Understanding the mechanisms driving soil organic carbon (SOC) accumulation is critical for deciphering terrestrial carbon cycling and advancing sustainable soil management. However, microbial metabolism is recognized as a central regulator of SOC dynamics, the specific roles of carbon (C) and phosphorus (P) metabolic pathways in shaping SOC accumulation under contrasting agricultural management practices remain poorly understood in tea agroecosystems. In this study, we systematically evaluated the impacts of organic versus conventional management on soil C:N:P stoichiometry, microbial metabolic constraints, and carbon use efficiency (CUE) across three Wuyi Rock tea cultivars (Shuixian, Gaocong Shuixian, and Rougui) in subtropical China. Organic management universally enhanced dissolved organic carbon availability across cultivars. However, it also induced microbial P limitation in Shuixian and Gaocong Shuixian, driven by lower soil available phosphorus (SAP) to dissolved organic carbon (DOC) ratios. Conversely, conventional management alleviated P limitation but intensified C limitation in Shuixian through accelerating C mineralization. CUE exhibited nonlinear responses to stoichiometric imbalances. Organic management promoted higher CUE in Rougui through optimized SOC:total P (TP) ratios and reduced beta-1,4-glucosidase (BG) to alkaline phosphatase (AP) enzyme allocation. Conversely, Shuixian under organic management showed diminished CUE due to disproportionate investments in C-acquisition enzymes (e.g., BG, cellobiosidase). Structural equation modeling identified soil moisture and DOC as primary drivers of microbial C and P limitation, respectively. Intriguingly, microbial stoichiometric homeostasis (H-'>1.5) maintained stable microbial biomass C:P ratios under resource fluctuations. However, prolonged organic management disrupted this homeostasis in Rougui, concomitant with intensified P limitation. While organic management altered SOC dynamics, its effect on total SOC concentration was cultivar-specific and was associated with a C-nutrient accessibility trade-off whereby elevated C storage constrained microbial nutrient acquisition efficiency. These findings highlight the critical role of C:N:P stoichiometry in regulating microbial energy partitioning and reveal trade-offs between SOC dynamics and nutrient accessibility under contrasting management, providing a theoretical foundation for designing balanced soil management strategies that optimized both C storage and microbial metabolic efficiency in tea agroecosystems.

Plant-associated microbiomes play critical roles in regulating plant growth, nutrient acquisition, and stress adaptation. However, whether geographically distinct plant provenances retain heritable signatures that influence microbiome assembly under uniform environmental conditions remains poorly understood. In this study, 16S rRNA amplicon sequencing was employed to characterize root-associated bacterial communities of clonally propagated Tripterygium wilfordii derived from nine provenances and cultivated under identical soil conditions, with additional sampling from native populations. Host provenance significantly affected community composition, explaining 27.0% and 32.6% of the variation in rhizosphere and endophytic communities, respectively. Rhizosphere bacterial diversity differed significantly among provenances, whereas endophytic communities showed stronger differentiation in community structure and deterministic host selection. Although native plants exhibited lower bacterial diversity, they recruited more potential plant growth-promoting bacteria compared with transplanted plants. Environmental factors, particularly historical mean annual precipitation and longitude of native habitats, significantly influenced community diversity and structure. Distance–decay patterns demonstrated that root-associated bacterial communities retained climatic imprints from their native provenances despite cultivation under common-garden conditions. This study provides evidence that plant provenance can leave persistent microbial signatures and highlights the importance of integrating host genetic background and microbiome characteristics to understand ecological adaptation and improve germplasm utilization in medicinal plants.

Plant-associated microbes play a crucial role in host growth, health, and stress resistance. Host plants significantly influence the assembly of their microbial communities. To examine the influence of plant provenance on bacterial composition and plant growth promoting (PGP) properties, we compared readily culturable bacteria isolated from the root interior and rhizosphere of Tripterygium wilfordii Hook f., a woody Chinese medicinal plant, across three provenances grown in different regions. Regardless of the host growing environment, the abundance of endophytic bacterial colonies followed the trend: Fujian provenances > Hunan provenances > Hubei provenances. A total of 227 isolates were classified into 21 genera from the root interior and 40 genera from the rhizosphere, with Pseudomonas and/or Bacillus as the dominant genera. The taxonomic composition varied across plant provenances and host growing environments. Plants from the same provenance but cultivated in different locations exhibited greater similarity in their endophytic bacterial composition. The majority of the assayed strains displayed one or more PGP traits. Local plants harbored a higher proportion of PGP strains than non-local plants. Our findings indicate that plant provenance significantly influences the composition of root-associated culturable bacteria, particularly endophytic communities. Plants in their native environments may recruit PGP bacteria to enhance their fitness.

