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<jats:p>The time delay in receiving conventional tissue nutrient analysis results caused red raspberry (<jats:italic>Rubus idaeus</jats:italic> L.) growers to be interested in rapid sap tests to provide real-time results to guide immediate nutrient management practices. However, sap analysis has never been conducted in raspberry. The present work aimed to evaluate the relationship of petiole sap nitrate (NO<jats:sub>3</jats:sub><jats:sup>–</jats:sup>), potassium (K<jats:sup>+</jats:sup>), and calcium (Ca<jats:sup>2+</jats:sup>) concentrations measured using compact ion meters and leaf tissue total nitrogen (TN), potassium (K), and calcium (Ca) concentrations measured using conventional tissue nutrient analysis. The relationship of petiole sap NO<jats:sub>3</jats:sub><jats:sup>–</jats:sup> and leaf tissue TN concentrations with plant growth and production variables was also explored. Fertilizer treatments of urea were surface applied to raised beds of established “Meeker” floricane red raspberry plots at control, low, medium, and high rates (0, 34, 67, and 101 kg N ha<jats:sup>–1</jats:sup>, respectively) in 2019 and 2020. The experiment was arranged in a randomized complete block design with three replications. Whole leaves were collected from representative primocanes in mid- and late- July and August 2019 and 2020 (i.e., four sampling time points per year). At each sampling time point, a subsample of leaves was used for petiole sap analyses of NO<jats:sub>3</jats:sub><jats:sup>–</jats:sup>, K<jats:sup>+</jats:sup>, and Ca<jats:sup>2+</jats:sup> concentrations using compact ion meters, and conventional tissue testing of leaf tissue TN, K, and Ca concentrations, respectively. There were no interactions between N fertilizer rate and year nor between N fertilizer rate and sampling time. No significant differences were found due to N fertilizer rate for petiole sap NO<jats:sub>3</jats:sub><jats:sup>–</jats:sup>, K<jats:sup>+</jats:sup>, Ca<jats:sup>2+</jats:sup> nor leaf tissue TN, K, Ca concentrations. However, significant year and sampling time effects occurred in measured petiole sap and leaf tissue nutrient concentrations. Overall, the correlations between petiole sap NO<jats:sub>3</jats:sub><jats:sup>–</jats:sup> and leaf tissue TN, petiole sap Ca<jats:sup>2+</jats:sup> and leaf tissue Ca, petiole sap K<jats:sup>+</jats:sup> and leaf tissue K concentrations were non-strong and inconsistent. Future research is warranted as the interpretation of correlations between raspberry petiole sap and leaf tissue nutrient concentrations were inconclusive.</jats:p>

<jats:p>Alkaline stress severely limits plant growth and yield worldwide. NF-YC transcription factors (TFs) respond to abiotic stress by activating gene expression. However, the biological function of NF-YC TFs in alfalfa (<jats:italic>Medicago sativa</jats:italic> L.) is not clear. In our study, an <jats:italic>NF-YC2</jats:italic> gene was identified and transgenic plants were obtained by constructing overexpression vector and cotyledon node transformation system in alfalfa. The open reading frame of <jats:italic>MsNF-YC2</jats:italic> is 879 bp with 32.4 kDa molecular mass. <jats:italic>MsNF-YC2</jats:italic> showed tissue expression specificity and was induced by a variety of abiotic stresses including drought, salt, and alkali stress in alfalfa. Under alkali stress treatment, transgenic plants exhibited higher levels of antioxidant enzyme activities and proline (Pro), correlating with a lower levels of hydrogen peroxide (H<jats:sub>2</jats:sub>O<jats:sub>2</jats:sub>), superoxide anion (O<jats:sub>2</jats:sub><jats:sup>–</jats:sup>) compared with wild-type (WT) plants. Transcriptomic results showed that overexpression of <jats:italic>MsNF-YC2</jats:italic> regulated the expression of phytohormone signal transduction and photosynthesis-related genes under normal and alkaline stress treatments. These results suggest that the <jats:italic>MsNF-YC2</jats:italic> gene plays crucial role enhance alkali adaptation abilities in alfalfa.</jats:p>

