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Accurate estimation of forest stand carbon storage is critical for assessing ecosystem functions and informing sustainable forest management. Most existing models depend heavily on stand age, a strategy that is often unreliable in natural forests, and they typically ignore species interactions, limiting their applicability across forest types. To overcome these issues, we developed a dynamic carbon storage model based on the Richards equation that replaces stand age with a growth interval period (defined as the time difference between two successive growth stages, Tn = T2 − T1) and explicitly incorporates site quality and species composition. This approach enables consistent estimation for both natural and plantation forests. Using field data from six dominant tree species in Wuyishan City, Fujian Province, we calibrated and validated the model through five-fold cross-validation. It achieved high accuracy, with an efficiency coefficient (EA) above 99% and a relative mean absolute error (RMA) under 7%, effectively reflecting how site conditions and mixed-species structures influence carbon dynamics. Total forest carbon storage in the study area was estimated at 7.32 million tons. Simulations show a gradual decline in carbon accumulation over time, consistent with natural growth saturation in aging stands. Scenario analyses further identified practical zones for sustainable harvesting in major plantation types, underscoring the model’s management relevance. The model does not yet include climate variability, disturbances, or below-ground carbon pools. Adding these components in future work would strengthen its utility for regional carbon assessment and support more robust carbon-neutral forestry planning.

Aims The conservation tillage i.e. reduced tillage (incl. no tillage and minimum tillage) and straw return, plays an important role in the promotion of sustainable agriculture. However, comprehensive cognition is still weak on how conservation tillage improves soil. Methods Here, we collected 7613 paired observations from 308 publications to reveal the improvement of soil by conservation tillage in perspective of coupled soil nutrients and soil functional enzyme activities. Results (1) Conservation tillage had positive effect on soil organic matter, total nitrogen, total phosphorus, total potassium, dissoluble organic carbon, available nitrogen, ammonium nitrogen, available phosphorus, available potassium, microbial carbon, and microbial nitrogen (7.44–30.56%) via promoting soil enzyme activity, while significantly reduced nitrate nitrogen (-11.55%), and this effect was more concentrated in soil surface. (2) The accumulation of soil nutrients under conservation tillage was closely related to the soil functional enzyme activities with slope ranges from -0.07 to 0.94. The complexity of coupling and cycling among soil elements caused single soil functional enzyme and the accumulation of multiple nutrients were intensively related. (3) Soil depth contributes to differentiation of soil nutrients accumulation and is influenced by the type of tillage and crop. Besides, geography, climate and initial soil properties had limited moderating effects on nutrient response to conservation tillage. Conclusions Overall, conservation tillage promotes nutrient accumulation by improving the soil biochemical environment to enhance soil enzyme activity. This could effectively improve soil fertility and biochemical environment for sustainable agricultural development. The research could provide valuable references for sustainable agricultural management.

Fruit cracking not only affects the appearance of netted melons ( L. var. reticulatus Naud.) but also decreases their marketability. Herein, to comprehensively understand the role of expansin (EXP) proteins in netted melon, bioinformatics methods were employed to discover the gene family in the melon genome and analyze its characteristic features. Furthermore, transcriptomics analysis was performed to determine the expression patterns of melon ( ) genes in crack-tolerant and crack-susceptible netted melon varieties. Thirty-three genes were identified. Chromosomal location analysis revealed that gene distribution was uneven on 12 chromosomes. In addition, phylogenetic tree analysis revealed that genes could be categorized into four subgroups, among which the EXPA subgroup had the most members. The same subgroup members shared similar protein motifs and gene structures. Thirteen duplicate events were identified in the 33 genes. Collinearity analysis revealed that the genes had 50, 50, and 44 orthologous genes with genes in cucumber, watermelon, and , respectively. However, only nine orthologous genes were observed in rice. Promoter -acting element analysis demonstrated that numerous -acting elements in the upstream promoter region of genes participate in plant growth, development, and environmental stress responses. Transcriptomics analysis revealed 14 differentially expressed genes (DEGs) in the non-cracked fruit peels between the crack-tolerant variety 'Xizhoumi 17' (N17) and the crack-susceptible variety 'Xizhoumi 25' (N25). Among the 14 genes, 11 were upregulated, whereas the remaining three were downregulated in N17. In the non-cracked (N25) and cracked (C25) fruit peels of 'Xizhoumi 25', 24 DEGs were identified, and 4 of them were upregulated, whereas the remaining 20 were downregulated in N25. In the two datasets, only exhibited consistently upregulated expression, indicating its importance in the fruit peel crack resistance of netted melon. Transcription factor prediction revealed 56 potential transcription factors that regulate expression. Our study findings enrich the understanding of the gene family and present candidate genes for the molecular breeding of fruit peel crack resistance of netted melon.

