A case study on the impacts of future climate change on soybean yield and countermeasures in Fujin city of Heilongjiang province, China

Global climate change poses a great impact on crop growth, development and yield. Soybean production in Northeast China, which is one of the traditional dominant soybean production areas in China, is of great significance for developing the domestic soybean industry and reducing dependence on imported soybeans. Therefore, it is crucial to evaluate the impacts of future climate change on soybean yield in Northeast China, and to propose reasonable adaptation measures. In this study, we took Fujin city of Heilongjiang province in Northeast China as an example, and used the CROPGRO-soybean model in DSSAT (Decision Support System for Agrotechnology Transfer) to simulate the impacts of future climate change on soybean yield in the four periods of the 2020s (2021-2030), 2030s (2031-2040), 2040s (2041-2050) and 2050s (2051-2060) under two representative concentration pathway (RCP) scenarios (RCP4.5 and RCP8.5), and further determine the best agronomic management practices. The results showed that the calibrated and validated model is suitable for simulating soybean in the study area. By analyzing the meteorological data under future climate scenarios RCP4.5 and RCP8.5 from the PRECIS regional climate model, we found that the average temperature, cumulative precipitation and cumulative solar radiation would mostly increase during the growing season in Fujin city of Heilongjiang province. Combined with the model simulation results, it is shown that under the effect of CO2 fertilization, future climate change will have a positive impact on soybean yield. Compared to the baseline (1986-2005), the soybean yield would increase by 0.6% (7.4%), 3.3% (5.1%), 6.0% (16.8%) and 12.3% (20.6%) in the 2020s, 2030s, 2040s and 2050s under RCP4.5 (RCP8.5).Moreover, the optimal sowing dates and the optimal supplemental irrigation amount under RCP4.5 (RCP8.5) are May 10 (May 5) and 50 mm (40mm), respectively. Under future climate conditions, the agronomic management practices, such as advancing the sowing date and supplementary irrigation in the key stage of soybean growth would increase soybean yield and make soybean growth more adaptable to future climate change

Hijacking common mycorrhizal networks for herbivore-induced defence signal transfer between tomato plants

Common mycorrhizal networks (CMNs) link multiple plants together. We hypothesized that CMNs can serve as an underground conduit for transferring herbivore-induced defence signals. We established CMN between two tomato plants in pots with mycorrhizal fungus Funneliformis mosseae, challenged a ‘donor' plant with caterpillar Spodoptera litura, and investigated defence responses and insect resistance in neighbouring CMN-connected ‘receiver' plants. After CMN establishment caterpillar infestation on ‘donor' plant led to increased insect resistance and activities of putative defensive enzymes, induction of defence-related genes and activation of jasmonate (JA) pathway in the ‘receiver' plant. However, use of a JA biosynthesis defective mutant spr2 as ‘donor' plants resulted in no induction of defence responses and no change in insect resistance in ‘receiver' plants, suggesting that JA signalling is required for CMN-mediated interplant communication. These results indicate that plants are able to hijack CMNs for herbivore-induced defence signal transfer and interplant defence communication

Interval job scheduling with machine launch cost

We study an interval job scheduling problem in distributed systems. We are given a set of interval jobs, with each job specified by a size, an arrival time and a processing length. Once a job arrives, it must be placed on a machine immediately and run for a period of its processing length without interruption. The homogeneous machines to run jobs have the same capacity limits such that at any time, the total size of the jobs running on any machine cannot exceed its capacity. Launching each machine incurs a fixed cost. After launch, a machine is charged a constant cost per time unit until it is terminated. The problem targets to minimize the total cost incurred by the machines for processing the given set of interval jobs. We focus on the algorithmic aspects of the problem in this article. For the special case where all the jobs have a unit size equal to the machine capacity, we propose an optimal offline algorithm and an optimal 2-competitive online algorithm. For the general case where jobs can have arbitrary sizes, we establish a non-trivial lower bound on the optimal solution. Based on this lower bound, we propose a 5-approximation algorithm in the offline setting. In the non-clairvoyant online setting, we design a O(μ)-competitive Modified First-Fit algorithm which is near optimal (μ is the max/min job processing length ratio). In the clairvoyant online setting, we propose an asymptotically optimal O(logμ)-competitive algorithm based on our Modified First-Fit strategy.Ministry of Education (MOE)This work was supported by the Singapore Ministry of Education Academic Research Fund Tier 1 under Grant 2019-T1002-042, by the NationalNatural Science Foundation of China under Grant 61902063, and by the Provincial Natural Science Foundation of Jiangsu, China under Grant BK20190342

