TY - JOUR
T1 - The role of sink demand in carbon partitioning and photosynthetic reinvigoration following shoot decapitation
AU - Tschaplinski, Timothy J.
AU - Blake, Terence J.
PY - 1989/2
Y1 - 1989/2
N2 - Photosynthesis, growth, and carbon partitioning of vigorous coppice shoots were compared with the slower growing intact shoots of Populus maximowiczii×nigra L. MN9 to determine the relationship between carbon partitioning and photosynthetic rate. Relative height growth rate of coppice shoots was 2.2 times that of intact shoots with net photosynthetic rate 1.9 times that of intact shoots. Coppice leaves exported a larger proportion of newly‐fixed assimilate (11% compared with 6%) after a 4‐h chase. The greater export from coppice leaves was correlated with a greater proportion of [14C]‐labelled photosynthate deposited as starch in stems 4 cm below the point of label application. Coppice leaf assimilate levels were reduced to 15% that of leaves on intact plants, but coppice leaves had twice the concentration of labelled sucrose. Carbohydrates constituted 55% of the water‐soluble [14C]‐labelled photosynthate in leaves of coppice shoots compared with 40% in intact shoots. The results suggest that carbon allocation and partitioning in coppice shoots were altered towards production and export of new assimilate, and support the hypothesis that photosynthetic rate is responsive to sink demand for assimilates.
AB - Photosynthesis, growth, and carbon partitioning of vigorous coppice shoots were compared with the slower growing intact shoots of Populus maximowiczii×nigra L. MN9 to determine the relationship between carbon partitioning and photosynthetic rate. Relative height growth rate of coppice shoots was 2.2 times that of intact shoots with net photosynthetic rate 1.9 times that of intact shoots. Coppice leaves exported a larger proportion of newly‐fixed assimilate (11% compared with 6%) after a 4‐h chase. The greater export from coppice leaves was correlated with a greater proportion of [14C]‐labelled photosynthate deposited as starch in stems 4 cm below the point of label application. Coppice leaf assimilate levels were reduced to 15% that of leaves on intact plants, but coppice leaves had twice the concentration of labelled sucrose. Carbohydrates constituted 55% of the water‐soluble [14C]‐labelled photosynthate in leaves of coppice shoots compared with 40% in intact shoots. The results suggest that carbon allocation and partitioning in coppice shoots were altered towards production and export of new assimilate, and support the hypothesis that photosynthetic rate is responsive to sink demand for assimilates.
KW - Carbohydrate
KW - Populus maximowiczii×nigra
KW - net photosynthesis
KW - starch deposition
UR - http://www.scopus.com/inward/record.url?scp=84989714139&partnerID=8YFLogxK
U2 - 10.1111/j.1399-3054.1989.tb06164.x
DO - 10.1111/j.1399-3054.1989.tb06164.x
M3 - Article
AN - SCOPUS:84989714139
SN - 0031-9317
VL - 75
SP - 166
EP - 173
JO - Physiologia Plantarum
JF - Physiologia Plantarum
IS - 2
ER -