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Although cutting is a useful method for vegetative propagation and tree breeding, there is a difference in rooting ability between tree species and even between node positions within a species. A large number of F¹ hybrids of Shorea (Shorea curtisii × S. leprosula) (Dipterocarpaceae) have recently been found in Singapore. Given that some of the hybrid traits appear to have higher physiological performances than those of their parent species, understanding the rooting ability of the leafy-stem cuttings of F¹ hybrids may contribute to performance improvement in dipterocarp trees. In this study, we compared the rooting abilities of cuttings taken from seedlings of F¹ hybrids and their parent species at different node positions. The cuttings of F¹ hybrids showed rooting ability with small internode differences, and the rooting rate (32.2%) was almost intermediate between those of S. curtisii (42.0%) and S. leprosula (21.0%). The rooting rates of hybrids and parents fell into the middle range of previously reported values for 21 closely related Shorea species. Overall, the rooting ability of F¹ hybrids is comparable with that of their parent species and/or other Shorea species in the red meranti group. Thus, F¹ hybrids could be mass propagated through cuttings.

Growth and photosynthetic response of four indigenous tree seedlings, i.e. Dyera costulata, Dipterocarpus baudii, Neobalanocarpus heimii and Gonystylus affinis were studied under different light conditions in a degraded secondary forest. Maximum photosynthesis (A) was measured at 2 and 12 months after planting. The ratio of variable to maximum fluorescence (Fv/Fm) was determined. Leaves measured at 2 and 12 months after planting were old leaves present on the seedlings and new leaves that had expanded after planting respectively. Seedling growth was measured over four years. Changes in the growth rate and Amax with canopy openness were categorised into two groups. The growth and Amax of the first group (D. costulata and D. baudii) were maximum at 30—40% canopy openness. This group may be suitable for planting under large canopy gaps. The second group (G. affinis and N. heimii) showed maximum growth and Amax at relatively low canopy openness (less than 20%). Leaves in the second group suffered chronic photoinhibition under large gap. These species were suitable to be planted under low light conditions. Pertumbuhan dan gerak balas fotosintesis empat spesies pokok asli iaitu Dyera costulata, Dipterocarpus baudii, Neobalanocarpus heimii dan Gonystylus affinis terhadap keadaan cahaya yang berlainan di hutan sekunder tersusut nilai dikaji. Fotosintesis maksimum (Amax) disukat pada 2 dan 12 bulan selepas penanaman. Nisbah kependafluoran boleh ubah kepada kependafluoran maksimum (Fv / Fm) ditentukan. Daun yang disukat pada usia 2 bulan dan 12 bulan selepas penanaman ialah masing-masing daun tua yang terdapat pada anak benih dan daun baharu yang berkembang selepas penanaman. Pertumbuhan anak pokok disukat selama empat tahun. Perubahan kadar pertumbuhan dan Amax dengan keterbukaan kanopi dikategorikan kepada dua kumpulan. Pertumbuhan dan Amax untuk kumpulan pertama (D. costulata dan D. baudii) mencapai tahap maksimum pada 30%—40% keterbukaan kanopi. Kumpulan ini mungkin sesuai ditanam di bawah ruang hutan yang besar. Kumpulan kedua (G. affinis dan N. heimii) menunjukkan pertumbuhan dan Amax yang maksimum pada keterbukaan kanopi yang agak kecil (kurang daripada 20%). Daun dalam kumpulan kedua mengalami fotorencat yang kronik di bawah ruang hutan yang besar. Spesies ini lebih sesuai ditanam di bawah keadaan cahaya yang rendah.

Tropical forests take up more carbon (C) from the atmosphere per annum by photosynthesis than any other type of vegetation. Phosphorus (P) limitations to C uptake are paramount for tropical and subtropical forests around the globe. Yet the generality of photosynthesis-P relationships underlying these limitations are in question, and hence are not represented well in terrestrial biosphere models. Here we demonstrate the dependence of photosynthesis and underlying processes on both leaf N and P concentrations. The regulation of photosynthetic capacity by P was similar across four continents. Implementing P constraints in the ORCHIDEE-CNP model, gross photosynthesis was reduced by 36% across the tropics and subtropics relative to traditional N constraints and unlimiting leaf P. Our results provide a quantitative relationship for the P dependence for photosynthesis for the front-end of global terrestrial C models that is consistent with canopy leaf measurements. Phosphorus (P) limitation is pervasive in tropical forests. Here the authors analyse the dependence of photosynthesis on leaf N and P in tropical forests, and show that incorporating leaf P constraints in a terrestrial biosphere model enhances its predictive power.

Understanding how plants are constructed-i.e., how key size dimensions and the amount of mass invested in different tissues varies among individuals-is essential for modeling plant growth, carbon stocks, and energy fluxes in the terrestrial biosphere. Allocation patterns can differ through ontogeny, but also among coexisting species and among species adapted to different environments. While a variety of models dealing with biomass allocation exist, we lack a synthetic understanding of the underlying processes. This is partly due to the lack of suitable data sets for validating and parameterizing models. To that end, we present the Biomass And Allometry Database (BAAD) for woody plants. The BAAD contains 259 634 measurements collected in 176 different studies, from 21 084 individuals across 678 species. Most of these data come from existing publications. However, raw data were rarely made public at the time of publication. Thus, the BAAD contains data from different studies, transformed into standard units and variable names. The transformations were achieved using a common workflow for all raw data files. Other features that distinguish the BAAD are: (i) measurements were for individual plants rather than stand averages; (ii) individuals spanning a range of sizes were measured; (iii) plants from 0.01-100 m in height were included; and (iv) biomass was estimated directly, i.e., not indirectly via allometric equations (except in very large trees where biomass was estimated from detailed sub-sampling). We included both wild and artificially grown plants. The data set contains the following size metrics: total leaf area; area of stem cross-section including sapwood, heartwood, and bark; height of plant and crown base, crown area, and surface area; and the dry mass of leaf, stem, branches, sapwood, heartwood, bark, coarse roots, and fine root tissues. We also report other properties of individuals (age, leaf size, leaf mass per area, wood density, nitrogen content of leaves and wood), as well as information about the growing environment (location, light, experimental treatment, vegetation type) where available. It is our hope that making these data available will improve our ability to understand plant growth, ecosystem dynamics, and carbon cycling in the world's vegetation.

