Articles
GROWTH AND SOURCE-SINK RELATIONSHIPS IN ‘TITAN’ RED RASPBERRY
Article number
352_21
Pages
151 – 158
Language
Abstract
A basic plant growth curve for ‘Titan’ red raspberry (Rubus idneus L.) was produced from sequential, destructive sampling of 2 year old potted plants.
Data showed that raspberry plants undergo seasonal shifts in dry matter partitioning between primocanes, floricanes and roots.
Primocane dry matter accumulation underwent three phases of growth.
Growth increased linearly up to peak harvest, leveled off during harvest, and then started to increase linearly again after the harvest period.
Floricanes experienced a gain in dry weight up to full bloom and did not experience any significant increase in dry weight until the end of the season, when a second flush of laterals emerged from previously dormant buds.
Roots experienced an initial loss in dry weight, as floricanes underwent bud break and primocanes emerged.
However, roots exhibited a significant increase in dry weight gain during the period that coincided with the onset of fruiting, followed by another loss in dry matter accumulation at peak harvest.
Radiolabeling experiments revealed that direction of export changed over the season and that sinks nearest the labelled leaflets had the highest intensity of label.
Furthermore, areas of rapid dry matter accumulation (primocane meristems, fruits and root meristems) also showed high levels of radioactive intensity.
Primocanes and floricanes do not appear to be sharing fixed carbon products during the fruiting period.
Roots may actually compete for photosynthate with primocane meristems early in the fruiting period, resulting in a reduction of primocane growth.
Meanwhile, floricanes may be importing reserves from the root system later in the fruiting period.
Data showed that raspberry plants undergo seasonal shifts in dry matter partitioning between primocanes, floricanes and roots.
Primocane dry matter accumulation underwent three phases of growth.
Growth increased linearly up to peak harvest, leveled off during harvest, and then started to increase linearly again after the harvest period.
Floricanes experienced a gain in dry weight up to full bloom and did not experience any significant increase in dry weight until the end of the season, when a second flush of laterals emerged from previously dormant buds.
Roots experienced an initial loss in dry weight, as floricanes underwent bud break and primocanes emerged.
However, roots exhibited a significant increase in dry weight gain during the period that coincided with the onset of fruiting, followed by another loss in dry matter accumulation at peak harvest.
Radiolabeling experiments revealed that direction of export changed over the season and that sinks nearest the labelled leaflets had the highest intensity of label.
Furthermore, areas of rapid dry matter accumulation (primocane meristems, fruits and root meristems) also showed high levels of radioactive intensity.
Primocanes and floricanes do not appear to be sharing fixed carbon products during the fruiting period.
Roots may actually compete for photosynthate with primocane meristems early in the fruiting period, resulting in a reduction of primocane growth.
Meanwhile, floricanes may be importing reserves from the root system later in the fruiting period.
Publication
Authors
Gina E. Fernandez, Marvin P. Pritts
Keywords
Rubus, dry matter partitioning, 14CO2 labeling
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