The crop straw degradation is essential for soil fertility and agroecosystem sustainability. In this study, our field experiment found that iron-based nanoagents (i.e., α-Fe2O3/g-C3N4 heterojunction) could promote straw degradation by enhanced hydroxyl radical (•OH) generation and subsequent microbial activation. Specifically, as the control, Fe3O4 promoted early-stage degradation (8.51% increase) by driving a transient •OH burst that stimulated microbial hydrolytic enzyme activity. In contrast, α-Fe2O3/g-C3N4 enabled a sustained degradation process, achieving a 25.7% initial increase and a 9.93% final cumulative enhancement. This superior performance was due to sustained cumulative •OH generation which promoted recalcitrant lignin structure breakdown and selectively reshaped soil microbiome. In this regard, a specialized fungal consortium (notably Ascomycota) was enriched and its efficient lignin-degrading network with bacteria species was formed. Taken together, our findings highlighted that nanoagents had either transient-stimulation or persistent-priming advantages, providing a tunable strategy for straw returning management. This work established a mechanistic framework for developing agri-nanotechnologies for sustainable agriculture and waste recycling.

[目的]探究油菜素内酯(BR)对越南安息香(东京野茉莉,Styrax tonkinensis)种子发育过程中脂肪酸合成相关酶活性及油脂积累的影响,为揭示外源油菜素内酯促进东京野茉莉种子脂肪酸合成和油脂积累的生理机制提供一定的理论和实践依据.[方法]以 10 年生东京野茉莉结实母树为研究对象,设置喷施 4 种浓度(1、5、10、20 μmol/L)油菜素内酯处理,记为BR1、BR5、BR10、BR20,以喷施蒸馏水为对照.分别于花后 45、65、95 和 125 d实施喷施处理,于花后 50、70、100 和 130 d取样,测定种实发育过程中的FAS(脂肪酸合成酶)、ACC(乙酰辅酶A羧化酶)、DGAT(二酰甘油酰基转移酶)活性,以及果实鲜质量和种子粗脂肪质量分数,分析不同浓度BR处理对东京野茉莉种实发育过程中脂肪酸合成相关酶活性及油脂积累的影响.[结果]BR处理对东京野茉莉种实发育过程中脂肪酸合成相关酶活性有显著影响.东京野茉莉种子FAS活性变化十分显著,在花后 50 d,各处理间的FAS活性较低,随后上升,到花后 100 d达到最大峰值,后缓慢下降.且在花后 100 d,BR5 和BR10 处理的FAS活性同时达到最大值,都为对照组的 1.8 倍,活性分别为 329.104 和 326.744 nmol/(min·mg).东京野茉莉种子的ACC活性在发育期呈现"上升—下降—上升"的趋势.在花后70d时,BR5 处理的ACC活性值达到波峰位置,活性为 20.50 nmol/mg,是对照组的 5.9 倍.在 4 个时期中不同处理的DGAT活性先上升后下降,在花后100 d达到最高峰,各BR处理明显高于对照组,其中BR5 处理后的DGAT活性达到最大值,为 6.03 nmol/mg,是对照组的 1.2 倍.BR处理对东京野茉莉种子FAS、ACC和DGAT活性总体上具有促进作用,以BR5 处理效果最为显著.在 4 个时期中,均以中等浓度的BR处理促进东京野茉莉种子粗脂肪质量分数的效果最佳;在花后 70 d,各处理下的种子粗脂肪质量分数存在显著性差异,BR5 处理下的种子粗脂肪质量分数显著地高于其他处理.不同浓度的BR处理后,东京野茉莉果实鲜质量总体上有所增加.除花后100 d外,其他时期以BR5 处理对果实鲜质量的增加效果最好.各处理的东京野茉莉种子脂肪酸合成相关酶活性与种子粗脂肪质量分数和果实鲜质量存在显著的正相关关系.[结论]FAS、ACC和DGAT活性动态变化表明,BR处理能够提高种子脂肪酸合成相关酶活性,促进种实发育过程中脂肪酸的合成.相关分析结果表明,东京野茉莉种子脂肪酸合成相关酶活性与果实鲜质量和种子粗脂肪质量分数存在显著正相关关系.

