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Journal of Integrative Agriculture  2021, Vol. 20 Issue (5): 1239-1249    DOI: 10.1016/S2095-3119(20)63189-6
Special Issue: 油料作物合辑Oil Crops
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Ultrastructural studies of seed coat and cotyledon during rapeseed maturation
CAO Jian-bo2*, HE Li-min2*, Chinedu Charles NWAFOR3, QIN Li-hong2, ZHANG Chun-yu3, SONG Yan-tun1, HAO Rong1 
1 Key Laboratory of Arable Land Conservation (Middle and Lower Reaches of Yangtse River), Ministry of Agriculture and Rural Affairs/Hubei Key Laboratory of Soil Environment and Pollution Remediation/College of Resources and Environment, Huazhong Agricultural University, Wuhan 430070, P.R.China
2 Public Laboratory of Electron Microscopy, Huazhong Agricultural University, Wuhan 430070, P.R.China
3 National Key Laboratory of Crop Genetic Improvement/College of Plant Science and Technology, Huazhong Agricultural University, Wuhan 430070, P.R.China
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油菜(甘蓝型,Brassica napus L)是世界上最重要的油料作物。油菜在种子成熟后期快速地积累油脂。然而,在种子成熟后期,人们对油菜种子的油脂积累和种皮颜色变化机制却知之甚少。本研究中,我们分析了油菜种子发育后期即开花后25天至70天,种皮、糊粉层和子叶的超微结构特征。研究结果表明,子叶中的叶绿体退化成非光合作用的质体从而导致子叶由绿色转变为黄色。糊粉层中的叶绿体退化成没有包膜的质体残余物,而子叶细胞中的叶绿体则退化成具有完整内膜和外膜的前质体。从开花后40天到70天,在糊粉层和子叶细胞中,叶绿体退化成没有类囊体的质体,油体与质体或蛋白体直接接触互作,细胞内的内质网较少;同时,油菜种子中的叶绿素含量降低并伴随着油脂含量升高。这些结果说明,在油菜种子发育后期,油脂的快速合成不依赖叶绿体光合作用产生的NADPH(主要的还原力),可能是利用氧化磷酸戊糖途径等其他来源的还原力。质体、细胞质或油体中的甘油三酯合成相关的酶可能参与了子叶和糊粉层细胞中甘油三酯的合成。

Brassica napus L. (B. napus) is an important oil crop worldwide and it rapidly accumulates oil at late stage of seed maturation. However, little is known about the cellular mechanism of oil accumulation and seed color changes during the late stage of rapeseed development.  Here, we analyzed the ultrastructure of seed coat, aleurone and cotyledon in embryos of B. napus from 25 to 70 days after flowering (DAF).  The pigments, which were deposited on the cell wall of palisade cells in seed coat, determined dark black color of rapeseed.  The chloroplasts degenerated into non-photosynthetic plastids which caused the green cotyledon to turn into yellow.  The chloroplasts in aleurone and cotyledon cells respectively degenerated into remnants without inner and outer envelope membranes and ecoplasts with intact inner and outer envelope membranes.  From 40 to 70 DAF, there were degraded chloroplasts without thylakoid, oil bodies contacting with plastids or protein bodies, big starch deposits of chloroplasts degrading into small particles then disappearing, and small endoplasmic reticulum (ER) in aleurone and cotyledon cells.  Additionally, there were decreases of chlorophyll content and dramatic increases of oil content in rapeseed.  These results suggested that the rapid oil accumulation was independent on the NADPH synthesized by photosynthesis of chloroplasts and probably utilized other sources of reductant, such as the oxidative pentose phosphate pathway during the late stage of rapeseed development.  The triacylglycerol assembly presumably utilizes the enzymes in the plastid, cytosol or oil body of cotyledon and aleurone cells.
Keywords:  rapeseed        seed coat        plastid development        oil synthesis        ultrastructure  
Received: 06 November 2019   Accepted:
Fund: This work was supported by grants from the National Natural Science Foundations of China (41877528, 41471432 and 31500977).
Corresponding Authors:  Correspondence HAO Rong, E-mail:    
About author:  * These authors contributed equally to this study.

Cite this article: 

CAO Jian-bo, HE Li-min, Chinedu Charles NWAFOR, QIN Li-hong, ZHANG Chun-yu, SONG Yan-tun, HAO Rong. 2021. Ultrastructural studies of seed coat and cotyledon during rapeseed maturation. Journal of Integrative Agriculture, 20(5): 1239-1249.

