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Abstract A wide‐beamwidth dielectric resonator antenna with small radiator is used to design a wide‐angle scanning phased array. The proposed dielectric resonator antenna element uses concave structure for wide‐beamwidth, and the metal patches on the top of the dielectric resonator are used to reduce the size of radiator. The simulated half‐power beamwidth of dielectric resonator antenna is 157.8° and 140.9° in the E‐ and H‐planes, respectively, while the size of the radiator of the dielectric resonator antenna is only 9.7 × 9.7 × 10 mm3 (0.162λ0 × 0.162λ0 × 0.167λ0). One 1 × 8 linear phased array is designed based on the dielectric resonator antenna element. Due to the small size of dielectric resonator radiator, the mutual coupling between the array elements is very small and each element in the array has the similar radiation pattern with wide‐beamwidth. Because of these critical features, the phased array can scan from −67° to +67° with a gain fluctuation less than 1 dB and a maximum side lobe level less than −10 dB. Measurement results agree well with simulation.

A parasitic surface (PS) based wide beam width patch antenna operating at 5 GHz is presented. The half-power beam widths (HPBWs) of the patch antenna are improved by the PS, which is composed of a parasitic ring and six parasitic patches. The parasitic ring is used to increase the HPBW in the E-plane, while the six parasitic patches are used to increase the HPBW in the H-plane. Simulation results show that the PS has little effect on the impedance bandwidth of the patch antenna but can increase the HPBW by 66.7° (from 85.1° to 151.8°) in the E-plane and 88.7° (from 78.9° to 167.6°) in the H-plane at 5 GHz. At the same time, the PS decreases the boresight gain of the patch antenna from 5.42 to 3.06 dBi. Measurement results agree well with the simulation.

Positive interspecific interactions in resource capture and soil property modification benefit the establishment of mixed plantations, contingent on environmental conditions. However, primary species frequently reject companion tree species frequently arises in forest management practices. To understand this contradiction, we investigated the effects of five planting patterns involving two local companion tree species (Phoebe chekiangensis and Torreya grandis) and Phyllostachys edulis on the soil nitrogen (N) and phosphorus (P) content, enzyme activities, net N mineralization rates, microbial composition, fungal functional groups, and the AMO gene abundance under both shade and full light conditions using a pot experiment. Under the full light condition, altered soil properties were predominantly influenced by interspecific interaction compared to intraspecific interactions, leading to an overall enhancement in nutrient availability and enzymatic activities. Under the shade condition, mixing with P. edulis similarly facilitated increased NH4+-N content, ammonification rate, and urease activity. However, P. edulis significantly decreased ammonia monooxygenase and its encoding gene, as evidence by the unbalanced ratio of net ammonification to net nitrification (2.2-fold) under the shade condition, resulting in high NH4+-N/NO3–-N ratios. Additionally, the shade condition induced soil microbial communities in the mixture to resemble those of monocultured dominant species (P. edulis). Our findings also indicated that specific plant-fungal associations in companion species were disrupted when intercropped with P. edulis. Therefore, this study highlights how the performance of companion species, linked to soil NH4+-N/NO3–-N ratios and plant-fungal associations, leads to their suppression by P. edulis under shade conditions.