Class III peroxidase (PRX) functions as a pivotal enzyme in lignin polymerization and participates in the regulation of cell wall hardening and elongation. Nevertheless, comprehensive investigations on PRX involvement in the rind cracking of melon ( ) remain absent. In this study, melon was used as experimental material. Physiological analyses were performed to compare peroxidase activity and lignin accumulation between cracking-susceptible and resistant cultivars, as well as between cracked and non-cracked rinds. Genome-wide identification, phylogenetic analysis, chromosome localization, collinearity analysis, and -acting element prediction were conducted to characterize the melon PRX gene family. Transcriptome sequencing was used to analyze expression patterns across different rind types, and quantitative real-time polymerase chain reaction (qRT-PCR) was performed for validation. Protein-protein interaction networks were predicted to explore the functional associations of candidate genes. Peroxidase activity and lignin accumulation were significantly higher in cracking-susceptible cultivars compared to cracking-resistant cultivars, with cracked rinds displaying elevated levels relative to intact rinds. Sixty-four genes were identified in the melon genome, and phylogenetic analysis categorized them into six subgroups. The genes were unevenly distributed across 12 chromosomes, and collinearity analysis uncovered eight duplicated gene pairs within the melon genome. Comparative synteny analysis revealed that the number of collinear gene pairs between melon and other Cucurbitaceae species, specially cucumber and watermelon, was greater than that observed with the more distantly related . Promoter acting element examination revealed that the 64 genes harbored 25 classes of elements associated with hormones, stress responses, and growth and development. Transcriptome data from melon rinds revealed that the genes could be clustered into six groups based on expression patterns across different rind types. Among these, genes in clusters 1 and 6 exhibited higher transcript levels in cracked rinds compared to non-cracked rinds. Moreover, quantitative real-time polymerase chain reaction analyses confirmed that , , and were expressed at significantly elevated levels in cracked rinds compared with those of non-cracked rinds. Protein interaction network prediction showed that these three candidate genes interacted with multiple proteins involved in the lignin synthesis pathway, suggesting their potential regulatory roles in rind cracking of melon through mediating lignin polymerization. These findings identified candidate genes influencing rind cracking in melon, thereby offering potential molecular targets for the breeding of cracking-resistant cultivars.

IntroductionWilt is a soil-borne disease caused by Fusarium that has become a serious threat to wax gourd production. Disease-resistant graft wax gourds are an effective treatment for Fusarium wilt. However, there are few reports on the defense mechanism of graft wax gourd against wilt diseases.MethodsIn the present study, disease and growth indices were compared between grafted and original wax gourds after infection with Fusarium . High level of disease resistance was observed in the grafted wax gourd, with a lower disease index and low impacts on growth after infection. RNA-seq was performed to identify the differentially expressed genes (DEGs) between the adjacent treatment time points in the grafted and original wax gourds, respectively. Then a comparative temporal analysis was performed and a total of 1,190 genes were identified to show different gene expression patterns between the two wax gourd groups during Fusarium infection.Result and discussionHere, high level of disease resistance was observed in the grafted wax gourd, with a lower disease index and low impacts on growth after infection. The DEG number was higher in grafted group than original group, and the enriched functional categories and pathways of DEGs were largely inconsistent between the two groups. These genes were enriched in multiple pathways, of which the mitogen-activated protein kinase (MAPK) signaling pathway enhanced the early defense response, and cutin, suberin, and wax biosynthesis signaling pathways enhanced surface resistance in grafted wax gourd in comparison to original group. Our study provides insights into the gene regulatory mechanisms underlying the resistance of grafted wax gourds to Fusarium wilt infection, which will facilitate the breeding and production of wilt-resistant rootstocks.

