Evapotranspiration and its partitioning during and following a mountain pine beetle infestation of a lodgepole pine stand in the interior of British Columbia, Canada

IntroductionMassive tree mortality events in western Canada due to widespread infestation by mountain pine beetle (MPB) are expected to impact local-to-regional evapotranspiration (ET) dynamics during and after a disturbance. How ecosystem-level ET and its components may vary with canopy-tree mortality (treefall) and subsequent understory recovery remains unclear.MethodsWe used 10 years of continuous eddy-covariance and remote-sensing data (2007–2016) and machine-learning models based on random forest and xgboost to determine forest- and climate-driven effects at temporal scales appropriate for a lodgepole pine-dominated stand following a major, five-year MPB disturbance initiated in the summer of 2006.ResultsTotal annual ET over the 10 years ranged from 207.2 to 384.6 mm, with annual plant transpiration (T) contributing to 57 ± 5.4% (mean ± standard deviation) of annual ET. Annual ET initially declined (2007–2011) and then increased (2011–2016), with ET and T/ET increasing at statistically non-significant rates of approximately 3.2 and 1.2% per year from 2007 to 2016. Air temperature (Ta) and vapor pressure deficit (VPD) were the most important predictors of seasonal variation in ET and T/ET during the 10-year period, with high Ta, VPD, and photosynthetically active radiation (PAR) causing ET and T/ET to increase. Annual ET increased with both increasing spring Ta and decreasing VPD. Annual T/ET was shown to increase with increasing VPD and decrease with increasing volumetric soil water content at a 5-cm depth (VWC5). Enhanced vegetation index (EVI, an indicator of canopy greenness) lagged T and overstory tree mortality, whereas previous- and current-year values of EVI were shown to be poor predictors of annual ET and T/ET.Discussion and conclusionsThese findings suggest that the promotion of climate factors on forest ecosystem-level water vapor fluxes may offset reductions promoted by MPB outbreaks. Climate processes affected water vapor fluxes more than biotic factors, like stand greenness, highlighting the need to include climate-regulatory mechanisms in predictive models of ET dynamics during and subsequent to stand disturbance. Climate and forest-greenness effects on water vapor fluxes need to be explored at even longer time scales, e.g., at decadal scales, to capture long-drawn-out trends associated with stand disturbance and its subsequent recovery

Parameterization, Validation and Comparison of Three Tillering Models for Irrigated Rice in the Tropics

Tillering plays an important role in determining rice grain yield. Several models have been developed to predict tiller production in irrigated rice. In this paper we tested three models using data drawn from a wide range of plant densities and N inputs in two field experiments conducted at the International Rice Research Institute, Philippines during the 1997 and 1998 dry seasons. Two rice cultivars (IR64 and IR72) were used in the experiments. Plant samples were taken at intervals to determine number of tillers, leaf area index (LAI), biomass, relative growth rate (RGR) and leaf N concentration. The models were parameterized using an iteration procedure of the simplex method. Previous models (TIL and SINK) using the original values of parameters for IR64 failed to predict the number of tillers of IR64 in 1997. However, when re-parameterized, both models described the 1997 data well for both cultivars. The two models also predicted fairly well the number of tillers of different transplanting spacing and N input treatments of IR72 in 1998 using IR72 parameters derived from the 1997 experiment. A simple RGR model was comparable with the TIL and SINK models in descriptive and predictive ability. It appears that all three models could be used for predicting tiller production of irrigated rice

Global analysis of basic leucine zipper transcription factors in trifoliate orange and the function identification of PtbZIP49 in salt tolerance

