(1) Background: Blue light is important for the formation of maize stomata, but the signal network remains unclear. (2) Methods: We replaced red light with blue light in an experiment and provided a complementary regulatory network for the stomatal development of maize by using transcriptome and metabolomics analysis. (3) Results: Exposure to blue light led to 1296 differentially expressed genes and 419 differential metabolites. Transcriptome comparisons and correlation signaling network analysis detected 55 genes, and identified 6 genes that work in the regulation of the HY5 module and MAPK cascade, that interact with PTI1, COI1, MPK2, and MPK3, in response to the substitution of blue light in environmental adaptation and signaling transduction pathways. Metabolomics analysis showed that two genes involved in carotenoid biosynthesis and starch and sucrose metabolism participate in stomatal development. Their signaling sites located on the PHI1 and MPK2 sites of the MAPK cascade respond to blue light signaling. (4) Conclusions: Blue light remarkably changed the transcriptional signal transduction and metabolism of metabolites, and eight obtained genes worked in the HY5 module and MAPK cascade.

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Soil erosion by water is a major cause of land degradation. Agricultural practices and many other ecological environmental problems contribute to land degradation worldwide, especially in arid and semi-arid areas. Miyun County, which is located in a mountainous region of North China, is an important natural ecological zone and surface source of drinking water for Beijing and is very vulnerable to soil erosion due to its thin soil layer and human activities. Landsat images from 2003 and 2013 were used to analyze the land-use and land-cover change (LULCC) over this period. The revised universal soil loss equation (RUSLE) model integrated with Geographic Information System (GIS) was used to quantify soil loss and to map erosion risk. In addition, the response of soil erosion to LULCC was evaluated. The results showed that the areas under cropland, forest, and water bodies increased over the study period by 66.03, 243.44, and 9.01 km2, respectively. The increase in forested land indicated that the improved ground vegetation cover was due to the implementation of active ecological measures. Between 2003 and 2013, light soil erosion increased by 587.46 km2, and extremely severe soil erosion increased by 9.57 km2. The extents of slight, moderate, severe, and very severe soil erosion, however, decreased by 8.02, 445.21, 142.69, and 1.11 km2, respectively. A total of 57.5% of land with moderate soil erosion has been converted to light soil erosion, which could be highly beneficial for the improvement of vegetation control of soil and water losses. In terms of area, forestland exhibited the greatest increase, while moderate soil erosion exhibited the greatest decrease over the study period. Land-use change led to an alteration in the intensity of soil erosion due to changes or loss of vegetation. The conversion from high intensity soil erosion to low intensity was attributed to the implementation of ecological environmental protection. The results generated from this study may be useful for planners and land-use managers to make appropriate decisions for soil conservation.

Background Light quality severely affects biosynthesis and metabolism-associated process of glutathione. However, the role of specific light is still unclear on the glutathione metabolism. In this article, comparatively transcriptome and metabolome methods are used to fully understand the blue and red-light conditions working on the glutathione metabolism in maize seedling leaf. Results There are 20 differently expressed genes and 4 differently expressed metabolites in KEGG pathway of glutathione metabolism. Among them, 12 genes belong to the glutathione S-transferase family, 3 genes belong to the ascorbate peroxidase gene family and 2 genes belong to the ribonucleoside-diphosphate reductase gene family. Three genes, G6PD, SPDS1, and GPX1 belong to the gene family of glucose 6-phosphate dehydrogenase, spermidine synthase, and glutathione peroxidase, respectively. Four differently expressed metabolites are identified. Three of them, Glutathione disulfide, Glutathione, and l-γ-Glutamyl-L-amino acid are decreased while L-Glutamate is increased. In addition, Through PPI analysis, two annotated genes gst16 and DAAT, and 3 unidentified genes 100381533, pco105094 and umc2770, identified as RPP13-like3, BCAT-like1and GMPS, were obtained. By the analysis of protein sequence and PPI network, we predict that pco105094 and umc2770 were involved in the GSSG-GSH and AsA-GSH cycle in the network of glutathione metabolism. Conclusions Compared to red light, blue light remarkably changed the transcription signal transduction and metabolism of glutathione metabolism. Differently expressed genes and metabolic mapped to the glutathione metabolism signaling pathways. In total, we obtained three unidentified genes, and two of them were predicted in current glutathione metabolism network. This result will contribute to the research of glutathione metabolism of maize.

Reforestation is an effective way to alleviate deforestation and its negative impacts on ecosystem services. In tropical rainforest ecosystem, however, frequent typhoons and heavy rainfall can result in landslides and uprooting of many seedlings, making reforestation efforts very difficult, especially within extremely degraded sites where soil conditions cannot support any plant life. Here, we described a reforestation protocol which is based on tropical rainforest successional processes to not only prevent landslides and tree uprooting due to frequent typhoon and heavy rain, but also accelerate tropical forest succession. This protocol first used the slope and soil layer of the undisturbed old-growth tropical rainforest as a reference to reconstruct slope and soil layers. Then multiple tropical tree species with high growth and survival rate were separately monocultured in the reconstructed soil layers. In the year of 2015 and 2016, we tested the effectiveness of this protocol to recover a 0.2 km2 extremely degraded tropical rainforest which consists of bare rock and thus does not support any plant life, in Sanya city, China. Our results showed that, both typhoons and heavy rains did not result in landslide or any tree damages in the area this reforestation protocol was used. Moreover, our separately monocultured eight fast-growing tree species have much higher fast-growing related functional traits than those for tree species in the adjacent undisturbed tropical seasonal forest, which in turn resulted in large soil water and nutrient loss within 3 years. This seemed to simulate a quick transition from primary succession (consist of bare rock and cannot support any plant life) to mid-stage of secondary tropical rainforest succession (many fast-growing pioneer tree species induced high soil water and nutrient loss). Thus, mixing the late-successional tropical tree species with each of the separately monocultured eight fast-growing tree species can accelerate recovery to the undisturbed tropical rainforest as soon as possible. Overall, based on tropical rainforest successional processes, our research provides an effective protocol for quickly and effectively restoring an extremely degraded tropical rainforest ecosystem. We expect that this work will be important for the future recovery of other extremely degraded tropical rainforest ecosystems.