Sprawling road networks cutting through forested areas continue to be a potent catalyst of deforestation in tropical regions. Yet, pantropical assessments limited by the lack of high-resolution global maps of tropical forest loss induced by road networks. Here, we harnessed the road dataset from the Global Roads Inventory Project and the forest loss dataset from Global Forest Change, to produce global tropical high-resolution maps of road impact index spanning 2001 to 2020. We find that the forest area within a 1-km distance from roads accounts for about one-sixth, but its proportion of forest loss is nearly one-third, the road impact index is 2.45 times higher than those beyond the zone. The road impact index of all countries shows a decreasing trend with the distance from roads and increasing from 2001 to 2020. Our findings emphasize the urgent need for globalized efforts to protect the intact forests and rehabilitate degraded forests along roadside.

Elucidating changes in the structure and function of plant communities along different elevation ranges will help researchers to analyze the strategies plant communities use in environments and processes influencing niche differentiation. The aims of this paper are to reveal the underlying mechanisms and ecological processes governing the development of subtropical forest ecosystem plant communities. This paper analyzes the forest vegetation of the Wuyi Mountains across the following three elevation ranges: low elevation, mid elevation, and high elevation, spanning from 560 to 2150 m. Twenty and twenty-three dominant tree and shrub layer species, respectively, were identified based on their importance values, and their niches and species associations were further analyzed based on the elevation range. The results showed interspecific associations between tree and shrub species, with the strongest associations observed at mid-elevations. The analysis of niche width and overlap showed that the number of pairs of species with a higher degree of niche overlap decreased with increasing elevation, suggesting that resource use varied at different elevations for both tree and shrub layer species, which may be related to the adaptive capacity of plants at different elevations to the environment and resource use strategies. These findings should contribute to a deeper understanding of the ecological functioning and structural framework of plant communities on Wuyi Mountain.

【Objective】 This study explored new method accounting for economic value of forest assets, solved the problems existing in evaluation of forest resource assets, and calculated the price of forest assets scientifically, reasonably and fairly to provide support for precise evaluation of forest resources assets.【Method】 Artificial C. lanceolata,artificial P. massoniana,natural P. massoniana,artificial hard broad-leaved tree, natural hard broad-leaved tree and artificial Eucalyptus were selected to construct a forest price evaluation model with variable interest rate using the harvest present value method and Korf stock growth equation.The measured sample data were used to estimate parameters by MATLAB,and the residual standard deviation（SEE）,total relative error（TRE）,average systematic error（MSE）,mean relative error absolute value（MPSE） and mean prediction accuracy（MPE） were selected to evaluate model applicability.The results from the constructed model with a fixed interest rate of 4% were compared with those from traditional evaluation methods such as replacement cost method, income present value method and market price inversion algorithm.【Result】（1） The constructed volume growth model for the six tree species（groups） had SEE and MPSE of less than 10%,TRE and MSE of within ±10% and MPE of less than 3%,indicating high model accuracy and suitability for evaluation of forest resources assets.（2） Through iterative calculation, the interest rates of artificial C. lanceolata,artificial P. massoniana,natural P. massoniana,artificial hard broad-leaved tree, natural hard broad-leaved tree and artificial Eucalyptus were 7.5%,6.6%,5.7%,5.8%,5.3% and 7.9%,respectively.（3） Compared with traditional evaluation methods, the prices of six tree species（groups） calculated by the constructed model of arbor forest increased with the increase of stand age, which was in line with the normal relationship between forest price and age.（4） The forest prices of different age groups calculated by the constructed model showed that the old group had large prices than the young group.The forest prices calculated by the model with fixed interest rate showed unreasonable upside down results except for artificial C. lanceolata and artificial Eucalyptus with less mature ages.【Conclusion】 The price evaluation model of arbor forest with variable interest rate solved the problem of inconsistent evaluation results due to different evaluation methods and achieved compatible results with the replacement cost method, harvest present value method and market price inversion algorithm.

