Chang-Lian Peng

Red young leaves represent a common phenomenon among tropical and subtropical forest tree species. This study examined the seasonal patterns of leaf reddening and the mechanisms underlying temperature‐mediated anthocyanin accumulation in young leaves of tree species at different successional stages in the Dinghushan forest. Nineteen mid‐successional and 34 late‐successional tree species in Dinghushan forest were selected to investigate young leaf coloration and physiological parameters in summer and winter under field conditions. Two mid‐successional and two late‐successional dominant tree species were selected for pot experiment to examine the response of young leaf coloration and physiological parameters to seasonal temperature variation. In Dinghushan forest, more than half of mid‐ and late‐successional tree species accumulated anthocyanins in young leaves year‐round, whereas approximately 40% of late‐successional species accumulated anthocyanins exclusively in winter. In the pot experiment, young leaves of mid‐successional dominant species accumulated anthocyanins under high summer temperature, whereas those of late‐successional dominant species accumulated anthocyanins under low winter temperature. Anthocyanins' accumulation was positively correlated with soluble sugars in both field and pot experiment. Furthermore, anthocyanins' accumulation did not significantly influence antioxidant capacity. The results revealed distinct seasonal patterns of leaf reddening in young leaves of tree species at different successional stages in subtropical forests. Leaf reddening appears to be regulated by temperature and induced by soluble sugars. Furthermore, red coloration provides photoprotection for young leaves. These findings enhance our understanding of successional dynamics in subtropical forests.

Background: Soil cadmium (Cd) contamination poses threats to ecosystems and human health, and the plant arbuscular mycorrhizal fungi (AMF) symbiotic system represents a promising green remediation strategy. However, the underlying mechanisms are complex and context-dependent, and systematic comparative studies remain scarce regarding differential regulation of Cd tolerance enhancement in plants of the same genus but different ecotypes. This study used a native species ( Sphagneticola calendulacea ), invasive species ( Sphagneticola trilobata ), and their hybrid as materials. It conducted an integrated analysis of the synergistic effects of inoculating Funneliformis mosseae (FM) on the rhizosphere microenvironment and mineral element uptake of three plants under a Cd stress gradient. The objective was to elucidate the interactive mechanisms by which FM enhances plant Cd tolerance and to evaluate its remediation potential. Results: Results indicate that FM regulation of rhizosphere pH exhibits species specificity but generally alleviates Cd induced acidification. FM significantly enhances acid phosphatase activity in rhizosphere soil and substantially promotes plant phosphorus (P) uptake. FM comprehensively altered plant mineral element uptake, including promoting root accumulation of sodium (Na), magnesium (Mg), and calcium (Ca), shoot potassium (K) allocation, and copper (Cu) and zinc (Zn) absorption. Conclusions: This study elucidates how FM enhances P uptake and systematically optimizes elemental absorption homeostasis by regulating rhizosphere pH and phosphatase activity. These synergistic effects improve Cd tolerance in Sphagneticola species and highlight the broad potential of AMF-plant symbioses for Cd remediation. It provides crucial theoretical foundations and germplasm selection references for targeted soil restoration using ecologically distinct Sphagneticola ecotypes and their optimal FM partners.

Mikania micrantha, commonly known as mile-a-minute weed, is listed among the world’s top 10 worst weeds. Although native to humid regions of South America, it has recently been found to colonize arid habitats as well. Despite pronounced seasonal hydroclimatic variations in South China and increasing drought due to global climate change, the mechanisms underlying M. micrantha’s drought tolerance remain poorly understood. In this study, we compared the photosynthetic responses of M. micrantha leaves and stems between the dry (June) and wet (December) seasons through field experiments. We measured changes in phenotype, photosynthetic characteristics, and the content of antioxidant and osmotic adjustment substances, using the co-occurring native vine Paederia scandens as a control. The results revealed that during the dry season, M. micrantha leaves exhibited wilting, along with significant reductions in relative water content (RWC), chlorophyll (Chl), soluble sugar (SS), and soluble protein (SP). In contrast, the stems of M. micrantha maintained relatively stable phenotypes and chlorophyll levels compared to those of P. scandens. Notably, M. micrantha stems exhibited significant increases in vessel wall thickness, vessel density, total phenol content, and the activities of peroxidase (POD) and ascorbate peroxidase (APX). Furthermore, compared to P. scandens, M. micrantha stems displayed a greater increase in cortex proportion, flavonoid content, and soluble protein content. Expression analysis of bZIP transcription factors further revealed drought-responsive upregulation of specific genes (bZIP60, ZIP42-1), suggesting their potential involvement in drought response. These results indicate that although the leaves of M. micrantha are susceptible to prolonged drought, the stems exhibit considerable resilience, which may be attributed to a combination of traits including structural modifications in stem anatomy, enhanced antioxidant capacity, and osmotic adjustment. These insights suggest that stem-specific adaptations are key to its drought tolerance, providing a theoretical foundation for understanding the habitat distribution of M. micrantha and informing effective management strategies.

