Stem Damage Research Articles

Modelling internal stem damage in savanna trees: Error in aboveground biomass with terrestrial laser scanning and allometry

Abstract Forests and woodlands are critical terrestrial carbon stores. Tree aboveground biomass (AGB) can be estimated using allometric models and terrestrial laser scanning (TLS). However, internal tree stem damage from biotic decay is an unresolved source of error for both TLS and allometries, with implications for accurate carbon assessment. We destructively harvested 63 TLS‐scanned trees in an Australian savanna, quantified internal damage in each tree by sampling cross sections at multiple heights, and modelled the effect of damage on AGB estimation for individual trees and total estimated biomass. We tested the performance of TLS AGB modelling against five allometries, applying both database and field‐measured wood specific gravity. For TLS‐modelled and allometric AGB estimates, we tested if tree size and level of internal stem damage contributed to AGB deviations. Approximately half of the trees in the study sustained 1–10% damage by volume, which was most extensive in the base and main trunk, decreasing into the crown. On average, damaged trees had 5% internal stem damage (by volume, SD = 6.65%), with some as high as 30%. We found TLS‐derived quantitative structural models (TLS‐QSMs) using field‐measured wood specific gravity to be most accurate in estimating total biomass (R2 = 0.99, +0.59% bias). TLS‐QSMs tended to overpredict AGB of large, damaged trees, and AGB estimates from allometric models were largely unaffected by internal damage. For individual trees, all methods were effective for predicting field‐measured AGB (R2 > 0.84) and several ASMs performed well (± ~10% bias). In the absence of local wood specific gravity calibration, a pantropical ASM was most accurate. For systems where internal stem damage is low (<10% of tree volume), TLS can be used to estimate AGB with low levels of error, however more damaged wooded ecosystems (>10%) are likely to produce inflated biomass estimates if TLS is used without calibration for damage. Internal stem damage should be quantified in ASMs and incorporated into TLS‐modelled AGB calibration to avoid biomass overestimation and maintain high standards of precision in forest carbon accounting.

Advancements in Wood Quality Assessment: Standing Tree Visual Evaluation—A Review

(1) The early assessment of wood quality, even while trees are standing, provides significant benefits for forest management, sales efficiency, and market diversification. Its definition cannot be in absolute terms but must always be linked to the material’s intended use. (2) In this contribution, a review of the scientific literature is given to discuss the visually evaluable attributes that define wood quality in standing trees, the applicability of the techniques used for their assessment, and the effectiveness of these attributes and technologies in predicting quality, to finally highlight future research needs. (3) The visual characteristics generally used to evaluate wood quality are linked to stem form and dimension, branchiness, and stem damage, but their assessment is challenging due to time and resource constraints. To address these challenges, laser-based and image-based techniques have been applied in field surveys. (4) Laser scanners offer detailed and accurate measurements. Photogrammetry, utilizing images to reconstruct 3D models, provides a cost-effective and user-friendly alternative. Studies have demonstrated the effectiveness of these tools in surveying the visible properties of stems and branches, but further development is necessary for widespread application, particularly in software development, with faster and more effective algorithmic advancements for automatic recognition and subsequent measurement of pertinent characteristics being critical for enhancing tool usability. (5) However, predicting wood quality from these surveys remains challenging, with a limited correlation between the visible tree characteristics assessed and the sawn product quality. Empirical studies evaluating products downstream in the forest-wood supply chain could provide valuable insights. In this sense, the implementation of traceability systems could facilitate the linkage between data on standing trees and the quality of the sawn product. Also, further research is needed to develop models that can accurately predict internal tree characteristics and their impact on product quality.