Long-term monocultures of tea and the excessive use of chemical fertilizer lead to the degradation of soil quality. Improving the soil quality of ex-tea plantations through vegetation restoration is an important task. However, the changes in soil nutrients, fungal communities, and the effects of microorganisms on soil nutrients after reforestation remain unclear. Therefore, in this study, we aimed to explore the effects of Pinus and Chinese fir on soil nutrients and fungal communities in ex-tea plantation areas that were subjected to the reforestation modes of pure forest and mixed forest by measuring soil chemical properties and ITS rRNA gene sequences. The results showed that (1) after reforestation, the relative normalized difference vegetation index (NDVI) of the Mixed forest, Mixed Pine and Mixed Fir areas increased (p < 0.05) compared to that of pure forest; (2) the soil organic carbon (SOC), total nitrogen (TN), and N:P ratios of the mixed forest increased by an average of 54%, 90%, and 299% (p < 0.05) compared to pure forest, whereas the total phosphorus (TP) and available potassium (AK) decreased by an average of 39% and 89% (p < 0.05); and (3) there was no significant difference in the diversity of the fungal communities of the pure and mixed forests, but the fungal phyla Mucoromycota, Glomeromycota, and Rozellomycota were significantly different in the pure and mixed forests. This differing microbial composition led to a significant increase (p < 0.05) in symbiotrophs (ecotomycorhizal, ericoid mycorhizal) in the mixed forest, which was negatively correlated with the soil TP and positively correlated with the TN and the N:P ratio. In addition, there was also a significant decrease (p < 0.05) in complex nutrient types (ectomycorrhizal-fungal parasite-plant saprotroph-wood saprotroph), which were negatively correlated with the SOC and TN, and arbuscular mycorrhizas, which were positively correlated with the TP. Our results show that the chemical properties of soils and the structure of the fungal communities changed significantly due to the reforestation of Chinese fir and Pinus, and the mixed forest mode of reforestation was more conducive to improving the soil quality; therefore, a mixed forest of Chinese fir and Pinus can be used to improve degraded soils in ex-tea planting areas.

参考沿海防护林高盐低磷的实际情况,设置0(N0)、2(N1)、4(N2)、6(N3)和8(N4)g?kg-1 NaCl 5 个单一处理组以及N2-P1[0.5 g?kg-1 Ca(H2 PO4)2]、N2-P2[1.5 g?kg-1 Ca(H2 PO4)2]、N3-P1、N3-P2、N4-P1 和N4-P2 6 个复合处理组,研究不同浓度NaCl单一胁迫及NaCl胁迫下施磷对台湾相思(Acacia confusa Merr.)幼苗干物质积累、根形态及营养元素含量的影响.结果显示:总体上看,NaCl单一胁迫及低浓度(4 g?kg-1)NaCl胁迫下施磷均会明显减少台湾相思幼苗根干质量、总干质量、总根长、总根表面积和总根体积;中浓度(6 g?kg-1)NaCl胁迫下施磷对幼苗干物质积累和根形态的改善效果不显著,但施 1.5 g?kg-1 Ca(H2 PO4)2 后幼苗根干质量和总干质量高于NaCl单一胁迫.从不同级别根直径(D)看,低径级(0.0 mm＜D≤0.5 mm)的根对NaCl单一胁迫较为敏感,且在低浓度NaCl胁迫下施磷后受抑制更加明显;而高径级(D＞5.0 mm)的根对NaCl单一胁迫有一定抗性,中浓度NaCl胁迫下施磷后的总根长、总根表面积和总根体积明显高于 NaCl 单一胁迫.与对照[0 g?kg-1 NaCl,0.0 g?kg-1 Ca(H2 PO4)2]相比,NaCl单一胁迫及NaCl胁迫下施磷会使根中Na含量明显增加,其他 7 种元素含量总体下降.高浓度(8 g?kg-1)NaCl胁迫导致幼苗死亡,而施磷后幼苗对NaCl胁迫有一定的抵抗作用,其中以施 0.5 g?kg-1 Ca(H2 PO4)2的效果较好.相关性分析结果显示:NaCl单一胁迫下台湾相思幼苗根中P含量与总根长、根尖数、根分枝数和根组织密度呈显著或极显著正相关,与平均根直径呈显著负相关;NaCl胁迫下施磷后幼苗根中Mn和K含量与根干质量、总干质量、总根长、总根表面积和总根体积均呈显著或极显著正相关.综上所述,在沿海种植台湾相思幼苗时,建议低盐土壤不施磷,中高盐土壤可根据具体土壤盐胁迫程度添加磷,同时适量添加Mn和K.

