J Integr Plant Biol. ›› 1992, Vol. 34 ›› Issue (2): -.

• Research Articles •    

Ultrastructure of Protein Bodies and Plastids in Cotyledon of Nelumbo nucifera Gaertn.at Seed Germination

Shi Gno-xin,Xu Xiang-shen, Chen Wei-pei, Wang Wen and Du Kai-he   

Abstract: The present article deals mainly with the formation and dissolution of protein bodies and development of plastids in cotyledon cells of Nelumbo nucifera during seed germination. Electron microscopic studies reveal that protein bodies are formed after imbibition of the cotyledons before germination. They are produced through accumulation of protein material in small vacuoles delivered from the exudates of endoplasmic reticulum or by fragmentation of endoplasmic reticulum itself. In the period of germination, most of the material in the protein bodies dissolute and they coalesce with each other forming large vacuoles. The protein residue of the vacuoles condenses into small blocks with high electron density adhering to the tonoplast or freely floating in the vacuole. Thus, it suggests that the protein bodies of the germinating N. nucifera cotyledons are originated from vacuoles formed by endoplasmic reticulum. Part of the plastids found in cotyledonous cells of mature N. nucifera seeds exists as proplastids. They develop continuously after imbibition of the cotyledons. During the period of seed germination, many concentric lamellae are developed along the plastid membrane on which they later coalesce with the neighboring concentric lameUae forming loosely organized prolamellar bodies which condense into paracrystalline lattices. No ribosomes are present in the inter spaces of paracrystatline lattice. One to several prolamellar bodies can be developed in one plastid.

Key words: Nelumbo nucifera Gaertn., Protein bodies, Plastids, Cotyledons, Ultra Structure

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