Characterization of low-damage cutting of alfalfa stalks by self-sharpening cutters made of gradient materials

Abstract The use of self-sharpening cutters can increase crop survival and regrowth by reducing the extent of stem damage incurred during the mowing stage and reducing the healing time at the harvest site. In this study, a self-sharpening cutter was prepared using a two-stage rare earth catalytic carbon–nitrogen–boron co-infiltration process, and the self-sharpening and wear-resistant properties of the cutter were verified by using metallographic organization testing, hardness testing, friction and wear performance testing, and the homemade tool wear test bench, and the low-damage cutting characteristics of the cutter were examined through field tests on alfalfa. The results show that the thickness of the penetration layer on the back face of a self-sharpening cutter made of gradient material is about 800 μm, with a maximum hardness of 1,800 HV. The coefficient of friction of the gradient material self-sharpening cutter is 67% lower than that of the commercially available 65Mn cutter. Gradient material self-sharpening cutter wear resistance is 2.15 times more than that of commercially available 65Mn cutter. The gradient material self-sharpening cutter reduces cutting damage by 11.42% compared to the commercially available 65Mn cutter. The application and promotion of self-sharpening cutting blades with gradient materials reduce alfalfa cutting damage, thereby improving reproductive yield.

Periodic colonization of Trichogramma japonicum for bio-control of yellow stem borer (Scirpophaga incertulas) in summer low-land rice (Oryza sativa)

Yellow stem borer [Scirpophaga incertulas (Walker)], is a major pest of low-land rice (Oryza sativa L.), causing 30–40% yield losses. The use of biological control agents to suppress yellow stem borer (YSB) population and damage across Asia includes inundative releases of the egg parasitoid, Trichogramma japonicum Ashmead. However, information on the time and number of parasitoids’ releases are lacking to control YSB in summer low-land rice. Therefore, an experiment was conducted during summer seasons of 2018 and 2019 at ICAR-National Institute of Biotic Stress Management, Raipur, Chhattisgarh to standardize the time and number of T. japonicum releases for effective biocontrol of YSB. Experiment consisted of 3 different treatment schedules, viz. T1, Four releases of T. japonicum at weekly intervals on the 7th, 14th, 21st, 28th days after planting (DAT); T2, Four releases of T. japonicum at weekly intervals on the 14th, 21st, 28th, 35th DAT; T3, Four releases of T. japonicum at weekly intervals on the 21st, 28th, 35th, 42nd DAT; and T4, Control (no release of wasps). Significant reduction of YSB-induced damage symptoms was observed in the treatment schedule (T2) consisting of four releases of T. japonicum (@50,000 wasps/ha/release) at weekly intervals on the 14th, 21st, 28th, 35th DAT of rice which significantly reduced the dead heart (9.1%, 45.83% reduction over control) and the white ear (1.8%, 47.05% reduction over control), as compared to untreated control plots (T4) (16.8% dead heart, 3.4% white ear) in summer 2018. Similarly, in summer 2019, the reduction in dead heart and white ear by the treatment (T2) was 43.35% and 46.15% over control, respectively. The significant reduction of YSB-induced damages corresponded with the increased grain yield in (T2) from 2018–19 i.e. 12.74–20.18% across the seasons. The results suggest that the (T2) augmentative releases provided ecologically viable bio-control of YSB during the summer seasons in low-land rice.

Stem breaks as an indirect measure of megafaunal herbivory in tropical forests: An experimental study

AbstractTo simulate megafaunal (pig, tapir, and elephant) foraging, we cut 1228 saplings in a Sundaic rainforest. In total, 89%–94% of cut stems survived after 13.5 months. About 90% of naturally occurring break scars were at heights ≤1 m, implicating pigs, not elephants or tapirs, as the main source of stem damage in this forest.Abstract in Malay is available with online material.

Metaverse Applications in Bioinformatics: A Machine Learning Framework for the Discrimination of Anti-Cancer Peptides

