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Phytotoxic air pollutants such as atmospheric nitrogen dioxide (NO2) are among the major stresses affecting tree photosynthesis in urban areas. We clarified the relationship between NO2 concentrations and photosynthetic function for three major urban trees, Prunus × yedoensis, Rhododendron pulchrum, and Ginkgo biloba, planted in Kyoto and surrounding cities, combining our published data and new data collected from 2020 to 2023. High NO2 increased long-term water use efficiency for all species. High NO2 decreased photosynthesis in P. yedoensis and R. pulchrum, while for G. biloba, NO2 imposed little effect on photosynthesis. We then focused on the decrease in NO2 due to (1) air pollution control measures from 2005 to 2023 and (2) the economic recession caused by the COVID-19 pandemic, and examined whether these factors improved photosynthesis in urban trees. The historic decrease in NO2 improved leaf photosynthesis for P. yedoensis and R. pulchrum, while the COVID-19 pandemic reduced NO2 by only 0.3 ppb and did not further improve photosynthesis in these tree species. This report shows that air pollution control measures improved photosynthesis in urban trees over several years in Japan, and is valuable because it demonstrates that air pollution control measures can increase CO2 uptake by urban trees. [ABSTRACT FROM AUTHOR]

We demonstrate exceptionally high slow-neutron diffraction efficiency (≈ 70% of transmitted intensity diffracted to the first order) from a holographic nanodiamond–polymer composite grating of only tens of micrometers thickness at the average neutron wavelength of 5.3 nm. By meticulous choice of materials for extreme refractive index modulation in a thin grating structure, we overcome typical wavelength and angular selectivity issues usually encountered when pursuing high diffraction efficiencies with a thick grating. This achievement paves the way for the implementation of flux-efficient diffractive elements, well-suited for polychromatic beams, and weakly collimated slow-neutron beams. [ABSTRACT FROM AUTHOR]

Typhulaceae Jülich is one of the cold-adapted fungal families in basidiomycetes. The representative genera, Typhula (Pers.) Fr. and Pistillaria Fr., are distinguished by the discontinuity between stems and hymenia in the former and the continuity in the latter (Fries 1821). This taxonomic criterion is ambiguous, and consequently, the view of Karsten (1882) has been widely accepted: Typhula develops basidiomata from sclerotia, while basidiomata develop directly from substrata in Pistillaris. However, Corner (1970) observed basidiomata of Pistillaria petasitis S. Imai developing from sclerotia in Hokkaido, Japan. We later recognized that P. petasitis basidiomata also emerged directly from substrates on the ground in Hokkaido. An aberrant form of Typhula hyperborea H. Ekstr. was found in Upernavik, West Greenland. This specimen had a stem-like structure on a Poaceae plant, and sclerotia developed on its tip. Similar phenomena were found in other Typhula species in Japan. In this study, we aimed to elucidate the life cycle plasticity in the genera Typhula and Pistillaria through the interactions between their ecophysiological potential and environmental conditions in their localities. We collected and prepared strains of the above fungi from sclerotia or basidiomata, and we elucidated the taxonomical relationship and determined the physiological characteristics of our strains. Our findings imply that both Typhula and Pistillaria have the potential to produce sclerotia as well as the capacity for mycelial growth at ambient air temperatures in each locality where samples were collected. These findings suggest that Typhula spp. develope basidiomata not only from the sclerotia dispersed by the basidiospores but also from mycelia generated by the spore germination, which formed basidiomata multiple times, depending on their growth environments. [ABSTRACT FROM AUTHOR]

