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Summary: Although the signalling pathway of blue light (BL)‐dependent stomatal opening is well characterized, little is known about the interspecific diversity, the role it plays in the regulation of gas exchange and the source of energy used to drive the commonly observed increase in pore aperture.Using a combination of red and BL under ambient and low [O2] (to inhibit respiration), the interaction between BL, photosynthesis and respiration in determining stomatal conductance was investigated. These findings were used to develop a novel model to predict the feedback between photosynthesis and stomatal conductance under these conditions.Here we demonstrate that BL‐induced stomatal responses are far from universal, and that significant species‐specific differences exist in terms of both rapidity and magnitude. Increased stomatal conductance under BL reduced photosynthetic limitation, at the expense of water loss. Moreover, we stress the importance of the synergistic effect of BL and respiration in driving rapid stomatal movements, especially when photosynthesis is limited.These observations will help reshape our understanding of diurnal gas exchange in order to exploit the dynamic coordination between the rate of carbon assimilation (A) and stomatal conductance (gs), as a target for enhancing crop performance and water use efficiency. [ABSTRACT FROM AUTHOR]

Summary: The sessile lifestyle of plants requires accurate physiology adjustments to be able to thrive in a changing environment. Plants integrate environmental timing signals to control developmental and stress responses.Here, we identified Far1 Related Sequence (FRS) 7 and FRS12, two transcriptional repressors that accumulate in short‐day conditions, as regulators of Arabidopsis glucosinolate (GSL) biosynthesis.Loss of function of FRS7 and FRS12 results in plants with increased amplitudes of diurnal expression of GSL pathway genes. Protein interaction analyses revealed that FRS7 and FRS12 recruit the NOVEL INTERACTOR OF JAZ (NINJA) to assemble a transcriptional repressor complex.Genetic and molecular evidence demonstrated that FRS7, FRS12 and NINJA jointly regulate the expression of GSL biosynthetic genes, and thus constitute a molecular mechanism that modulates specialized metabolite accumulation. [ABSTRACT FROM AUTHOR]

Global budgets ascribe 4-10% of atmospheric methane ( CH4) sinks to upland soils and have assumed until recently that soils are the sole surface for CH4 exchange in upland forests., Here we report that CH4 is emitted from the stems of dominant tree species in a temperate upland forest, measured using both the traditional static-chamber method and a new high-frequency, automated system., Tree emissions averaged across 68 observations on 17 trees from May to September were 1.59 ± 0.88 μmol CH4 m−2 stem h−1 (mean ± 95% confidence interval), while soils adjacent to the trees consumed atmospheric CH4 at a rate of −4.52 ± 0.64 μmol CH4 m−2 soil h−1 ( P < 0.0001). High-frequency measurements revealed diurnal patterns in the rate of tree-stem CH4 emissions., A simple scaling exercise suggested that tree emissions offset 1-6% of the growing season soil CH4 sink and may have briefly changed the forest to a net CH4 source. [ABSTRACT FROM AUTHOR]

Summary • Although fructan accumulation is reported in photosynthetically active organs, the long-term storage of fructan mainly occurs in more heterotrophic tissues. Significant amounts of fructan are stored in the internodes during grain filling of wheat (Triticum aestivum ). The uppermost internode (peduncle) of wheat consists of a lower unexposed (i.e. enclosed by the flag leaf sheath and thus heterotrophic part, P l ) and an upper exposed autotrophic part (P u ). • Diurnal and long-term changes of fructan and sucrose (the precursor of fructan synthesis) contents were studied in P l and P u of potted wheat plants. • At mid grain-filling the sucrose concentration in P u increased almost threefold during the light period and decreased in the following night. Diurnal changes in sucrose concentration were much less expressed in P l . Fructan concentration was significantly higher in P l than in P u and did not change during the light period. • In another experiment, field grown wheat plants were sampled at regular intervals between 5 d before anthesis and grain maturity. At the time of maximum fructan content, 88% of the fructans in the total peduncle were stored in the heterotrophic P l . Within P l , fructan accumulation started in the older segments. The reason for the sharp separation of fructan storage between P l and P u remains unclear. [ABSTRACT FROM AUTHOR]

Glass chambers were used to isolate 0·75 m deep water columns in situ in deepwater rice fields in Thailand to evaluate the contribution by various factors to the pronounced diurnal changes in O2 concentrations in the floodwater. Chambers filled with distilled water provided estimates of O2 flow from the air into the water, indicating the importance of eddy currents associated with wind action and evaporative cooling. Darkening the natural water gave estimates for O2 evolution due to photosynthesis, while comparisons between columns with and without rice distinguished between O2 evolution and consumption by the rice and the biomass other than rice respectively. Removal of the above water portions of the rice shoots showed the importance of the emergent portion of the canopy to O2 movement from the air into the aquatic part of the ecosystem. This flow may be associated with O2 flow through the lacunae and via air envelopes around the leaf, and with turbulence caused by swaying of the rice leaves in the wind. The changes in O2 concentration were analysed quantitatively using several simplifying assumptions. One major input was a net O2 flow from the air into the water, about half being due to a net flow across the air water interface and the other half to flow associated with the rice plants. During the night, these flows were less than the O2 uptake by the biomass, hence O2 concentrations decreased. In the underwater portion of the rice stand, about 60% of the O2 uptake was due to the rice and about 40% due to the biomass other than rice. During the day, the O2 requirements by respiration were more than compensated for by O2 evolution due to photosynthesis, resulting in increases in O2 concentration of the water. [ABSTRACT FROM AUTHOR]