Bioinformatics and genomics are driving a healthcare revolution, particularly in the domain of drug discovery for anticancer peptides (ACPs). The integration of artificial intelligence (AI) has transformed healthcare, enabling personalized and immersive patient care experiences. These advanced technologies, coupled with the power of bioinformatics and genomic data, facilitate groundbreaking developments. The precise prediction of ACPs from complex biological sequences remains an ongoing challenge in the genomic area. Currently, conventional approaches such as chemotherapy, target therapy, radiotherapy, and surgery are widely used for cancer treatment. However, these methods fail to completely eradicate neoplastic cells or cancer stem cells and damage healthy tissues, resulting in morbidity and even mortality. To control such diseases, oncologists and drug designers highly desire to develop new preventive techniques with more efficiency and minor side effects. Therefore, this research provides an optimized computational-based framework for discriminating against ACPs. In addition, the proposed approach intelligently integrates four peptide encoding methods, namely amino acid occurrence analysis (AAOA), dipeptide occurrence analysis (DOA), tripeptide occurrence analysis (TOA), and enhanced pseudo amino acid composition (EPseAAC). To overcome the issue of bias and reduce true error, the synthetic minority oversampling technique (SMOTE) is applied to balance the samples against each class. The empirical results over two datasets, where the accuracy of the proposed model on the benchmark dataset is 97.56% and on the independent dataset is 95.00%, verify the effectiveness of our ensemble learning mechanism and show remarkable performance when compared with state-of-the-art (SOTA) methods. In addition, the application of metaverse technology in healthcare holds promise for transformative innovations, potentially enhancing patient experiences and providing novel solutions in the realm of preventive techniques and patient care.

Zhodnocení růstu proveniencí borovice černé (Pinus nigra Arnold) ve středních Čechách ve věku 51 let

The paper contains the evaluation of 9 European black pine provenances on the research trial No. 41 – Roblín (Czech Republic) at the age of 51 years. The tested provenances originated from Bosnia and Herzegovina, Serbia, Croatia, Bulgaria, Greece, France and Slovakia. The evaluation is based on an assessment of following factors: total height, dbh, stem form, health state, defoliation, diameter of main branches, stem damage, crown density, twisted growth, stem nature pruning, cross-section, and taper. Obtained data sets were statistically analysed. The best growth both in quantitative and qualitative traits was recognised for the provenance 9 – Les Barres, Oise (France), which was excellent in height growth, health status and stem shape, and also for the Serbian provenance 2 – Crni Vrh, Titovo Užice, which excelled not only in growth rate, stem shape and health status, but also in diameter of main branches. Less suitable provenance seem to be 3 – Prušačka Rjeka, Banja Luka from Bosnia and Herzegovina (worse growth, stem nature pruning, cross-section and taper) and Croatian 5 – Južna Kandija, Osijek (worse growth, stem shape, and health). The most important for explaining the differences between provenances were the diameter at the breast height, crown density and defoliation.

Vyhodnocení růstu proveniencí borovice lesní v Čechách

This study examines the variability of Scots pine provenances in four Czech research plots from the same series of experiments conducted in 1972. 121 provenances from the Czech Republic and Slovakia were evaluated in terms of growth and morphological characteristics. The quantitative traits measured for each tree were its tree height and DBH. The stem volume was also calculated according to the volume equation (Petráš, Pajtík 1991). Among the qualitative traits, stem form, health status, branch thickness in the crown, stem damage, stem twist, stem clearing, stem cross-section, and taper were evaluated. The large variance in growth characteristics of provenances does not specify the suitability of a particular reproductive material for a given area. Slovak provenances even from a relatively small land unit (Šaštín area) planted in the same research plot have different quantitative and qualitative traits. However, the evaluation of the test plots of Scots pine in Bohemia showed impaired growth performance of most of the Slovak provenances. Therefore, it is necessary to test more provenances from a larger area of the Scots pine range to obtain the possibility of using a wider range of reproductive material of the tree in our conditions. In the long term, further provenance trials with new reproductive material are needed to assess suitability under changing natural conditions.

