Abstract
Conifer somatic embryo germination and early seedling growth are fundamentally different than in their zygotic counterparts in that the living maternal megagametophyte tissue surrounding the embryo is absent. The megagametophyte contains the majority of the seed storage reserves in loblolly pine and the lack of the megagametophyte tissue poses a significant challenge to somatic embryo germination and growth. We investigated the differences in seed storage reserves between loblolly pine mature zygotic embryos and somatic embryos that were capable of germination and early seedling growth. Somatic embryos utilized in this study contained significantly lower levels of triacylglycerol and higher levels of storage proteins relative to zygotic embryos. A shift in the ratio of soluble to insoluble protein present was also observed. Mature zygotic embryos had roughly a 3:2 ratio of soluble to insoluble protein whereas the somatic embryos contained over 5-fold more soluble protein compared to insoluble protein. This indicates that the somatic embryos are not only producing more protein overall, but that this protein is biased more heavily towards soluble protein, indicating possible differences in metabolic activity at the time of desiccation.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
Abbreviations
- ABA:
-
Abscisic acid
- PEG:
-
Polyethylene glycol
- TAG:
-
Triacylglycerol
References
Attree SM, Pomeroy MK, Fowke LC (1992) Manipulation of conditions for the culture of somatic embryos of white spruce for improved triacylglycerol biosynthesis and desiccation tolerance. Planta 187:395–404
Attree SM, Pomeroy MK, Fowke LC (1995) Development of white spruce (Picea-Glauca (Moench) Voss) somatic embryos during culture with abscisic-acid and osmoticum, and their tolerance to drying and frozen storage. J Exp Bot 46:433–439
Beardmore T, Charest PJ. (1995) Black spruce somatic embryo germination and desiccation tolerance. I. Effect of abscisic acid, cold, and heat treatments on the germinability of mature black spruce somatic embryos. Can J For Res 25:1763–1772
Becwar MR, Nagmani R, Wann SR (1990) Initiation of embryogenic cultures and somatic embryo development in loblolly pine (Pinus taeda). Can J For Res 20:810–817
Feirer RP, Conkey JH, Verhagen SA (1989) Triglycerides in embryonic conifer calli: a comparison with zygotic embryos. Plant Cell Rep 8:207–209
Groome MC, Axler SR, Gifford DJ (1991) Hydrolysis of lipid and protein reserves in loblolly pine seeds in relation of protein electrophoretic patterns following imbibition. Physiol. Plant 83:99–106
Gupta PK, Durzan DJ (1987) Biotechnology of somatic polyembryogenesis and plantlet regeneration in loblolly pine. Biotechnology 5:147–151
King JE, Gifford DJ (1997) Amino acid utilization in seeds of loblolly pine during germination and early seedling growth. Plant Physiol 113:1125–1135
Klimaszewska K, Morency F, Jones-Overon C, Cooke J (2004) Accumulation pattern of seed storage proteins in zygotic embryos of Pinus strobes and in somatic embryos from different maturation treatments. Physiol Plant 121:682–690
Lowry OH, Rosebrough NJ, Farr AL, Randall RJ (1951) Protein measurement with the Folin phenol reagent. J Biol Chem 193:265–275
Mhaske VB, Chengalrayan K, Hazra S (1998) Influence of osmotica and abscisic acid on triglyceride accumulation in peanut somatic embryos. Plant Cell Rep 17:742–746
Pullman GS, Buchanan M (2003) Loblolly pine (Pinus taeda L.): stage-specific elemental analyses of zygotic embryo and female gametophytic tissue. Plant Sci 164:943–953
Pullman GS, Johnson S, Peter G, Cairney J, Xu N (2003a) Improving loblolly pine somatic embryo maturation: comparison of somatic and zygotic embryo morphology, germination, and gene expression. Plant Cell Rep 21:747–758
Pullman GS, Montello P, Cairney J, Xu N, Feng X (2003b) Loblolly pine (Pinus taeda L.) somatic embryogenesis: maturation improvements by metal analysis of zygotic and somatic embryos. Plant Sci 164:955–969
Stasolla C, Kong L, Yeung EC, Thorpe TA (2002) Maturation of somatic embryos in conifers: Morphogenesis, physiology, biochemistry, and molecular biology. In Vitro Cell Dev Biol-Plant 38:93–105
Stone SL, Gifford DJ (1997) Structural and biochemical changes in loblolly pine (Pinus taeda L.) seeds during germination and early seedling growth. I. Storage protein reserves. Int J Plant Sci 158:727–737
Stone SL, Gifford DJ (1999) Structural and biochemical changes in loblolly pine (Pinus taeda L.) seeds during germination and early seedling growth. II. Storage triacylglycerols and carbohydrates. Int J Plant Sci 160:663–671
Taber RP, Zhang C, Hu WS (1998) Kinetics of Douglas-fir (Pseudotsuga menziesii) somatic embryo development. Can J Bot 76:863–871
Todd CD, Gifford DJ (2002) The role of the megagametophyte in maintaining loblolly pine (Pinus taeda L.) seedling arginase gene expression in vitro. Planta 215:110–118
Todd CD, Gifford DJ (2003) Loblolly pine arginase responds to arginine in vitro. Planta 217:610–615
Acknowledgements
This work was supported by funds from NSERC awarded to DJG. This work is in memory of Dr. David Gifford who passed away prior to publication.
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Brownfield, D.L., Todd, C.D., Stone, S.L. et al. Patterns of storage protein and triacylglycerol accumulation during loblolly pine somatic embryo maturation. Plant Cell Tiss Organ Cult 88, 217–223 (2007). https://doi.org/10.1007/s11240-006-9193-0
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s11240-006-9193-0