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Species in the Amorphophallus genus are important cash crops in many tropical and subtropical Asian countries. Although several molecular markers have been employed to determine relationships and assess genetic variation in the Amorphophallus genus, some conflicts remain in infrageneric classification and evolution. To aid in the phylogenetic research of the Amorphophallus genus, we collected one sample of Amorphophallus tonkinensis Engler and Gehrmann 1911 from southwestern China. We assembled the first chloroplast genome of this species using high-throughput sequencing. The assembled genome was 169,341 bp long with a typical quadripartite structure (GenBank accession number: PP234804). The lengths of the large single-copy region, small single-copy region, and two inverted repeats were 90,705 bp, 15,640 bp, 31,498 bp, and 31,498 bp, respectively. We annotated 129 genes across the chloroplast genome of A. tonkinensis. The phylogenetic trees suggested that the Amorphophallus species distributed in continental Asia split into two main clades. The chloroplast genome reported in our study provided valuable genomic resources for the future phylogenetic research of the Amorphophallus genus. [ABSTRACT FROM AUTHOR]

Konjac species (Amorphophallus spp.) are the only plant species in the world that are rich in a large amount of konjac glucomannan (KGM). These plants are widely cultivated as cash crops in tropical and subtropical countries in Asia, including China. Pectobacterium carotovorum subsp. carotovorum (Pcc) is one of the most destructive bacterial pathogens of konjac. Here, we analyzed the interactions between Pcc and susceptible and resistant konjac species from multiple perspectives. At the transcriptional and metabolic levels, the susceptible species A. konjac and resistant species A. muelleri exhibit similar molecular responses, activating plant hormone signaling pathways and metabolizing defense compounds such as phenylpropanoids and flavonoids to resist infection. Interestingly, we found that Pcc stress can lead to rapid recombination of endophytic microbial communities within a very short period (96 h). Under conditions of bacterial pathogen infection, the relative abundance of most bacterial communities in konjac tissue decreased sharply compared with that in healthy plants, while the relative abundance of some beneficial fungal communities increased significantly. The relative abundance of Cladosporium increased significantly in both kinds of infected konjac compared to that in healthy plants, and the relative abundance in resistant A. muelleri plants was greater than that in susceptible A. konjac plants. Among the isolated cultivable microorganisms, all three strains of Cladosporium strongly inhibited Pcc growth. Our results further elucidate the potential mechanism underlying konjac resistance to Pcc infection, highlighting the important role of endophytic microbial communities in resisting bacterial pathogen infections, especially the more direct role of fungal communities in inhibiting pathogen growth. [ABSTRACT FROM AUTHOR]

Black pepper (Piper nigrum L.) is an important tropical cash crop in China and suffers huge economic losses every year due to foot rot disease. In order to clarify the pathogen in black pepper main producing area and screen potential fungicides for disease control. Seven strains were isolated from Wanning City of Hainan Province and identified by morphological characteristics and ITS sequence specificity. The laboratory toxicities of 20 fungicides, registered for the control of oomycete diseases, were determined by the mycelial growth rate method. Results showed that all three strains isolated from black pepper foot rot disease samples, were Phytophthora capsici. Among the 20 tested oomycete fungicides, pyraclostrobin, fluazinam, thiram, dimethomorph, cyazofamid, and metalaxyl showed the highest activity in suppressing the mycelial growth of three P. capsici isolates (EC50 < 1 μg/mL), followed by oxine-copper, chlorothalonil, mancozeb, zineb, copper hydroxide (1 μg/mL < EC50 < 10 μg/mL), and then cuprous oxide, copper oxychloride, azoxystrobin, carvacrol, cymoxanil, berberine (10 μg/mL < EC50 < 50 μg/mL). Chitosan and fosetyl-aluminium exhibited the lowest inhibition activity (EC50 > 300 μg/mL). This study would help further the understanding and management of tropical P. capsici diseases. [ABSTRACT FROM AUTHOR]

Oil palm (Elaeis guineensis Jacq.) is an economically important tropical oil crop widely cultivated in tropical zones worldwide. Being a tropical crop, low-temperature stress adversely affects the oil palm. However, integrative leaf transcriptomic and proteomic analyses have not yet been conducted on an oil palm crop under cold stress. In this study, integrative omics transcriptomic and iTRAQ-based proteomic approaches were employed for three oil palm varieties, i.e., B × E (Bamenda × Ekona), O × G (E. oleifera × Elaeis guineensis), and T × E (Tanzania × Ekona), in response to low-temperature stress. In response to low-temperature stress at (8 °C) for 5 days, a total of 5175 up- and 2941 downregulated DEGs in BE-0_VS_BE-5, and a total of 3468 up- and 2443 downregulated DEGs for OG-0_VS_OG-5, and 3667 up- and 2151 downregulated DEGs for TE-0_VS_TE-5 were identified. iTRAQ-based proteomic analysis showed 349 up- and 657 downregulated DEPs for BE-0_VS_BE-5, 372 up- and 264 downregulated DEPs for OG-0_VS_OG-5, and 500 up- and 321 downregulated DEPs for TE-0_VS_TE-5 compared to control samples treated at 28 °C and 8 °C, respectively. The KEGG pathway correlation of oil palm has shown that the metabolic synthesis and biosynthesis of secondary metabolites pathways were significantly enriched in the transcriptome and proteome of the oil palm varieties. The correlation expression pattern revealed that TE-0_VS_TE-5 is highly expressed and BE-0_VS_BE-5 is suppressed in both the transcriptome and proteome in response to low temperature. Furthermore, numerous transcription factors (TFs) were found that may regulate cold acclimation in three oil palm varieties at low temperatures. Moreover, this study identified proteins involved in stresses (abiotic, biotic, oxidative, and heat shock), photosynthesis, and respiration in iTRAQ-based proteomic analysis of three oil palm varieties. The increased abundance of stress-responsive proteins and decreased abundance of photosynthesis-related proteins suggest that the TE variety may become cold-resistant in response to low-temperature stress. This study may provide a basis for understanding the molecular mechanism for the adaptation of oil palm varieties in response to low-temperature stress in China. [ABSTRACT FROM AUTHOR]

