树木年轮中养分元素含量的平均值及其角分布

Tree rings for analysis were selected from Cedrus deodara growing on a yellow-brown soil in Nanjing City, Pinus massoniana growing on a red soil in the red soil field station at Yintan, Jiangxi Province, and Pinus massoniana growing on a yellow-brown soil in a mining area in Nanjing. Cd, Pb, Cu, Mn, Zn, K and P contents were analysed and average values as well as angular distributions were determined. In cases where the relative deviation was below 0.30, it would be appropriate to use average values to represent the element contents in the tree rings. However, for large standard deviations, the values of the angular distribution would better describe the element contents of rings. The element contents of the environment, particularly the soils, could be obtained from these values.     

树木年轮化学元素含量分析的正确取样方法

实测表明，在同一年轮中：Ｃｄ，Ｐｂ，Ｚｎ，Ｍｎ和Ｃｕ等重金属元素在早材中的含量高于晚材；在年轮平面的不同方位含量也不同，呈角分布。为了能得到年轮元素含量对于时间和方位的平均值；必须覆盖整个年轮环域均匀地雕刻一薄层木质进行取样。     

江西红壤地区马尾松的年轮与其根部土壤中化学元素含量的相关性研究

对采自江西红壤地区的六株马尾松的圆盘年轮样及它们当年的根据土壤,进行Ａｌ,Ｐ,Ｆｅ,Ｃｏ,Ｃｕ,Ｚｎ,Ｂａ,Ｐｂ等元素含量分析。实测结果表明年轮元素含量的分布平均值Ｃ（Ｚ）与当年中土壤中元素含量的分布平均值Ｃ（Ｚ）之间存在统计相关性,     

Study on Model of Correlation Between Chemical Element Contents in Tree Rings and Soils near Tree Roots

The chemical element contents in tree rings are correlated with those in the soils near the tree roots,The results in the present study showed that the correlation between them could be described using the following logarithmic linear correlation model:lgC‘(Z)=a(Z) b(Z)lgC(Z).Therefor,by determining the chrono-sequence C(Z,t),where Z is the atomic number and t the year,of elemental contents in the annual growth rings of trees,we could get the chrono-sequence C‘(Z,t) of elemental contents in the soil,thus inferring the dynaminc variations of relevant elemental contents in the soil.     

钾肥种类及用量对滇重楼矿质元素积累和根际土壤养分含量的影响

分析氯化钾(KCl)和硫酸钾(K2SO4)两种钾肥及用量对滇重楼及根际土壤矿质元素积累的影响,为滇重楼栽培中的钾肥选择及施用提供理论依据。采用盆栽试验,以滇重楼不施钾肥为对照(CK),设氯化钾和硫酸钾配施比例分别为100∶0、75∶25、50∶50、25∶75、0∶100,通过微波消解、原子荧光光谱(AFS)和电感耦合等离子体质谱(ICP-MS)的方法测定滇重楼根茎及根际土壤矿质元素。与CK相比,施用KCl和K2SO4增加了滇重楼根茎部和根际土壤矿质元素的积累量,并随施钾水平的提高而增加;两种钾肥比例下滇重楼对矿质元素的积累普遍呈“升-降-升-升-升”的规律;硫酸钾提高滇重楼根茎及根际土壤矿质元素含量幅度较氯化钾大。为降低滇重楼过量积累有毒有害矿质元素的风险,种植滇重楼时钾肥的施用可按氯化钾和硫酸钾为25∶75的比例配施。     

长期定位施肥对玉米根际土壤团聚体有机碳与钾素含量及其相互关系的影响

  目的  探讨长期定位施肥对玉米根际土壤中不同形态钾素含量变化及其与团聚体组分有机碳含量间的耦合关系,为红壤合理施肥提供理论依据。  方法  依托红壤长期施肥定位试验（始于1986年）,采集不施肥（CK）、氮磷肥（NP）、氮磷钾肥（NPK）、2倍氮磷钾肥（DNPK）和氮磷钾配施有机肥（NPKM）5个处理玉米根际土壤,测定不同粒级土壤团聚体的有机碳、交换性钾和非交换性钾含量,探明它们之间的相关关系。  结果  各施肥处理玉米根际土壤不同粒级团聚体组分中 > 2 mm组分均显著低于0.25 ~ 2 mm和 < 0.25 mm组分,但NPKM处理 > 2 mm的组分最高,< 0.25 mm组分则显著低于其他处理;而各团聚体组分间、同一粒级不同处理间全钾含量均无显著差异。与NP处理相比,NPK处理在 > 2 mm、0.25-2mm和 < 0.25mm团聚体的交换性钾含量分别增加了64.83%、31.12%和32.43%,非交换性钾含量分别提高了11.74%、16.86%和14.54%。相关分析表明,> 2 mm团聚体中有机碳与交换性钾、非交换性钾含量均呈现出显著的正相关关系（R2分别为0.72和0.77,P < 0.05）,且 > 2 mm团聚体中有机碳含量增加0.1 g kg?1,交换性钾和非交换性钾含量分别提高5.69 mg kg?1和 2.37 mg kg?1。  结论  在南方红壤地区,长期有机无机肥配施是提高玉米根际土壤大团聚体比例的重要措施,且大团聚体中有机碳含量的增加促进了交换性钾和非交换性钾含量的提高,可为满足作物根系的钾素需求奠定基础。     

