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Castander-Olarieta A, Moncaleán P, Pereira C, Pěnčík A, Petřík I, Pavlović I, Novák O, Strnad M, Goicoa T, Ugarte MD, Montalbán IA. Cytokinins are involved in drought tolerance of Pinus radiata plants originating from embryonal masses induced at high temperatures. TREE PHYSIOLOGY 2021; 41:912-926. [PMID: 32348507 DOI: 10.1093/treephys/tpaa055] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/05/2019] [Revised: 04/07/2020] [Accepted: 04/21/2020] [Indexed: 05/22/2023]
Abstract
Vegetative propagation through somatic embryogenesis is an effective method to produce elite varieties and can be applied as a tool to study the response of plants to different stresses. Several studies show that environmental changes during embryogenesis could determine future plant development. Moreover, we previously reported that physical and chemical conditions during somatic embryogenesis can determine the protein, hormone and metabolite profiles, as well as the micromorphological and ultrastructural organization of embryonal masses and somatic embryos. In this sense, phytohormones are key players throughout the somatic embryogenesis process as well as during numerous stress-adaptation responses. In this work, we first applied different high-temperature regimes (30 °C, 4 weeks; 40 °C, 4 days; 50 °C, 5 min) during induction of Pinus radiata D. Don somatic embryogenesis, together with control temperature (23 °C). Then, the somatic plants regenerated from initiated embryogenic cell lines and cultivated in greenhouse conditions were subjected to drought stress and control treatments to evaluate survival, growth and several physiological traits (relative water content, water potential, photosynthesis, stomatal conductance and transpiration). Based on those preliminary results, even more extreme high-temperature regimes were applied during induction (40 °C, 4 h; 50 °C, 30 min; 60 °C, 5 min) and the corresponding cytokinin profiles of initiated embryonal masses from different lines were analysed. The results showed that the temperature regime during induction had delayed negative effects on drought resilience of somatic plants as indicated by survival, photosynthetic activity and water- use efficiency. However, high temperatures for extended periods of time enhanced subsequent plant growth in well-watered conditions. High-temperature regime treatments induced significant differences in the profile of total cytokinin bases, N6-isopentenyladenine, cis-zeatin riboside and trans-zeatin riboside. We concluded that phytohormones could be potential regulators of stress-response processes during initial steps of somatic embryogenesis and that they may have delayed implications in further developmental processes, determining the performance of the generated plants.
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Affiliation(s)
| | | | - Catia Pereira
- Department of Forestry Science, NEIKER, Arcaute 01080, Spain
- Department of Life Sciences, Universidade de Coimbra, Coimbra 3000-456, Portugal
| | - Aleš Pěnčík
- Laboratory of Growth Regulators, Faculty of Science, Institute of Experimental Botany of the Czech Academy of Sciences, Palacký University, Olomouc 783 71, Czech Republic
| | - Ivan Petřík
- Laboratory of Growth Regulators, Faculty of Science, Institute of Experimental Botany of the Czech Academy of Sciences, Palacký University, Olomouc 783 71, Czech Republic
| | - Iva Pavlović
- Laboratory of Growth Regulators, Faculty of Science, Institute of Experimental Botany of the Czech Academy of Sciences, Palacký University, Olomouc 783 71, Czech Republic
| | - Ondřej Novák
- Laboratory of Growth Regulators, Faculty of Science, Institute of Experimental Botany of the Czech Academy of Sciences, Palacký University, Olomouc 783 71, Czech Republic
| | - Miroslav Strnad
- Laboratory of Growth Regulators, Faculty of Science, Institute of Experimental Botany of the Czech Academy of Sciences, Palacký University, Olomouc 783 71, Czech Republic
| | - Tomas Goicoa
- Department of Statistics, Computer Science and Mathematics, Universidad Pública de Navarra, Pamplona 31006, Spain
| | - Maria D Ugarte
- Department of Statistics, Computer Science and Mathematics, Universidad Pública de Navarra, Pamplona 31006, Spain
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