Abstract Background KNOTTED1-like homeobox (KNOX) genes, plant-specific homologous box transcription factors (TFs), play a central role in regulating plant growth, development, organ formation, and response to biotic and abiotic stresses. However, a comprehensive genome-wide identification of the KNOX genes in Moso bamboo (Phyllostachys edulis), the fastest growing plant, has not yet been conducted, and the specific biological functions of this family remain unknown. Results The expression profiles of 24 KNOX genes, divided into two subfamilies, were determined by integrating Moso bamboo genome and its transcriptional data. The KNOX gene promoters were found to contain several light and stress-related cis-acting elements. Synteny analysis revealed stronger similarity with rice KNOX genes than with Arabidopsis KNOX genes. Additionally, several conserved structural domains and motifs were identified in the KNOX proteins. The expansion of the KNOX gene family was primarily regulated by tandem duplications. Furthermore, the KNOX genes were responsive to naphthaleneacetic acid (NAA) and gibberellin (GA) hormones, exhibiting distinct temporal expression patterns in four different organs of Moso bamboo. Short Time-series Expression Miner (STEM) analysis and quantitative real-time PCR (qRT-PCR) assays demonstrated that PeKNOX genes may play a role in promoting rapid shoot growth. Additionally, Gene Ontology (GO) and Protein–Protein Interaction (PPI) network enrichment analyses revealed several functional annotations for PeKNOXs. By regulating downstream target genes, PeKNOXs are involved in the synthesis of AUX /IAA, ultimately affecting cell division and elongation. Conclusions In the present study, we identified and characterized a total of 24 KNOX genes in Moso bamboo and investigated their physiological properties and conserved structural domains. To understand their functional roles, we conducted an analysis of gene expression profiles using STEM and RNA-seq data. This analysis successfully revealed regulatory networks of the KNOX genes, involving both upstream and downstream genes. Furthermore, the KNOX genes are involved in the AUX/IAA metabolic pathway, which accelerates shoot growth by influencing downstream target genes. These results provide a theoretical foundation for studying the molecular mechanisms underlying the rapid growth and establish the groundwork for future research into the functions and transcriptional regulatory networks of the KNOX gene family.

To address the issue of phosphorus limitation in agricultural and forestry production and to identify green and economical alternatives to chemical phosphorus fertilizers, this paper reviews the utilization of phosphorus in plant–soil systems and explores the considerable potential for exploiting endogenous phosphorus resources. The application of phosphate-solubilizing microorganisms (PSMs) is emphasized for their role in phosphorus activation and plant growth promotion. A focus is placed on microbial interactions as an entry point to regulate the functional rhizosphere microbiome, introducing the concept of synthetic communities. This approach aims to deepen the understanding of PSM interactions across plant root, soil, and microbial interfaces, providing a theoretical foundation for the development and application of biological regulation technologies to enhance phosphorus utilization efficiency.

Green bamboo (Bambusa oldhamii) shoots are not only delicious but also highly nutritious. However, their palatability and quality changed significantly upon being unearthed, making them unsuitable for commercial sale and subsequently diminishing their market value. To clarify the mechanisms that regulate the quality of green bamboo shoots at different growth stages, we conducted a comprehensive analysis of the metabolome and transcriptome at the unearthed height of 0 cm (H0), 5 cm (H5), and 10 cm (H10). Metabolome analysis identified 149 differentially accumulated metabolites (DAMs) among H0, H5, and H10, primarily comprising phenolic acids, lipids and flavonoids. Metabolic pathways enriched by these DAMs included phenylpropanoid biosynthesis, phenylalanine metabolism, flavonoid biosynthesis, linoleic acid metabolism and alpha-linolenic acid metabolism. Further transcriptome analysis identified 2976 differentially expressed genes (DEGs) among H0, H5, and H10. Additionally, KEGG analysis indicated that these DEGs mainly enriched pathways associated with metabolic pathways, biosynthesis of secondary metabolites, and phenylalanine metabolism. We screened out 10 DEGs and 16 intermediate metabolites of these pathways. Furthermore, we identified six DEGs with expression patterns highly correlated with the content of lignin and the total flavonoids from H0 to H5 and H10. Finally, RT-qPCR analysis of six genes validated the transcriptome sequencing data. Our findings indicate significant quality variations in green bamboo shoots from H0 to H5 and H10. These variations are closely related to key genes involved in the synthesis of lignin and flavonoids, which result in the flavor and quality changes of green bamboo shoots from the belowground stage to unearthed stage.