The paper studied the influence of peatmass change and water level on forest regeneration after a fire in U Minh Thuong National Park.It measured the peakmass before and after a fire in the study area, used t-tests and one-way analysis of variance to analyze forest growth in different thickness of peat and gave the relationship between peak chemical and growth of melaleuca forest after a fire.However,there are some problems, which must be solved.Some sentences contain grammatical mistakes or are not complete sentences, such as, in page 2, MATERIAL AND METHODS as well as at least one Spelling errors,such as, in Line 111, "D1.3' would be "D1.3"and format error, such as, in Line160-161, " SO4+" would be "SO4+".Also the figure information is wrong for this paper in L126 as well as not clear figure.In addition, the formular is error in L148.There are so many errors smilar to the above.Your manuscript needs careful editing and particular attention to English grammar, spelling, and sentence structure, especially in Material and Methods.The writing attitude should also be improved.

In order to solve the problem in that the classical forest land expectation value method ignores the actual forest stock volume when assessing the income at the end of the current production cycle in the forest, and fill the research gap in this area, the technical system of the forest land asset evaluation was enriched. The forest land returns were divided into two parts, i.e., the segmented forest land return price from the growth of the actual forest stand to the end of the growth cycle (Bu1), and the segmented forest land return price for an infinite number of growth cycles after the growth of the actual forest stand to the end of the growth cycle (Bu2). Through structure, the forest land gain price expansion model was obtained, and the stand quality including the average diameter at breast height, average height, stock volume, and outturn of stand as dummy variables were used to construct the growth harvest model related to asset evaluation. Taking Cunninghamia lanceolata forest land as an example, the traditional asset evaluation methods were comparatively analyzed. The residual standard deviation (RSD) of the growth model was less than 10%, the total relative error (TRE) and mean system error (MSE) were within ±10%, the mean prediction errors (MPE) were less than 5%, and the mean percentage standard errors (MPSE) were less than 10%, respectively. Combining the forest land net present value expansion model with the traditional evaluation method, the evaluation value of the forest land assets was subsequently calculated, and accordingly, the forest land asset evaluation prime stand factors were predicated. It was found that the valuation results of the forest land net present value expansion model were consistent with the actual situation. The forest land net present value expansion model can therefore be used for asset evaluation of tree forest land (including natural uneven-aged forest land), bamboo forest land, shrub forest land, and economic forest land, and provide new technical support for forest land asset evaluation.

为明晰不同解磷菌株对杉木(Cunninghamia lanceolata)幼苗光合特性的影响,探讨利用解磷菌提升杉木光合能力的可能,以 1 年生杉木无性系扦插幼苗为研究对象,以 2 株不动杆菌属(Acinetobacter)高效解无机磷菌株WP1 和WP10 及 1 株克雷伯氏菌属(Klebsiella)高效解有机磷菌株YP9 为供试菌株,采用盆栽土培实验,分析不同菌株及组合处理在接菌 30,120 和 210 d后,杉木幼苗光合色素质量分数、叶绿素荧光参数、叶片丙二醛含量、超氧化物歧化酶活性和可溶性糖质量分数的变化趋势,以明确不同解磷菌促进杉木幼苗生长的潜力.结果表明:1)不同菌株处理均对杉木幼苗光合色素的产生具有促进作用,且混菌株处理优于单菌株处理(P<0.05),尤其是三菌株混合处理的促进作用更显著,其叶绿素a和类胡萝卜素质量分数于 120 d时达到最高,而叶绿素b质量分数和叶绿素a/b质量分数比值分别于210 d时和 30d时达到最高;2)各菌株处理下的初始荧光(Fo)显著小于对照处理(P<0.05),其中三菌株混合处理的最低,而最大荧光(Fm)、可变荧光(Fv)和潜在光化学效率(Fv/Fo)显著高于对照处理(P<0.05);3)混菌株处理的最大光化学效率(Fv/Fm)与叶绿素a/b质量分数比值相关性不显著,三菌株混合处理及WP1 和WP10 菌株混合处理的Fv/Fo和Fv/Fm 相关性不显著,而所有菌株处理的叶绿素a/b质量分数比值和Fv/Fo 均呈显著负相关(P<0.05);4)混菌株处理的杉木幼苗叶片丙二醛含量显著低于单菌株处理,而超氧化物歧化酶活性和可溶性糖质量分数显著高于单菌株处理(P<0.05).上述结果表明 3 株解磷菌混合处理能促进叶绿素收集传递光能,减少光合系统受到的损伤,使杉木幼苗适应生长环境并增强其生存竞争能力.