Styrax tonkinensis has great potential as a biofuel feedstock source having industrial oilseeds with excellent fatty acids (FAs) composition and good fuel properties. Photosynthesis in the developing pericarp could affect the carbon distribution in kernel. During kernel development, more carbon sources are allocated to starch rather than lipid, when the pericarp photosynthesis is reduced by fruit shading treatment. After shading the fruits at 50 days after flowering (DAF), samples of shaded fruit (FSK) and controls (CK) were collected at 80 DAF and analyzed using the proteomic method. We identified 3,181 proteins, of which 277 were differentially expressed proteins, all downregulated in the FSK group. There were 56 proteins found involved in carbohydrate metabolism and lipid biosynthesis leading to oil accumulation with their iTRAQ ratios of FSK/CK ranging from 0.7123 to 1.1075. According to the qRT-PCR analyses, the key genes related to FA and triacylglycerol (TAG) biosynthesis were significantly downregulated between 60 and 90 DAF especially at 80 DAF, while the key genes involved in starch biosynthesis and FA desaturase had no significant difference between the two groups at 80 DAF. Fruit shading is a negative treatment for lipid accumulation but not starch accumulation by restraining enzymic protein expression involved in FA and TAG biosynthesis during S. tonkinensis kernel development.

Background: Styrax tonkinensis is an economic tree species with high timber, medicine, oil, and ornamental value. Its seed, containing a particularly high oil content, are widely studied for their biodiesel properties by nutritional components and oil body ultrastructure. However, their comprehensive biochemical compositions have not been studied. Methods: During S. tonkinensis kernel development, we collected samples from four time points for metabolite profiling and classification through gas chromatography-mass spectrometry and liquid chromatography-mass spectrometry. Results: A total of 187 and 1556 metabolites were obtained, respectively. All of the metabolites were grouped into 19 and 21 classes by their chemical properties and into 8 clusters based on their change trends, respectively. Among all the metabolites, carboxylic acids and derivatives, flavonoids, fatty acyls, glycerophospholipids, organooxygen compounds, prenol lipids, and steroids and steroid derivatives were the main components. Alanine, glutamine, tryptophan, tyrosine and valine were the five most abundant amino acids. Palmitic acid, stearic acid, oleic acid and linoleic acid were the four major free fatty acids. Flavans, flavonoid glycosides and o-methylated flavonoids were the three major flavonoids. The differential metabolites distributions between different time points were identified. A pathway enrichment was performed, which was mainly focused on three groups, amino acids metabolism, carbon flow from sucrose to lipid and secondary metabolites biosynthesis. Conclusions: It’s the first time to analyze the metabolite fingerprinting for developing S. tonkinensis kernels and identify varied kinds of flavonoids. We performed metabolite profiling, classification and pathway enrichment to assess the comprehensive biochemical compositions. Our results described the change in major metabolites and main metabolic processes during S. tonkinensis kernel development and provided a variety of bases for seed applications as biofuel or medicine.

系统性地分析了野茉莉属主要油料树种的种子含油率、油脂脂肪酸组成及燃料特性.研究测定了野茉莉属8个油料树种种子的形态指标、含油率、油脂脂肪酸组成及理化性质,并预估其脂肪酸甲酯理化性质.结果表明:野茉莉属8个油料树种种子含油率为22.24％ ～ 54.86％,其油脂脂肪酸碳链长度主要介于C14 ～ C20,主要组分为油酸和亚油酸;油脂碘值(Ⅰ)为114.16 ～ 124.34g/100 g,皂化值(KOH)为159.89 ～168.98mg/g;脂肪酸甲酯运动黏度为3.55～3.60 mm2/s,十六烷值为48.87～50.73,密度为862.88 ～ 864.58 kg/m3,高热值为40.67～41.10 kJ/g,冷滤点为-6.70～-1.54℃;通过主成分分析将8个树种分为3大类.通过综合分析,野茉莉属8个油料树种均可作为非粮柴油植物的初步筛选树种.