Imidacloprid is widely detected in surface water from sub-tropical or tropical agricultural regions of China. However, there is scanty information on the ecological risk assessment of imidacloprid in surface water near tropical crop systems due to the lack of toxicity data on local aquatic organisms. In this study, the acute toxicity risk threshold-hazardous concentration at the 5th percentile of the species (HC5 ) -of imidacloprid to local aquatic organisms in surface water was obtained based on web-interspecific correlation estimation (Web-ICE) and species sensitivity distribution (SSD) models, then its ecological risk assessment in surface water near rice-vegetable practice in Chengmai (Hainan) was temporally and spatially assessed by risk quotient (RQ). The results showed that the risk threshold HC5 of imidacloprid in the aquatic environment around the rice-vegetable rotation in Chengmai is 4.30 μg/L, 41.7% of water samples with the RQ of higher than 1. Also, the RQ values corresponding to the median and maximum concentrations of imidacloprid in surface water from our study were significantly higher than the RQ values in surface water from other regions of China, indicating that imidacloprid residues had higher potential ecological risks to aquatic organisms in surface water from tropical ricevegetable rotation field. In addition, there was the highest potential ecological risk occurring in April, the sowing time (RQ>1 in 92.3% surface water), vegetable planting period (mean RQ=2.53 with RQ>1 with 68% water surface water), and the central regions of Chengmai during the practice of ricevegetable rotation, indicating that there were significant spatiotemporal and crop-related characteristics of the ecological risk of imidacloprid in surface water. It thus contrives to limit and reasonably use imidacloprid by planting period and region in the practice of rice-vegetable rotation in Chengmai, Hainan. [ABSTRACT FROM AUTHOR]

With increasing labor shortage and production costs, water scarcity and climate change, there is increased interest in ratooning as a green, resource-efficient technology to boost sustainable rice production, especially in China. Since the performance of ratoon rice (regenerating a second crop from the stubble left in the fields after the main harvest) and the impact of agronomic practices on its yield have shown mixed results across the world, a better understanding is needed to determine under which conditions ratoon rice performs well. The objectives are (i) to quantify variation in rice yield of main and ratoon crops, (ii) to assess genetic variation in and impact of agronomic practices on rice yield, focusing on the yield of ratoon crop and total yield (main and ratoon crops), and (iii) review of economic and environmental benefits of ratoon rice in comparison with single and double rice cropping. In researching ratoon rice, we compiled a database from 68 studies published from 2000 to 2023. Descriptive data analysis was performed. Studies from non-tropical regions account for about 70%. Large variation exists in the yield of ratoon crop across the studies, with lower yield from the tropics than non-tropics. The ratio of yield of ratoon crop to that of main crop also varied widely from 0.13 to 0.67 with 0.36 and 0.5 in tropics and non-tropics, respectively. The yield of ratoon crop was positively related to the yield of main crop, crop duration and nitrogen fertilizer application rate, which were generally higher in non-tropics. Hybrid varieties out-yielded inbred varieties in both main and ratoon crops in non-tropical regions. Direct seeding and AWD had a positive impact on the yield of ratoon crop. The impact of stubble cutting height was mixed. While agronomic nitrogen use efficiency (AEN) during entire ratoon rice cropping was similar to that reported for single rice cropping in previous studies, AEN for ratoon crop in tropical regions tended to be lower than those from previous studies on single rice cropping. Ratoon rice cropping reduced labor input and production cost and increased net economic return compared with double rice cropping. We propose a research agenda, with the focus on improvement of genetic and agronomic practices to explore the potential of ratoon rice cropping, especially in the tropics. This study provides insight into the progress in ratoon rice research over the past two decades globally, and specifically in the tropics. • Ratoon rice cropping has recently received attention in non-tropical conditions. • Data on ratoon rice cropping from 68 studies were compiled and analyzed. • Large genetic exists in yield of ratoon crop with low yield in the tropics. • Yield of ratoon crop was related to that of main crop and nitrogen application. • We propose research on genetic improvement and improving agronomy in the tropics. [ABSTRACT FROM AUTHOR]

Maize (Zea mays L.) is a tropical crop, and low temperature has become one of the main abiotic stresses for maize growth and development, affecting many maize growth processes. The main area of maize production in China, Jilin province, often suffers from varying degrees of cold damage in spring, which seriously affects the quality and yield of maize. In the face of global climate change and food security concerns, discovering cold tolerance genes, developing cold tolerance molecular markers, and creating cold-tolerant germplasm have become urgent for improving maize resilience against these conditions and obtaining an increase in overall yield. In this study, whole-genome sequencing and genotyping by sequencing were used to perform genome-wide association analysis (GWAS) and quantitative trait locus (QTL) mapping of the two populations, respectively. Overall, four single-nucleotide polymorphisms (SNPs) and 12 QTLs were found to be significantly associated with cold tolerance. Through joint analysis, an intersection of GWAS and QTL mapping was found on chromosome 3, on which the Zm00001d002729 gene was identified as a potential factor in cold tolerance. We verified the function of this target gene through overexpression, suppression of expression, and genetic transformation into maize. We found that Zm00001d002729 overexpression resulted in better cold tolerance in this crop. The identification of genes associated with cold tolerance contributes to the clarification of the underlying mechanism of this trait in maize and provides a foundation for the adaptation of maize to colder environments in the future, to ensure food security. [ABSTRACT FROM AUTHOR]