Photosynthesis-transpiration coupling model at canopy scale in terrestrial ecosystem

At the hypothesis of big leaf, an ecosystem photosynthesis-transpiration coupling cycle model was established by the scaled SMPT-SB model from single leaf to canopy, and model parameterization methods were discussed. Through simulating the canopy light distribution, canopy internal conductance to CO <inf>2</inf> can be scaled from single leaf to canopy by integrating to canopy using the relationship between single internal conductance and photosynthetic photon flux density. Using the data observed by eddy covariance method from the Changbai Mountains site of ChinaFLUX, the application of the model at the canopy scale was examined. Under no water stress, the simulated net ecosystem photosynthesis rate fitted with the observed data very well, the slope and R² of the line regression equation of the observed and simulated values were 0.7977 and 0.8892, respectively (n = 752), and average absolute error was 3.78 &mu;mol CO<inf>2</inf> m^-2 s^-1; the slope, R² and average absolute error of transpiration rate were 0.7314, 0.4355 and 1.60 mmol H<inf>2</inf>O m^-2 s^-1, respectively (n = 752). The relationship between canopy photosynthesis, transpiration and external environmental conditions was discussed by treating the canopy as a whole and neglecting the comprehensive feedback mechanism within canopy, and it was noted that the precipitation course affected the transpiration rate simulation badly. Compared to the models based on eco-physiological processes, the SMPT-SB model was simple and easy to be used. And it can be used as a basic carbon and water coupling model of soil-plant-atmosphere continuum. Copyright by Science in China Press 2005

Slip distribution and footwall topography of the Yanggao-Tianzhen Fault (northern Shanxi Graben): implications for the along-strike variations in fault activity and regional deformation

Spatial patterns in fault activity were examined along the Yanggao-Tianzhen Fault (YTF) in the northern Shanxi Graben, North China. First, we reconstructed the distribution of fault slips and quantified slip rates at seven sites along the fault, based on satellite image interpretation, field investigation, topographic surveying, and optically stimulated luminescence dating. The T3 terraces and their contemporaneous alluvial fans with a best-estimate age of 31.7 ± 1.4 kyr were used as strain markers to estimate slip magnitudes. We determined vertical slip and dip-slip rates of ∼0.10–0.31 mm/yr and ∼0.11–0.37 mm/yr, respectively, at the surface. Assuming fault dips of 40 ± 10° at seismogenic depths, we predicted extension rates of ∼0.17–0.55 mm/yr. This suggests that at least 10% and up to 28%–54% (95% confidence interval) of the total extension of the northern Shanxi Graben is inhomogeneously partitioned by different sections of the YTF. We also evaluated the along-fault relative tectonic activity by analyzing of five widely used geomorphic indices: hypsometric integral, basin elongation ratio, asymmetric factor, valley-floor-width-to-height ratio, and mountain front sinuosity. The determined fault slip rates and geomorphic indices demonstrate that the most prominent fault activity center occurred in the middle of the fault, and that fault activity wanes toward the fault tips. Moreover, the fault activity is highly heterogeneous and fluctuates along the fault strike, which may be attributed to either fault segmentation and linkage or the possible strike-slip component of motion along the fault. Further exploration of fault kinematics and paleoseismic history is warranted.Published versionThis study was jointly financed by the National Key Research and Development Program of China (2017YFC1500101), the Second Tibetan Plateau Scientific Expedition and Re-search Program (2019QZKK0901), and the National Natural Science Founda-tion of China (42002233)

Field observations of surface ruptures accompanying a tsunami and supershear earthquake along a plate boundary strike-slip fault

