Distribution of [¹⁴C]‐labeled photosynthates within intensively cultured Populus clones during the establishment year

Abstract

Seasonal patterns of [14C]‐labeled photosynthate distribution within two intensively cultured Populus clones with contrasting phenology (P. tristis × P. balsamifera cv. ‘Tristis no. 1′; P. × euramericana cv. Eugenei) were investigated during the establishment year. During active shoot elongation upper mature leaves exported 14C acropetally to the expanding leaves and elongating internodes, and basipetally to the stem. Little 14C was exported to lower mature leaves or lateral branches. At budset the 14C export pattern shifted dramatically in the basipetal direction, i.e., to the lower stem, hardwood cutting, and roots. The timing of budset was the primary factor determining the differences between the clones, except that in all cases Tristis exported more 14C to the roots than Eugenei. After budset lower mature leaves had a similar export pattern to upper leaves, but the quantity of 14C exported to the roots was slightly higher. The results confirm the importance of autumn foliage for root growth in poplar. Clonal differences in seasonal patterns of photosynthate distribution offer potential for the poplar breeder seeking to match a clone's growth pattern with the specific growing season of the site.

Effect of Initiation Timing of Drought Stress on Carbohydrate Content and Vegetative Growth in Japanese Apricot (Prunus mume Sieb. et Zucc.) ‘Nanko’

“…Preferential carbohydrate accumulation in the roots has been shown to occur in autumn, as various 14 C studies using apple trees have shown (Hansen, 1967;Kandiah, 1979;Quinlan, 1969). This could account for roots gaining sink strength as the season progresses in autumn, as confirmed by Isebrands and Nelson (1983) throughout the research of 14 C labeling in the poplar tree. These reports suggest a strong possibility that carbohydrates are transported to roots Table 1.…”

Carbon and nitrogen allocation in trees

“…No such detailed quantitative information on carbon and nitrogen allocation is available for any tree species. However, there is considerable descriptive information for carbon allocation in Populus (Isebrands and Nelson, 1983; Dickson, 1986;Bonicel et al, 1987), and for carbon and nitrogen allocation in fruit trees (Titus and Kang, 1982;Tromp, 1983;Kato, 1986 (Schulze, 1982 (Dickson and Nelson, 1982;Smith and P;aul, 1988 (Schulze, 1982 (Pearcy et al, 1987). However, only a small portion of total leaf mass is renewed each year.…”

Carbon allocation and morphology of cherrybark oak seedlings and sprouts under three light regimes

“…Slight accumulations of 14 C in these tissues probably reflects retransport of 14 C-assimilates from root tissues rather than direct transport from source leaves (Dickson et al, 1990). Isebrands and Nelson (1983) also found low levels of 14 C in unlabeled branch tissues in Populus clones and, therefore, were not "parasitic" on the rest of the plant.…”

“…Labeling methods followed those used by Isebrands and Nelson (1983) and Lockhart et al (2003). A plastic cup and tygon tubing were taped to the primary first flush stem of each cherrybark oak seedling.…”