Effect of Elevated CO2 on the Growth of Two Different Climate-origin Forbs in Four Levels of Nitrogen Nutrition

Two different climate-origin forbs, Chenopodium album L. (native to temperate regions) and Amaranthus patulus Benol (native to neo-tropical regions), were grown in growth chambers at two CO2 levels, 350 and 700 ppm, under [our levels of nitrogen nutrition. Elevated CO2 resulted in increased total biomass and decreased leaf-nitrogen concentration in C. allmm. A decrease in specific leaf area (SLA) was observed with C. album in enriched C0'l' but not in A. patulus. There were no apparent CO2 effects on the growth of A. patulus, but CO2 effects on the growth of C. album were amplified as the nutrient level increased. There was no significant change in allocation between the top (shoot) and root of either species in relation to CO~ enrichment. At present, the two species are co-existing in the eutrophic soil conditions of early successional stages, such as in waste or abandoned fields. However, under elevated CO2 conditions, C. album will probably increase its relative dominance and distribution while A. patulus wiII not. The results imply that the effects of CO2 level on the plants will depend on their climatic origins

Molecular clouds towards RCW 49 and Westerlund 2; Evidence for cluster formation triggered by cloud-cloud collision

We have made CO(J=2-1) observations towards the HII region RCW 49 and its ionizing source, the rich stellar cluster Westerlund 2 (hereafter Wd2), with the NANTEN2 sub-mm telescope. These observations have revealed that two molecular clouds in velocity ranges of -11 to +9 km/s and 11 to 21 km/s respectively, show remarkably good spatial correlations with the Spitzer IRAC mid-infrared image of RCW 49, as well a velocity structures indicative of localized expansion around the bright central regions and stellar cluster. This strongly argues that the two clouds are physically associated with RCW 49. We obtain a new kinematic distance estimate to RCW 49 and Wd2 of 5.4^{+ 1.1}_{- 1.4} kpc, based on the mean velocity and velocity spread of the associated gas. We argue that acceleration of the gas by stellar winds from Wd2 is insufficient to explain the entire observed velocity dispersion of the molecular gas, and suggest a scenario in which a collision between the two clouds ~4 Myrs ago may have triggered the formation of the stellar cluster.Comment: A version with higher resolution figures is available from http://www.a.phys.nagoya-u.ac.jp/~naoko/research/apjl2009/fur09_rev_highreso.pd

Phenological characteristics of reproduction and seed formation in Durio zibethinus Murray

Phenological characteristics during the reproductive processes of flower budding, flowering, fruiting and seed formation were investigated in a Durio zibethinus Murray tree growing in an experimental field of Universiti Putra Malaysia (UPM) in Selangor, Peninsular Malaysia. The survival curve showed that the relative fall rate of reproductive organs was lower at the mixed stages of flower budding, flowering and fruiting than at the early fruiting stage. The fall of flower buds commenced after the flower budding was completed. However, the falls of flowers and fruits occurred within a few days after the formation of flowering and fruiting. The periods of flower budding, flowering and fruiting were 34, 19 and 28 days, respectively. The fruit weight growth was approximated by a logistic equation, where the intrinsic growth rate varied from 0.419 to 0.794 week-1. The forming seeds germinated or possessed germination ability at the fruit growth stage where the fruit weight reached the asymptote of the logistic growth curve. Total numbers of emerged flower buds, flowers and fruits over the whole reproductive period were 1629, 1467 and 1412 per tree, respectively. The percentage of fruits with germination ability was estimated to be 1.2% of the number of fruiting ones

Cross-sectional performance of hollow square prisms with rounded edges

Hollow-section columns are one of the mechanically superior structures with high buckling resistance and high bending stiffness. The mechanical properties of the column are strongly influenced by the cross-sectional shape. Therefore, when evaluating the stability of a column against external forces, it is necessary to accurately reproduce the cross-sectional shape. In this study, we propose a mathematical method to describe a polygonal section with rounded edges and vertices. This mathematical model would be quite useful for analyzing the mechanical properties of plants and designing plant-mimicking functional structures, since the cross-sections of the actual plant culms and stems often show rounded polygons.Comment: 9 pages, 8 figure

Development of outfitting and human body representation method Using Virtual/Augumented Reality ; Interactive Clothes Modeling for Apparel Production System

Article先進繊維技術科学に関する研究報告 平成11年度成果報告 6: 65-66(2000)research repor

Light reduction by regional haze and its effect on simulated leaf photosynthesis in a tropical forest of Malaysia

The general level of haze has increased rapidly in tropical regions over the last decades. To reveal the effects of haze on tropical forest ecosystem, photosynthetic photon flux density (PFD) at the top of and within a tropical forest canopy was measured on days with and without visible haze, in the Pasoh Forest Reserve, Peninsular Malaysia. Total daily PFD at 40 m aboveground on hazy days was only about 50% of that on the days without visible haze. The reduction of PFD on hazy days was much larger at 50 cm aboveground within the forest. During the period with haze, the forest understory received few PFD higher than 50 μ mol photons m−2 s−1. Photosynthetic carbon gain was estimated to examine the potential effect of PFD extinction by haze. Under hazy conditions, the simulated net carbon gain, which included photosynthetic carbon gain of daytime and respiratory carbon loss at night, decreased to about −6 mmol CO2 m−2 for an ‘average’ shade leaf of understory plants. This marked decrease of leaf carbon gain might have important impacts on the growth and survival of understory plants, and therefore on the regeneration of tree species in the tropical forest

