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Grasping how climate change will affect the tropical region's leaf potassium, calcium, and magnesium content is pivotal for enhancing our comprehension of plant stoichiometry. Currently, there is limited research on leaf potassium, calcium, and magnesium in tropical plants, which is particularly evident with the increasing importance of tropical rainforest biodiversity studies. This study investigated the impact of geographical and climatic factors on the leaf potassium, calcium, and magnesium content in 346 plants (including woody plants, herbs, and vines) on Hainan Island. The findings demonstrated that the average leaf potassium, calcium, and magnesium contents were 5.77, 11.86, and 2.92 mg·g−1, respectively, which were less than that in the Chinese flora. Mean annual precipitation (MAP) has a promoting effect on leaf potassium content (p < 0.05), suggesting that artificial potassium fertilization is needed due to the increasing MAP. Leaf potassium and magnesium content were positively correlated with latitude (p < 0.05) and longitude (p < 0.01); and there was a negative correlation between leaf calcium content and latitude (p < 0.05), showing that geographical factors have a significant impact on the potassium, calcium, and magnesium content of plant leaves. Additionally, the variables regulating leaf potassium, calcium, and magnesium varied across woody plants, herbs, and vines. Therefore, it is necessary to make corresponding adjustments according to local conditions and the plant functional types during nutrient management. In conclusion, this study sheds light on their potential responses to global changes and is instrumental in informing the management of these nutrients in tropical rainforest plants. [ABSTRACT FROM AUTHOR]

The carbon, nitrogen and water cycles of terrestrial ecosystems are important biogeochemical cycles. Addressing the relationship of leaf nitrogen (N) and carbon isotope discrimination (Δ) will enhance the understanding of the links between these three cycles in plant leaves because Δ can reflect time-integrated leaf-level water-use efficiency (WUE) over the period when the leaf material is produced. Previous studies have paid considerable attention to the relationship. However, these studies have not effectively eliminated the interference of environmental factors, inter-species, and inter-individual differences in this relationship, so new research is necessary. To minimize these interferences, the present work explored the relationship at the three levels of community, population, and plant individual. Three patterns of positive, negative and no relationship were observed across communities, populations, and individuals, which is dependent on environmental conditions, species, and plant individuals. The results strongly suggested that there is no general pattern for the relationship between leaf N and Δ. Furthermore, the results indicated that there is often no coupling between leaf-level long-term WUE and leaf N in the metabolic process of carbon, N and water in leaves. The main reason for the lack of this relationship is that most plants do not invest large amounts of nitrogen into photosynthesis. In addition, the present study also observed that, for most plant species, leaf N was not related to photosynthetic rate, and that variations in photosynthetic rates are mainly driven by stomatal conductance. [ABSTRACT FROM AUTHOR]

Leaf stoichiometry effectively indicates the response and adaptation of plants to environmental changes. Although numerous studies on leaf stoichiometry patterns have focused on the mid-latitudes and specific species of plants, these patterns and the effect of the climate change on them across a broad range of plants have remained poorly characterized in hot and humid regions at low latitudes. In the present study, leaf N, P, N:P, C:N, and C:P ratios, were determined from 345 plant leaf samples of 268 species at four forest sites in Hainan Island, China. For all plants, leaf N (3.80 ± 0.20 mg g−1) and P (1.82 ± 0.07 mg g−1) were negatively correlated with latitude and mean annual temperature (MAT) but were positively correlated with longitude. Leaf N was found to be positively correlated with altitude (ALT), and leaf P was positively correlated with mean annual precipitation (MAP). The leaf C:N ratio (278.77 ± 15.86) was significantly correlated with longitude and ALT, leaf C:P ratio (390.69 ± 15.15) was significantly correlated with all factors except ALT, and leaf N:P ratio (2.25 ± 0.10) was significantly correlated with ALT, MAT, and MAP. Comparable results were observed for woody plants. The results suggest that leaf stoichiometry on Hainan Island is affected by changes in geographical and climatic factors. In addition, the low N:P ratio indicates that plant growth may be limited by N availability. Moreover, the significant correlation between leaf N and P implies a possible synergistic relationship between N and P uptake efficiency in the plants of this region. This study helps to reveal the spatial patterns of leaf stoichiometry and their response to global climate change in a variety of plants in tropical regions with hot and humid environments, which may provide an insight in nutrient management in tropical rainforest. [ABSTRACT FROM AUTHOR]