Banana is a major fruit crop grown in tropical and subtropical regions worldwide. Among cultivars, "FenJiao, FJ" (Musa spp. ABB, Pisang Awak subgroup) is a popular variety of bananas, due to its better sugar-acid blend and relatively small fruit shape. However, because the traditional FJ variety grows relatively high in height, it is vulnerable to lodging and unsuitable for harvesting. In this study, we sought desirable banana mutants by carrying out ethyl methanesulfonate (EMS) mutagenesis with the FJ cultivar. After the FJ shoot tips had been treated with 0.8% (v/v) EMS for 4 h, we obtained a stably inherited mutant, here called " ReFen 1 " (RF1), and also observed a semi-dwarfing phenotype. Compared with the wild type (FJ), this RF1 mutant featured consistently improved agronomic traits during 5-year field experiments conducted in three distinct locations in China. Notably, the RF1 plants showed significantly enhanced cold tolerance and Sigatoka disease resistance, mainly due to a substantially increased soluble content of sugar and greater starch accumulation along with reduced cellulose deposition. Therefore, this study not only demonstrated how a powerful genetic strategy can be used in fruit crop breeding but also provided insight into the identification of novel genes for agronomic trait improvement in bananas and beyond. [ABSTRACT FROM AUTHOR]

As an important economic tree species in China, tea trees play a critical role in promoting economic development. However, the expanding area of tea plantations in China over the recent years has reduced the biodiversity of the ecosystem and accelerated ecological problems. Identifying the spatial distribution of the tea plantation accurately is important for the monitoring of the tea plantation as well as the development of the tea industry. In this study, Wangzhai Town, located in the central of Wuyi County in Zhejiang Province, was chosen as the study area, and Gaofen-1 (GF-1) data on December 28, 2017, and all available Sentinel-2 data in 2017 were downloaded to study the tea plantations extraction method. The spectral and texture features of tea plantations are similar with crops on the high spatial resolution remote sensing image which results in the mixture of the tea plantations and crops. The Normalized Difference Vegetation Index (NDVI) time series data can reflect the phenological changes of the tea trees and crops, which can be used to improve the separability of tea plantations and crops. In this study, a phenology-based approach was applied to the NDVI time series to distinguish tea plantations from crops by comparing the similarity of the seasonal changes of NDVI time series. Due to the influence of cloud and fog on the satellite image, the complete Sentinel-2 time series data is difficult to be obtained. Therefore, the high temporal resolution Moderate-resolution Imaging Spectroradiometer (MODIS) reflection product (MCD43A4) in 2017 was used to reconstruct the complete Sentinel-2 NDVI time series data (5 m spatial resolution, 5 d temporal resolution) based on Bayesian Maximum Entropy (BME) spatial-temporal fusion algorithm. Then, the Dynamic Time Wraping (DTW) distance was calculated based on the DTW algorithm to characterize the similarity of NDVI time series between the tea plantation samples and other pixels to be classified. Combining the advantages of GF-1 in spatial details and the high temporal resolution of reconstructed Sentinel-2 NDVI time series in capturing the difference of growth process of tea trees, the tea plantation was identified based on random forest algorithm. Two identification schemes: 1) spectral and texture features based on GF-1; 2) spectral, texture features based on GF-1 and DTW distance were set up to investigate the impact of NDVI time series on the tea plantation identification. The results showed that: 1) the reconstructed NDVI time series data derived from MODIS and Sentinel-2 based on spatio-temporal fusion algorithm is able to capture the seasonal dynamics of different objects, and the DTW distance can capture the difference of NDVI time series data between crops and tea plantations and can be used for tea plantations extraction; 2) the accuracy、 error rate、precision、recall and F1score were 96.91%、3.09%、89.00%、83.09% and 0.86 respectively combining texture and spectral information of GF-1 and Sentinel-2 NDVI time series information, which were 94.72%、5.28%、73.09%、84.61% and 0.78 respectively without Sentinel-2 NDVI time series information. Overall, the results of combining GF-1 and Sentinel-2 time series data performed better than that only based on the spectral and texture features of GF-1. These results confirmed that combining high spatial resolution with high temporal resolution time series remote sensing data is an effective method to improve the identification accuracy of tea plantations. [ABSTRACT FROM AUTHOR]

