Author(s)

María E. Materán¹, Patricia L. Sáez^2*, Manuel Sánchez-Olate², León A. Bravo³, Roberto Rodríguez⁴, Darcy Ríos², Rafael E. Coopman⁵

¹Centro Biotecnológico de Guayana, Universidad Nacional Experimental de Guayana, Guayana, Venezuela.
²Facultad de Ciencias Forestales, Departamento de Silvicultura y Laboratorio Cultivo de Tejidos Vegetales, Centro de Biotecnología, Universidad de Concepción, Casilla 160-C, Concepción, Chile.
³Laboratorio de Fisiología y Biología Molecular Vegetal, Instituto de Agroindustria, Departamento de Ciencias Agronómicas y Recursos Naturales, Facultad de Ciencias Agropecuarias y Forestales and Center of Plant, Soil Interaction and Natural Resources Biotechnology, Scientific and Technological Bioresource Nucleus, Universidad de La Frontera, Casilla 54-D, Temuco, Chile.
⁴Departamento de Biología de Organismos y Sistemas, Facultad de Biología, Universidad de Oviedo, Oviedo, España.
⁵Laboratorio de Ecofisiología para la Conservación de Bosques, Instituto de Conservación, Biodiversidad y Territorio, Facultad de Ciencias Forestales y Recursos Naturales, Universidad Austral de Chile, Casilla 567, Valdivia, Chile.

The aim of the present study was to evaluate the applicability of maximal photochemical efficiency of photosystem II (Fv/Fm) as an early estimate of P. radiata micrografts viability coming from different position (basal vs. apical) in the ortets. We hypothesize that Fv/Fm variation is a good indicator of micrograft’s viability and phenological stage during micrograft development. The micrografts were established in QL medium supplemented whit 0.1 mg·L^-1 IBA and 1 mg·L^-1 BAP and cultured at 25°C ± 2°C and 80 μmol photons m^-2s^-1 of photosynthetic active radiation by 16 h per day. During the establishment and consolidation phase, we found significant differences in Fv/Fm with respect to time and buds positions provenience. During establishment, basal shoot tips have lower Fv/Fm than apical shoot tips, which agrees with the lowest viability (35%). However, during the consolidation phase, the trend changed and basal shoot tips presented higher Fv/Fm than apical shoot tips and showed an increase in ETR and NPQ, with respect to apical shoots and ortet. Although the measurement of fluorescence parameters implies the insertion of the fluorometer sonde in vitro, this implies aseptic considerations, but always conveies a contamination risk. We conclude that fluorescence (Fv/Fm, ETR, NPQ) can be indicators of the micrograft’s development according to the shoot tips position in the ortet and can be useful early-indicators of the scions’ physiological condition during micrograft transition from establishment to consolidation.

Maximum PSII Photochemical Efficiency, Micrograft, P. radiata

Materán, M. , Sáez, P. , Sánchez-Olate, M. , Bravo, L. , Rodríguez, R. , Ríos, D. and Coopman, R. (2015) Photochemical Efficiency during the Establishment and Consolidation Phases of in Vitro Pinus radiata Micrograft Made from Scions of Different Ontogenetic Age. American Journal of Plant Sciences, 6, 228-239. doi: 10.4236/ajps.2015.61026.