Background and Aims For a comprehensive understanding of the mechanisms of changing plant photosynthetic capacity during plant evolutionary history, knowledge of leaf gas exchange and optical properties are essential, both of which relate strongly to mesophyll anatomy. Although ferns are suitable for investigating the evolutionary history of photosynthetic capacity, comprehensive research of fern species has yet to be undertaken in this regard. Methods We investigated leaf optical properties, gas exchange and mesophyll anatomy of fern species with a wide range of divergence time, using 66 ferns from natural habitats and eight glasshouse-grown ferns. We used a spectroradiometer and an integrating sphere to measure light absorptance and reflectance by the leaves. Key Results The more newly divergent fern species had a thicker mesophyll, a larger surface area of chloroplasts facing the intercellular airspaces (S c), thicker cell walls and large light absorptance. Although no trend with divergence time was obtained in leaf photosynthetic capacity on a leaf-area basis, when the traits were expressed on a mesophyll-thickness basis, trends in leaf photosynthetic capacity became apparent. On a mesophyll-thickness basis, the more newly divergent species had a low maximum photosynthesis rate, accompanied by a low S c. Conclusions We found a strong link between light capture, mesophyll anatomy and photosynthesis rate in fern species for the first time. The thick mesophyll of the more newly divergent ferns does not necessarily relate to the high photosynthetic capacity on a leaf-area basis. Rather, the thick mesophyll accompanied by thick cell walls allowed the ferns to adapt to a wider range of environments through increasing leaf toughness, which would contribute to the diversification of fern species. [ABSTRACT FROM AUTHOR]

To investigate the direct physiological effects of CNU (canopy nitrogen uptake), three mist solutions (control, [N.sub.1], and [N.sub.2] with 0.03, 13.1, and 32.7 kg [NH+.sub.4]-N*[ha.sup.-1], respectively) were sprayed on Japanese red pine (Pinus densiflora Sieb. et Zucc.) seedlings three times a week for three months. Waterproof sheets protected the surface soil during misting to avoid adding N to the soil. The results show N mist treatments to foliage increased needle N availability in proportion to N dose, which was large enough to cause greater N and chlorophyll content in the needles. This suggests that N is rapidly absorbed, is directly assimilated by the needles, and is used in photosynthesis. These increases resulted in higher maximum net [CO.sub.2] assimilation rates ([A.sub.max]) and maximum quantum yield of PSII photochemistry ([F.sub.v]/[F.sub.m]) of pine seedlings and subsequently increased bud and root biomass. Increased root biomass reduced the sensitivity of the shoot-to-root ratio to increased N availability in the foliage. In conclusion, our study supported the idea that CNU should be taken into consideration when evaluating the impacts of elevated atmospheric N deposition on forest C sequestration and biomass allocation. Resume: Pour etudier les effets physiologiques indirects de l'absorption d'azote (N) par la canopee, trois solutions (temoin, [N.sub.1] et [N.sub.2] contenant respectivement 0,03, 13,1 et 32,7 kg [N-NH+.sub.4]*[ha.sup.-1]) ont ete pulverisees sur des semis de pin rouge du Ja-pon (Pinus densiflora Siebold & Zucc.) trois fois par semaine pendant trois mois. Des feuilles impermeables protegeaient le sol de surface lors des applications pour eviter d'ajouter N dans le sol. Les resultats montrent que la vaporisation de N sur le feuillage a augmente la disponibilite de N dans les aiguilles proportionnellement a la dose de N, qui etait suffisamment elevee pour augmenter la teneur en N et en chlorophylle dans les aiguilles. Cela signifie que N est rapidement absorbe, di-rectement assimile par les aiguilles et utilise dans la photosynthese. Ces apports ont entraine une augmentation du taux maximal d'assimilation nette de [CO.sub.2] ([A.sub.max]) et du rendement quantique maximum de la photochimie de PSII (F [.sub.v]/[F.sub.m]) des se-mis de pin et une augmentation subsequente de la biomasse des bourgeons et des racines. L'augmentation de la biomasse des racines a reduit la sensibilite du rapport tige a racines a la disponibilite accrue de N dans le feuillage. En conclusion, notre etude supporte l'idee qu'on devrait tenir compte de l'absorption de N par la canopee lorsqu'on evalue les impacts des depots eleves de N atmospherique sur la sequestration de C et l'allocation de la biomasse dans les forets. [Traduit par la Redaction], Introduction Understanding the role and extent of canopy nitrogen up-take (CNU) is critical to fully understanding the impact of elevated atmospheric N deposition on forest C sequestration. The global rate [...]