Harvesting efficiency and understory damage with different cutting methods on two storied stands of silver birch and Norway spruce

Uneven-aged forests set certain challenges for cut-to-length harvesting work. It is a challenge to cost-effectively remove larger trees while leaving a healthy understory for regrowth. The study’s aim was to evaluate productivity and costs of harvesting two-storied Silver birch (Betula pendula Roth) and Norway spruce (Picea abies (L.) H. Karst.) stands by creating time consumption models for cutting, and using existing models for forwarding. Damage to the remaining understory spruce was also examined. Four different harvesting methods were used: 1) all dominant birches were cut; 2) half of them thinned and understory was preserved; compared to 3) normal thinning of birch stand without understory; and 4) clear cutting of two-storied stand. Results showed the time needed for birch cutting was 26–30% lower when the understory was not preserved. Pulpwood harvesting of small sized spruces that prevent birch cutting was expensive, especially because of forwarding of small amounts with low timber density on the strip roads. Generally, when taking the cutting and forwarding into account, the unit cost at clear cuttings was lowest, due to lesser limitations on work. It was noted that with increasing removal from 100 to 300 m3 ha–1, the relative share of initial undamaged spruces after the harvest decreased from 65 to 50% when the aim was to preserve them. During summertime harvesting, the amount of stem damage was bigger than during winter. In conclusion, two-storied stands are possible to transit to spruce stands by accepting some losses in harvesting productivity and damages on remaining trees.

Shifts in internal stem damage along a tropical precipitation gradient and implications for forest biomass estimation.

Woody biomass is a large carbon store in terrestrial ecosystems. In calculating biomass, tree stems are assumed to be solid structures. However, decomposer agents such as microbes and insects target stem heartwood, causing internal wood decay which is poorly quantified. We investigated internal stem damage across five sites in tropical Australia along a precipitation gradient. We estimated the amount of internal aboveground biomass damaged in living trees and measured four potential stem damage predictors: wood density, stem diameter, annual precipitation, and termite pressure (measured as termite damage in downed deadwood). Stem damage increased with increasing diameter, wood density, and termite pressure and decreased with increasing precipitation. High wood density stems sustained less damage in wet sites and more damage in dry sites, likely a result of shifting decomposer communities and their differing responses to changes in tree species and wood traits across sites. Incorporating stem damage reduced aboveground biomass estimates by > 30% in Australian savannas, compared to only 3% in rainforests. Accurate estimates of carbon storage across woody plant communities are critical for understanding the global carbon budget. Future biomass estimates should consider stem damage in concert with the effects of changes in decomposer communities and abiotic conditions.

Molecular Mechanisms Underlying Abnormal Activation of T Cells in Idiopathic Aplastic Anemia and Hypoplastic Myelodysplastic Neoplasms