Abstract Key message Short-term nitrogen (N) deposition stimulates phosphorus (P) demand owing to the growth improvment of Phyllostachys edulis seedlings. Increased N loads led to the acquisition and utilization of sufficient P, while the limitation of P starvation could be alleviated by the higher activity of soil acid phosphatase and P use efficiency rather than P resorption from senescent organs. Context Plants in most terrestrial ecosystems are usually subjected to natural phosphorus (P) deficiency or surplus by overfertilization associated with increasing global nitrogen (N) deposition. As the widely distributed gramineous plant in Southern China, moso bamboo (Phyllostachys edulis (Carrière) J. Houz) grows fast and it also shows a relatively good growth performance under the variable N and P conditions. However, few studies focus on the special mechanism of P mobilization and utilization of moso bamboo, especially with the N loads. Aims The objective of this study was to figure out the mechanisms of P mobilization and utilization in P. edulis seedlings under varying levels of soil P and N deposition conditions in the subtropical region of China. Methods We grew P. edulis seedlings under 3 experimental N deposition rates (0 (N −), 30 (N +), and 60 (N + +) kg N ha−1·a−1) and 3 levels of soil P (2.99 mg·kg−1, soil available P content under natural conditions, denoted as P1; 20 mg·kg−1, P2; and 40 mg·kg−1, P3). We measured growth traits and analyzed the related P use indices. Results Dry weight and P accumulation of new leaves and stems increased with increasing N loads under the 3 P treatments, with the positive effects of N deposition being stronger in the P2 and P3 treatments. Compared with N − , N + , and N + + significantly increased P use efficiency (PUE) (+ 15.54% and + 12.47%, respectively) regardless of soil P conditions. The P resorption efficiency showed a decreasing tendency under variable P conditions with increasing N, whereas PUE was further increased. Acid phosphatase (APase) activity and soil available P content were significantly improved by N loads in P1. Conclusion Phyllostachys edulis seedlings showed high growth plasticity and P mobilization mechanisms under different soil P availability with N loads. In general, N addition stimulated P demand of P. edulis seedlings owing to the growth promotion in the short period of experiment. A special P use mechanism in P deficiency conditions was that the limitation of P starvation was alleviated by the higher soil APase activity and PUE instead of P resorption from senescent organs. The long-term effect of N deposition on P mobilization and utilization in P. edulis forests requires further monitoring.

Breeding early maturing cultivars is one of the most important objectives in pear breeding. Very early maturing pears provide an excellent parental material for crossing, but the immature embryo and low seed germination of their hybrid progenies often limit the selection and breeding of new early maturing pear cultivars. In this study, we choose a very early maturing pear cultivar ‘Pearl Pear’ as the study object and investigate the effects of cold stratification, the culture medium, and the seed coat on the germination and growth of early maturing pear seeds. Our results show that cold stratification (4 °C) treatment could significantly improve the germination rates of early maturing pear seeds. A total of 100 days of cold-temperature treatment in 4 °C and in vitro germination on White medium increased the germination rate to 84.54%. We also observed that seed coat removal improved the germination of early maturing pear seeds, with middle seed coat removal representing the optimal method, with a high germination rate and low contamination. The results of our study led to the establishment of an improved protocol for the germination of early maturing pear, which will greatly facilitate the breeding of new very early maturing pear cultivars.

Summary Phosphate‐mobilizing bacteria (PMB) play a critical role in the regulation of phosphorus availability in the soil. The microbial genes pqqC and phoD encode pyrroloquinoline quinone synthase and bacterial alkaline phosphatase, respectively, which regulate inorganic and organic phosphorus mobilization, and are therefore used as PMB markers. We examined the effects of soil properties in three Moso bamboo forest sites on the PMB communities that were profiled using high‐throughput sequencing. We observed differentiated responses of pqqC‐ and phoD‐harbouring PMB communities to various soil conditions. There was significant variation among the sites in the diversity and structure of the phoD‐harbouring community, which correlated with variation in phosphorus levels and non‐capillary porosity; soil organic carbon and soil water content also affected the structure of the phoD‐harbouring community. However, no significant difference in the diversity of pqqC‐harbouring community was observed among different sites, while the structure of the pqqC‐harbouring bacteria community was affected by soil organic carbon and soil total nitrogen, but not soil phosphorus levels. Overall, changes in soil conditions affected the phoD‐harbouring community more than the pqqC‐harbouring community. These findings provide a new insight to explore the effects of soil conditions on microbial communities that solubilize inorganic phosphate and mineralize organic phosphate.

