亚热带人工林下植被根际土壤酶化学计量特征

为探讨林下植被根际土壤酶化学计量特征及其对林分类型和季节的响应,该研究以江西省泰和县千烟洲试验站典型人工杉木(Cunninghamialanceolata)、马尾松(Pinusmassoniana)和湿地松(Pinuselliottii)林林下优势灌草檵木(Loropetalum chinense)、杨桐(Adinandra millettii)、格药柃(Eurya muricata)、狗脊蕨(Woodwardia japonica)和暗鳞鳞毛蕨(Dryopteris atrata)为对象,在植被生长初期(4月)和旺盛期(7月)测定优势灌草根际土壤与碳(C)循环相关的β-1,4-葡萄糖苷酶(BG)、与氮(N)循环相关的β-1,4-N-乙酰葡糖氨糖苷酶(NAG)和亮氨酸氨基肽酶(LAP)、与磷(P)循环相关的酸性磷酸酶(AP)活性、酶化学计量比及土壤理化性质。结果发现:(1)根际土壤与C和N循环相关的酶活性以及BG:AP(酶C:P)在不同林下植被之间存在显著差异,而与P循环相关的酶活性差异不显著。林分类型和取样季节显著影响BG:(NAG+LAP)(酶C:N),且林下植被类型、林分类型和取样季节交互影响酶C:P。主成分分析表明,根际土壤酶的活性及计量比在不同林下植被(檵木不同于格药柃,且二者显著区别于其他物种)、林分类型(杉木林区别于马尾松、湿地松林)和取样季节之间均存在显著差异。土壤硝态氮(NO_3~--N)、铵态氮(NH_4~+-N)、可溶性有机碳(DOC)含量和碳氮比(C:N)是影响林下植被根际土壤酶的活性及化学计量比的主要因素。(2)标准主轴回归分析表明,林下植被根际土壤lg(BG)、lg(NAG+LAP)和lg(AP)之间存在显著线性关系,lg BG:lg(NAG+LAP):lg AP(酶C:N:P)约为1:1:1.3,酶C:P及(NAG+LAP):AP(酶N:P)分别为0.14和0.15。AP远大于BG和NAG+LAP的活性,导致lg(BG)和lg(NAG+LAP)与lg(AP)的回归斜率极显著偏离1。说明林下植被根际土壤酶的活性及计量比受植被种类、林分类型及取样季节影响,且基质有效性在其中发挥重要作用。相较于C循环和N循环,微生物会分配更多资源用于P循环相关酶的生产,暗示亚热带人工林林下植被根际土壤微生物生长和活性更易受P限制。     

辽东栎林次生演替过程中土壤酶化学计量特征变化

土壤胞外酶驱动地下生态系统的养分循环等过程,而目前土壤酶活性随着植被次生演替的变化机制尚不明确。本文采用空间代替时间的方法,选取陕西富县的农田为对照,研究了30、60和120年生辽东栎林土壤酶活性及其化学计量的变化以及驱动因子(植被特征、土壤物理化学特征、微生物生物量)。结果表明：随着演替的进行,β-1,4-葡萄糖苷酶(BG)、β-N-乙酰氨基葡萄糖苷酶(NAG)及亮氨酸氨肽酶(LAP)活性显著增加,而碱性磷酸酶(AP)活性先增加后减小然后再增加,在120年生林地达到最大值,BG、LAP+NAG及AP酶活性分别为25.96～40.96、57.10～128.05、65.41～126.60 nmol·g^-1·h^-1。农田土壤的BG/(LAP+NAG)和BG/AP大于30年生林地,而(LAP+NAG)/AP呈相反的趋势。农田土壤微生物代谢主要受C和P养分的限制;而随着演替的进行,BG/(LAP+NAG)逐渐增加,(LAP+NAG)/AP和BG/AP先增加而后减小,从而缓解C和P养分对微生物代谢的限制,但造成N养分限制。冗余分析表明,土壤微生物量P、...     