Idiopathic aplastic anemia (AA) and hypoplastic myelodysplastic neoplasms (MDS-h) are severe hematopoietic disorders characterized by pancytopenia and hypoplastic bone marrow. There is compelling evidence that these distinct clinical entities share a common pathophysiology based on the damage of hematopoietic stem and progenitor cells (HSPCs) by cytotoxic T cells. Expanded T cells overproduce proinflammatory cytokines, resulting in decreased proliferation and increased apoptosis of HSPCs. To uncover the molecular mechanisms underlying this abnormal immune response, we used RNA-Seq for the transcriptome analysis of T cells from patients with idiopathic AA and MDS-h. CD3+ cells were isolated from peripheral blood of 15 patients with AA or MDS-h at diagnosis and 6 healthy blood donors. The RNA-Seq library was constructed by NEB Next Ultra II Directional RNA Library Prep Kit and the data were analysed by R software 4.0.2. Functional annotation of differently expressed genes was performed using DAVID database and Gene Set Enrichment Analysis (GSEA). Principal component analysis-based clustering of RNA-Seq data defined the three major components for AA and MDS-h patients, and healthy individuals (Fig. 1A). As expected, the control samples formed a distinct group, meanwhile patient samples partially clustered together. The same results were obtained using unsupervised hierarchical clustering. The differential expression analysis (DEA) identified 256 significantly upregulated and 96 downregulated genes (ІlogFCІ>1, FDR<0.05) in patients compared to controls. Notably, the DEA detected many long noncoding RNAs (lncRNAs) including upregulated lncRNAs associated with immunological disturbances (e.g. CDC42-IT1 and NEAT1), and oncogenesis (e.g. ACAP2-IT1, and FAM238A). Particularly, NEAT1 positively regulates differentiation of CD4+ T cells into Th17 cells through STAT3 protein. Autoreactive T cells may be further stimulated by increased expression of S100A8/A9 detected in the patient cells. Gene Ontology (GO) analysis annotated the upregulated genes in AA/MDS-h to biological processes associated with oxygen transport, B cell receptor signaling pathway, innate immune response, positive regulation of inflammatory response, and apoptotic process, etc. (adjusted p<0.05) (Fig. 1B). The downregulated genes were significantly enriched in processes related to adaptive immune response, cell surface receptor signaling pathway, mitochondrial ATP synthesis coupled proton transport, etc. (adjusted p<0.05) (Fig.1B). B cell receptor signaling pathway was enriched by upregulated genes such as BANK1, MEF2C, and SYK whose deregulation is associated with autoimmune disorders. Herein, the activation of apoptosis is likely driven via AP-1 positive modulators that showed increased expressions in the patients. These modulators are essential for T cell activation and regulatory T cell differentiation. Pathway enrichment analysis determined the following signaling pathways (adjusted p<0.05): B cell receptor signaling pathway, osteoclast differentiation, oxidative phosphorylation, chemical carcinogenesis - reactive oxygen species, and cytokine-cytokine receptor interaction. The GSEA using the Hallmark gene sets showed that DNA Repair and Oxidative Phosphorylation were significantly negatively correlated with patient phenotype (Fig. 1C). Both GSEA and pathway analysis revealed that oxidative phosphorylation was supressed in patient-derived T cells. This is consistent with previous metabolic findings demonstrating that a transition from oxidative phosphorylation to glycolysis is a sign of T cell activation and it is critical for support of rapid cell growth. In conclusion, our study suggests the possible mechanisms of aberrant T cellular-immunity in idiopathic AA and MDS-h. Consistent with abnormal biological features of T cells, a large number of deregulated genes in the patients was involved in immune and inflammatory responses. Furthermore, our analyses revealed novel pathways, such as oxidative phosphorylation, as well as candidates ( TLR2, and CDC42-IT1) for functional studies. The deregulation of multiple lncRNAs in the patients indicates their implication in the molecular pathogenesis and thus their roles in bone marrow failure need to be explored. Supported by AZV (NU21-03-00565), and MH CZ-DRO (UHKT, 00023736).

Novel Combination of Erythropoietin and Romiplostim to Treat Chemotherapy-Induced Anemia and Thrombocytopenia via Pharmacodynamic Interaction on Hematopoietic Stem and Progenitor Cells.

Chemotherapy-induced anemia and thrombocytopenia (CIAT) in cancer patients are often caused by the damage of hematopoietic stem and progenitor cells (HSPCs) in the bone marrow. We have previously shown that romiplostim, a thrombopoietin receptor agonist that could stimulate the expansion of HSPCs, could synergize with recombinant human erythropoietin (rHuEPO) to promote erythropoiesis in addition to stimulating platelet production, whereas rHuEPO could influence the platelet count through stem cell competition. Therefore, we hypothesize that a combination of romiplostim with rHuEPO can alleviate CIAT simultaneously, while minimizing the risk of thrombosis. In this study, we demonstrated that rHuEPO and romiplostim exhibit no stimulatory effects on the growth and invasion of LA-7 cancer cells both in vitro and in vivo. Using a rat model with carboplatin-induced anemia and thrombocytopenia, we showed that the red blood cells and hemoglobin concentration recovered faster, and the secondary thrombocytopenia was alleviated in the rHuEPO and romiplostim combination therapy groups compared with the corresponding rHuEPO monotherapy groups. The rebound phenomenon of platelets was inhibited compared with the romiplostim monotherapy group. In vitro study further demonstrated that romiplostim expands HSPCs and synergizes with rHuEPO to promote erythropoiesis, while rHuEPO inhibited megakaryopoiesis. Furthermore, we developed a mechanism-based pharmacokinetic-pharmacodynamic model to quantify the effects of the two drugs. This study suggests that rHuEPO and romiplostim combination therapy can treat CIAT simultaneously in rats while minimizing the risk of thrombosis, indicating that combination therapy might be superior to monotherapy in the supportive therapy of cancer patients undergoing chemotherapy.