Moso bamboo (Phyllostachys edulis) is the most widely distributed bamboo species in the subtropical regions of China. Due to the fast-growing characteristics of P. edulis, its growth requires high nutrients, including phosphorus. Previous studies have shown that SPX proteins play key roles in phosphorus signaling and homeostasis. However, the systematic identification, molecular characterization, and functional characterization of the SPX gene family have rarely been reported in P. edulis. In this study, 23 SPXs were identified and phylogenetic analysis showed that they were classified into three groups and distributed on 13 chromosomes. The analysis of conserved domains indicated that there was a high similarity between PeSPXs among SPX proteins in other species. RNA sequencing and qRT-PCR analysis indicated that PeSPX6 and PeSPX-MFS2, which were highly expressed in roots, were clearly upregulated under low phosphorus. Co-expression network analysis and a dual luciferase experiment in tobacco showed that PeWRKY6 positively regulated the PeSPX6 expression, while PeCIGR1-2, PeMYB20, PeWRKY6, and PeWRKY53 positively regulated the PeSPX-MFS2 expression. Overall, these results provide a basis for the identification of SPX genes in P. edulis and further exploration of their functions in mediating low phosphorus responses.

INDETERMINATE DOMAIN (IDD) proteins, a family of transcription factors unique to plants, function in multiple developmental processes. Although the IDD gene family has been identified in many plants, little is known about it in moso bamboo. In this present study, we identified 32 PheIDD family genes in moso bamboo and randomly sequenced the full-length open reading frames (ORFs) of ten PheIDDs. All PheIDDs shared a highly conserved IDD domain that contained two canonical C2H2-ZFs, two C2HC-ZFs, and a nuclear localization signal. Collinearity analysis showed that segmental duplication events played an important role in expansion of the PheIDD gene family. Synteny analysis indicated that 30 PheIDD genes were orthologous to those of rice (Oryza sativa). Thirty PheIDDs were expressed at low levels, and most PheIDDs exhibited characteristic organ-specific expression patterns. Despite their diverse expression patterns in response to exogenous plant hormones, 8 and 22 PheIDDs responded rapidly to IAA and 6-BA treatments, respectively. The expression levels of 23 PheIDDs were closely related to the outgrowth of aboveground branches and 20 PheIDDs were closely related to the awakening of underground dormant buds. In addition, we found that the PheIDD21 gene generated two products by alternative splicing. Both isoforms interacted with PheDELLA and PheSCL3. Furthermore, both isoforms could bind to the cis-elements of three genes (PH02Gene17121, PH02Gene35441, PH02Gene11386). Taken together, our work provides valuable information for studying the molecular breeding mechanism of lateral organ development in moso bamboo.

Two types of bamboo shoots, high bamboo (Phyllostachys prominens) shoots (HBSes) and moso bamboo (Phyllostachys edulis) shoots (MBSes), underwent a fast post-harvest lignification process under room temperature storage. To explore the mechanism of lignification in two types of bamboo shoots after post-harvest during room temperature storage, the measurement of cell wall polymers (lignin and cellulose) and enzyme activities of phenylalanine ammonialyase (PAL) and peroxidase (POD), and relative expression of related transcription networks factors (TFs) were performed. The results suggested that the lignification process in HBSes is faster than that in MBSes because of incremental increase in lignin and cellulose contents within 6 days and the shorter shelf-life. Additionally, compared with the expression pattern of lignification-related TFs and correlation analysis of lignin and cellulose contents, MYB20, MYB43, MYB85 could function positively in the lignification process of two types of bamboo shoots. A negative regulator, KNAT7, could negatively regulate the lignin biosynthesis in two types of bamboo shoots. In addition, MYB63 could function positively in HBSes, and NST1 could function negatively in MBSes. Notably, MYB42 may function differently in the two types of bamboo shoots, that is, a positive regulator in HBSes, but a negative regulator in MBSes. Transcription networks provide a comprehensive analysis to explore the mechanism of lignification in two types of bamboo shoots after post-harvest during room temperature storage. These results suggest that the lignification of bamboo shoots was mainly due to the increased activity of POD, higher expression levels of MYB20, MYB43, MYB63, and MYB85 genes, and lower expression levels of KNAT7 and NST1 genes, and the lignification process of HBSes and MBSes had significant differences.