大兴安岭北部不同海拔天然林土壤胞外酶化学计量特征及其季节动态

研究了大兴安岭北部奥克里堆山不同海拔(750～1420 m)天然林土壤胞外酶活性(EEA)和酶计量比的变化特征及影响机制。结果表明: 海拔、季节及其交互作用对β-葡萄糖苷酶(BG)、N-乙酰-β-氨基葡萄糖苷酶(NAG)、亮氨酸氨基肽酶(LAP)和酸性磷酸酶(AP)活性均存在显著影响。5月,BG和NAG活性随海拔升高呈逐渐增大趋势,AP活性随海拔升高呈先升高后降低的趋势。7月,NAG活性随海拔升高而增大,AP活性则先升高后降低。9月,不同海拔上NAG活性变化幅度较大,在1420 m处活性最高,为124.22 nmol·h^-1·g^-1。随着海拔的升高,酶化学计量比ln(BG)∶ln(NAG+LAP)呈降低的趋势。除海拔830 m外,7月化学计量比值最高。土壤C、N、P转化酶活性对数转换后的比值为1∶1.25∶0.82。海拔和土壤温度是影响土壤胞外酶的主要因素,土壤温度与BG、NAG和AP呈显著正相关。ln(BG)∶ln(NAG+LAP)和ln(NAG+LAP)∶ln(AP)与pH分别呈显著正相关和负相关,与DOC分别呈显著负相关和正相关,而ln(BG)∶ln(AP)受土壤容重的影响较大。     

凋落物添加和移除对杉木人工林土壤水解酶活性及其化学计量比的影响

土壤生态酶化学计量比可用于评估微生物碳(C)、氮(N)和磷(P)养分的需求状况。以往从凋落物输入量变化对生态酶化学计量比的角度来探讨杉木人工林土壤养分状况的研究较少。以亚热带杉木人工林为研究对象,采用随机区组实验设计,对12块杉木人工林样地进行3种凋落物处理(凋落物添加(LA);凋落物移除(LR);对照(CK)),通过测定土壤C、N和P水解酶(β-葡糖苷酶(BG)、半纤维素酶(CB)、β-乙酰葡糖胺糖苷酶(NAG)、亮氨酸氨基肽酶(LAP)和酸性磷酸酶(AP))的活性及土壤理化性质,探讨凋落物添加和移除对杉木人工林土壤养分状况的影响。结果表明:LR显著抑制了AP、BG、CB、NAG和LAP活性,同时降低了土壤含水量(SMC)、有机碳(SOC)、总氮(TN)、总磷(TP)和有效氮含量;而LA对以上指标均存在显著的正效应,表明凋落物输入量变化主要是通过改变土壤水分和养分状况来影响水解酶的活性。LR和CK处理下土壤酶活性比ln(BG+CB):ln(AP)和ln(NAG+LAP):ln(AP)均低于全球尺度上土壤酶活性比ln(BG+CB):ln(AP)(0.62)和ln(NAG+LAP):ln(AP)(0.44),表明亚热带地区杉木人工林土壤微生物生长受磷限制;LA处理的土壤的ln(BG+CB):ln(AP)和ln(NAG+LAP):ln(AP)均高于全球尺度,表明LA在一定程度上缓解了土壤磷限制,生态酶化学计量比响应的差异表明磷可能是驱动亚热带杉木人工林土壤生态酶化学计量比内在联系的关键因子。相关分析表明SMC、SOC和有效氮含量与土壤酶活性及其化学计量比呈极显著正相关关系,因此,生态酶化学计量比可作为表征土壤当前养分有效性状况的重要指标,该研究可为亚热带杉木人工林土壤养分管理和可持续性经营提供科学的基础理论。     

中亚热带典型人工林土壤酶活性及其化学计量特征

以中亚热带典型的马尾松林、湿地松林和马尾松-木荷混交林(针阔混交林)为研究对象,分析不同林分类型下0～10和10～20 cm土层的β-D-葡萄糖苷酶(BG)、β-N-乙酰氨基葡萄糖苷酶(NAG)、亮氨酸氨基肽酶(LAP)、酸性磷酸酶(AP)、多酚氧化酶(POX)、过氧化物酶(POD)6种土壤酶活性,以及酶化学计量比及土壤理化性质特征,分析驱动中亚热带典型林分类型土壤酶活性及其计量比变异的主要因素。结果表明: 林分类型显著影响了土壤BG和LAP活性,表现为湿地松林10～20 cm土层土壤BG显著高于马尾松林,而LAP在马尾松林最高;湿地松林10～20 cm土层土壤BG/(NAG+LAP)、BG/AP显著高于马尾松林,而马尾松林(NAG+LAP)/AP显著高于湿地松林和针阔混交林;林分类型间酶化学计量的向量长度在10～20 cm土层差异显著,表现为湿地松林>针阔混交林>马尾松林。3种人工林酶化学计量的向量角度均大于45°,其中在湿地松林10～20 cm土层向量角度显著大于马尾松林。冗余分析表明,土壤碳质量指数和有机碳与全磷的比值(C/P)以及土壤含水量和C/P分别是0～10和10～20 cm土层土壤酶活性及其化学计量的关键影响因素,土壤碳和磷的数量和质量,以及土壤含水量在调节中亚热带人工林生态系统养分循环中发挥关键作用。     