With the rapid development of GAN (generative adversarial network), recent years have witnessed an increasing number of tasks on reference-guided facial attributes transfer. Most state-of-the-art methods consist of facial information extraction, latent space disentanglement, and target attribute manipulation. However, they either adopt reference-guided translation methods for manipulation or monolithic modules for diverse attribute exchange, which cannot accurately disentangle the exact facial attributes with specific styles from the reference image. In this paper, we propose a deep realistic facial editing method (termed LMGAN) based on target region focusing and dual label constraint. The proposed method, manipulating target attributes by latent space exchange, consists of subnetworks for every individual attribute. Each subnetwork exerts label-restrictions on both the target attributes exchanging stage and the training process aimed at optimizing generative quality and reference-style correlation. Our method performs greatly on disentangled representation and transferring the target attribute's style accurately. A global discriminator is introduced to combine the generated editing regional image with other nonediting areas of the source image. Both qualitative and quantitative results on the CelebA dataset verify the ability of the proposed LMGAN. [ABSTRACT FROM AUTHOR]

Global changes in precipitation and atmospheric N deposition affect the geochemical cycle of the element and its hydrological cycle in the ecosystem. It may also affect the relationship between plant water use efficiency (WUE) and nutrients, as well as the relationship between plant nutrients. Desert ecosystems are vulnerable to global changes. Haloxylon ammodendron is the dominant species in the Asian desert. Revealing the variations in these relationships in H. ammodendron with precipitation and N deposition will enhance our understanding of the responses of plants to global change in terms of trade-off strategies of nutrient absorption, water and element geochemical cycles in desert ecosystems. Thus, we conducted field experiments with different amounts of water and N. This study showed that WUE of H. ammodendron was not correlated with nitrogen content (N), phosphorus content (P), and potassium content (K) when water and N supply were varied (p > 0.05 for WUE vs. N, P, and K), suggesting lack of coupling between water use and nutrient economics. This result was associated with the lack of correlation between plant nutrients and gas exchang in H. ammodendron. However, water addition, N addition and the interaction between both of them all played a role in the correlation between plant N, P and K owing to their different responses to water and N supplies. This indicates that global changes in precipitation and N deposition will affect N, P and K geochemical cycles in the Asian deserts dominated by H. ammodendron, and drive changes in the relationships between plant nutrients, resulting in changes in the trade-off strategy of plant absorption of N, P, and K. [ABSTRACT FROM AUTHOR]

Variations in precipitation and atmospheric N deposition affect water and N availability in desert and thus may have significant effects on desert ecosystems. Haloxylon ammodendron is a dominant plant in Asian desert, and addressing its physiological acclimatization to the changes in precipitation and N deposition can provide insight into how desert plants adapt to extreme environments by physiological adjustment. Carbon isotope ratio (δ13 C) in plants has been suggested as a sensitive long-term indicator of physiological acclimatization. Therefore, this study evaluated the effect of precipitation change and increasing atmospheric N deposition on δ13 C of H. ammodendron. Furthermore, H. ammodendron is a C 4 plant; whether its δ13 C can indicate water use efficiency (WUE) has not been addressed. In the present study, we designed a field experiment with a completely randomized factorial combination of N and water and measured δ13 C and gas exchange of H. ammodendron. Then we calculated the degree of bundle-sheath leakiness (φ) and WUE of the assimilating branches of H. ammodendron. δ13 C and φ remained stable under N and water supply, while N addition, water addition and their interaction affected gas exchange and WUE in H. ammodendron. In addition, δ13 C had no correlation with WUE. These results were associated with the irrelevance between δ13 C and the ratio of intercellular to ambient CO 2 concentration (ci / ca), which might be caused by a special value (0.37) of the degree of bundle-sheath leakiness (φ) or a lower activity of carbonic anhydrase (CA) of H. ammodendron. In conclusion, δ13 C of H. ammodendron is not sensitive to global change in precipitation and atmospheric N deposition and cannot be used for indicating its WUE. [ABSTRACT FROM AUTHOR]