<jats:p>The accurate and robust detection of fruits in the greenhouse is a critical step of automatic robot harvesting. However, the complicated environmental conditions such as uneven illumination, leaves or branches occlusion, and overlap between fruits make it difficult to develop a robust fruit detection system and hinders the step of commercial application of harvesting robots. In this study, we propose an improved anchor-free detector called TomatoDet to deal with the above challenges. First, an attention mechanism is incorporated into the CenterNet backbone to improve the feature expression ability. Then, a circle representation is introduced to optimize the detector to make it more suitable for our specific detection task. This new representation can not only reduce the degree of freedom for shape fitting, but also simplifies the regression process from detected keypoints. The experimental results showed that the proposed TomatoDet outperformed other state-of-the-art detectors in respect of tomato detection. The F<jats:sub>1</jats:sub> score and average precision of TomatoDet reaches 95.03 and 98.16%. In addition, the proposed detector performs robustly under the condition of illumination variation and occlusion, which shows great promise in tomato detection in the greenhouse.</jats:p>

<jats:p><jats:italic>Quercus mongolica</jats:italic>, a common tree species for building and landscaping in northern China, has great commercial and ecological value. The seedlings of <jats:italic>Q. mongolica</jats:italic> grow poorly and develop chlorosis when introduced from high-altitude mountains to low-altitude plains. Effective cultivation measures are key to improving the quality of seedlings. To investigate the complex responses of <jats:italic>Q. mongolica</jats:italic> to different cultivation measures, we compared the adaptability of 3-year-old <jats:italic>Q. mongolica</jats:italic> seedlings to pruning (P), irrigation (W), and fertilization [F (nitro compound fertilizer with 16N-16P-16K)]. Physiological measurements and transcriptome sequencing were performed on leaves collected under the P treatments (control, cutting, removal of all lateral branches, and removal of base branches to one-third of seedling height), the W treatments (0, 1, 2, 3, 4, or 5 times in sequence), and the F treatments (0, 2, 4, and 6 g/plant). Analyses of the physiological data showed that P was more effective than W or F for activating intracellular antioxidant systems. By contrast, W and F were more beneficial than P for inducing the accumulation of soluble sugar. OPLS-DA identified superoxide dismutase, malondialdehyde, and peroxidase as critical physiological indices for the three cultivation measures. Transcriptome analyses revealed 1,012 differentially expressed genes (DEGs) in the P treatment, 1,035 DEGs in the W treatment, and 1,175 DEGs in the F treatment; these DEGs were mainly enriched in Gene Ontology terms related to the stress response and signal transduction. Weighted gene coexpression network analyses indicated that specific gene modules were significantly correlated with MDA (one module) and soluble sugar (four modules). Functional annotation of the hub genes differentially expressed in MDA and soluble sugar-related modules revealed that <jats:italic>Q. mongolica</jats:italic> responded and adapted to different cultivation measures by altering signal transduction, hormone levels, reactive oxygen species, metabolism, and transcription factors. The hub genes HOP3, CIPK11, WRKY22, and BHLH35 in the coexpression networks may played a central role in responses to the cultivation practices. These results reveal the mechanism behind the response of <jats:italic>Q. mongolica</jats:italic> to different cultivation measures at the physiological and molecular levels and provide insight into the response of plants to cultivation measures.</jats:p>