As one of the most widely distributed and highly conserved transcription factors in eukaryotes, basic leucine zipper proteins (bZIPs) are involved in a variety of biological processes in plants, but they are largely unknown in citrus. In this study, 56 bZIP family members were identified genome-wide from an important citrus rootstock, namely trifoliate orange (Poncirus trifoliata L. Raf.), and these putative bZIPs were named PtbZIP1–PtbZIP56. All PtbZIPs were classified into 13 subgroups by phylogenetic comparison with Arabidopsis thaliana bZIPs (AtbZIPs), and they were randomly distributed on nine known (50 genes) chromosomes and one unknown (6 genes) chromosome. Sequence analysis revealed the detailed characteristics of PtPZIPs, including their amino acid length, isoelectric point (pI), molecular weight (MW), predicted subcellular localization, gene structure, and conserved motifs. Prediction of promoter elements suggested the presence of drought, low-temperature, wound, and defense and stress responsive elements, as well as multiple hormone-responsive cis-acting elements. Spatiotemporal expression analysis showed the transcriptional patterns of PtbZIPs in different tissues and under dehydration, high salt, ABA, and IAA treatments. In addition, 21 PtbZIPs were predicted to have direct or indirect protein–protein interactions. Among these, PtbZIP49 was experimentally proven to interact with PtbZIP1 or PtbZIP11 by using a yeast two-hybrid assay and bimolecular fluorescence complementation (BiFC). Subcellular localization analysis further revealed that PtbZIP1, PtbZIP11, and PtbZIP49 were localized in the nucleus. Moreover, PtbZIP49 was functionally identified as having an important role in salt stress via ectopic expression in A. thaliana and silenced in trifoliate orange using virus-induced gene silencing (VIGS). This study provided comprehensive information on PtbZIP transcription factors in citrus and highlights their potential functions in abiotic stress

Review of holistic research on NetZero Energy Homes : energy simulation, energy monitoring, and performance improvement

A NetZero Energy Home (NZEH) is designed, modelled, and constructed to produce as much energy as it consumes on an annual basis, with the required energy generated from renewable energy resources. This paper reviews holistic research on NZEHs from the perspectives of energy simulation, energy monitoring, actual energy performance, and operation/design improvement. HOT2000, developed by Natural Resources Canada, is utilised as the tool to simulate the energy performance of NZEHs. Using multiple NZEHs as the case projects, sensor-based monitoring systems are developed to evaluate the actual energy performance of NZEHs, and the results are used to analyse the discrepancy among different NZEHs and to compare with the simulated results. Based on comprehensive analysis and comparison, operation and design strategies are proposed to improve the performance of NZEHs

Exploring payback-year based feed-in tariff mechanisms in Australia

Solar energy applications are crucial to urban sustainable development and energy investment. Among the policies incentivising solar energy utilisation, Feed-in Tariff has been widely applied to stimulate the adoption of solar photovoltaic systems in the residential sector. This paper presents a payback-year-based Feed-in Tariff determination mechanism from the investment perspective, as suggested by recent research survey data. As an important indicator, the time required to recover the investment (i.e., payback year) in a residential PV project is then formulated using the proposed algorithm to determine Feed-in Tariff rates. The proposed mechanism is demonstrated in a case study in Victoria, Australia. Sensitivity analysis is used to identify the optimum Feed-in Tariff ranges for two popular types of rooftop PV systems, i.e., 3 kW and 5 kW, as examples. The results identify the desirable Feed-in Tariff range for individual energy investors as 20.29 A¢/kWh to 28.25 A¢/kWh, and this should be considered as a point of reference in determining the Feed-in Tariff rate in a manner that takes into account end-users’ expectations. The proposed mechanisms and methodology would be useful for policymakers in adjusting Feed-in Tariff incentive policies at a national or regional level

