Altitudinal changes in Rubisco and APX activities in Aconogonum weyrichii in the alpine region of Mt. Fuji

o identify the determinants of the altitudinal distribution of an alpine herbaceous plant (Aconogonum weyrichii) from an eco-physiological viewpoint, we investigated the leaf characteristics concerned with photosynthetic capacity and tolerance of oxidative stress throughout this species altitude distribution on Mt. Fuji. Larger amounts of leaf nitrogen and Rubisco were found in populations growing at higher altitudes; however, initial activity of Rubisco did not increase with altitude in the summer, indicating that inactivation of Rubisco occurred in the higher populations. This inactivation would lead to a decrease in photosynthetic nitrogen use efficiency. When the leaves of A. weyrichii began to turn yellow in autumn, amounts of leaf nitrogen and Rubisco remarkably decreased in all populations throughout the altitude distribution. However, Rubisco activity in the higher populations did not decline until immediately before defoliation, suggesting that recovery from Rubisco inactivation occurred in these populations. The higher populations had a higher activity of APX than lower populations, contributing to maintaining Rubisco activity and photosynthetic production until the end of the growing period, which, in turn, are necessary for survival at higher altitudes

High-spectral resolution observations of the 3.29 micron emission feature: Comparison to QCC and PAHs

Two of the most promising explanations for the origin of the interstellar emission features observed at 3.29, 3.4, 6.2, 7.7, 8.6, and 11.3 microns are: quenched carbonaceous composite (QCC) and polycyclic aromatic hydrocarbons (PAHs). High resolution spectra are given of the 3.29 micron emission feature which were taken with the Cooled Grating Array Spectrometer at the NASA Infrared Telescope Facility and previously published. These spectra show that the peak wavelength of the 3.29 micron feature is located at 3.295 + or - 0.005 micron and that it is coincident with the peak absorbance of QCC. The peak wavelength of the 3.29 micron feature appears to be the same in all of the sources observed thus far. However, the width of the feature in HD 44179 and Elias 1 is only 0.023 micron, which is smaller than the 0.043 micron width in NGC 7027, IRAS 21282+5050, the Orion nebula, and BD+30 deg 3639. Spectra of NGC 7027, QCC, and PAHs is shown. QCC matches the 3.29 micron interstellar emission feature very closely in the wavelength of the peak, and it produces a single feature. On the other hand, PAHs rarely match the peak of the interstellar emission feature, and characteristically produce multiple features