The abundance of PYR/PYL/RACR-type abscisic acid (ABA) receptors can be modulated through transcriptional regulation, ubiquitination-mediated degradation, and the protein expression level, which directly influence the intensity and efficiency of the ABA signaling pathway. Here, we report that the FYVE domain-containing protein FYVE4, a plant-specific component of the endosomal sorting complex required for transport III (ESCRT-III), negatively modulates ABA signaling. In this study, we showed that FYVE4 directly binds to ABA receptors, overexpression of FYVE4 promotes its degradation, and impaired FYVE4 function leads to the accumulation of ABA receptor PYL4. In line with this, the loss-of-function fyve4-1 mutants display hypersensitivity to ABA treatment during plant growth as well as a corresponding stomatal closure phenomenon and a more drought-tolerant phenotype, enriching the role of the plant ESCRT machinery in the regulation of water loss of stomatal control induced by ABA signaling. Taken together, our results suggest that FYVE4 affects ABA signaling through regulating PYL4 degradation, providing a deeper understanding of the role of the ESCRT complexes in studying adverse stresses.

The increasing atmospheric nitrogen deposition, characterized by a rising proportion of nitrate nitrogen (NO₃⁻-N), is exacerbating the spread of invasive plant species. Despite this trend, the response mechanisms of Mikania micrantha, a highly invasive plant, to NO₃⁻-N remain poorly understood. This study investigates the unique adaptation strategies of M. micrantha to elevated NO₃⁻-N levels, providing novel insights into its invasive success under changing nitrogen deposition patterns. Field experiments showed that M. micrantha rhizosphere soil contained higher NO₃^–N content and protease activity compared to companion plants (Paederia scandens, Ipomoea nil, and Ipomoea cairica). Both roots and stems of M. micrantha had higher NO₃^–N content and demonstrated stronger nitrogen metabolism capabilities. Pot experiments further showed that increasing NO₃⁻-N concentrations (0 mM–40 mM) significantly promoted M. micrantha growth, with optimal phenotypic responses (main stem length, leaf number, branch number, and biomass) observed at 5 mM NO₃⁻-N. Nitrogen metabolism enzyme assays revealed that nitrate reductase (NR), nitrite reductase (NiR), glutamate dehydrogenase (GDH), and free amino acid content increased progressively with NO₃⁻-N concentration. Transcriptome sequencing and qPCR analyses identified upregulation of key genes related to transcription factors, nitrate transporter-related, nitrogen metabolism enzyme, and amino acid synthesis pathway. These findings demonstrate that M. micrantha employs a multifaceted strategy to exploit elevated NO₃⁻-N conditions: enhanced NO₃⁻-N uptake from soil, efficient transport to stems, and robust nitrogen metabolism facilitated by coordinated gene expression. This study reveals the adaptation mechanisms of M. micrantha to NO₃⁻-N enrichment, offering critical insights for predicting and managing invasive species responses to global atmospheric nitrogen deposition changes. The results highlight the importance of considering nitrogen composition, rather than just quantity, in invasive species management strategies.

High-temperature stress hinders seed filling, reducing seed quality and crop yield. However, the molecular mechanisms underlying this process remain unclear. Here, we identify SAP AND MIZ1 DOMAIN-CONTAINING LIGASE1 (SIZ1) as a key regulator of seed filling under prolonged high temperatures in Arabidopsis (Arabidopsis thaliana). SIZ1 and WRINKLED1 (WRI1) are co-expressed during seed filling, and overexpressing either gene enhances seed filling and promotes fatty acid biosynthesis under high-temperature stress. Genetic and biochemical analyses revealed that SIZ1 stabilizes WRI1 by promoting its SUMOylation at Lys-257 and Lys-266, thereby inhibiting its interaction with the CULLIN3-based ubiquitin E3 ligase adaptor protein BTB/POZMATH (BPM) and preventing its ubiquitination and degradation. Mutating these SUMOylation sites accelerates WRI1 degradation, impairing its function in seed filling under high-temperature stress. Furthermore, high-temperature stress induces SIZ1 expression and reduces WRI1 levels, suggesting that SIZ1-mediated SUMOylation counteracts high-temperature stress-induced WRI1 instability. These findings establish SIZ1 as a crucial factor in maintaining WRI1 stability and seed filling under high-temperature stress, providing valuable genetic resources and a theoretical foundation for addressing prolonged high-temperature stress in agricultural production.