Improving acclimatization through the photoautotrophic culture of coconut (Cocos nucifera) seedlings: an in vitro system for the efficient exchange of germplasm
- 339 Downloads
An in vitro photoautotrophic step based on the supply of CO2-enriched air (1,600 μmol mol−1) during the light phase and ambient air (350 μmol mol−1 CO2) during the dark phase has been used to promote the ex vitro establishment of coconut (Cocos nucifera L.) seedlings. The introduction of this step into a previously developed in vitro protocol was found to improve the quality of the seedlings (as assessed by fresh weight increase, physical stature, leaf area and thickness, stomatal density, and chlorophyll a content, and primary and secondary root production), the proportion of seedlings successfully transferred to soil (improvement from 40% to 100%) and achieved in a shorter time (reduction from 10 to 6 mo). Best results using this photoautotrophic growth step were obtained when a low medium concentration of sucrose (43.8 mM or lower) was used, when it was applied to seedlings that had already reached 4 or 5 mo of age in the in vitro culture step, and when seedlings were cultured in the photoautotrophic system for 2 mo or more before transfer to soil. Our improved protocol is more efficient and it reduces the cost per plant for the international exchange of coconut germplasm.
KeywordsPhotoautotrophic culture Coconut embryo culture CO2-enrichment International germplasm exchange
The project was partly funded by the Australian Centre for International Agricultural Research, via project HORT/1998/061. The authors would like to thank Mrs. Erlinda Rillo from the Philippine Coconut Authority, Albay Research Station, who provided the seedlings used in the experiments, and Mr. Graham Kerven and Mr. Sisunandar of the School Agriculture and Food Sciences, University of Queensland for their technical assistance on chlorophyll analysis and some aspects of manuscript preparation, respectively.
- Ashburner GR, Faure MG, Franz PR, Tomlinson DR, Pulo P, Burch JM, Thompson WK (1994) Coconut embryo culture for remote locations. In: Proceedings of the Workshop on coconut improvement in the South Pacific, Taveuni, Fiji, 10 12 Nov 1993. Australian Centre for International Agricultural Research, Canberra Australia, pp 25–28Google Scholar
- Assy-Bah B (1986) In vitro culture of coconut zygotic embryos. Oleagineux 41:321–326Google Scholar
- Engelmann F, Batugal P (2002) Background on the development and implementation of the coconut embryo in vitro culture project. In: Engelmann F, Batugal P, Oliver J (eds) Coconut embryo in vitro culture: Part II. IPGRI-APO, Serdang, pp 1–4Google Scholar
- Mkumbo KE, Sallu RS, Marrealle R, Tembo S (2002) Increasing the efficiency of in vitro culture of zygotic coconut embryos to promote germplasm collecting in Tanzania. In: Engelmann F, Batugal P, Oliver JT (eds) Coconut embryo in vitro culture part II. IPGRI-APO, Serdang, pp 109–121Google Scholar
- Nguyen QT, Kozai T, Nguyen KL, Nguyen UV (1998) Photoautotrophic micropropagation of tropical plants. In: Altman A, Ziv M, Izhar S (eds) Plant biotechnology and in vitro biology in the 21st century. Proceedings of the IXth International Congress of the International Association of Plant Tissue Culture and Biotechnology, Jerusalem, Israel, pp 659–662Google Scholar
- Pospisilova J, Solarova J, Catsky J (1992) Photosynthetic responses to stresses during in vitro cultivation. Photosynthetica 26:3–18Google Scholar
- Rillo EP, Cueto CA, Medes WR, Areza-Ubaldo MB (2002) Development of an improved embryo culture protocol for coconut in the Philippines. In: Engelmann F, Batugal P, Oliver J (eds) Coconut embryo in vitro culture: part II. IPGRI-APO, Serdang, pp 41–79Google Scholar
- Xiao YL, Kozai T (2004) Commercial application of a photoautotrophic micropropagation system using large vessels with forced ventilation: plantlet growth and production cost. HortSci 39:1387–1391Google Scholar