Purpose: Significant leaching losses of nitrogen (N) and phosphorus (P) from soil occurred during the summer fallow period of intensive plastic-shed vegetable production systems, which could be resolved by catch crops. Materials and methods: We firstly estimated the economic profits and then evaluated the efficiencies of six catch leafy vegetables on reducing N and P leaching losses. Meanwhile, responses of soil nutrient contents and the yield as well as the quality of subsequent lettuce were observed under plot-scale experiment. Results and discussion: The six leafy vegetables as catch crops can bring approximately 23, 000–43, 000 yuan RMB hm–2 extra economic profits to farmers. There were five catch treatments that reduced the NO3–-N leaching losses from 22.7 kg hm–2 under the control treatment to 4.6–15.8 kg hm–2. The total P leaching losses were lower under all six catch crop treatments (with 10.5–22.3 kg hm–2) than that under the control treatment (with 39.2 kg hm–2). The mitigation efficiency of catch crops on N and P leaching losses was dependent on the vegetable variety. Overall, vegetable crops did not exhaust soil available N but increased soil available P by 42.1% and organic matter content by 16.8%. The catch crop-based vegetable plantation did not influence yield and N and P uptake capacities of subsequent lettuce. As such, the qualities of lettuce (including the soluble protein, sugar, vitamin, and nitrate contents) were also not influenced following the plantation of catch crops. Conclusions: Leafy vegetable as catch crop during the fallow season increased farmer's income while reducing N and P leaching losses. Moreover, there were no negative effects on subsequent vegetable production and qualities. We can also attempt to reduce the input of N and P chemical fertilizers to subsequent vegetable, as increased available P and organic matter were found in the catch crop treatments. [ABSTRACT FROM AUTHOR]

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Sugarcane is a major crop in tropical and subtropical regions of the world. In China, the application of large amounts of nitrogen (N) fertilizer to boost sugarcane yield is commonplace, but it causes substantial environmental damages, particularly soil, and water pollution. Certain rhizosphere microbes are known to be beneficial for sugarcane production, but much of the sugarcane rhizosphere microflora remains unknown. We have isolated several sugarcane rhizosphere bacteria, and 27 of them were examined for N-fixation, plant growth promotion, and antifungal activity. 16S rRNA gene sequencing was used to identify these strains. Among the isolates, several strains were found to have a relatively high activity of nitrogenase and ACC deaminase, the enzyme that reduces ethylene production in plants. These strains were found to possess nifH and acdS genes associated with N-fixation and ethylene production, respectively. Two of these strains, Pantoea dispersa -AA7 and Enterobacter asburiae -BY4 showed maximum plant growth promotion (PGP) and nitrogenase activity, and thus they were selected for detailed analysis. The results show that they colonize different sugarcane tissues, use various growth substrates (carbon and nitrogen), and tolerate various stress conditions (pH and osmotic stress). The positive effect of AA7 and BY4 strains on nifH and stress-related gene (SuCAT , SuSOD , SuPAL , SuCHI , and SuGLU) expression and the induction of defense-related processes in two sugarcane varieties, GT11 and GXB9, showed their potential for stress amelioration and PGP. Both bacterial strains increased several sugarcane physiological parameters. i.e., plant height, shoot weight, root weight, leaf area, chlorophyll content, and photosynthesis, in plants grown under greenhouse conditions. The ability of rhizobacteria on N-fixing in sugarcane was also confirmed by a 15N isotope-dilution study, and the estimate indicates a contribution of 21–35% of plant nitrogen by rhizobacterial biological N fixation (BNF). This is the first report of sugarcane growth promotion by N-fixing rhizobacteria P. dispersa and E. asburiae strains. Both strains could be used as biofertilizer for sugarcane to minimize nitrogen fertilizer use and better disease management. [ABSTRACT FROM AUTHOR]

BACKGROUND: Selenium is an important, essential element of life. The development of selenium-enriched agricultural products is a safe and effective way to increase the level of human selenium intake in China. The evaluation and utilization planning of selenium-enriched land resources are important aspects of land quality geochemical surveys, to serve the development of characteristic agricultural products and to overcome poverty. OBJECTIVES: To improve the methodology for selenium-enriched land assessment and to develop more effective and safe land-use planning methods.METHODS: The research results on selenium content in soil and crops, the origin of soil selenium, the soil selenium occurrence and its bioavailability factors, the soil-crop system selenium absorption and transport, and the interaction between selenium and heavy metal cadmium were reviewed in this article.RESULTS: The geochemical background of selenium in top soils in China was 0.2 mg/kg, significantly lower than the average in world soils(0.4 mg/kg). Generally, the soils had a low selenium level, and it was believed that the use of 0.40 mg/kg selenium as a selenium-enriched soil standard had a strong scientific basis. Selenium in soils was mostly from a geological setting, however, in some cases anthropogenic activities may be an important source of soil selenium. The genetic mechanism of selenium-enriched soils can be categorized as high geological background, weathering accumulation and anthropogenic input as well as a multi-factor combination. The association of selenium with cadmium and other heavy metals was pervasive because of similar geochemical behavior and geological origin. The species and bio-availability of selenium in soils were mainly controlled by its source and soil physic-chemical properties such as pH, Eh, and contents of organic matter, iron oxides and aluminum oxides. In turn, these factors affect the availability of selenium-enriched land and became the theoretical basis and considerations for formulating local standards for selenium-enriched soil. The accumulation ability of selenium varied greatly between crop cultivars. Selection native crop types with higher selenium accumulation ability and low accumulation with Cd as well as other toxic metals was of practical meaning. Some existing selenium-enriched agricultural product standards did not fully consider the purpose of human selenium supplementation, and there were problems such as poor coordination between standards. It was urgent to strengthen the formulation of selenium-enriched agricultural product standards.CONCLUSIONS: Selenium-enriched land suitability assessment, local selenium-enriched soil standard establishment and selenium-enriched crop plantation planning should consider the concentration of selenium and heavy metals in soils, their source and genesis, bio-availability and influencing factors, transport and accumulation in soil-crop system, the synergistic or antagonistic effects between selenium and other chemicals such as cadmium, as well as plantation suitability of crop cultivars under local climate, soil conditions and landscape. According to the availability of selenium-enriched land resources, classification, zoning, scientific planning and reasonable planting management are carried out. In order to meet the needs of investigation and evaluation of selenium-enriched land resources, availability analysis, and research on the health effects of selenium-enriched agricultural products, it is recommended to strengthen the research and application of extraction, separation, analysis, and determination methods for soil and crop selenium content and species. [ABSTRACT FROM AUTHOR]