滇西并流河谷区土壤酶活性化学计量学特征与环境因子的关系

横断山河谷区具有极高的景观异质性,气候与植被类型多样化程度较高。为探讨土壤C、N、P、S四种生物元素在滇西怒江、澜沧江、金沙江及元江并流河谷区的区域循环特征,在各河谷的森林、草地、农田中分别取浅层(0～10 cm)土样,测定了土壤中C、N、P、S的循环酶,即β-葡萄糖苷酶(BG)、N-乙酰-β-D-氨基葡萄糖苷酶(NAG)、酸性磷酸酶(AP)、硫酸脂酶(SU)活性,分析了土壤酶活性及其化学计量学特征与环境因素之间的关系。结果表明: 不同流域和不同土地类型下AP、NAG活性均有显著差异;4种酶活性之间均呈显著正相关,BG、NAG、SU活性由东南向西北随采样点的海拔升高而逐渐升高;在各流域土壤中,酶活性的生态化学计量比均为AP∶SU > BG∶SU > NAG∶SU > BG∶NAG > BG∶AP > NAG∶AP;与各流域内的林地和草地相比,农田土壤BG∶NAG较高,而NAG∶AP较低(元江流域除外);农田土壤中AP∶SU、BG∶SU、NAG∶SU在元江流域小于草地和林地,在澜沧江流域和金沙江流域则大于林地而小于草地。土壤酶活性及其化学计量学特征受到土壤理化性质、气候及区位的综合影响,其中土壤理化性质的影响最大。农业活动对C∶N∶P相关酶化学计量学特征具有显著影响,降低了土壤中N分解酶与其他酶活性的计量比,表现为增加了BG∶NAG,降低了NAG∶AP,农业活动对其他酶化学计量学特征的影响较小。     

Effects of desertification on the C:N:P stoichiometry of soil,microbes, and extracellular enzymes in a desert grassland

为探讨荒漠草地沙漠化对“土壤-微生物-胞外酶”系统生态化学计量的影响机理, 该研究采用空间序列代替时间演替的方法, 研究了宁夏盐池荒漠草地沙漠化过程中土壤、土壤微生物及土壤胞外酶碳(C)、氮(N)、磷(P)生态化学计量的变异特征。结果表明: (1)随着荒漠草地沙漠化的不断加剧, 土壤C、N、P含量和土壤C:P、N:P均呈降低趋势, 而土壤C:N逐渐增加。(2)荒漠草地沙漠化过程中, 土壤微生物生物量C (MBC):微生物生物量P (MBP)、微生物生物量N (MBN):MBP和土壤β-葡萄糖苷酶(BG):N-乙酰氨基葡萄糖苷酶(NAG)逐渐降低, 而土壤BG:磷酸酶(AP)和NAG:AP基本表现为增加趋势。(3)随着荒漠草地沙漠化程度的加剧, 土壤微生物C利用效率CUE_C:N和CUE_C:P与土壤微生物N利用效率NUE_N:C和土壤微生物P利用效率PUE_P:C的变化趋势相反。(4)荒漠草地土壤、土壤微生物生物量和土壤胞外酶C:N化学计量(C:N, MBC:MBN, BG:NAG)与土壤、土壤微生物生物量和土壤胞外酶N:P化学计量(N:P, MBN:MBP, NAG:AP)显著负相关, 而土壤和胞外酶C:N化学计量(C:N, BG:NAG)与土壤和胞外酶C:P化学计量(C:P, BG:AP)显著正相关。土壤N:P与土壤MBN:MBP显著正相关, 而与土壤NAG:AP显著负相关。分析表明, 荒漠草地沙漠化过程中土壤微生物生物量及胞外酶活性随着土壤养分的变化而发生变化; 微生物-胞外酶C:N:P生态化学计量与土壤养分存在协变关系, 为理解荒漠草地土壤-微生物系统C、N、P循环机制提供理论依据。     