Failure assessment of hip stem due to pelvic positioning and femoral stem loosening

AbstractThe hip joint is subjected to different loads, leading to hip stem failure from the crack nucleation to the final implant failure. The main objective of the present work is to assess hip stem damage due to pelvic positioning and femur movement. The three‐dimensional finite element analysis (3D FEA) was created to simulate the artificial hip joint subjected to static or cyclic loading. The fatigue crack growth rate in the hip stem was investigated based on the extended finite element method (XFEM) with the cycle fatigue approach. The femoral stem loosening during adduction and abduction movements, which may have occurred, was considered. The numerical results showed that the von Mises stress value increases as the loosening distance increases, which appears with the decrease of the cup positioning angle. Furthermore, the pelvic positioning does not affect the crack initiation site, while the loosening and femur movement affect the crack initiation site. On the other hand, the fatigue crack growth rate was affected by pelvic positioning, loosening, and femur movement.

Gene silencing induced by the vector EuMY-YP∆CHS4 during the Fusarium sp. - Nicotiana benthamiana interaction

In the literature, RNA-based interference methods have been proposed for the control of pathogenic fungi in plants, such as virus-mediated silencing (VIGS). The objective of this work was to evaluate the functionality and efficiency of the VIGS EuMV-YP∆CHS4 vector, which contains a fragment of the Fusarium sp. chitin synthase 4 (CHS4) gene sequence, and was constructed from the EuMV-YP vector:∆AV1. The VIGS vector was evaluated under two conditions in Nicotiana benthamiana plants previously inoculated with Fusarium sp. and in plants with inoculation after the inoculation of the VIGS vector. The results showed that in both treatments with the EuMV-YP∆CHS4, a delay in leaf fall during the first days of infection and a decrease in the stem damage of almost one centimeter, compared to the control infected with the fungus. In addition, a reduction of up to 30% in the relative expression of the CHS4 gene was observed. These results suggest that the application of VIGS vectors may be efficient as a strategy to protect plants against Fusarium sp.

Role of morphological traits and cell wall components in imparting resistance to pink stem borer, Sesamia inferens Walker in maize.

Host Plant Resistance (HPR) is the most important component for sustainable management of insect pests. The purpose of the present work was to understand the role of various morphological and biochemical factors as defense mechanism and their interaction on different biological parameters attributed to survival and development of pink stem borer (PSB), Sesamia inferens Walker in maize. The resistant and moderately resistant genotypes (DMRE 63, CM 500 and WNZ Exotic pool) suffered least leaf injury rating (LIR), dead hearts (DH%), percentage stem tunneling (ST%), number of entry/exit holes (E/EH) and showed deleterious effects on biological parameters of pink stem borer as compared to susceptible ones (CM 202 and BML 6). Resistance index among the genotypes varied from 0.11 to 0.46. The variation in morphological traits such as number of nodes, internode distance and stem diameter could not distinguish all the resistant genotypes from that of susceptible genotypes in terms of its mean value. Higher levels of biochemical constituents, viz., p-Coumaric acid (p-CA), ferulic acid (FA), acid detergent fibre (ADF) and acid detergent lignin (ADL) were observed in resistant genotypes compared to susceptible ones. Antibiosis was expressed in terms of reduced pupal weight when fed on WNZ Exotic pool, whereas larval weight and larval survival affected when fed on DMRE 63. Higher concentration of p-CA content in pith of resistant maize genotypes prolonged the pupal period of pink stem borer. Higher concentration of p-CA and FA contents in rind reduced the adult emergence, as they showed significant negative correlation between them. The larval period was prolonged with higher levels of ADF and ADL contents in maize genotypes either in rind or both rind and pith as both ADF and ADL content showed a significant positive correlation with the larval period. The Pearson correlation analysis of most of the biochemical constituents revealed significant negative correlation with damage parameters. The correlation coefficients between p-CA with DH (%), ST (%) and E/EH were r= -0.9642**, r= -0.9363**, and r= -0.9646**, respectively. Similarly, the correlation coefficients between FA with DH (%), ST (%) and E/EH were r= -0.9217*, r= -0.9563**, and r= -0.9434**, respectively and ADF with DH (%), ST (%) and E/EH were r= -0.9506**, r= -0.9611**, and r= -0.9709**, respectively. The study confirms that stem damage parameters can also be used as selection criteria along with LIR to identify resistant genotypes against pink stem borer. Based on the correlation analysis it was concluded that resistance to pink stem borer in maize is the result of interaction of several morphological and biochemical traits rather than a single factor. The findings obtained from the present study can be utilised in pink stem borer resistance breeding programmes to enhance and diversify the basis of resistance.

