Photosynthetic activity in relation to a gradient of leaf nitrogen content within a canopy of Siebold's beech and Japanese oak saplings under elevated ozone.

The primary objective of this study was to describe parameters related to the leaf biochemical assimilation capacity of photosynthesis, such as the maximum rates of carboxylation (V) and electron transport (J), as a function of the leaf nitrogen content throughout a canopy of Siebold's beech and Japanese oak grown under elevated ozone (O) conditions during a growing season. To this end, we investigated the relationship between photosynthetic traits and leaf nitrogen content in various canopy positions of two tree species under free-air O exposure (60 nmol mol, during daylight hours) in June, August, and October 2012. We observed O-induced reduction in V and J without reduction of leaf nitrogen content in both tree species.

Functional improvements in β-lactoglobulin by conjugating with soybean soluble polysaccharide.

Soybean soluble polysaccharide (SSPS) was hydrolyzed by autoclaving for 6 and 12 h to obtain SSPS (6 h) and SSPS (12 h). Bovine β-lactoglobulin (BLG) was conjugated with each SSPS by the Maillard reaction to improve its function. Conjugation between BLG and each SSPS was confirmed by Sodium dodecyl sulfate polyacrylamide gel electrophoresis and isoelectric focusing.

Photosynthetic response of early and late leaves of white birch (Betula platyphylla var. japonica) grown under free-air ozone exposure.

Betula platyphylla var. japonica (white birch) has heterophyllous leaves (i.e.

Model-based analysis of avoidance of ozone stress by stomatal closure in Siebold's beech (Fagus crenata).

Background And Aims: Resistance of plants to ozone stress can be classified as either avoidance or tolerance. Avoidance of ozone stress may be explained by decreased stomatal conductance during ozone exposure because stomata are the principal interface for entry of ozone into plants. In this study, a coupled photosynthesis-stomatal model was modified to test whether the presence of ozone can induce avoidance of ozone stress by stomatal closure.

Canopy carbon budget of Siebold's beech (Fagus crenata) sapling under free air ozone exposure.

To determine the effects of ozone (O3) on the canopy carbon budget, we investigated photosynthesis and respiration of leaves of Siebold's beech saplings under free air O3 exposure (60 nmol mol(-1), during daytime) in relation to the within-canopy light gradient; we then calculated the canopy-level photosynthetic carbon gain (PCG) and respiratory carbon loss (RCL) using a canopy photosynthesis model. Susceptibilities of photosynthesis and respiration to O3 were greater in leaves of upper canopy than in the lower canopy. The canopy net carbon gain (NCG) was reduced by O3 by 12.

Photosynthetic traits of Siebold's beech and oak saplings grown under free air ozone exposure in northern Japan.

We set up a free-air ozone (O(3)) exposure system for determining the photosynthetic responses of Siebold's beech (Fagus crenata) and oak (Quercus mongolica var. crispula) to O(3) under field conditions. Ten-year-old saplings of beech and oak were exposed to an elevated O(3) concentration (60 nmol mol(-1)) during daytime from 6 August to 11 November 2011.

Ozone-induced stomatal sluggishness develops progressively in Siebold's beech (Fagus crenata).

We investigated the effects of ozone and leaf senescence on steady-state stomatal conductance and stomatal response to light variation. Measurements were carried out in a free-air ozone exposure experiment on a representative deciduous broadleaved tree species in Japan (Fagus crenata). Both steady-state and dynamic stomatal response to light variation varied intrinsically with season due to leaf senescence.