Heat shock protein 90 (HSP90) plays critical roles in plant growth and development, as well as in response to abiotic stresses such as heat and cold. To comprehensively analyze the HSP90 gene family and determine the key HSP90 gene responsive to temperature stress in pumpkin (Cucurbita moschata Duch.), bioinformatics and molecular biology techniques were used in this study. A total of 10 CmoHSP90 genes were identified from the pumpkin genome, encoding amino acids of 567–865, with protein molecular weight of 64.32–97.36 kDa. Based on the phylogenetic analysis, they were classified into four groups. The members in each group contained similar conserved motifs and gene structures. The 10 CmoHSP90 genes were distributed on the 9 chromosomes of C. moschata. Four pairs of segmental duplication genes (CmoHSP90-1/CmoHSP90-10, CmoHSP90-2/CmoHSP90-7, CmoHSP90-3/CmoHSP90-6, and CmoHSP90-4/CmoHSP90-9) were detected. Synteny analysis revealed that 10 C. maxima HSP90 genes and 10 C. moschata HSP90 genes were orthologous genes with 17 syntenic relationships. Promoter analysis detected 23 cis-acting elements including development-, light-, stress-, and hormone-related elements in the promoter regions of pumpkin HSP90 genes. Further analysis showed that the transcript levels of CmoHSP90-3 and CmoHSP90-6 were remarkably up-regulated by heat stress, while CmoHSP90-6 and CmoHSP90-10 were significantly up-regulated by cold stress, suggesting that these HSP90 genes play critical roles in response to temperature stress in pumpkins. The findings will be valuable for understanding the roles of CmoHSP90s in temperature stress response and should provide a foundation for elucidating the function of CmoHSP90s in C. moschata.

Heat shock protein 90 (HSP90) plays critical roles in plant growth and development, as well as in response to abiotic stresses such as heat and cold. To comprehensively analyze the HSP90 gene family and determine the key HSP90 gene responsive to temperature stress in pumpkin (Cucurbita moschata Duch.), bioinformatics and molecular biology techniques were used in this study. A total of 10 CmoHSP90 genes were identified from the pumpkin genome, encoding amino acids of 567-865, with protein molecular weight of 64.32-97.36 kDa. Based on the phylogenetic analysis, they were classified into four groups. The members in each group contained similar conserved motifs and gene structures. The 10 CmoHSP90 genes were distributed on the 9 chromosomes of C. moschata. Four pairs of segmental duplication genes (CmoHSP90-1/CmoHSP90-10, CmoHSP90-2/CmoHSP90-7, CmoHSP90-3/CmoHSP90-6, and CmoHSP90-4/CmoHSP90-9) were detected. Synteny analysis revealed that 10 C. maxima HSP90 genes and 10 C. moschata HSP90 genes were orthologous genes with 17 syntenic relationships. Promoter analysis detected 23 cis-acting elements including development-, light-, stress-, and hormone-related elements in the promoter regions of pumpkin HSP90 genes. Further analysis showed that the transcript levels of CmoHSP90-3 and CmoHSP90-6 were remarkably up-regulated by heat stress, while CmoHSP90-6 and CmoHSP90-10 were significantly up-regulated by cold stress, suggesting that these HSP90 genes play critical roles in response to temperature stress in pumpkins. The findings will be valuable for understanding the roles of CmoHSP90s in temperature stress response and should provide a foundation for elucidating the function of CmoHSP90s in C. moschata.

The red tide in Hongsha Bay caused by Skeletonema costatum (S. costatum) from April 27 to May 4, 2006, was monitored in this study. The dynamic variety of environmental factors, including chlorophyll a (chl a), temperature, salinity, pH, dissolved oxygen, chemical oxygen demand, nitrate, ammonium, nitrite, phosphate (PO43−), silicate, and iron (Fe), was observed and analyzed during the red tide in Hongsha Bay for the first time. The results indicated that the concentration of dissolved inorganic nitrogen was high (26.34 μmol/L) in Hongsha Bay. Because of the heavy rainfall from April 13 to 15, a large input of nutrients surged into the bay, causing an increase in the concentration of various nutrients, especially PO43−, which showed an obvious increase (from 0.72 to 1.45 μmol/L). The abundant nutrients provided fundamental nutrient supply for the rapid proliferation of S. costatum. Three critical environmental factors, including water temperature, and PO43− and Fe concentration, played an important role in this red tide. Water temperature had a significant positive correlation with chl a. The water temperature shift was one of the critical environmental factors affecting the S. costatum red tide in Hongsha Bay. With the occurrence of the red tide, the concentration of PO43− rapidly decreased. Inorganic PO43− was rapidly depleted at the blooming stage, causing the red tide to gradually dissipate. Phosphate was the limiting factor of S. costatum proliferation in this red tide. Iron was also a factor. Salinity shift had little effect on the growth of S. costatum.