荒漠草地沙漠化对土壤‐微生物‐胞外酶化学计量特征的影响

为探讨荒漠草地沙漠化对"土壤-微生物-胞外酶"系统生态化学计量的影响机理,该研究采用空间序列代替时间演替的方法,研究了宁夏盐池荒漠草地沙漠化过程中土壤、土壤微生物及土壤胞外酶碳(C)、氮(N)、磷(P)生态化学计量的变异特征。结果表明:(1)随着荒漠草地沙漠化的不断加剧,土壤C、N、P含量和土壤C:P、N:P均呈降低趋势,而土壤C:N逐渐增加。(2)荒漠草地沙漠化过程中,土壤微生物生物量C (MBC):微生物生物量P (MBP)、微生物生物量N (MBN):MBP和土壤β-葡萄糖苷酶(BG):N-乙酰氨基葡萄糖苷酶(NAG)逐渐降低,而土壤BG:磷酸酶(AP)和NAG:AP基本表现为增加趋势。(3)随着荒漠草地沙漠化程度的加剧,土壤微生物C利用效率CUEC:N和CUEC:P与土壤微生物N利用效率NUEN:C和土壤微生物P利用效率PUEP:C的变化趋势相反。(4)荒漠草地土壤、土壤微生物生物量和土壤胞外酶C:N化学计量(C:N, MBC:MBN, BG:NAG)与土壤、土壤微生物生物量和土壤胞外酶N:P化学计量(N:P,MBN:MBP,NAG:AP)显著负相关,而土壤和胞外酶C:N化学计量(C:N,BG:NAG)与土壤和胞外酶C:P化学计量(C:P,BG:AP)显著正相关。土壤N:P与土壤MBN:MBP显著正相关,而与土壤NAG:AP显著负相关。分析表明,荒漠草地沙漠化过程中土壤微生物生物量及胞外酶活性随着土壤养分的变化而发生变化;微生物-胞外酶C:N:P生态化学计量与土壤养分存在协变关系,为理解荒漠草地土壤-微生物系统C、N、P循环机制提供理论依据。     

不同林龄油茶人工林土壤酶化学计量及其影响因素

土壤酶化学计量比是揭示微生物生长代谢过程及评价土壤养分资源限制状况的重要指标。油茶是中国南方主要的木本油料作物,近年来愈来愈受关注,但鲜有从生态化学计量学的角度深入理解人工经济林的土壤微生物养分限制状况。本文以亚热带地区不同林龄油茶人工林土壤为研究对象,采用时空互代法在区域尺度上随机选取32个不同林龄油茶人工林并将其分为四个林龄组(9年幼龄林;9—20年近熟林;21—60年成熟林; 60年过熟林),通过测定土壤碳(C)、氮(N)、磷(P)转化酶活性(β-葡糖苷酶(BG)、α-纤维素酶(CBH)、β-乙酰葡糖胺糖苷酶(NAG)、亮氨酸氨基肽酶(LAP)、酸性磷酸酶(AP))及土壤理化因子,探讨不同林龄油茶人工林土壤C、N、P转化酶化学计量特征及其与土壤理化因子的关系。结果表明:五种C、N、P转化酶活性均有随林龄增大而增加的趋势,且AP活性显著高于其它四种酶活性。相关分析结果表明,五种土壤C、N、P转化酶活性均与土壤有机碳和总氮显著相关,与土壤总磷和速效磷含量不相关。土壤酶化学计量比ln(CBH+BG)∶ln(NAG+LAP)、ln(CBH+BG)∶ln(AP)和ln(NAG+LAP)∶ln(AP)均随林龄增大而一定程度增加。亚热带区油茶人工林土壤酶C∶N∶P化学计量比为1∶1∶1.5,这与全球生态系统土壤酶C∶N∶P化学计量比1∶1∶1相偏离,表明亚热带地区油茶人工林土壤微生物生长受磷素限制。冗余分析(RDA)进一步揭示土壤有机碳含量是影响土壤酶活性和酶化学计量比的主要因子。因此,在油茶人工林经营管理中应考虑磷和外源碳的投入,提高土壤微生物酶活性,缓解油茶人工林生态系统的磷限制。研究结果可为亚热带区油茶人工林土壤养分管理和可持续利用提供基础理论支撑。     

不同肥料对稻田红壤碳、氮、磷循环相关酶活性的影响

采用中国科学院千烟洲生态站1998年开始的定位试验数据,研究不同肥料(猪粪、秸秆、化肥)对稻田红壤碳、氮、磷养分及相关酶活性[3-1,4-葡萄糖苷酶(βG)、β-1,4-N-乙酰葡糖氨糖苷酶(NAG)、L-亮氨酸氨基肽酶(LAP)、酸性磷酸酶(AP)]的影响.结果表明:施用猪粪(OM)土壤中的βG、NAG和LAP活性显著高于其他处理,比对照(不施任何肥料)分别高1.4、2.6和1.9倍;土壤C/N提高、βG/(NAG+LAP)降低,说明施用猪粪有利于土壤中纤维素的降解和有机碳的积累.施用化肥提高了土壤中βG、NAG和LAP活性,而AP活性比对照低34％;土壤βG/AP和(NAG+LAP)/AP较高,而C/P和N/P较低,说明施用化肥导致稻田红壤无机磷的积累,抑制了土壤中分解磷酸多糖和磷脂的微生物功能.     