Healing of bark wounds in Norway spruce seedlings can be negatively affected by treatment with methyl jasmonate

Key messageTreatment with methyl jasmonate can slow down the healing of stem bark wounds in Norway spruce seedlings.In woody plants, healing of bark wounds is a tolerance trait involved in recovery from stem damage. Yet, little is known on how wound healing may be affected by plant protection treatments such as methyl jasmonate application (MeJA, a plant hormone triggering increased resistance to pests). Here, we examined if MeJA can affect healing of an existing and a subsequently inflicted stem wound on Norway spruce (Picea abies) seedlings, the effect of treatment on plant growth, and potential trade-offs between healing and resistance to insect damage. Seedlings from 18 full-sib families were mechanically wounded (or not) on the lower stem and treated with MeJA (or water) one week after. Two months later, another wound was inflicted and wound area was measured during six months. Growth of non-wounded and wounded seedlings were compared, and correlations between family estimates of healing rates and field insect damage were examined. We found that MeJA slowed down wound healing. For the first and second wound, respectively, MeJA-treated seedlings experienced 15% and 9% slower healing rates, and wounds remained 58% and 69% larger in size compared to water-treated seedlings. Stem wounding and MeJA together were more detrimental to seedling diameter than height growth, relative to each treatment alone. Finally, resistance to field insect damage and wound healing rates were not significantly correlated. We conclude that MeJA-mediated seedling protection may trade-off with bark wound healing, which may be negative for seedling vigor. However, further studies are needed to evaluate if such effects outweigh the benefits that MeJA provides.

Neutrophilic inflammation promotes SARS-CoV-2 infectivity and augments the inflammatory responses in airway epithelial cells.

In response to viral infection, neutrophils release inflammatory mediators as part of the innate immune response, contributing to pathogen clearance through virus internalization and killing. Pre- existing co-morbidities correlating to incidence to severe COVID-19 are associated with chronic airway neutrophilia. Furthermore, examination of COVID-19 explanted lung tissue revealed a series of epithelial pathologies associated with the infiltration and activation of neutrophils, indicating neutrophil activity in response to SARS-CoV-2 infection. To determine the impact of neutrophil-epithelial interactions on the infectivity and inflammatory responses to SARS-CoV-2 infection, we developed a co-culture model of airway neutrophilia. This model was infected with live SARS-CoV-2 virus the epithelial response to infection was evaluated. SARS-CoV-2 infection of airway epithelium alone does not result in a notable pro-inflammatory response from the epithelium. The addition of neutrophils induces the release of proinflammatory cytokines and stimulates a significantly augmented proinflammatory response subsequent SARS-CoV-2 infection. The resulting inflammatory responses are polarized with differential release from the apical and basolateral side of the epithelium. Additionally, the integrity of the \epithelial barrier is impaired with notable epithelial damage and infection of basal stem cells. This study reveals a key role for neutrophil-epithelial interactions in determining inflammation and infectivity.