Atmospheric nitrogen (N) deposition can increase the susceptibility of vascular plants to other stresses, but the physiological basis of such a response remains poorly understood. This study was designed to clarify the physiological mechanisms and to evaluate bioindicators of N deposition impact on vascular plants. We evaluate multiple physiological responses to ~4 years of simulated additional N deposition (30–90 kg N ha−1 year−1) on three age-classes (1a, 3a, and 5a) of Moso bamboo. A saturating response to the additional N deposition was found both in foliar N concentration and in Pn. However, 3- and 5-year-old bamboo seemed to be less tolerant to extremely high N deposition than 1-year-old bamboo since they were saturated at a lower N addition. Furthermore, C/N/P stoichiometric ratios were very sensitive to N deposition in all three-age classes of bamboo, but the responses to N deposition in the various age-classes were diverse. We also found that the highest additional N deposition suppressed stomatal conductance and transpiration rate, suggesting an induced water stress. The stress induced by the high N load was also seen in photochemistry, where it reduced potential and actual photosynthetic use of light energy, diminished photo-protection capacity, and increased risk of the photo-damage. High additional N deposition contributed to a decrease in the foliar soluble protein contents and to an increase in the peroxidase activity (POD). Our study suggested, for the first time, that although the photosynthetic rate was enhanced by the increased N deposition in Moso bamboo, long-term high N load causes negative effects, such as damage to photosystem II. In Moso bamboo photochemical parameters are more sensitive to N deposition than photosynthetic rate or foliar N concentration. Furthermore, plant age should be taken into account when assessing plants' susceptibility to changes in global change drivers, such as N deposition. These findings facilitate the revealing of the risks potentially caused to vascular plants by increased N deposition before any visible symptoms of injury are seen.

A bamboo shoot is the immature stem of the woody grass and a nutritious and popular vegetable in East Asia. However, it undergoes a rapid xylogenesis process right after harvest, even being stored in a cold chamber. To investigate the molecular regulation mechanisms of xylogenesis in Moso bamboo (Phyllostachys edulis) shoots (MBSes) during cold storage, the measurement of cell wall polymers (cellulose, hemicellulose, and lignin) and related enzyme activities (phenylalanine ammonia lyase (PAL), cinnamyl alcohol dehydrogenase (CAD), peroxidase (POD), and xylan xylosyltransferase (XylT)) and transcriptomic analysis were performed during cold storage. It was noticed that cellulose and lignin contents increased, while hemicellulose content exhibited a downward trend. PAL, CAD, and POD activity presented an upward trend generally in MBS when stored at 4 °C for 16 days. XylT activity showed a descending trend during the stages of storage, but slightly increased during the 8th to 12th days after harvest at 4 °C. Transcriptomic analysis identified 72, 28, 44, and 31 functional unigenes encoding lignin, cellulose, xylan biosynthesis enzymes, and transcription factors (TFs), respectively. Many of these secondary cell wall (SCW)-related genes showed higher expression levels in the later period of cold storage. Quantitative RT-PCR analysis of the selected genes conformed to the expression pattern. Our study provides a comprehensive analysis of MBS secondary wall biosynthesis at the molecular level during the cold storage process. The results give insight into the xylogenesis process of this economically important vegetable and shed light on solving this problem of the post-harvest industry.

Biochar amendment has been proposed as a strategy to improve acidic soils after overuse of nitrogen fertilizers. However, little is known of the role of biochar in soil microbial biomass carbon (MBC) and bacterial community structure and diversity after soil acidification induced by nitrogen (N) deposition. Using high-throughput sequencing of the 16S rRNA gene, we determined the effects of biochar amendment (BC0, 0 t bamboo biochar ha ^−1 ; BC20, 20 t bamboo biochar ha ^−1 ; and BC40, 40 t bamboo biochar ha ^−1 ) on the soil bacterial community structure and diversity in Moso bamboo plantations that had received simulated N deposition (N30, 30 kg N ha ^−1 yr ^−1 ; N60, 60 kg N ha ^−1 yr ^−1 ; N90, 90 kg N ha ^−1 yr ^−1 ; and N-free) for 21 months. After treatment of N-free plots, BC20 significantly increased soil MBC and bacterial diversity, while BC40 significantly decreased soil MBC but increased bacterial diversity. When used to amend N30 and N60 plots, biochar significantly decreased soil MBC and the reducing effect increased with biochar amendment amount. However, these significant effects were not observed in N90 plots. Under N deposition, biochar amendment largely increased soil bacterial diversity, and these effects depended on the rates of N deposition and biochar amendment. Soil bacterial diversity was significantly related to the soil C/N ratio, pH, and soil organic carbon content. These findings suggest an optimal approach for using biochar to offset the effects of N deposition in plantation soils and provide a new perspective for understanding the potential role of biochar amendments in plantation soil.