Summary: The mechanisms underlying plant tolerance to boron (B) excess are far from fully understood. Here we characterized the role of the miR397‐CsiLAC4/CsiLAC17 (from Citrus sinensis) module in regulation of B flow. Live‐cell imaging techniques were used in localization studies. A tobacco transient expression system tested modulations of CsiLAC4 and CsiLAC17 by miR397. Transgenic Arabidopsis were generated to analyze the biological functions of CsiLAC4 and CsiLAC17. CsiLAC4’s role in xylem lignification was determined by mRNA hybridization and cytochemistry. In situ B distribution was analyzed by laser ablation inductively coupled plasma mass spectrometry. CsiLAC4 and CsiLAC17 are predominantly localized in the apoplast of tobacco epidermal cells. Overexpression of CsiLAC4 in Arabidopsis improves the plants’ tolerance to boric acid excess by triggering high‐B‐dependent lignification of the vascular system’s cell wall and reducing free B content in roots and shoots. In Citrus, CsiLAC4 is expressed explicitly in the xylem parenchyma and is modulated by B‐responsive miR397. Upregulation of CsiLAC4 in Citrus results in lignification of the xylem cell walls, restricting B flow from xylem vessels to the phloem. CsiLAC4 contributes to plant tolerance to boric acid excess via high‐B‐dependent lignification of cell walls, which set up a ‘physical barrier’ preventing B flow.

The integration of forestry and agriculture has promoted edible fungi cultivation in forest understory spaces. However, the impact of spent mushroom substrates on forest soils remains unclear. This study explored the use of seafood mushroom spent substrates (SMS) and grass substrates to cultivate Dictyophora indusiata. After cultivation, soil pH stabilized, organic carbon increased by 34.02–62.24%, total nitrogen rose 1.1–1.9-fold, while soil catalase activity increased by 43.78–100.41% and laccase activity surged 3.3–11.2-fold. The 49% Cenchrus fungigraminus and 49% SMS treatment yielded the highest 4-coumaric acid levels in the soil, while all treatments reduced maslinic and pantothenic acid content. SMS as padding material with C. fungigraminus enhanced soil bacterial diversity in the first and following years. Environmental factors and organic acids influenced the recruitment of genus of Latescibacterota, Acidothermus, Rokubacteriales, Candidatus solibacter, and Bacillus, altering organic acid composition. In conclusion, cultivating D. indusiata understory enhanced environmental characteristics, microbial dynamics, and organic acid profiles in forests’ soil in short time.

Boron (B) toxicity severely restricts Citrus growth and productivity in high-B soil and irrigation water environments. Although exogenous Zinc (Zn) has been reported to mitigate B toxicity in plants, the underlying physiological regulation mechanisms—particularly in Citrus—remain incompletely understood. In this study, seedlings of two Citrus species differing markedly in B tolerance—Citrus sinensis (sweet orange, B-tolerant) and C. grandis (sour pomelo, B-sensitive)—were subjected to three boric acid treatments (10, 200, and 400 μM) and five ZnSO₄ treatments (0.002, 0.05, 0.1, 0.2, and 0.25 mM) in a fully factorial design over 15 weeks. Comprehensive physiological assessments—including growth parameters, photosynthetic performance, mineral-nutrient profiling (in leaves and roots), and antioxidant enzyme activity—were conducted to decipher the mechanistic basis of Zn-mediated B detoxification. Results showed that 400 μM BA alone triggered severe B toxicity symptoms in the older leaves of C. grandis, whereas 0.25 mM Zn independently led to chlorosis symptoms similar to Fe deficiency in the apical leaves of both Citrus species. Either B or Zn toxicity affected photosynthesis in matured leaves. Exogenous Zn at 0.05–0.20 mM alleviated B toxicity symptoms in B-sensitive C. grandis, yet consistent alleviation of Zn toxicity by excess B was not observed across all measured variables. Severe B toxicity caused a significant reduction in Fe, N, P and Ca contents and a significant increase in Cu and Mn contents in C. grandis roots, yet it only led to a significant reduction in Mn, N, P and Ca contents in C. grandis leaves. Unlike this, B toxic treatments in C. sinensis resulted in a significant reduction in merely Fe content and a significant increase in Cu, Mn, N and K contents in roots, and a significant reduction in Mn and Ca contents in the leaves. Under basal B supply, 0.05–0.20 mM Zn supplementation dose-dependently increased root Zn, Cu and Mn contents as well as leaf Zn and Cu contents in both Citrus species, but concurrently decreased root Fe content and leaf Fe and Ca contents—additionally, in C. grandis, leaf N, P, K and Mg contents were further reduced. Regarding antioxidant responses in C. grandis, B toxicity significantly suppressed leaf CAT activity while enhancing APX and GPX activities. Under B toxicity conditions, 0.2 mM Zn supplement significantly restored CAT activity and suppressed APX and GPX activities. These antioxidant modulations were highly dependent on species identity and treatment combination, and were markedly more pronounced in B-sensitive C. grandis. Collectively, this work clarifies the physiological interplay between Zn and B in Citrus, uncovers divergent adaptive strategies employed by contrasting citrus species under combined B–Zn stress, and provides a mechanistic foundation for optimizing exogenous Zn application to mitigate B toxicity in citrus production.

Continuous cropping poses a significant challenge to the sustainable cultivation of Dictyophora indusiata, often leading to soil degradation, microbial imb

This study aimed to determine seed germination characteristics of citron (Citrus medica) and improve its germination. Citron was used as materials to observe its characters. Effects of seed coat removal, seed size and fruit maturity on citron seed germination were investigated. The findings indicated that the average normal seed weight was found to be 0.110 g while small 0.037 g; citron seed have ovoid shape (93.7%), spheroid (3.3%), and semi-deltoid (3.0%); seed percentage was 1%. After seed coat was removed, days taken to initial germination of citron seed were shortened by 5.6 d while germination percentage and germination potential and germination speed index of seeds significantly increased by 4.9%, 6.0% and 0.37, respectively. No significant differences taken to initial germination and germination potential were found between small and normal seed, but germination percentage and germination speed index of small seed was significantly lower than that of normal seed by 13.0% and 10.4, respectively. Early and immature fruit harvest with greenish-yellow skin had no significant impact on seed germination. The findings of this study will serve as a valuable reference for seed propagation strategies for C. medica.