UNASSIGNED: It is widely accepted that substantial nighttime sap flux (J s,n) or transpiration (E) occurs in most plants, but the physiological implications are poorly known. It has been hypothesized that J s,n or E serves to enhance @entity1568 uptake or deliver @entity26 ; however, no clear evidence is currently available. In this study, sap flux (J s) in @entity38242 * urophylla with apparent stem photosynthesis was measured, including control trees which were covered by @entity3775 foil (approximately 1/3 of tree height) to block stem photosynthesis. We hypothesized that the nighttime water flux would be suppressed in trees with lower stem photosynthesis. The results showed that the green tissue degraded after 3  months, demonstrating a decrease in stem photosynthesis. The daytime J s decreased by 21.47  %, while J s,n decreased by 12.03  % in covered trees as compared to that of control, and the difference was statistically significant (P   <   0.01). The linear quantile regression model showed that J s,n decreased for a given daytime transpiration water loss, indicating that J s,n was suppressed by lower stem photosynthesis in covered trees. Predawn (   pd) of covered trees was marginally higher than that of control while lower at predawn stomatal conductance (g s), indicating a suppressed water flux in covered trees. There was no difference in leaf @entity505 content and   @entity7352 between the two groups, while leaf @entity1568 content and   @entity13140 were significantly higher in covered trees than that of the control (P   <   0.05), indicating that J s,n was not used for @entity1568 uptake. These results suggest that J s,n may act as an @entity26 pathway since green tissue has a higher respiration or @entity26 demand than non-green tissue. Thus, this study demonstrated the physiological implications of J s,n and the possible benefits of nighttime water use or E by the tree.

Suppression of nighttime sap flux with lower stem photosynthesis in XXXX trees.

@entity38242 :: ('71139', 'Species') :: ['Eucalyptus grandis'] @entity1568 :: ('MESH:D009584', 'Chemical') :: ['nitrogen'] @entity3775 :: ('MESH:D000535', 'Chemical') :: ['aluminum'] @entity26 :: ('MESH:D010100', 'Chemical') :: ['oxygen'] @entity7352 :: ('CHEBI:36928', 'Chemical') :: ['(13)C'] @entity505 :: ('MESH:D002244', 'Chemical') :: ['carbon'] @entity13140 :: ('CHEBI:36934', 'Chemical') :: ['(15)N']
@entity38242 :: (71139,Species) :: ['Eucalyptus']