Photosynthetic rates of four tree species in the upper canopy of a tropical rain forest at the Pasoh Forest Reserve in Peninsular Malaysia

Measurements of photosynthesis (A) and stomatal conductance (gs) were conducted using the leaves of four tropical tree species (Dipterocarpus sublamellatus, Neobalanocarpus heimii, Ptychopyxis caput-medusae, and Xanthophyllum amoneum) in the canopy of the lowland forest at the Pasoh Forest Reserve in peninsular Malaysia. A canopy walkway was used to reach the canopy of 30- to 40-m-tall trees and diurnal changes in A and gs were determined. The diurnal patterns for A differed between days and between species, though A of the four species were similar but quite low. In general, A increased with increasing photosynthetically active radiation (PAR) before noon, then declined. As well, a linear relationship was detected between gs and A, but no statistically significant correlation could be confirmed between these two factors for D. sublamellatus and P. caput-medusae in November and July. The value of gs decreased with increasing vapor pressure deficit for D. sublamellatus, but the other species did not show this response

Mechanisms of Neuronal Death in Synucleinopathy

α-synuclein is a key molecule in the pathogenesis of synucleinopathy including Parkinson's disease and multiple system atrophy. In this mini-review, we mainly focus on recent data obtained from cellular models of synucleinopathy and discuss the possible mechanisms of neurodegeneration. Recent progress suggests that the aggregate formation of α-synuclein is cytoprotective and that its precursor oligomer (protofibril) may be cytotoxic. The catechol-derived quinones are the candidate molecules that facilitate the oligomer formation of α-synuclein. Furthermore, the cellular membranes are shown to be the primary targets injured by mutant α-synucleins, and the mitochondrial dysfunction seems to be an initial step in the neuronal death

Disruption of GM2/GD2 synthase gene resulted in overt expression of 9-O-acetyl GD3 irrespective of Tis211

GM2/GD2 synthase gene knockout mice lack all complex gangliosides, which are abundantly expressed in the nervous systems of vertebrates. In turn, they have increased precursor structures GM3 and GD3, probably replacing the roles of the depleted complex gangliosides. In this study, we found that 9-O-acetyl GD3 is also highly expressed as one of the major glycosphingolipids accumulating in the nervous tissues of the mutant mice. The identity of the novel component was confirmed by neuraminidase treatment, thin layer chromatography-immunostaining, two-dimensional thin layer chromatography with base treatment, and mass spectrometry. All candidate factors reported to be possible inducer of 9-O- acetylation, such as bitamine D binding protein, acetyl CoA transporter, or O-acetyl ganglioside synthase were not up-regulated. Tis21 which had been reported to be a 9-O-acetylation inducer was partially down-regulated in the null mutants, suggesting that Tis21 is not involved in the induction of 9-O-acetyl-GD3 and that accumulated high amount of GD3 might be the main factor for the dramatic increase of 9-O-acetyl GD3. The ability to acetylate exogenously added GD3 in the normal mouse astrocytes was examined, showing that the wild-type brain might be able to synthesize very low levels of 9-O-acetyl GD3. Increased 9-O-acetyl GD3, in addition to GM3 and GD3, may play an important role in the compensation for deleted complex gangliosides in the mutant mice

Diurnal CO2 exchange variation in evergreen leaves of the tropical tree, durian (Durio zibethinus Murray)

Diurnal variation of in situ CO2 exchange was investigated during the stage where young and old leaves co-exist in three shoots of tropical evergreen trees of Durio zibethinus Murray growing in an experimental field of Universiti Putra Malaysia. The quantitative proportion of young to old leaves and specific leaf area differed among the three samples. The dark respiration rates in the nighttime and daytime were related exponentially to air temperature. The Q10 ranged between 1.72 and 1.78 for the nighttime dark respiration, and 2.16 and 4.07 for the daytime dark respiration. The relationship between net photosynthetic rate and photosynthetic photon flux density was graphed using a hyperbolic function, where as the specific leaf area decreased the asymptotic rates tended to decrease. CO2 exchange per day was effected by leaf age. The total dark respiration (sum of nighttime and daytime dark respiration) was high and net photosynthesis was low in the shoot where the proportion of young leaves was high. The photosynthetic efficiency of different aged-leaves, which was defined as the ratio of net photosynthesis to dark respiration, ranged from 32 to 152%. Photosynthetic efficiency was low in the shoot with a high proportion of young leaf area, because of low net photosynthesis and high dark respiration. Characteristics of leaf photosynthesis were discussed with respect to leaf physiology and phenology