The effect on reproduction of the dynamics of resource allocation was studied in an emergent and masting tree species, Dryobalanops aromatica (Dipterocarpaceae), in a lowland dipterocarp forest in Sarawak, Malaysia. Girdling of the reproductive shoots (5 mm diameter) caused an increase in abortion during the flowering period, but did not affect the fruit set at the middle or final stages of seed maturation. In contrast, 50% defoliation significantly affected fruit setting, but had little effect on flowering. The total leaf area of reproductive shoots was significantly correlated with final fruit set and total fruit mass. Control of the carbohydrate supply to reproductive shoots by girdling and defoliation made no difference to fruit size, but the fruit number was highly sensitive to carbohydrate availability. Total non-structural carbohydrate (TNC) decreased during the flowering period mainly in the branch (P<0.05), but fluctuated little in any organs during fruit maturation. Leaf nitrogen and photosynthetic capacity of the reproductive shoots were not significant variables for reproduction. Our results suggest that D. aromatica uses current photosynthates in the leaves of reproductive shoots as a carbon source during fruit development, but requires stored assimilates in the branch for flowering. However, since TNC was still present in all organs even after flowering, our study also suggests that storage of carbohydrate resources might not be the decisive factor in the occurrence or frequency of flowering in this species.

Three umami substances (glutamate, 5′-inosinate, and 5′-guanylate) were found by Japanese scientists, but umami has not been recognized in Europe and America for a long time. In the late 1900s, umami was internationally recognized as the fifth basic taste based on psychophysical, electrophysiological, and biochemical studies. Three umami receptors (T1R1 + T1R3, mGluR4, and mGluR1) were identified. There is a synergism between glutamate and the 5′-nucleotides. Among the above receptors, only T1R1 + T1R3 receptor exhibits the synergism. In rats, the response to a mixture of glutamate and 5′-inosinate is about 1.7 times larger than that to glutamate alone. In human, the response to the mixture is about 8 times larger than that to glutamate alone. Since glutamate and 5′-inosinate are contained in various foods, we taste umami induced by the synergism in daily eating. Hence umami taste induced by the synergism is a main umami taste in human.

The causative agent of the COVID-19 pandemic, SARS-CoV-2, is steadily mutating during continuous transmission among humans. Such mutations can occur in the spike (S) protein that binds to the ACE2 receptor and is cleaved by TMPRSS2. However, whether S mutations affect SARS-CoV-2 cell entry remains unknown. Here, we show that naturally occurring S mutations can reduce or enhance cell entry via ACE2 and TMPRSS2. A SARS-CoV-2 S-pseudotyped lentivirus exhibits substantially lower entry than that of SARS-CoV S. Among S variants, the D614G mutant shows the highest cell entry, as supported by structural and binding analyses. Nevertheless, the D614G mutation does not affect neutralization by antisera against prototypic viruses. Taken together, we conclude that the D614G mutation increases cell entry by acquiring higher affinity to ACE2 while maintaining neutralization susceptibility. Based on these findings, further worldwide surveillance is required to understand SARS-CoV-2 transmissibility among humans. SARS-CoV-2 D614G spike protein mutation is one of the predominant circulating vital mutants. Here, Ozono et al. demonstrate that D614G mutation increases in vitro cell entry by acquiring higher affinity to ACE2.

Elevated levels of type I interferon (IFN) during pregnancy are associated with intrauterine growth retardation, preterm birth, and fetal demise through mechanisms that are not well understood. A critical step of placental development is the fusion of trophoblast cells into a multinucleated syncytiotrophoblast (ST) layer. Fusion is mediated by syncytins, proteins deriving from ancestral endogenous retroviral envelopes. Using cultures of human trophoblasts or mouse cells, we show that IFN-induced transmembrane proteins (IFITMs), a family of restriction factors blocking the entry step of many viruses, impair ST formation and inhibit syncytin-mediated fusion. Moreover, the IFN inducer polyinosinic:polycytidylic acid promotes fetal resorption and placental abnormalities in wild-type but not in Ifitm-deleted mice. Thus, excessive levels of IFITMs may mediate the pregnancy complications observed during congenital infections and other IFN-induced pathologies.

Atomic energy has played an important role in international relations as a means of state power. From 1945 to 1959, Japan was significantly influenced by developments in atomic energy as a result of the Anglo-American “special relationship.” During World War II, Britain and the United States cooperated to develop atomic weapons to use against Japan. In the ensuing Cold War era, the two countries advanced peaceful uses of atomic energy for Japan to counter the influence of the Soviet Union through psychological warfare. The U.S. Atomic Energy Peace Mission visited Japan in May 1955. However, the Japanese government altered its nuclear policy to solicit support from Britain because the United States was falling behind in atomic energy development. A British nuclear reactor was used as the first commercial nuclear power station, in 1959, whereby Britain earned parity with the United States in the context of nuclear power.