<jats:p>To ensure food security given the current scenario of climate change and the accompanying ecological repercussions, it is essential to search for new technologies and tools for agricultural production. Microorganism-based biostimulants are recognized as sustainable alternatives to traditional agrochemicals to enhance and protect agricultural production. Marine actinobacteria are a well-known source of novel compounds for biotechnological uses. In addition, former studies have suggested that coral symbiont actinobacteria may support co-symbiotic photosynthetic growth and tolerance and increase the probability of corals surviving abiotic stress. We have previously shown that this activity may also hold in terrestrial plants, at least for the actinobacteria <jats:italic>Salinispora arenicola</jats:italic> during induced heterologous symbiosis with a wild Solanaceae plant <jats:italic>Nicotiana attenuata</jats:italic> under <jats:italic>in vitro</jats:italic> conditions. Here, we further explore the heterologous symbiotic association, germination, growth promotion, and stress relieving activity of <jats:italic>S. arenicola</jats:italic> in tomato plants under agricultural conditions and dig into the possible associated mechanisms. Tomato plants were grown under normal and saline conditions, and germination, bacteria-root system interactions, plant growth, photosynthetic performance, and the expression of salt stress response genes were analyzed. We found an endophytic interaction between <jats:italic>S. arenicola</jats:italic> and tomato plants, which promotes germination and shoot and root growth under saline or non-saline conditions. Accordingly, photosynthetic and respective photoprotective performance was enhanced in line with the induced increase in photosynthetic pigments. This was further supported by the overexpression of thermal energy dissipation, which fine-tunes energy use efficiency and may prevent the formation of reactive oxygen species in the chloroplast. Furthermore, gene expression analyses suggested that a selective transport channel gene, <jats:italic>SlHKT1,2</jats:italic>, induced by <jats:italic>S. arenicola</jats:italic> may assist in relieving salt stress in tomato plants. The fine regulation of photosynthetic and photoprotective responses, as well as the inhibition of the formation of ROS molecules, seems to be related to the induced down-regulation of other salt stress response genes, such as <jats:italic>SlDR1A</jats:italic>-related genes or <jats:italic>SlAOX1b.</jats:italic> Our results demonstrate that the marine microbial symbiont <jats:italic>S. arenicola</jats:italic> establishes heterologous symbiosis in crop plants, promotes growth, and confers saline stress tolerance. Thus, these results open opportunities to further explore the vast array of marine microbes to enhance crop tolerance and food production under the current climate change scenario.</jats:p>

<jats:p><jats:italic>Zoysia matrella</jats:italic> [L.] Merr. is one of the three most economically important <jats:italic>Zoysia</jats:italic> species due to its strong salt tolerance and wide application. However, the molecular mechanisms regulating salt tolerance in <jats:italic>Z. matrella</jats:italic> remain unknown. The protein disulfide isomerase <jats:italic>ZmPDI</jats:italic> of <jats:italic>Z. matrella</jats:italic> was obtained by salt stress screening with yeast cells, and its expression was significantly upregulated after salt stress. Based on the obtained <jats:italic>ZmPDI</jats:italic> overexpression transgenic <jats:italic>Z. matrella</jats:italic> plants, we carried out salt tolerance identification and found that <jats:italic>ZmPDI</jats:italic> can significantly enhance the salt tolerance of <jats:italic>Z. matrella</jats:italic>. Root samples of <jats:italic>OX-ZmPDI</jats:italic> transgenic and wild-type plants were collected at 0 and 24 h after salt treatments for RNA-seq and data-independent acquisition (DIA) proteome sequencing. Combined analysis of the transcriptome and proteome revealed that <jats:italic>ZmPDI</jats:italic> may enhance the salt tolerance of <jats:italic>Z. matrella</jats:italic> by regulating <jats:italic>TUBB2</jats:italic>, <jats:italic>PXG4</jats:italic>, <jats:italic>PLD</jats:italic>α<jats:italic>2</jats:italic>, <jats:italic>PFK4</jats:italic>, and <jats:italic>4CL1</jats:italic>. This research presents the molecular regulatory mechanism of the <jats:italic>ZmPDI</jats:italic> gene in <jats:italic>Z. matrella</jats:italic> for resistance to salt stress and facilitates the use of molecular breeding to improve the salt tolerance of grasses.</jats:p>