Cassava (Manihot esculenta Crantz) is one of the most important food crops grown in the tropical regions of the world. Even though cassava is also cultivated and consumed in southern China, there is little knowledge of the composition of the cassava grown here. Therefore, 16 cassava germplasms collected from Hainan Province in China were used in the present work to determine the proximate composition, amino acid, mineral, and hydrogen cyanide contents of their roots. The results showed significant differences among the cassava germplasms. The cassava germplasms contained 85.56 - 90.50 g/100 g carbohydrate, 0.03 - 1.28 g/100 g crude lipid, 1.41 - 4.74 g/100 g crude protein, 2.90 - 8.60 g/100 g moisture, and 2.89 - 4.38 g/100 g ash. The mineral contents were 62.89 - 467.36, 425.01 - 1474.71, and 070 - 7.95 mg/kg for Ca, Mg, and Pb, respectively; and 1523.08 - 4749.46, 75.57 - 766.33, 9.57 - 282.83, 4.48 - 26.69, 0.75 - 373.60, and 10.43 - 29.04 mg/kg for K, Na, Zn, Mn, Cu, and Fe, respectively. The HCN content ranged from 0.32 - 1.53 mg/g. Among the 16 cassava germplasms, ZMH1071, ZMJ615, and SC12 yielded higher carbohydrate content and lower HCN content, making them suitable for direct consumption or processing; and germplasm M484 yielded high cyanide and carbohydrate content, making it more suitable for starch processing. [ABSTRACT FROM AUTHOR]

• We explore the fraught practices of ecological civilization in Yunnan. • Development is constituted by diverse, situated interests, pursuits and relations. • Maca commercialization involves complex discourses and practices of nature. • Farmers evolved from recipients of development to agricultural entrepreneurs. In this paper we argue that research on development in frontier regions needs to incorporate an explicitly environmental and ecological dimension, because economic frontiers are increasingly regarded as ecological frontiers in state and public discourses alike. We elaborate this argument by examining how the state-capital coalition has intervened in the development of Yunnan, a southwestern frontier of China, and how this process has involved the construction of an ecological civilization. This paper conceptualises the campaign of ecological civilization as the performance of state power through the discourses and practices of nature, and in this process, development is a highly situated and contingent process entangled with the complex negotiations between the state's ambition of socio-political assimilation, the volatility of the market and the agency of local communities. In specific, we focus on economic and ecological practices of using land for the plantation of the commercial crop maca. In the past decade or so, maca production in Yunnan has undergone a drastic process of rapid expansion and subsequently an equally rapid decline. Local authorities colluded with large enterprises to domesticate maca and promote maca production for land-based capital accumulation and poverty alleviation. Meanwhile, local farmers underwent a transformation, albeit contested, incomplete and full of back and forth, from passive recipients of development to active agricultural entrepreneurs. This article advances debates on frontier development and the role of nature in such processes, through the specific lens of ecological civilization in contemporary China. [ABSTRACT FROM AUTHOR]

Changes in monthly streamflow and the potential influences and feedbacks of agricultural activities are investigated. Significant decreases in streamflow are observed in northern China, including the Yellow, Huaihe and Haihe river basins, while in southern China streamflow increases significantly in the Yangtze, Pearl and South river basins. This spatial pattern of changes in streamflow indicates that the imbalance in water resources between northern (dry) and southern (wet) China has increased during past decades. On the one hand, available water resources are a controlling factor determining the expansion of irrigated land and the structure of crop plantation (i.e. rice, wheat, corn or bean); on the other hand, crop planting structure and effective irrigated areas are important determinants of changes in streamflow. The increasing effective irrigation and rice planting areas in northern China may increase water withdrawal from rivers, causing subsequent decreases in streamflow, while in southeastern China, decreasing effective irrigation areas enhance the increases in streamflow. [ABSTRACT FROM AUTHOR]