Towards zero carbon housing in Victoria through policy instruments

Buildings consume a significant amount of energy, resulting in detrimental impacts on the environment. Building operations in Australia are responsible for 26% of the country’s energy consumption, resulting in 280,000 tons of CO2 emissions each day. In addressing the detrimental impacts of residential buildings, zero carbon housing has been proposed as a solution to achieve energy conservation and reduce greenhouse gas emissions. While the benefits of such housing are widely recognised, there is limited uptake in Australia. In addressing this uptake challenge, the research presented in this paper explores existing policy mechanisms and opportunities to integrate or develop policy incentives to promote zero carbon housing in Victoria. This paper presents the analysis of policy incentives on zero carbon housing and feed-in tariff based on systematic research process and approaches. Comprehensive questionnaires and semi-structured interview questions were predesigned for seven groups of stakeholders, including homeowners or prospective homebuyers, staff of home builders, staff of government agency, staff of electricity distributors, staff of electricity retailers, house designers/consults, and solar photovoltaic industry professions. A workshop was then conducted to verify the predesigned questions, based on which semi-structured interviews were conducted with the government policy department and online surveys were launched for other groups of stakeholders. Based on the collected data and information, comprehensive analysis was undertaken to propose a policy framework to promote the uptake of zero carbon housing in Victoria. This research identified a hierarchical structure of policy and incentives promoting zero carbon housing in Victoria, including market expectations, subsidies and incentives for homebuyers, rating and certifying schemes, and design and marketing strategies. A payback period based mechanism to determine feed-in tariff is also proposed as an alternative to market price based mechanism. The proposed policy framework regarding zero carbon housing and feed-in tariff can be referred to by the state government agencies to promote zero carbon housing in the studied region. This research is also transferable and can be referred to by other states and globally. Overall, this research fosters sustainable housing concepts and shape the sustainability of the residential building sector

Identification of a Two-m6A RNA Methylation Regulator Risk Signature as an Independent Prognostic Biomarker in Papillary Renal Cell Carcinoma by Bioinformatic Analysis

N6-Methyladenosine (m6A), the most common form of mRNA modification, is dynamically regulated by the m6A RNA methylation regulators, which play an important role in regulating the gene expression and phenotype in both health and disease. However, the role of m6A in papillary renal cell carcinoma (pRCC) is unknown. The purpose of this work is to investigate the prognostic value of m6A RNA methylation regulators in pRCC; thus, we can build a risk score model based on m6A RNA methylation regulators as a risk signature for predicting the prognosis of pRCC. Here, we investigated the expression and corresponding clinical data by bioinformatic analysis based on 289 pRCC tissues and 32 normal kidney tissues obtained from TCGA database. As a result, we identified the landscape of m6A RNA methylation regulators in pRCC. We grouped all pRCC patients into two clusters by consensus clustering to m6A RNA methylation regulators, but we found that the clusters were not correlated to the prognosis and clinicopathological features of pRCC. Therefore, we additionally built a two-m6A RNA methylation regulator risk score model as a risk signature by the univariate Cox regression analysis and least absolute shrinkage and selection operator (LASSO) Cox regression. The risk signature was constructed as follows: 0.031HNRNPC+0.199KIAA1429. It revealed that the risk score was associated with the clinicopathological features such as pT status and pN status of pRCC. More importantly, the risk score was an independent prognostic marker for pRCC patients. Thus, m6A RNA methylation regulators contributed to the malignant progression of pRCC influencing its prognosis

Genetic dissection of tetraploid cotton resistant to Verticillium wilt using interspecific chromosome segment introgression lines

Verticillium wilt (caused by the pathogen Verticillium dahliae) is of high concern for cotton producers and consumers. The major strategy for controlling this disease is the development of resistant cotton (Gossypium spp.) cultivars. We used interspecific chromosome segment introgression lines (CSILs) to identify quantitative trait loci (QTL) associated with resistance to Verticillium wilt in cotton grown in greenhouse and inoculated with three defoliating V. dahliae isolates. A total of 42 QTL, including 23 with resistance-increasing and 19 with resistance-decreasing, influenced host resistance against the three isolates. These QTL were identified and mapped on 18 chromosomes (chromosomes A1, A3, A4, A5, A7, A8, A9, A12, A13, D1, D2, D3, D4, D5, D7, D8, D11, and D12), with LOD values ranging from 3.00 to 9.29. Among the positive QTL with resistance-increasing effect, 21 conferred resistance to only one V. dahliae isolate, suggesting that resistance to V. dahliae conferred by most QTL is pathogen isolate-specific. The At subgenome of cotton had greater effect on resistance to Verticillium wilt than the Dt subgenome. We conclude that pyramiding different resistant QTL could be used to breed cotton cultivars with broad-spectrum resistance to Verticillium wilt