<jats:p>An ever-increasing population has issued an open challenge to the agricultural sector to provide enough food in a sustainable manner. The upsurge in chemical fertilizers to enhance food production had resulted in environmental problems. The objective of the current study is to assess the utilization of biostimulants for sustainable agricultural production as an alternative to chemical fertilization. For this purpose, two pot experiments were conducted to examine the response of radish against individual and combined applications of biostimulants. In the first experiment, the effects of chemical fertilizer (CK), glycine (G), lysine (L), aspartic acid (A), and vitamin B complex (V) were studied. The results demonstrated that V significantly improved the transpiration rate (81.79%), stomatal conductance (179.17%), fresh weight (478.31%), and moisture content (2.50%). In the second experiment, tested treatments included chemical fertilizer (CK), Isabion<jats:sup>®</jats:sup> (I), glycine + lysine + aspartic acid (GLA), moringa leaf extract + GLA (M1), 25% NPK + M1 (M2). The doses of biostimulants were 5g L<jats:sup>−1</jats:sup> glycine, 1g L<jats:sup>−1</jats:sup> lysine, 2g L<jats:sup>−1</jats:sup> aspartic acid, and 10 ml L<jats:sup>−1</jats:sup> moringa leaf extract. The photosynthetic rate improved significantly with GLA (327.01%), M1 (219.60%), and M2 (22.16%), while the transpiration rate was enhanced with GLA (53.14%) and M2 (17.86%) compared to the Ck. In addition, M1 increased the stomatal conductance (54.84%), internal CO<jats:sub>2</jats:sub> concentration (0.83%), plant fresh weight (201.81%), and dry weight (101.46%) as compared to CK. This study concludes that biostimulants can effectively contribute to the sustainable cultivation of radish with better growth and yield.</jats:p>

<jats:p>Due to their limited coding capacity, plant viruses have to depend on various host factors for successful infection of the host. Loss of function of these host factors will result in recessively inherited resistance, and therefore, these host factors are also described as susceptibility genes or recessive resistance genes. Most of the identified recessive resistance genes are members of the <jats:italic>eukaryotic translation initiation factors 4E</jats:italic> family (<jats:italic>eIF4E</jats:italic>) and its isoforms. Recently, an eIF4E-type gene, <jats:italic>novel cap-binding protein</jats:italic> (<jats:italic>nCBP</jats:italic>), was reported to be associated with the infection of several viruses encoding triple gene block proteins (TGBps) in Arabidopsis. Here, we, for the first time, report that the knockdown of <jats:italic>nCBP</jats:italic> in potato (<jats:italic>StnCBP</jats:italic>) compromises the accumulation of potato virus S (PVS) but not that of potato virus M (PVM) and potato virus X (PVX), which are three potato viruses encoding TGBps. Further assays demonstrated that StnCBP interacts with the coat proteins (CPs) of PVS and PVM but not with that of PVX, and substitution of PVS CP in the PVS infectious clone by PVM CP recovered the virus infection in <jats:italic>StnCBP</jats:italic>-silenced transgenic plants, suggesting that the recognition of PVS CP is crucial for <jats:italic>StnCBP</jats:italic>-mediated recessive resistance to PVS. Moreover, the knockdown of nCBP in <jats:italic>Nicotiana benthamiana</jats:italic> (<jats:italic>NbnCBP</jats:italic>) by virus-induced gene silencing suppressed PVX accumulation but not PVM, while NbnCBP interacted with the CPs of both PVX and PVM. Our results indicate that the <jats:italic>nCBP</jats:italic> orthologues in potato and tobacco have conserved function as in Arabidopsis in terms of recessive resistance against TGB-encoding viruses, and the interaction between nCBP and the CP of TGB-encoding virus is necessary but not sufficient to determine the function of <jats:italic>nCBP</jats:italic> as a susceptibility gene.</jats:p>