• Optimizing fertilization schemes from N fertilizer production to use using novel methods. • Controlled-release urea (CRU) use improves energy efficiency and economic benefit. • CRU use weakens resource structure and promotes carbon emissions. • CRU use promotes environmental sustainability. • Single CRU use realizes the best coordinated development. Fertilization methods significantly affects sustainability of agricultural production through controlling nutrient efficiency and related environmental emissions as well as energy and economic performance at crop cultivation and fertilizer production stage. Therein, controlled-release urea (CRU) use has been proved to raise nitrogen use efficiency and reduce some nitrogen-related environmental emissions. However, related studies have not been found to address whether CRU can promote coordinated development of crop production based on the energy efficiency, carbon emission intensity, environmental performance and economic benefit from this fertilizer production to crop plantation, which could affect reasonable utilization of CRU due to prejudiced conclusions based on inadequate decision-making information derived from one or two or three aspects abovementioned. To this end, this study proposed a set of evaluation system, composed of energy efficiency, carbon emission intensity, and emergy-based environmental performance through integrating environmental emissions' impact as well as economic benefit, to investigate the coordinated development of rice production with different fertilization schemes composed of altering ratios of CRU to common urea (CU). In doing so, we attempt to search for the relative balance between long-run sustainability of crop production and short-term gains of stakeholders. The presented approach was applied to a study case, from Sichuan Province, China, based on three fertilization schemes, i.e., N1 (single CU), N2 (single CRU), and N3 (blend application of 60% CRU and 40% CU) with the expanded analysis boundary from N fertilizer production to its application in rice plantation. The results indicate that: (1) relative to N1, introduction of CRU increases energy efficiency by 33.15% and 53.09% for N3 and N2 respectively in terms of kJ/kg rice, production efficiency by 0.85% and 3.39% for N3 and N2 respectively in terms of Adjusted emergy yield rate, and economic benefit by 14.53% and 17.95% for N3 and N2 respectively in terms of Benefit-cost ratio, or increased by 15.87% and 26.98% for N3 and N2 respectively in terms of Adjusted benefit to cost ratio, mainly derived from improving N use efficiency and saving labor; (2) introduction of CRU weakens resource structure by 0.98% and 3.23% for N3 and N2 respectively, and raises environmental load by 0.31% and 2.51% for N3 and N2 respectively due to enlarging share of purchased non-renewable resources and promoting methane emission respectively; (3) introduction of CRU enhances environmental sustainability by 0.27% and 0.55% for N3 and N2 respectively relative to N1, and (4) generally N2 realizes the best coordinated development, followed by N3 and N1. Improving resource structure and mitigating carbon emissions should be emphasized when popularizing CRU use in rice production. [ABSTRACT FROM AUTHOR]

There is a global concern of pollinator declines and linked ecosystem service losses. However, although land-use changes are a primary threat to biodiversity, how land-use change affects pollinator communities, pollination networks and fruit-set of food crops is poorly understood. The impact of land-use changes is especially understudied in tropical systems, even though most tropical crops are highly dependent on animal pollination. Using 40 sites to investigate diurnal and nocturnal flower visitors in small-scale agroecosystems across land-use gradients in Thailand and tropical South-western China, we show that habitat structure shapes pollinator communities at local (floral species richness) and landscape level (percentage of tree plantation in a 500 m radius and percentage forest in a 5 km radius), influencing both the species richness of pollinators and their visitation rates. These, in turn, alter plant-pollinator network structure: community-level specialization increases with floral species richness and percentage of forest cover. However, the specialization decreases with percentage of tree plantation, illustrating that natural habitat better supports specialized species. Furthermore, fruit-sets of several crops were affected by land-use. Notably, fruit-set of mango was positively associated with the percentage of forest cover in the surrounding landscape. These findings reveal how land-use influence pollinator communities and highlight how natural habitats may safeguard ecosystem services. • The local floral species richness and land-use type influence the pollinator communities. • Habitat structure change crop production in tropical small-holder agroecosystems. • Pollinator specialization increases with floral species richness and percentage of forest cover. • Mango fruit set was positively associated with the percentage of forest cover in the surrounding landscape. [ABSTRACT FROM AUTHOR]

This paper collected and arranged competitive scientific research projects undertaken by Tropical Crops Genetic Resources Institute of Chinese Academy of Tropical Agricultural Sciences in 2003-2014. Through statistica analysis on quantity of projects, funded amount, age of person responsible, professional title of person responsible, academic degree of person responsible, research object, it discussed relevant characteristics and rules. Finally, it came up with pertinent measures and recommendations, in the hope of providing services for decision-making and scientific and technological manaement. [ABSTRACT FROM AUTHOR]

Background and aims: Growth, morphological traits, and mycorrhizal colonization of fine roots show high degree of plasticity in response to changes in nutrient availability, causing shifts in root nutrient-foraging strategy. However, little is known about how this plasticity associated with root branching orders respond to atmospheric nitrogen (N) deposition in subtropical coniferous forests. Methods: We used soil block sampling method to examine the responses of six key root functional parameters (including three morphological traits (specific root length (SRL), root tissue density (RTD), and root diameter), two growth indices (total root length (TRL) and biomass) on an areal basis across five root orders, and ectomycorrhizal (EM) tip colonization) to different doses and species of N addition in a slash pine ( Pinus elliottii) plantation in subtropical China. Results: TRL, root biomass in all root orders, and EM tip colonization increased significantly with N addition. However, SRL, RTD, and root diameter did not change in any root orders. In comparison to low doses of N input, high doses of N input exerted greater effects on lower-order roots. In regard to species of N added, stronger responses in lower-order roots were observed under ammonium-based than nitrated-based N input. Foliar P content was significantly decreased and stoichiometric N:P ratio was markedly increased in response to high dose of ammonium-based N input. Conclusions: Fine root growth and EM tip colonization displayed higher degree of plasticity than morphological traits in response to N addition. The plastic responses were not root-order dependent, but dependent on both N dose and species, especially for ephemeral lower-order roots that are mostly like to be the main nutrient acquisition structures. Our results imply that while N limitation was alleviated by exogenous N input, P limitation may persist or even be exacerbated, thus causing an increase of absorptive root length, biomass, and dependence on ectomycorrhizae for nutrient acquisition in subtropical slash pine plantation forests. [ABSTRACT FROM AUTHOR]