Strike-slip earthquakes near major subduction zones have received less attention than thrust or reverse earthquakes in subduction zone areas. The occurrence of the 2018 Palu Mw 7.5 earthquake in eastern Indonesia provides an unprecedented opportunity to investigate the characteristics of one of these events. The Palu earthquake occurred on the left-lateral, north-south-striking Palu-Koro fault, which is the main plate boundary structure accommodating the convergence between blocks in a triple junction area. It excited a significant tsunami, which unusually is associated with strike-slip earthquakes, and also ruptured at a supershear speed, which is mostly observed on strike-slip faults in continents. Based on our fieldwork, we speculate that the normal slip component of the offshore rupture section in Palu bay on the middle segment probably favours tsunami genesis. Our field investigation has revealed evidence of a simple geometry as well as slip partitioning of dip-slip and strike-slip motion on two subparallel strands on the main segment, both of which may have contributed to the supershear of the rupture propagation. Instead of only a transtensive behaviour of the middle segment, our results also illustrate the transpressional property of the northern and southern rupture segments, which shows more complex behaviour than that of a common continental strike-slip fault.This study was funded by the National Nonprofit Fundamental Research Grant of China, IGCEA (IGCEA1901), the National Research and Development Program of China (2017YFC1500101) and the National Natural Science Foundation of China (42072250)

Coseismic surface rupture during the 2018 Mw 7.5 Palu earthquake, Sulawesi Island, Indonesia

Sulawesi Island is located at the triple junction between the converging Australian, Sunda, and Philippine plates. The magnitude (Mw) 7.5 Palu earthquake occurred on 28 September 2018 on Sulawesi Island and caused serious casualties. The causative fault of the Palu earthquake was the left-lateral, strike-slip Palu-Koro fault, which has a rapid slip rate. We experienced this earthquake in Palu City and conducted field investigations on coseismic surface ruptures 1 d after the earthquake. Field surveys revealed that the coseismic surface ruptures were characterized by left-lateral offset, en echelon tensional cracks, mole tracks within a narrow zone, and large areas of sand liquefaction that increased the damage and losses. We measured the coseismic displacements along surface ruptures and observed a maximum coseismic offset of ∼6.2 m. The rupture traces in the north Palu Basin near Palu City mark the previously unmapped Palu-Koro fault. Based on the field investigations, we determined the exact location of the Palu-Koro fault within the Palu Basin and found that the Palu-Koro fault zone can be divided into three branches: F1, F2, and F3, forming a typical flower structure

Elevated CO₂ Reduces the Resistance and Tolerance of Tomato Plants to <em>Helicoverpa armigera</em> by Suppressing the JA Signaling Pathway

<div><p>Both resistance and tolerance, which are two strategies that plants use to limit biotic stress, are affected by the abiotic environment including atmospheric CO₂ levels. We tested the hypothesis that elevated CO₂ would reduce resistance (i.e., the ability to prevent damage) but enhance tolerance (i.e., the ability to regrow and compensate for damage after the damage has occurred) of tomato plants to the cotton bollworm, <em>Helicoverpa armigera</em>. The results showed that elevated CO₂ reduced resistance by decreasing the jasmonic acid (JA) level and activities of lipoxygenase, proteinase inhibitors, and polyphenol oxidase in wild-type (WT) plants infested with <em>H. armigera</em>. Consequently, the activities of total protease, trypsin-like enzymes, and weak and active alkaline trypsin-like enzymes increased in the midgut of <em>H. armigera</em> when fed on WT plants grown under elevated CO₂. Unexpectedly, the tolerance of the WT to <em>H. armigera</em> (in terms of photosynthetic rate, activity of sucrose phosphate synthases, flower number, and plant biomass and height) was also reduced by elevated CO₂. Under ambient CO₂, the expression of resistance and tolerance to <em>H. armigera</em> was much greater in wild type than in <em>spr2</em> (a JA-deficient genotype) plants, but elevated CO₂ reduced these differences of the resistance and tolerance between WT and <em>spr2</em> plants. The results suggest that the JA signaling pathway contributes to both plant resistance and tolerance to herbivorous insects and that by suppressing the JA signaling pathway, elevated CO₂ will simultaneously reduce the resistance and tolerance of tomato plants.</p> </div