Aims Endophyte is a new microbial resource, which has a complex micro-ecological relationship with plants. In this paper, the antagonistic effect of endophytic fungi on the growth of salt-tolerant plants was confirmed by adding endophytic fungi to the plants and testing the physiological characteristics and biomass of the seedlings.Methods Two salt-tolerant endophytic fungi Botryosphaeria Z1（T3）, Hypoxylon Y6（T4）, and their mixture（T2） were cultured in solid fermentation and added to potted soil planted with seedlings of Casuarina equisetifolia at different salinity（mass fraction: 0, 3‰, 6‰ and 9‰）, which were treated with an added fungal of seedlings.The addition of microbiological medium（T1） and no added microbiological medium（CK） were treated as two experimental controls, which was to confirm the effect of the fungal, but not the microbiological medium.Samples were taken at 15 day intervals, four times, for a total of 60 days, and the relative electronic conductivity（REC）, malondialdehyde（MDA）, soluble sugar（SS）, soluble protein（SP）, proline（PRO）, superoxide dismutase（SOD）, peroxidase（POD）, catalase（CAT）, reactive oxygen（H 2 O 2 ） of leavesand the biomass of seedling were determined each time.Important findings We found that the biomass of seedlings treated by fungal strain was significantly increased under salt stress, and the physiological characteristics were significantly affected by soil salinity, time and fungal species. At 3‰ salinity, the content of SS and SP, and the activity of SOD and CAT were higher in T2 treatment than in CK and T1 after 15 days of treatment, but the REC was significantly lower in T2, T3 and T4 treatments during the stress period. At 9‰ salinity, T2 treatment significantly reduced the REC and the content of H 2 O 2 and MDA, but significantly increased the content of SS and the activity of SOD and CAT. Especially, SP content and POD activity were also significantly increased in T2 treatment after 60 days. A stepwise regression was used to model the relationship between physiological characteristics and biomass of seedlings treated with the strains, and the path analysis showed that REC, POD and SS were the main physiological factors affecting biomass. In conclusion, the effects of different fungus on the content of osmoregulatory substances, oxidase activity and biomass of seedlings were different, and the antagonistic effect of the mixed fungus was the most obviously. Thus, the relationship between osmotic regulatory substances, antioxidant enzymes, biomass and endophytic fungi of Casuarina equisetifolia under salt stress was clarified, which provided a basic for the further study on the stress resistant engineering fungi for Casuarina equisetifolia.

为探究种间竞争对木麻黄和台湾相思生长的影响,利用相邻混植和独立盆栽试验测定木麻黄和台湾相思生长和养分含量的变化,分析两者的种间竞争差异.结果表明,混植对木麻黄树高和根冠比影响显著(P<0.05),但对地径无显著影响(P>0.05).与单植栽培方式相比,混植栽培方式下木麻黄树高和地上生物量分别增加57.28％、20.92％,而根总长、根总表面积以及根总体积分别减少62.67％、51.25％和285.19％;混植对台湾相思树高影响显著(P<0.01),对其地径、根冠比无显著影响(P>0.05);在混植栽培方式下,台湾相思树高、地径、总生物量、根总长、根总表面积以及根总体积分别减少119.17％、17.72％、35.75％、11.15％、33.79％和44.62％.根系在磷信号刺激下,仅有台湾相思L4和SA4径级增加;木麻黄叶中Na含量降低81.63％,而P元素和K元素分别增加11.38％、12.30％,根中Na、P、K元素含量分别减少26.17％、28.29％和21.45％.台湾相思叶中Na、K元素含量分别降低6.23％、7.78％,P元素增加7.55％,根中Na、P、K元素含量分别增加24.81％、22.05％、24.53％.木麻黄和台湾相思在混植栽培方式下,均通过改变自身形态或营养成分抑制对方,说明邻株竞争可以改变沿海人工林中植物的适应性和群落结构,也表明植物根系在邻株竞争中存在重要作用.因此,研究结果可为沿海防护林的更新恢复和经营管理提供理论指导.