Taking Tropical Crops Genetic Resources Institute (TCGRI) of Chinese Academy of Tropical Agricultural Sciences (CATAS) as an example, this paper discussed current situation of construction of sci-tech platform, analyzed existing problems, and finally came up with pertinent recommendations. [ABSTRACT FROM AUTHOR]

Taking Tropical Crops Genetic Resources Institute (TCGRI) of Chinese Academy of Tropical Agricultural Sciences (CATAS) as an example, this paper discussed current situation of management of official overseas trips of staff in agric-scientific research institutions, analyzed existing problems, and finally came up with pertinent recommendations. [ABSTRACT FROM AUTHOR]

Abstract: A total of 638 isolates of rice blast (Magnaporthe oryzae) were isolated in 2002–2009 from different rice varieties in different regions of Sichuan, China and inoculated onto seven rice varieties (Lijiangxintuanheigu, IR24, Minghui 63, Duohui 1, Chenghui 448, Neihui 99-14 and RHR-1) to differentiate the virulence types of the fungus and trace the changes. The virulence to the seven varieties was respectively scored at 1, 2, 4, 8, 16, 32 and 64. The total scores of individual M. grisea isolates which were the sum of scores infecting differential varieties could, in turn, be used for the nomenclature of the virulence types due to their accordance to the special virulence patterns. The 638 tested isolates were then differentiated into 56 different virulence types. Type 15 virulent to Lijiangxintuanheigu, IR24 and Minghui 63, and Type 127 virulent to all of the seven varieties were the most dominant virulence types respectively with the occurrence frequencies of 15.99% and 15.83%. Type 19 and other seven virulence types were not monitored during 2002–2009. Type 15 was the predominant virulence type in 2002, 2003, 2004 and 2007, whereas Type 127 had been the most dominant virulence type after 2005 except for the year 2007 when the province underwent severe drought. Five hundred and seven out of the 638 tested isolates were virulent to Minghui 63, and 89.58% of the 384 isolates virulent to either Duohui 1, Chenghui 448 or Neihui 99-14 were virulent to Minghui 63, which indicated the impact of the extensive plantation of hybrid rice Minghui 63 as the restorer line on the virulence evolution of M. oryzae in Sichuan. The virulence pattern of the dominant virulence types suggested that the acquiring of virulence to all the major resistant restorer lines was the main routes of the evolution in virulence of M. oryzae to hybrid rice in Sichuan. The virulence frequencies of the 638 tested isolates to IR24, Minghui 63, Duohui 1, Chenghui 448, Neihui 99-14 and RHR-1 were respectively 74.6%, 79.5%, 73.8%, 37.0%, 39.0% and 40.4%. The analysis for the sources of the different virulence type isolates indicated the pathogen on the newly released resistant varieties were stronger than conventional rice varieties which had become susceptible in the field since 1980s. [Copyright &y& Elsevier]

Zheng, J., Ding, L., Hao, Z. & Ge, Q. 2012 (January): Extreme cold winter events in southern China during AD 1650-2000. Boreas, Vol. 41, pp. 1-12. 10.1111/j.1502-3885.2011.00225.x. ISSN 0300-9483. We defined extreme cold winter events as those with occurrence probabilities lower than the 10th percentile of the probability density function, based on observed winter temperatures in southern China since 1951. Subsequently, we constructed impact severity levels using documentary evidence for those events during 1951-2000, considering three indexes for the freezing of rivers/lakes, widespread snow/ice storms, and cold damage to subtropical/tropical crops. Using these criteria we identified 50 extreme cold winters for the period AD 1650-1949 based on ∼4000 pieces of comparable information extracted from local gazettes in southern China, after verification using data from three weather stations with long records. It was found that the frequencies of the extreme cold winter events since 1650 varied over time. The most frequent occurrences were found during AD 1650-1699 and in the first and second halves of the 19th century, with frequencies twice as high as in the second half of the 20th century. In contrast, the frequencies of extreme winters during the 18th century were close to that in the second half of the 20th century. High frequencies of extreme cold winters in AD 1650-1720 and AD 1795-1835 occurred during the sunspot Maunder and Dalton Minima. The intensities of some historical cold events, such as those during 1653-1654, 1670, 1690, 1861, 1892 and 1929, exceeded those of the coldest winter events since 1951. [ABSTRACT FROM AUTHOR]

Abstract: The effects of afforestation on soil carbon (C) stocks are of concern to the plantation carbon budget and the mitigation of global warming. China has the largest tree plantation areas in the world, but the effects of afforestation on soil C are poorly understood. We reviewed Chinese data of soil C, available from 70 publications, to analyze the change of soil C and its affecting factors following afforestation. Our results indicated that afforestation could accumulate soil C in China, with the accumulation rate of 42.05, 30.07 and 73.94gCm−2 yr−1 in 0–20, 20–40 and 0–40cm soil depths. Five years after afforestation, plantations began to accumulate soil C rapidly, and plantations with the age of 10–20 years old had the highest soil C accumulation rate. Afforestation on former cropland and wasteland had higher accumulation rates of soil C than on former grassland. In middle-temperature and warmer regions, the accumulation rate of soil C was higher than that in colder regions, and in semi-humid regions, the accumulation rate of soil C was significantly higher than that in semi-arid regions. Soil C accumulated rapidly in broadleaved and mixed plantations, and the accumulation rate in broadleaved was higher than that in coniferous plantations. Although some uncertainties existed with regard to the data and methods, a reasonable analysis of soil C change following afforestation in China was achieved for the first time. Future studies should be fulfilled with improved sampling and analytical techniques, reliable soil carbon models and synchronous investigation of soil nitrogen dynamics. [ABSTRACT FROM AUTHOR]