Stoichiometric characteristics of carbon,nitrogen and phosphorus in Phyllostachys edulis forests of China

Aims Stoichiometric ratios of carbon (C), nitrogen (N) and phosphorus (P) are important characteristics of the ecological processes and functions. Studies on population ecological stoichiometry can refine the content of flora chemometrics, determine the limited nutrient, and provide data for process-based modeling over large scale. Phyllostachys edulis is an important forest type, whose area accounts for 74% of total bamboo forest area in Southern China. However, little is known about the ecological stoichiometric in P. edulis. This study aimed to reveal C:N, C:P and N:P stoichiometry characteristics of the “plant-soil-litter” continuum and to provide a better understanding nutrient cycling and stability mechanisms in P. edulis forest in China. Methods The data were collected from the published literature containing C、N、P content in leaf or surface soil (0-20 cm) or littefall in P. edulis forests. Important findings 1) The leaf C, N, P content were estimated at 478.30 mg·g^-1, 22.20 mg·g^-1, 1.90 mg·g^-1 in P. edulis, and the corresponding C: N, C: P and N: P were 26.80, 299.60 and 14.40, respectively. Soil C, N, and P content in 0-20 cm were 21.53 mg·g^-1, 1.66 mg·g^-1, 0.41 mg·g^-1, with ratios of 14.20 for C:N, 66.74 for C:P and 4.28 for N:P. The C, N and P contents were 438.49 mg·g^-1, 13.39 mg·g^-1, 0.86 mg·g^-1 for litterfall, with the litter C:N, C:P and N:P being 25.53, 665.67, 22.55, respectively. 2) In the plant-soil-litter system in P. edulis forest, leaf had higher C:N, litter had higher C:P and N:P, while soil were the lowest. The N, P resorption rate was 39.68% and 54.74%, indicating that P. edulis forest growth and development was constrained by P or by both of N and P in China. 3) N content and N:P in leaf showed a tendency to increase with latitude, while the C:N of leaf declined with latitude. N:P of leaf increased with longitude, but the P content and the C:N of leaf showed a opposite trend. C: N of soil increased with longitude, whereas the N content of soil declined longitude. The N content of litter declined with longitude. 4) The leaf N content was negatively correlated with mean annual temperature and mean annual precipitation, but being more sensitive to temperature than precipitation. The positive correlations between N content and latitude support “Temperature-Plant Physiological” hypothesis, reflecting an adaptive strategy to environmental conditions.     

Salt accumulation in vegetative organs and ecological stoichiometry characteristics in typical halophytes in Xinjiang,China

AimsStudying salt accumulation in vegetative organs and carbon (C), nitrogen (N), phosphorus (P) stoichiometry in halophytes contributes to understand the adaptive strategy to saline environment and the distribution mechanism of nutrients and salinity of the halophytes.MethodsFour typical dominant species, including three perennial shrubs (Halocnemum strobilaceum, Suaeda microphylla and Kalidium foliatum) and an annual herb (Salicornia europaea) were selected for analyzing the salt accumulation and C, N, P stoichiometry relationships.Important findings 1) The salt accumulation showed “salt island” effect at peak growing stage; Na⁺, Cl^- and electrical conductivity all showed significant positive trends, when salt ions were transported from the root to the shoot of 4 halophytes. 2) P was the limiting growth element of perennial shrubs, while both N and P were limiting factors for the annual herb. 3) Different organs, species and their interactions affected C, N, P stoichiometry and salt icons except Mg²⁺. 4) C was negatively correlated with N and P, but there was a significant positive correlation between N and P. 5) Electrical conductivity, Na⁺and K⁺ were positively correlated with N, N:P ratio, and negatively correlated with C, C:N and C:P ratios, and yet K⁺, CO₃^2- had significant positive correlation with P. These results implied that there were some kind of mutual promoting relationships between nutrients and salinity in halophytes in the saline environment, and fertilizing with N could promote sodium chloride desalination.     