耦合基质区与裂隙网络的土壤优先流模型及验证

该文旨在通过分析土壤裂隙存在下的土壤优先流运动模式与特点,建立耦合基质区与裂隙网络的土壤优先流模型(crack preferential flow model,CP模型)。用控制体积有限元法求解两区土壤水分运动的基本方程,采用整体法将土壤基质水流运动方程和三维土壤裂隙网络区水流运动方程耦合。模拟与试验结果表明,增加降雨或灌溉强度能促进激活裂隙通道作为优先流通道,有利于优先流形成。CP模型及耦合方法较好地描述出了优先流运动的特点,模拟与实测的土壤饱和度均方根误差为0.016~0.025,决定系数均在0.78以上(P0.05),偏差为0.020~0.026,一致性指标为0.918~0.938。与等效连续体模型(Richards模型)相比较,CP模型模拟裂隙存在情况下土壤水流非均匀性规律更有效。研究丰富了土壤优先流理论,对提高农田水分利用率具有重要的意义。     

土壤溶质运移模型的研究及应用

土壤溶质运移的研究已成为土壤学、生态学、水资源学以及资源与环境科学等相关学科的基础和前沿研究领域。本文系统地论述了不同尺度下土壤溶质运移模型的研究进展,对其在农业生产、资源利用和环境保护方面的应用进行了简要综述,并就其未来发展趋势进行了展望。     

树木年轮中养分元素含量的角分布及其环境信息

The effects of nitrogen,phosphorus and potassium application level,seed rate and transplanting density on the growth and development of rice plants were studied to find out nutrient status in high-yielding rice plants and to increase grain yield by adequate fertilization.There was an equilibrium relationship among nutrient elements for high-yielding rice plant populations.The equilibrium index of nutrient amount ,content and distribution in high-yielding rice plants should be generally greater than-2 but less than 2.The optimum nutritive proportion of nitrogen:phosphorus:potassium assimilated by the plants was about 10:2:9 at the ripening stage.But the content and the proportion varied with the growth stages,Therefore,the nutrient in rice plant populations should be in a dynamic equilibrium.So as to achieve high yield.     

油松针叶萜烯组分相对含量同 环 境 和 生 长 因 子 的 关 系

在山西、河北、陕西和甘肃4省,选择油松12个种源的36个林分、288株成年油松样木。利用GC及GC/MS分析技术和相关、回归等方法,测定分析了油松针叶萜烯化合物相对含量以及化合物总数同环境因子和生长因子之间的关系。结果表明,化合物总数随海拔高度的升高而减少;部分化合物相对含量同环境因子存在相关关系;各化合物相对含量同油松高生长的单相关作用很小而存在复相关作用。     

修枝截干对二球悬铃木叶片光合特性的影响

采用Li-6400便携式光合作用测定系统对修枝截干和自然生长的二球悬铃木中部当年向南枝顶的完全展开叶进行单叶光合特性测定.结果表明,修枝截干和自然生长的二球悬铃木叶片的净光合速率(Pn)日变化均呈双峰曲线,有明显的"午休"现象,最高峰发生在11:00,次高峰在15:00,光强最大时(13:00) Pn最低,即两种生长状态下都受到光抑制.修枝截干二球悬铃木Pn[μmol(CO2)·m-2·s-1]的最高峰为12.16,次高峰为9.21,最低谷为6.47,分别比自然生长高27.06%、69.93%和159.84%,这暗示修枝截干可促进光合作用,减轻光抑制.修枝截干的Pn-光量子通量密度(PPFD)响应可拟合为Pn=12.30(1-1.135 3e-0.030 2PPFD/12.30)(R2 =0.989 1**),自然生长的为Pn=10.92(1-1.130 7e-0.030 5PPFD/10.92)(R2 =0.984 9**),修枝截干的最大光合速率(Pmax)、光补偿点、光饱和点及光合幅度的估算值分别为12.30 μmol(CO2)·m-2·s-1、51.67 μmol·m-2·s-1、1 927.32 μmol·m-2·s-1和1 875.65 μmol·m-2·s-1,分别比自然生长提高12.64%、17.33%、13.85%和13.76%,这意味着修枝截干可提高单叶对光能的利用.修枝截干的Pn-CO2浓度(Ci)响应可拟合为Pn=11.96(1-1.471 6e-0.028 7Ci/11.96)(R2=0.982 4**),自然生长的为Pn=10.70(1-1.465 7e-0.029 2Ci/10.70)(R2 = 0.981 0**),修枝截干的Pmax、CO2补偿点、CO2饱和点及CO2幅度估算值分别为11.96 μmol(CO2)·m-2·s-1、67.54 μmol·mol-1、872.02 μmol·mol-1和804.48 μmol·mol-1,分别比自然生长提高11.78%、-27.44%、0.39%和3.73%,说明修枝截干可增强叶片对低浓度CO2的同化能力.     