This paper summarized the research and development of pasture in the tropical areas, and simply generalized the problems and methods for improvement and expected the advancement of the tropical pasture. [ABSTRACT FROM AUTHOR]

The Xishuangbanna Prefecture (21°09′–22°36′ N; 99°58′–101°50′ E) in southern Yunnan is one of the major growing areas for tropical crops in China. Daffy temperature in Winter is about 8°C lower that in Summer. The effects of season on photosynthesis and antioxidant enzyme activities were studied in the tropical fruit tree species Artocarpus altilis (breadfruit), A. heterophyllus (jackfruit) and Garcinia mangostana (mangosteen), growing in an open site. In August 2002 and January 2003, maximum net CO2 assimilation was 17.1 ± 0.3 μmoles m-2 s-1 (mean ± SE) and 10.7 ± 0.5 in breadfruit; 11.7 ± 0.2 μmoles m-2 s-1 and 10.9 ± 0.6 in jackfruit; and 8.6 ± 0.1 μmoles m-2 s-1 and 6.3 ′ 0.4 in mangosteen, respectively. Concentrations of chlorophyll were lower in mangosteen and breadfruit in January than in August, while in January, photo-inhibition was evident in mangosteen and breadfruit by changes in leaf chlorophyll fluorescence. Concentrations of malondialdehyde (a product of membrane lipid peroxidation), carotenoid to chlorophyll ratios, and the activities of the antioxidant enzymes superoxide dismutase, catalase and peroxidase were higher in January than in August, in all species, especially the antioxidant enzyme activities in jackfruit. Moreover, in both August and January, mangosteen suffered severe mid-day photo-inhibition. These results indicate that jackfruit is chilling tolerant, breadfruit is chilling sensitive, and mangosteen is chilling and high-fight intensity sensitive. Breadfruit and mangosteen do not appear to be suitable crops to grow outdoors in southern Yunnan, China. [ABSTRACT FROM AUTHOR]

Coconut (Cocos nucifera L.) is an important economic fruit and oil crop largely cultivated in humid and sub-humid tropical coastal zones worldwide. To date proteomic profile analysis of coconut under cold stress yet not been conducted. In order to understand the cold stress tolerance in coconut, the iTRAQ approach was employed to dissect proteomic response of two coconut varieties Hainan Tall, BenDi (BD) and Aromatic coconut, XiangShui (XS) under cold stress. Under cold treatment at (8 °C) for 2 days, 193 up and 134 down-regulated in BD (Cn-DB-0_VS_Cn-DB-2) and 140 up and 155 down-regulated DEPs in XS (Cn-XS-0_VS_Cn-XS-2) were identified. The 5 days post cold treatment also identified increased abundance of up-regulated proteins in BD compared to XS. The 5 days post treatment (dpt) depicted 172-up/127-down and 108-up/134-down accumulated proteins for BD (Cn-DB-0_VS_Cn-DB-5) and XS (Cn-XS-0_VS_Cn-XS-5) respectively. A total of 22, 12 and 14 DEP categories were enriched in biological process, cellular component and molecular function respectively in Gene Ontology (GO) analysis of two coconut varieties. Metabolic and biosynthesis of secondary metabolites pathways were highly enriched in KEGG pathway analysis of DEPs between two varieties. Twenty-two different functional classes revealed differentially expressed proteins in two varieties. Among those, four major categories involved in metabolism, stress response, photosynthesis and respiration related DEPs increased abundance in two varieties. However, general function perdition only (GFPO) and stress-responsive proteins were greatly up-regulated in BD than XS. Increased abundance of stress response related proteins up-regulation under cold stress suggested that BD is cold-tolerant variety. Collectively, iTRAQ-based coconut leaf proteomic analysis showed that XS (aromatic) coconut variety is cold-sensitive compared to BD (Hainan Tall) variety. This study provided a basis for further functional analyses to understand the molecular mechanisms of tropical crops adapting to cold stress. Leaf proteomic approach determines the role of differentially expressed proteins (DEPs) under cold stress in crops. However, cold stress could damage the coconut fruit lead to decrease in crop yield during winter in China. Here, we report the first ever iTRAQ-based proteomic analysis of two coconut varieties in response to cold stress. The study identified the proteins involved in biosynthesis of secondary metabolites, photosynthesis, respiration, biotic and abiotic stresses under cold stress in two coconut varieties. Moreover, the increased abundance of stress-responsive and general function proteins in BD under cold stress suggested that Hainan Tall is cold-tolerant compared to aromatic coconut variety. Inhibition abundance of photosynthesis related proteins may reduce photodamage owing to the over energized state of thylakoid membrane lead to ROS generation during oxidative stress. This could be the reason for adaption of BD to low temperature stress. Nonetheless, further research may insight the mechanism involved in cold tolerance/sensitive in coconut in response to low temperature. Unlabelled Image • First iTRAQ-based proteomic analysis of coconut leaf under cold stress. • Aromatic coconut (XS) down-regulated abundant number of proteins of several DEPs categories under cold stress. • Cold stressed leaves of Hainan Tall (BD) up-regulated numerous number of proteins related to GFPO and stress-responsive. • Aromatic coconut revealed cold-sensitive under cold stress. • Hainan Tall variety identified as a cold-tolerant variety in response to low temperature. [ABSTRACT FROM AUTHOR]