Propagation of Ornamental Plants
24(2): 31-36, 2024
MORPHO-HISTOLOGICAL CHANGES DURING ARECANUT (ARECA CATECHU L.) SOMATIC EMBRYOGENESIS
Neema Mohamed1*, Aparna Veluru2, AparnnaWilson3, Fathimath Zaeema2,
Sudha Raju2 and Nagaraja Niduvalli Ramachandrappa4
1 ICAR - Indian Institute of Oil Palm Research, Research Centre, Palode, 695 562 Thiruvananthapuram, Kerala, India, *E-mail: neema.m@icar.gov.in 2 ICAR - Central Plantation Crops Research Institute, Kudlu, 671 124 Kasaragod, Kerala, India 3 Department of Bioscience, Mangalore University, Konaje, 574 199 Mangalore, Karnataka, India 4 ICAR - Central Plantation Crops Research Institute, Regional Station, 574 243 Vittal, Karnataka, India
Arecanut (Areca catechu L.) holds a significant position as a commercial plantation crop in India and is now gaining acceptance as an ornamental crop. Being a cross-pollinated plant, in vitro propagation is the only means of obtaining true to type progenies. Somatic embryogenesis in arecanut has gained prominence due to its potential for in vitro propagation. A study was conducted to acquire insights into the morphological and histological alterations occurring at different stages of arecanut somatic embryogenesis. Immature inflorescence explants were inoculated into Eeuwen’s Y3 medium, supplemented with the auxin picloram, with decreasing concentrations in subsequent subcultures. This resulted in the formation of initial callus, embryogenic callus, and somatic embryos, which eventually germinated and were utilized for the investigation. Various histological techniques, including sectioning, staining, and microscopy, were employed to analyze the cellular and tissue transformations. The initial calluses, originating from the explants, contained meristematic cells. The peripheral meristematic zone within the initial calluses exhibited continuous division, fostering the development of embryogenic calluses. The embryogenic callus displayed a light yellow color and resulted from the ongoing proliferation and differentiation of the initial calluses. Within the embryogenic calluses, a peripheral arrangement of meristematic cells was observed, with more vacuolated space in the internal regions compared to the outer layers. The presence of vascular bundles was noted in the somatic embryos, which featured thin-walled cells with small vacuoles. Furthermore, germinated somatic embryos revealed the existence of a vascular system connecting the root and shoot meristems.
Key words: calluses, histology, in vitro propagation, morphology, ornamental palm, tissue culture
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