<jats:p>Accurate tracking of seed dispersal is critical for understanding gene flow and seed bank dynamics, and for predicting population distributions and spread. Available seed-tracking techniques are limited due to environmental and safety issues or requirements for expensive and specialized equipment. Furthermore, few techniques can be applied to studies of water-dispersed seeds. Here we introduce a new seed-tracking method using safranine to stain seeds/fruits by immersing in (<jats:italic>ex situ</jats:italic>) or spraying with (<jats:italic>in situ</jats:italic>) staining solution. The hue difference value between pre- and post-stained seeds/fruits was compared using the HSV color model to assess the effect of staining. A total of 181 kinds of seeds/fruits out of 233 tested species of farmland weeds, invasive alien herbaceous plants and trees could be effectively stained magenta to red in hue (320–360°) from generally yellowish appearance (30–70°), in which the other 39 ineffectively-stained species were distinguishable by the naked eye from pre-stained seeds. The most effectively stained seeds/fruits were those with fluffy pericarps, episperm, or appendages. Safranine staining was not found to affect seed weight or germination ability regardless of whether seeds were stained <jats:italic>ex situ</jats:italic> or <jats:italic>in situ</jats:italic>. For 44 of 48 buried species, the magenta color of stained seeds clearly remained recognizable for more than 5 months after seeds were buried in soil. Tracking experiments using four species (<jats:italic>Beckmannia syzigachne</jats:italic>, <jats:italic>Oryza sativa</jats:italic> f. spontanea, <jats:italic>Solidago Canadensis</jats:italic>, and <jats:italic>Acer buergerianum</jats:italic>), representing two noxious agricultural weeds, an alien invasive plant, and a tree, respectively, showed that the safranine staining technique can be widely applied for studying plant seed dispersal. Identifying and counting the stained seeds/fruits can be executed by specially complied Python-based program, based on OpenCV library for image processing and Numpy for data handling. From the above results, we conclude that staining with safranine is a cheap, reliable, easily recognized, automatically counted, persistent, environmentally safe, and user–friendly tracking-seed method. This technique may be widely applied to staining most of the seed plant species and the study of seed dispersal in arable land and in disturbed and natural terrestrial or hydrophytic ecological systems.</jats:p>

<jats:p>Adjusting the sowing date to optimize temperature conditions is a helpful strategy for mitigating the adverse impact of high temperature on summer maize growth in the North China Plain (NCP). However, the physiological processes of variation in summer maize yield with sowing date-associated changes in temperature conditions around flowering remain to be poorly understood. In this study, field experiments with two maize varieties and three sowing dates (early sowing date, SD1, 21 May; conventional sowing date, SD2, 10 June; delay sowing date, SD3, 30 June) were conducted at Xinxiang of Henan Province in 2019 and 2020. Early sowing markedly decreased the daily mean temperature (<jats:italic>T</jats:italic><jats:sub>mean</jats:sub>), maximum temperature (<jats:italic>T</jats:italic><jats:sub>max</jats:sub>), and minimum temperature (<jats:italic>T</jats:italic><jats:sub>min</jats:sub>) during pre-silking, while delay sowing markedly decreased those temperatures during post-silking. Under these temperature conditions, both varieties under SD1 at 12-leaf stage (V12) and silking stage (R1) while under SD3 at R1 and milking stage (R3) possessed significantly lower malondialdehyde (MDA) content in leaf due to higher activities of superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT) compared to SD2. Therefore, SD1 at V12 and R1 stages and SD3 at R1 and R3 stages for both varieties showed significantly higher photosynthetic capacity, including higher SPAD, <jats:italic>F</jats:italic><jats:sub>v</jats:sub><jats:italic>/F</jats:italic><jats:sub>m</jats:sub>, <jats:italic>P</jats:italic><jats:sub>n</jats:sub>, <jats:italic>T</jats:italic><jats:sub>r</jats:sub>, and <jats:italic>G</jats:italic><jats:sub>s</jats:sub>, which promoted greater pre-silking dry matter (DM) accumulation for SD1 to increase the kernel number, and promoted greater post-silking DM accumulation for SD3 to increase the kernel weight, eventually increased the grain yield of SD1 and SD3 compared to SD2. Results of regression analysis demonstrated that <jats:italic>T</jats:italic><jats:sub>mean</jats:sub>, <jats:italic>T</jats:italic><jats:sub>max</jats:sub>, and <jats:italic>T</jats:italic><jats:sub>min</jats:sub> values from V12 to R1 stages lower than 26.6, 32.5, and 20.3°C are necessary for improving the kernel number, while <jats:italic>T</jats:italic><jats:sub>mean</jats:sub>, <jats:italic>T</jats:italic><jats:sub>max</jats:sub>, <jats:italic>T</jats:italic><jats:sub>min</jats:sub>, and accumulated temperature (AT) values from R1 to R3 stages lower than 23.2, 28.9, 17.3, and 288.6°C are necessary for improving the kernel weight. Overall, optimal temperature conditions around flowering can be obtained by early (21 May) or delay (30 June) sowing to improve the kernel number or kernel weight due to improved photosynthetic capacity, eventually increasing the grain yield of summer maize in the NCP.</jats:p>