Acacia confusa is an important species in coastal shelter forests. In order to explore the effects of salt and phosphorus fertilization on leaf photosynthesis and nutrient characteristics of the seedlings. NaCl solutions were configured in the concentrations of 0% (B0), 0.2% (B1), 0.4% (B2), 0.6% (B3) and 0.8% (B4), and superphosphate solutions in the concentrations of 0 g·kg-1(P0), 0.5 g·kg-1(P1), and 1.5 g·kg-1(P2). The photosynthesis and nutrient characteristics of the seedlings were determined after being watered by the six combined solutions of salt-phosphorus coupling fertilization. The results were as follows: (1) Salt stress significantly inhibited the growth and development of the seedlings, and the higher the salt content, the greater the effect. Phosphorus application under low-salt stress was unfavorable to the growth of the seedlings, while phosphorus application under medium-high one significantly slowed down the inhibition of the seedling growth. (2) The greater the salt stress, the higher the effects on the photosynthesis of the seedlings. The stomatal closure degree of phosphorus application increased under low and medium salt stress, which aggravated the effect of salt stress on photosynthesis of the seedlings. Appropriate phosphorus application under high-salt stress could significantly improve the photosynthetic capacity of the seedlings. (3) Salt stress significantly reduced chlorophyll content and caused harm to photosystem II. Phosphorus fertilization on the seedlings under low-salt stress had adverse effects on chlorophyll synthesis. Appropriate fertilization of phosphorus in high-salt stress could increase chlorophyll synthesis, stabilize cell membrane structure, and improve the potential photosynthetic capacity of leaves. (4) Salt stress had strong interference on the contents of Fe, Mn, Na, Cu and other metal elements in leaves. Phosphorus application under salt stress could effectively promote the absorption of some elements by seedlings. In conclusion, phosphorus application after salt stress can improve the photosynthesis and nutrient absorption ability of A. confusa seedlings on the whole. The results provides a theoretical basis for improving the salt tolerance and phosphorus utilization rate of A. confusa, and have guiding significance for the sustainable management of coastal shelter forests.

In order to clarify the combined impact of tree species composition, site quality, and stand age on the growth and harvest of mixed forests, the prediction models of average DBH and stand volume for mixed forests were established, respectively. The interval period and tree species composition coefficient (TSCC) were considered as independent variables. These models were then optimized by using the particle swarm optimization algorithm for reparameterization and evaluating their applicability. It was found that after introducing the site quality grade and TSCC, the average stand height prediction model showed a better fitting result. The fit accuracy of the average DBH prediction model and the stand volume prediction model were both improved with the help of the TSCC, mainly because the tree species composition affects the growth rate of the average stand height and average DBH and the maximum growth rate of the stand volume. The degree of the impact can be sorted as Cunninghamia lanceolata > Pinus massoniana > hard broad-leaved tree species (group). Overall, the established growth and harvest prediction models for mixed forests with the interval period and TSCC as independent variables have high fit accuracy and applicability.

对5种丛生竹叶片的光响应参数进行测定,并利用4种光响应模型进行数据拟合.结果显示:4种模型的拟合曲线与实测曲线较为接近,R2值为0.92～0.99,表明4种模型的拟合程度均较高.不同模型对最大净光合速率(Pmax)、光饱和点(LSP)、光补偿点(LCP)和暗呼吸速率(Rd)的拟合结果存在差异,其中,采用直角双曲线修正模型,5种丛生竹的Pmax拟合值与实测值最接近,而采用其他3个模型,5种丛生竹的Pmax、LSP、LCP和Rd拟合值大多与实测值存在一定差距.4种模型中,直角双曲线修正模型的拟合效果总体较好,可作为丛生竹的最优光响应曲线拟合模型.