滇南喀斯特地区不同季节土壤和灌木叶片化学计量特征及对水分添加的响应

干旱是影响南方喀斯特地区植物生长的重要限制因子, 气候变化会影响该地区的降水量和分布格局。研究该地区土壤和植物化学计量特征及其水分响应格局, 具有重要意义。自2017年4月开始, 在云南建水喀斯特植物群落进行加水试验, 2018年4月(旱季)和8月(雨季)分别采集土壤和优势灌木鞍叶羊蹄甲(Bauhinia brachycarpa)和假虎刺(Carissa spinarum)叶片样品, 测定碳、氢、氮、磷、硫、钾、钙、镁、铝、钠、铁、锰、锌、铜14种元素含量。结果表明, 水分添加影响了表层土壤中碳、氮、钠的含量, 相比于旱季, 雨季土壤中钠和硫含量明显减少, 其余土壤元素在水分添加和季节变化下并未表现出明显差异。土壤水分含量的增加使得鞍叶羊蹄甲和假虎刺叶片中钾含量下降, 钙含量上升。在水分条件变化下, 两种植物叶元素含量的稳定性与植物中元素的含量有关, 含量越接近极大值(基本元素碳、氢、氮等)或极小值(微量元素铜、锌等)的元素其变异系数越小(越稳定), 两种植物中含量接近于1 mg·g^-1的元素磷、硫、镁的变异系数最高。在土壤水分条件变化下, 假虎刺中碳、氮、磷等大量元素含量的稳定性显著高于鞍叶羊蹄甲。降水变化和水分添加导致的土壤水分变化, 对滇南喀斯特地区土壤和植物中不同元素含量的影响不同, 这些结果将为该地区的土壤、植被修复和管理提供科学参考。     

Storage of carbon,nitrogen and phosphorus in temperate shrubland ecosystems across Northern China

Aims Studying storage of carbon (C), nitrogen (N) and phosphorus (P) in ecosystems is of significance in understanding carbon and nutrient cycling. Previous researches in ecosystem C, N and P storage have biased towards forests and grasslands. Shrubland ecosystems encompass a wide gradient in precipitation and soil conditions, providing a unique opportunity to explore the patterns of ecosystem C, N and P storage in relation to climate and soil properties.
Methods We estimated densities and storage of organic C, N and P of shrubland ecosystems in Northern China based on data from 433 shrubland sites.
Important findings The main results are summarized as follows: the average organic C, N and P densities in temperate shrubland ecosystems across Northern China were 69.8 Mg·hm^-2, 7.3 Mg·hm^-2 and 4.2 Mg·hm^-2, respectively. The average plant C, N and P densities were 5.1 Mg·hm^-2, 11.5 × 10^-2 Mg·hm^-2 and 8.6 × 10^-3 Mg·hm^-2, respectively, and were significantly correlated with precipitation and soil nutrient concentrations. The average litter C, N and P densities were 1.4 Mg·hm^-2, 3.8 ×10^-2 Mg·hm^-2, 2.5 ×10^-3 Mg·hm^-2 and were significantly correlated with temperature and precipitation. The average soil organic C, N and P densities in the top 1 m were 64.0 Mg·hm^-2, 7.1 Mg·hm^-2 and 4.2 Mg·hm^-2, respectively and the former two were significantly correlated with temperature and precipitation. The total organic C, N and P storage of shrublands in Northern China were 1.7 Pg, 164.9 Tg and 124.8 Tg, respectively. The plant C, N and P storage were 128.4 Tg, 3.1 Tg and 0.2 Tg, respectively. The litter C, N and P storage were 8.4 Tg, 0.45 Tg, 0.027 Tg, respectively. Soil is the largest C, N and P pool in the studied area. The soil organic C, N and P storage in the top 1 meter were 1.6 Pg, 161.3 Tg and 124.6 Tg, respectively.     