Genetic Control of Pitch Canker Response in Southern Pine and Southern Pine Hybrids

Fusarium circinatum causes pine pitch canker (PPC) disease and associated symptoms such as resinous lesions, mechanical weakness, and crown dieback that may lead to mortality in Pinus and Pseudotsuga spp. There are no ameliorative techniques available for the disease, and the genetic resistance among populations to support commercial plantation deployment has not been well characterized. In this study, we characterize the genetic control of PPC disease tolerance (and/or resistance) and predict the tolerance of families in existing breeding populations: open-pollinated (OP) half-sib and control-pollinated full-sib (FS) slash pine (Pinus elliottii var. elliottii Engelm.), OP loblolly pine (Pinus taeda L.), and advanced-generation OP hybrid slash × P. caribaea (Pinus elliottii var. elliottii Engelm. × Pinus caribaea var. bahamensis, caribaea, and hondurensis) using F. circinatum isolates obtained from three locations in Georgia and FL, USA. We describe a new experimental design that improves the accuracy of breeding value predictions, provides more precise genetic parameter estimates, and facilitates comparisons within and among taxa as well as comparisons among isolates. We found strong evidence for genetic control of the ratio of stem damage by F. circinatum, especially in slash pine and slash × P. caribaea hybrids. Loblolly and slash × P. caribaea hybrids exhibited less damage than slash pine. We observed a spectrum of virulence among F. circinatum isolate sources, which were not equally virulent in different pine taxa.

Identification of the key morphological sweetpotato weevil resistance predictors in Ugandan sweetpotato genotypes using correlation and path‐coefficient analysis

AbstractSweetpotato weevils (SPWs) can cause up to 100% yield losses in sweetpotato (Ipomoea batatas). Nevertheless, there has been limited success in breeding for SPW resistance globally. This is attributed partly to difficulty in screening for resistance because resistance to the SPW is complex and is mediated by several resistance indicators. Measuring all these resistance indicators is costly and time consuming. To enhance efficiency in selection for SPW resistance, there is need to profile and identify key resistance indicators. Potentially, this will better enable breeders to timely and precisely select for SPW resistance. The objective of this study was to identify the most efficient morphological resistance indicators against SPW. Thirty sweetpotato genotypes that varied in resistance to SPW comprising local collections, released varieties, and breeding lines were evaluated at three locations for two seasons in Uganda using an alpha lattice design. Data were collected on storage root yield, SPW root and stem damage, and weevil resistance indicators such as vine vigor (VV), ground cover (GC), vine weight (VW), storage root neck length (NL), latex content, cortex thickness (CT), and dry matter content (DM). Genotype means for all measured traits varied significantly except for CT. Negative relationships were observed between SPW root damage and GC, VW, CT, VV, NL, and DM. However, path coefficient analysis showed storage root NL (direct effect of −0.43, p < 0.001) as the most important morphological resistance indicator. Therefore, NL could be the most reliable predictor of resistance to SPW among breeding clones, especially at early breeding stages.

Heavy crown thinning in redwood/Douglas-fir gave superior forest restoration outcomes after 10 years

Forest restoration thinning has the potential to enhance the structural complexity and accelerate the development of large trees important to wildlife, aesthetics, and wildfire resistance. These are key objectives for the restoration of even-aged secondary forests within Redwood National Park in Humboldt County, CA, USA. We evaluated the tree growth and stand structure 10 years after two thinning methods were applied at two intensities in a 40-year-old mixed redwood ( Sequoia sempervirens (Lamb. ex D. Don) Endl.)/Douglas-fir ( Pseudotsuga menziesii (Mirb.) Franco var. menziesii) stand. Heavy thinning enhanced the diameter growth of redwood and Douglas-fir trees more than light thinning. Crown thinning generally enhanced the structural diversity more than low thinning, and structural diversity increased progressively over the 10 years following thinning. Understory plant richness fluctuated between measurement years. Heavy thinning enhanced the understory shrub cover. The fastest-growing trees in heavily thinned stands were much more likely to sustain bear damage, especially redwood trees. Overall, different thinning methods and intensities induced a different suite of outcomes, yet none restored redwood dominance, but all treatments enhanced some other ecosystem values important for old-growth restoration such as large overstory trees, understory plant and shrubs, and elements of structural complexity, including tree-size variability, snags, down logs, and trees exhibiting stem or top damage.