Shoot culture dynamics of six Populus clones   总被引：1，自引：0，他引：1  

Sellmer JC  McCown BH  Haissig BE 《Tree physiology》1989,5(2):219-227

Shoot tips of five genotypically diverse Populus clones, P. alba x P. grandidentata 'Crandon,' P. nigra 'Betulifolia' x P. trichocarpa, P. nigra x P. laurifolia 'Strathglass,' P. maximowiczii x P. trichocarpa 'Androscoggin' and P. deltoides x P. nigra 'Eugenei,' were collected from hardwood cuttings, sterilized,and established in vitro. Stable shoot cultures were obtained from all clones except P. deltoides x P. nigra 'Eugenei'. The four poplar clones that formed stable shoot cultures together with a previously established P. tremula 'Erecta' clone were placed as two-node explants on either Murashige and Skoog medium or Woody Plant Medium containing benzyladenine to determine the rate of shoot multiplication, shoot growth and other responses of the clones. All five poplar clones showed rapid shoot multiplication when cultured in the presence of 0.4-1.0 microM benzyladenine on Murashige and Skoog medium, although P. tremula 'Erecta' produced a greater number of healthy shoots when grown on Woody Plant Medium. Individual shoot growth of all clones was more vigorous when the medium contained 0-0.1 microM benzyladenine, and 100% of such shoots rooted ex vitro.  相似文献   

Seasonal variation in the photosynthetic capacity of a willow (Salix cv. Aquatica gigantea) canopy. 1 Changes in the activity and amount of ribulose 1,5-bisphosphate carboxylase-oxygenase and the content of nitrogen and chlorophyll at different levels in the canopy     

Vapaavuori EM  Vuorinen AH 《Tree physiology》1989,5(4):423-444

The role of ribulose 1,5-bisphosphate carboxylase-oxygenase (Rubisco) in the regulation of photosynthesis in the field was assessed by following changes in the amount and activity of Rubisco and in the amounts of chlorophyll and total nitrogen in a willow (Salix cv. Aquatica gigantea) canopy during two growing seasons. An additional aim of this study was to determine how nitrogen is partitioned in the canopy and whether Rubisco and chlorophyll serve as sources of nitrogen. During both growing seasons, the total activity and the amount of Rubisco were high in young, sun-exposed leaves and decreased as the leaves aged and became shaded. In 1985, the specific activity was low (on average 0.8 micromol mm(-1) mg(-1) Rubisco protein) compared with the values obtained in 1986 (on average 1.8 micromol min(-1) mg(-1) Rubisco protein). These differences in the specific activity of Rubisco between the two years might be associated with changes in partitioning of nitrogen. During the cool summer of 1985, about 20% of the total nitrogen was partitioned to Rubisco compared with about 13% during the warm summer of 1986. Rubisco comprised a high proportion (about 60%) of the total soluble protein throughout the 1985 growing season, whereas during the 1986 growing season, the proportion of Rubisco in the total soluble protein fraction was lower and decreased markedly as the leaves became shaded. Chlorophyll did not serve as a source of nitrogen in the canopy. On the contrary, the proportion of total nitrogen in chlorophyll increased with time, which indicates acclimation of the thylakoid membranes to decreasing irradiance. The degree of activation of Rubisco in samples collected in 1986 was high in young, sun-exposed leaves, which suggests that in these leaves, Rubisco may limit the rate of CO(2) uptake. In the shaded leaves of the lower canopy, the degree of activation of Rubisco was low, which indicates that in these leaves, photosynthesis is limited by factors other than Rubisco.  相似文献   

An Entrepreneurial Tree Sprouts in Europe: Although their numbers are small compared to the United States, scientists in Europe are leaving academic research in growing numbers to start new high-tech companies     

Dickson D 《Science (New York, N.Y.)》1989,245(4922):1038-1040

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The idea of symmetry: felix klein and sophus lie     

Rowe D 《Science (New York, N.Y.)》1989,246(4932):940-941

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Support for plant biology     

Abelson PH 《Science (New York, N.Y.)》1989,246(4932):865

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Remembering Reconsidered. Ecological and Traditional Approaches to the Study of Memory. Ulric Neisser and Eugene Winograd, Eds. Cambridge University Press, New York, 1988. x, 390 pp., illus. $44.50. Emory Symposia in Cognition, vol. 2. From a conference, Atlanta, GA, Oct. 1985     

Schacter DL 《Science (New York, N.Y.)》1989,243(4896):1375-1376

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Broad training for social scientists     

Barkow JH 《Science (New York, N.Y.)》1989,243(4894):992

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Scientific competency through fun     

Koshland DE 《Science (New York, N.Y.)》1989,243(4894):989

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Government and quality in science     

Davis BD 《Science (New York, N.Y.)》1989,246(4931):736

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Space facility     

Korkegi RH 《Science (New York, N.Y.)》1989,244(4908):1030

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