解磷微生物能够活化土壤中的难溶性磷,筛选杉木(Cunninghamia lanceolata)根际高效解磷菌对于缓解南方红壤区杉木人工林土壤的磷素受限问题具有重要现实意义.以南方红壤区不同林龄(2,4,10,15 a)杉木人工林下的根际土壤为研究对象,通过平板分离初筛菌株、液体发酵复筛菌株和16S rDNA测序,筛选、鉴定高效根际解磷菌,采用单因素实验和正交试验确定高效解磷菌的最优培养条件.实验结果表明:1)15 a杉木根际土壤的解无机磷菌与解有机磷菌数量分别为3.64×105和2.14×105 cfu/g,均显著高于其他林龄(p<0.05),且各林龄解磷菌类型间存在显著差异(p<0.05);2)筛选出25株解无机磷菌和20株解有机磷菌,经平板初筛、液体发酵复筛和16SrDNA测序鉴定,分别得到一株解磷效果显著(p<0.05)的解无机磷菌株W1(溶磷量238.08μg/mL,不动杆菌属(Acinetobacter sp.))和解有机磷菌株Y9(溶磷量15.04μg/mL,克雷伯氏菌属(Klebsiella sp.));3)优化后W1的最佳培养条件为1.0％(质量分数)葡萄糖、1.50％(质量分数)酵母粉、初始pH 7.5、装液量30 mL、接种量3％(体积分数)、温度40℃,Y9的最佳培养条件为0.5％葡萄糖、1.25％酵母粉、初始pH 6.0、装液量20 mL、接种量9％、温度28℃.上述结果可为杉木根际解磷微生物的开发利用提供数据支持.

为阐明光强与酸雨及其交互作用对常绿阔叶树种幼苗生长的影响,在100％自然光(L1)、50％自然光(L2)和20％自然光(L3)3种光环境下分别设置对照(pH值7.0,ACK)、重度酸雨(pH值2.5,A1)、中度酸雨(pH值4.0,A2)及轻度酸雨(pH值5.6,A3)等处理,测定和分析木荷幼苗苗高、地径和各器官生物量.结果表明:胁迫150 d后,光强对木荷幼苗苗高和地径有极显著影响(P<0.01);酸雨仅对地径有显著影响(P<0.05),光强和酸雨对苗高和地径无明显交互作用.光强对木荷幼苗各器官生物量有极显著影响(P<0.01),遮阴总体抑制了幼苗生长;酸雨仅对幼苗叶和茎生物量产生极显著影响(P<0.01),光强和酸雨对叶生物量具有显著(P<0.05)的交互作用,而对茎生物量有极其显著(P<0.01)的交互作用;重度酸雨(A1)在3种光环境下分别显著降低了48.8％、13.8％和32.2％的茎生物量,却分别提高了24.4％、37.0％和7.6％的叶生物量.光强、酸雨和其交互作用均对茎重比和茎根比有极显著影响(P<0.01).综上所述,酸雨对苗木早期生长是抑制还是促进作用取决于其所处的光环境、pH值和器官,适度遮阴下酸雨促进效应明显.

虚拟地理环境平台技术的发展,为地理学过程的再现表达、集成建模、模拟预测提供技术支撑,也为区域分析与区域地理课程教学时面临的全局认识实践、抽象的区域地理概念与过程、教学资料的补充与拓展、教学理念的更新等提供新机遇.分析地理学虚拟仿真教学平台建设的研究现状与问题,归纳总结课堂虚拟仿真建设的意义,探讨区域分析与区域地理虚拟仿真建设的环境要素与框架,提出虚拟仿真教学平台4个子环境(数据环境、建模及模拟环境、交互环境和协同环境)建设的建议,并给出基本的建设框架和课程教学模式,以期为虚拟区域地理环境平台的研制与开发提供参考,并为学生学习表达地理环境、发现区域问题、总结区域规律、再现和模拟区域现象提供平台支撑.