A well-dispersed chemosensor based on cellulose nanocrystals (CNCs) with porphyrin pendants (CNC-SA-COOC6TPP) was facilely synthesized by the combination of carboxylation, extended esterification and dicyclohexylcarbodiimide (DCC) reaction. The CNC-SA-COOC6TPP nanomaterials promoted the solubility of porphyrin groups in water and the nanomaterials could be easily separated from water by filtering. The structure of CNC-SA-COOC6TPP nanomaterials could be verified by FT-IR, 1H NMR and XPS characterization. The TEM images showed that CNC-SA-COOC6TPP nanomaterials presented needle-like morphologies. The unique properties of high sensitivity and selectivity for Hg2+ of porphyrin-modified CNCs were investigated separately via fluorescence emission spectroscopy under characteristic excitation wavelengths of porphyrin moieties. Further investigation revealed that CNC-SA-COOC6TPP nanomaterials (0.01 wt% in H2O) could specifically detect Hg2+ with a detection limit for Hg2+ of ca. 5.0 × 10−8 mol L−1 (50 nM). In addition, Hg2+ was specifically detected with interference from other metal ions, which was attributed to the specific formation of the Hg2+–porphyrin complex with an interaction stoichiometry of one Hg2+ per porphyrin moiety. The concentration of all other metal ions could be qualitatively detected based on the relationship between fluorescence intensity and concentration. As a result, the good dispersion of cellulose nanocrystals and the high selectively and sensitivity of porphyrin pendants resulted in the highly efficient detection of Hg2+ in water, which makes CNC-SA-COOC6TPP a promising fluorescence chemosensor. [ABSTRACT FROM AUTHOR]

A well-dispersed chemosensor based on cellulose nanocrystals (CNCs) with porphyrin pendants (CNC-SA-COOC6TPP) was facilely synthesized by the combination of carboxylation, extended esterification and dicyclohexylcarbodiimide (DCC) reaction. The CNC-SA-COOC6TPP nanomaterials promoted the solubility of porphyrin groups in water and the nanomaterials could be easily separated from water by filtering. The structure of CNC-SA-COOC6TPP nanomaterials could be verified by FT-IR, 1H NMR and XPS characterization. The TEM images showed that CNC-SA-COOC6TPP nanomaterials presented needle-like morphologies. The unique properties of high sensitivity and selectivity for Hg2+ of porphyrin-modified CNCs were investigated separately via fluorescence emission spectroscopy under characteristic excitation wavelengths of porphyrin moieties. Further investigation revealed that CNC-SA-COOC6TPP nanomaterials (0.01 wt% in H2O) could specifically detect Hg2+ with a detection limit for Hg2+ of ca. 5.0 × 10−8 mol L−1 (50 nM). In addition, Hg2+ was specifically detected with interference from other metal ions, which was attributed to the specific formation of the Hg2+–porphyrin complex with an interaction stoichiometry of one Hg2+ per porphyrin moiety. The concentration of all other metal ions could be qualitatively detected based on the relationship between fluorescence intensity and concentration. As a result, the good dispersion of cellulose nanocrystals and the high selectively and sensitivity of porphyrin pendants resulted in the highly efficient detection of Hg2+ in water, which makes CNC-SA-COOC6TPP a promising fluorescence chemosensor. [ABSTRACT FROM AUTHOR]