Bates P D, Stymne S, Ohlrogge J. 2013. Biochemical pathways in seed oil synthesis. Current Opinion in Plant Biology, 16, 358–364.
Baud S, Lepiniec L. 2009. Regulation of de novo fatty acid synthesis in maturing oilseeds of Arabidopsis. Plant Physiology and Biochemistry, 47, 448–455.
Beeckman T, De Rycke R, Viane R, Inze D. 2000. Histological study of seed coat development in Arabidopsis thaliana. Journal of Plant Research, 113, 139–148.
Bethke P C, Libourel I G, Aoyama N, Chung Y Y, Still D W, Jones R L. 2007. The Arabidopsis aleurone layer responds to nitric oxide, gibberellin, and abscisic acid and is sufficient and necessary for seed dormancy. Plant Physiology, 143, 1173–1188.
Cartea E, De Haro-Bailón A, Padilla G, Obregón-Cano S, Del Rio-Celestino M, Ordás A. 2019. Seed oil quality of Brassica napus and Brassica rapa germplasm from northwestern Spain. Foods, 8, 292.
Chapman K D, Ohlrogge J B. 2012. Compartmentation of triacylglycerol accumulation in plants. The Journal of Biology Chemistry, 287, 2288–2294.
Groot E P, Vancaeseele L A. 1993. The development of the aleurone layer in canola (Brassica napus). Canadian Journal of Botany, 71, 1193–1201.
Haughn G, Chaudhury A. 2005. Genetic analysis of seed coat development in Arabidopsis. Trends in Plant Science, 10, 472–477.
He Y Q, Wu Y. 2009. Oil body biogenesis during Brassica napus embryogenesis. Journal of Integrative Plant Biology, 51, 792–799.
Helene V, Dongen J T, Van, Peter W, Daniela H, Peter G. 2003. Lipid storage metabolism is limited by the prevailing low oxygen concentrations within developing seeds of oilseed rape. Plant Physiology, 133, 2048–2060.
Houston N L, Hajduch M, Thelen J J. 2009. Quantitative proteomics of seed filling in castor: Comparison with soybean and rapeseed reveals differences between photosynthetic and nonphotosynthetic seed metabolism. Plant Physiology, 151, 857–868.
Hu Z Y, Hua W, Zhang L, Deng L B, Wang X F, Liu G H, Hao W J, Wang H Z. 2013. Seed structure characteristics to form ultrahigh oil content in rapeseed. PLoS ONE, 8, e62099.
Ichihara K, Noda M. 1980. Fatty acid composition and lipid-synthesis in developing safflower seeds. Phytochemistry, 19, 49–54.
Jarvis P, López-Juez E. 2013. Biogenesis and homeostasis of chloroplasts and other plastids. Nature Reviews Molecular Cell Biology, 14, 787–802.
Li C, Chen W. 1998. An investigation on the distribution of rape yellow seeds and its variation in seed coat colour. Journal of Southwest Agricultural University, 20, 256–259. (in Chinese)
Liebers M, Grübler B, Chevalier F, Lerbs-Mache S, Merendino L, Blanvillain R, Pfannschmidt T. 2017. Regulatory shifts in plastid transcription play a key role in morphological conversions of plastids during plant development. Frontiers in Plant Science, 8, 23.
Maraschin F D S, Kulcheski F R, Segatto A L A, Trenz T S, Barrientos-Diaz O, Margis-Pinheiro M, Margis R, Turchetto-Zolet A C. 2019. Enzymes of glycerol-3-phosphate pathway in triacylglycerol synthesis in plants: Function, biotechnological application and evolution. Progress in Lipid Research, 73, 46–64.
Marles M A S, Gruber M Y. 2004. Histochemical characterisation of unextractable seed coat pigments and quantification of extractable lignin in the Brassicaceae. Journal of the Science and Food Agrculture, 84, 251–262.
Pleite R, Pike M J, Garces R, Martinez-Force E, Rawsthorne S. 2005. The sources of carbon and reducing power for fatty acid synthesis in the heterotrophic plastids of developing sunflower (Helianthus annuus L.) embryos. Journal of Exprimental Botany, 56, 1297–1303.
Schwartz B, Yeung C, Meinke W. 1994, Disruption of morphogenesis and transformation of the suspensor in abnormal suspensor mutants of Arabidopsis. Development, 120, 3235–3245.
Shahid M, Cai G, Zu F, Zhao Q, Qasim M U, Hong Y, Fan C, Zhou Y. 2019. Comparative transcriptome analysis of developing seeds and silique wall reveals dynamic transcription networks for effective oil production in Brassica napus L. International Journal of Molecular Sciences, 20, E1982.
Sharkey T D, Weise S E. 2016. The glucose 6-phosphate shunt around the Calvin-Benson cycle. Journal of Exprimental Botany, 67, 4067–4077.
Velasco L, Rojas-Barros P, Fernandez-Martinez J A. 2005. Fatty acid and tocopherol accumulation in the seeds of a high oleic acid castor mutant. Industrial Crops and Products, 22, 201–206.
Vigeolas H, van Dongen J T, Waldeck P, Huhn D, Geigenberger P. 2003. Lipid storage metabolism is limited by the prevailing low oxygen concentrations oilseed rape. Plant Physiology, 133, 2048–2060.
Wei C, Li A, Zhang Y, Zhou W, Wang Y. 2009. Comparison of seed structure of progenies from intergeneric hybrids between Sinapis alba and Brassica napus. Acta Agronomica Sinica, 35, 1139–1145. (in Chinese)
Xu C C, Shanklin J. 2016. Triacylglycerol metabolism, function, and accumulation in plant vegetative tissues. Annual Review of Plant Biology, 67, 179–206.
Zhang C, Zhang W, Ren G, Li D, Cahoon R E, Chen M, Zhou Y, Yu B, Cahoon E B. 2015. Chlorophyll synthase under epigenetic surveillance is critical for vitamin E synthesis, and altered expression affects tocopherol levels in Arabidopsis. Plant Physiology, 168, 1503–1511.
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