增温对苔原土壤和典型植物叶片碳、氮、磷化学计量学特征的影响

为探讨苔原植被对气候变暖的响应模式, 采用开顶箱增温法, 研究了3个生长季增温对长白山苔原3种代表植物——牛皮杜鹃(Rhododendron aureum)、笃斯越桔(Vaccinium uliginosum)和东亚仙女木(Dryas octopetala var. asiatica)的叶片及土壤碳(C)、氮(N)、磷(P)含量及其比值的影响。结果表明: 增温使土壤N和P的含量分别增加5.88%和4.83%, C含量降低13.19%; 增温和对照(不增温)条件下, 植物叶片的C、N、P含量及其比值在生长季有明显的变化。增温使笃斯越桔和东亚仙女木叶片的P含量分别增加10.34%和12.87%, 牛皮杜鹃则降低了16.26%, 增温并没有明显改变3种植物叶片的C、N含量, 但牛皮杜鹃和东亚仙女木叶片的C:N值在增温条件下呈现增加趋势。增温使土壤可利用的N、P含量增加。增温对3种植物的C:N值, 牛皮杜鹃、笃斯越桔的P含量, 以及东亚仙女木的C:P值都产生了显著的影响。结果表明增温增加了长白山苔原P元素对植物生长的限制, 且3种植物叶片的C、N、P化学计量学特性对增温的响应模式和尺度没有表现出一致性。     

丛枝菌根真菌对杨树生长、气孔和木质部微观结构的影响

植物气孔与木质部导管及纤维的功能直接关系着植物的水分利用, 进而影响植物的生长。为研究丛枝菌根真菌(AMF)对杨树抗旱性的影响, 采用温室盆栽的方法, 研究两种水分条件下, 接种根内球囊霉(Rhizophagus irregularis)对速生杨107 Populus × canadensis (P. nigra × P. deltoides) ‘Neva’气孔及木质部微观结构的影响。结果表明: AMF的侵染显著提高了杨树幼苗地上和地下部分生物量, 对叶片气孔长度、茎部导管细胞直径和纤维细胞长度也有促进作用。AMF对生物量和导管细胞直径的增加幅度表现出干旱条件下>正常水分条件下, 而对气孔长度的提高幅度表现出干旱条件下<正常水分条件下。正常水分条件下, AMF增加了杨树叶片的气孔密度, 减小了纤维细胞直径, 对相对水分饱和亏缺无影响; 干旱条件下, AMF增加了纤维细胞直径, 降低了相对水分饱和亏缺, 对气孔密度无影响。综上所述, 干旱条件下, AMF对导管水分传输能力的促进作用明显增加, 而对气孔蒸腾能力的促进作用有所减少, 从而更利于杨树在遭遇干旱时保持水分, 减少干旱对菌根杨树造成的水分亏缺, 提高菌根杨树对干旱的耐受性。     

兰州市主要绿化植物气孔性状特征

气孔是植物叶片与外界环境进行水汽交换的门户, 利用气孔特征反映植物对环境变化的响应与适应有助于了解干旱区绿化植物的适应策略。于2019年7月通过气孔印迹法对兰州市40种主要绿化植物气孔性状进行观察与测定。采用标准化主轴估计和系统独立比较分析建立气孔性状间的相关关系; 通过计算Blomgerg’sK值以检验系统发育信号; 利用聚类分析和主成分分析对气孔性状特征进行功能群划分。结果表明: (1)在所研究的植物中, 气孔性状特征在个体间差异显著, 植物生长型(乔木、小乔木、灌木和草本)会显著影响气孔长度、宽度、开度和密度, 叶习性(落叶和常绿)仅对气孔开度有显著影响; (2)气孔长度与宽度、气孔开度与面积间均为显著的异速生长关系, 气孔密度与面积和开度间为负异速生长关系; (3)系统发育会对气孔性状的相关关系产生显著影响, 虽然气孔性状的系统发育保守性不强(K < 1), 但气孔开度和气孔开张比具有显著的系统发育信号; 4)依据气孔性状特征可以将绿化植物划分为: 低密度-大面积、高密度-小面积和中等密度-适中面积共3种功能群。结合系统发育和异速生长理论能更好地解释气孔性状变异及适应策略。     

Effects of calcium fertilizer on yield,quality and related enzyme activities of peanut in acidic soil

