Indian Journal of Horticulture
Year : 2009, Volume : 66, Issue : 1
First page : ( 109) Last page : ( 119)
Print ISSN : 0972-8538. Online ISSN : 0974-0112.

Syncytial nuclei formation and development in coconut fruits

Devakumar K.*, Prabakaran J.¹

Central Plantation Crops Research Institute (CPCRI), Kasaragod, 671 124.

*Corresponding author's: E-mail: k_devakumar@yahoo.com

¹Tamilnadu Agricultural University, (TNAU), Coimbatore-3, Tamilnadu.

Received:  June,  2008; Revised:  September,  2008; Accepted:  February,  2009.

Abstract

Coconut endosperm is unique because of its early liquid syncytial stages, which forms a hard matured kernal at later stages of fruit development. Many free floating, naked nuclei devoid of cell membrane could be observed in the liquid syncytium. Different types of morphologically distinct syncytial nuclei were observed during the course of coconut fruit development. In two months old coconut fruits, the syncytial nuclei of 10–20 μm size in diameter were formed from cytoplasmic aggregations. Two types of syncytial nuclei 20–40 μm and >60 μm in diameter suddenly appear in 3-month old fruits. These early stage synctial nuclei were present in less than 1000 nuclei/ml. The four-month old coconut fruits were characterized by the appearance of numerous 1–2 μm sized bodies which aggregate together in definite numbers forming a dense cluster around which nuclear membrane is synthesized to form syncytial nuclei of 10–30 μm in diameter. During the fifth month of coconut fruit development, several membranous spherical bodies seeded with few 1–2 μm actively moving bodies inside appear. These bodies continuously multiply and condense inside the spherical membrane leading to a dense syncytial nucleus. The syncytial nuclei at this stage are highly active and it merges with one another thus increasing in size to form syncytial nuclei of 40–60 μm in diameter. The individual syncytial nucleus then becomes highly compact and several such compact nuclei organize themselves into a sheet like structure and proceed to settle on the lower regions of the endothelial layer. The settled syncytial nuclei cellularize and grow along the entire endothelial surface which then hardens to form the matured kernel.

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Key words

Coconut, endosperm development, syncytial nuclei.

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