual, 1988, 6(1): 1-10.
[41]	Panand O, Chen X, McCouch S R.Development microsatel lite markers characterization of simple sequence length polymorphism (SSLPs) in rice (Oryza sativa L). Mol Gen Genet, 1996, 252(5): 597-607.
[42]	Iba K, Takamiya K I, Yoshihiro T.Formation of functionally active chloroplast is determined at a limited stage of leaf development in vi-rescent mutant of rice.Dev Genet, 1991, 12: 342-348.
[43]	夏冰, 阳树英, 刘清波. 生态因子对水稻叶片光合生理功能的影响综述. 作物研究, 2008(2): 140-142.
	Xia B, Yang S Y, Liu Q B.Effects of ecological factors on photosynthetic physiological functions of rice leaves.Crop Res, 2008(2): 140-142. (in Chinese with English abstract)
[44]	陈晓远, 凌木生, 高志红. 水分胁迫对水稻叶片可溶性糖和游离脯氨酸含量的影响. 河南农业科学, 2006(12): 26-30.
	Chen X Y, Ling M S, Gao Z H.Effects of water stress on soluble sugars and free proline content in leaves of rice.J Henan Agric Sci, 2006(12): 26-30. (in Chinese with English abstract)
[45]	杨东, 段留生, 谢华安, 黄庭旭. 水稻幼苗生长对弱光胁迫的响应及相关分析. 中国农学通报, 2011, 27(5): 70-79.
	Yang D, Duan L S, Xie H A, Huang T X.The response and correlation analysis of rice seedlings growth to low-light stress.Chin Agric Sci Bull, 2011, 27(5): 70-79. (in Chinese with English abstract)