AimsPeanut (Arachis hypogaea) is one of the calcium (Ca)-like crops. In acidic soil, low soil exchangeable Ca²⁺ content, which usually is caused by eluviation, can affect peanut pod development, even causes pod unfilled. The objective of this study was to investigate the effects of calcium fertilizer on yield, quality and related enzyme activities of peanut in acidic soil.Methods ‘Huayu22’ was used as materials, and field experiments were conducted in Wendeng, Weihai (2013) and Sanzhuang, Rizhao (2014), respectively. Three treatments were carried out, i.e. No Ca-application (T₀), 14 kg·667 m^-2 fused CaO (T₁) and 28 kg·667 m^-2 fused CaO (T₂). Top 3rd leaves of main stems were harvested to determine the activities of carbon and nitrogen metabolism enzyme every 15 days from anthesis to mature period. Additionally, the pod traits and yield were investigated at harvest time. Uniform dry pods were used to determine the quality of kernel.Important findings Application of calcium fertilizer significantly increased the pod yield of peanut in acid soil. Yield of T₁ treatment increased by 26.92% and T₂ increased by 21.65% on average at two sites. It might be related to higher pod numbers per plant, higher double kernel rate, and higher plumpness of kernel under T₁ and T₂ treatment than under T₀ treatment. Simultaneously, application of calcium fertilizer also significantly increased the protein and fat content of peanut in acidic soil. The protein content increased 2.02% and the fat content increased 3.01% on average in T₁ treatment, respectively. The protein content increased 1.56% and the fat content increased 2.58% in T₂ treatment, respectively. Additionally, Calcium fertilizer not only improved the lysine and total amino acid content but also improved oleic/linoleic acid (O/L) ratio of peanut in acidic soil. These might be due to higher activities of glutamine synthetase (GS), glutamate synthetase (GOGAT) and glutamate pyruvate transaminase (GPT) in the leaves of peanut in acidic soil under T₁ and T₂ treatments than under T₀ treatment. What’s more, the activity of GS of peanut treated with T₁ was higher than that treated with T₂. Application of Calcium fertilizer also improved the activities of phosphoenolpyruvate carboxylase (PEPCase), sucrose synthase (SS) and sucrose phosphate synthase (SPS) of peanut at early growing period, but the activities at late growth stage were lower than T₀ treatment. Our results demonstrate that the economic performance of 14 kg·667 m^-2 fused CaO was the best one among these three treatments applied.     

山西不同生态型大豆品种苗期耐低温性综合评价

为探明山西不同生态型大豆(Glycine max)品种对苗期低温胁迫的应答表现, 寻求大豆苗期耐低温性综合评价指标和评价方法, 选取了山西普遍种植的‘晋大53’、‘晋大70’和‘晋豆24’ 3个不同生态型大豆品种, 在苗期将材料分别置于14、17和20 ℃人工气候箱中, 保持昼夜恒温, 进行低温胁迫处理。分别测定了各品种光合与产量性状值, 用基因型主效应及其与环境互作(GGE)双标图分析各性状对品种的效应及性状间的相关性, 应用隶属函数法综合评价各品种的苗期耐低温性。结果显示: 低温胁迫下不同生态型大豆品种苗期延长1-12天; 苗期光合性状值均下降, 其中, 叶片气孔导度(G_s)和蒸腾速率(T_r)下降最明显; 产量性状值均呈下降趋势, 单株生物量和单株荚数下降最明显; 各项性状在不同品种中对低温的应答效应不同, 且性状间存在明显的相关性, 可作为耐低温性的评价指标。品种‘晋大70’的耐低温性最佳。     

中国典型陆地生态系统波文比特征及影响因素

波文比(β)是陆面过程中的重要参数, 影响着地表和大气间的能量交换, 明确β的空间变异规律和影响因素有助于对地表能量平衡和气候间反馈关系的预测。该研究收集了在中国不同生态系统类型开展的用涡度相关法(EC)测量地表能量平衡的公开发表文献, 构建了β和气象环境因子数据库, 分析了β在生态系统之间的差异、空间变异特征及影响因素。主要结果: (1)所有生态系统β平均值为0.95 ± 0.64, 变异系数67%, 偏度1.58, 峰度3.07, 整体服从对数正态分布, β平均值最高为灌木生态系统(1.26), 最低为湿地生态系统(0.49)。(2) β在生态系统类型间差异显著: 森林和湿地生态系统β无显著差异, 灌木生态系统β >草地生态系统 β >森林和湿地生态系统 β, 农田生态系统β介于草地生态系统与森林和湿地生态系统之间。(3) β随着纬度的增加而增加, 不随经度和海拔变化。纬度每增加1°,β增加0.038。(4) β随着年降水量(MAP)、年平均气温(MAT)、净辐射(R_n)、当年降水量(PPT)、当年平均气温(T_a)和叶面积指数(LAI)的增加而降低。(5)不同生态系统中β对生物和非生物因素的响应存在显著差异: 草地、森林和灌木生态系统的β对生物和非生物因素变化较为敏感, 而农田和湿地生态系统的β与所有生物和非生物因素均无显著相关关系。(6) MAP和R_n是β变化的直接影响因素, LAI通过影响R_n间接影响β。结果表明了植被类型与气候因素之间具有交互作用, 能量分配最主要的影响因素是降水, 叶面积对能量分配的调节作用并不显著。