ISSN:
1432-2285
Keywords:
Protein-storage vacuole
;
Protein body
;
Softwoods
;
Nitrogen storage
;
Overwintering
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
,
Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
Notes:
Summary The seasonal occurrence of protein-storage vacuoles in parenchyma cells of the inner bark and leaf tissues of seven softwood species was examined. Previously published results showed that these organelles often fill the phloem parenchyma cells of the inner bark tissues in overwintering hardwoods, whereas they are absent from this tissue during the summer. We hypothesize that the organelles are involved in the storage of reduced nitrogen during wintering, in a manner analogous to protein bodies of seeds. A survey of the phloem and cambial parenchyma tissues in six evergreen softwood species (Pinus strobus, P. sylvestris, Picea abies, P. glauca, Abies balsamea, and Thuja occidentalis) and in one deciduous softwood species (Larix decidua) was conducted. There was a large variation in the degree and timing of protein-storage vacuole formation between the individual genera and species. The organelles were not seen in summer samples of inner bark tissues of any of the genera or species examined. Protein-storage vacuoles were common in the bark tissues of Pinus, Abies and Thuja, occasionally seen in Picea, and rarely found in Larix during the winter. One-year-old leaves were also examined, since in all but Larix they are overwintering structures and can act as potential sites of nitrogen storage. Protein-storage vacuoles were present in Pinus and Thuja leaf tissue in both summer and winter, in Abies during winter only, and were absent from Picea leaf tissue at all times. These results indicate that the formation of protein-storage vacuoles prior to overwintering is not a ubiquitous phenomenon in softwoods.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00227525
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