缺锌和高锌胁迫下苹果根系有机酸对锌的内稳性的响应

To elucidate the mechanisms of tolerance to zinc (Zn) deficiency and Zn toxicity in the root of apple trees, the apple rootstock Malus hupehensis (Pamp.) Rehd seedlings were selected to study the responses of organic acids to Zn homeostasis in roots under low Zn (0 μmol L-1 ), adequate Zn (as control, 4 μmol L-1 ) and toxic Zn (100 μmol L-1 ) treatments. The differences of Zn concentrations and accumulations in the roots were highest, compared with those in the stems and leaves, when apple seedlings were subjected to low and toxic Zn treatments for 1 d. The concentrations and accumulations of oxalic and malic acids in the roots in the low and toxic Zn treatments increased by 20% to 60% compared with those of the control treatment. Significantly negative correlations were found between the total Zn concentrations and the concentrations of oxalic and malic acids in the roots under 1 d of low Zn treatment. However, contrary correlations were found for the toxic Zn treatment. Meanwhile, the maximum influx rates of Zn 2+ under low and toxic Zn treatments increased by 30% and 20%, respectively, compared with the rate of the control treatment. Both Zn deficiency and Zn toxicity increased the concentrations of organic acids in root after short-time Zn treatment, which could resist Zn stress through balanding Zn homeostasis in M. hupehensis Rehd.     

Assessment of the arbuscular mycorrhizal fungal community in roots and rhizosphere soils of Bt corn and their non-Bt isolines

Polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) in combination with sequencing of amplified partial 18S ribosomal DNA was used to assess the effects of transgenic Bt corn 5422Bt1 (event Bt 11) and 5422CBCL (event MON810) on the community structure of a non-target microorganism, namely the arbuscular mycorrhizal fungi (AMF) Glomus in corn roots and rhizosphere soils, relative to their non-Bt isolines 5422 (conventional parent) and 5422wx (conventional hybrid). AMF colonization in roots of different corn genotypes was also assessed using microscopic visualization. No adverse effect was detected on the indigenous AMF colonization of the roots of Bt hybrids 5422Bt1 and 5422CBCL. Two-way indicator species analysis (TWINSPAN^®) and detrended correspondence analysis (DCA) of the DGGE data from corn roots presented differences between Bt and non-Bt corn isolines (5422Bt1 vs. 5422wx, and 5422CBCL vs. 5422wx). However, differences were also recognized between the two non-Bt corn cultivars (5422 vs. 5422wx), and between the two Bt corn lines (5422Bt1 vs. 5422CBCL) in roots. Our results suggest that corn genotypes may have a greater influence on the AMF community structure of plant roots and rhizosphere soils than other factors, such as the age of the growing plants.     

Nitrogenase activity and nitrogen-fixing bacteria associated with the roots ofAtriplex spp. growing in saline sodic soils of Pakistan

Summary TwoAtriplex spp. growing in low-fertility saline sodic soils were assayed for root-associated nitrogenase activity. The excised washed and unwashed root of the two species.A. lentiformis andA. amnicola, showed high root-associated nitrogenase activity. Acetylene-reducing activity seemed to be directly influenced by moisture. The highest number of diazotrophs, enumerated using a most probable number technique was observed on the root surface. Most of the isolated diazotrophs were identified asEnterobacter agglomerans. Root-associated nitrogenase activity inAtriplex spp. may explain the high protein and biomass content of these plants growing in low-fertility saline sodic soils.     

Interactions between tree roots,mycorrhizas, a saprotrophic fungus and the decomposition of organic substrates in a microcosm

Summary A microcosm technique has been used to evaluate the effects of tree seedling root systems, their mycorrhizas and a saprotrophic basidiomycete fungus and their interactions in the decomposition of organic substrates. The component elements were added to the experimental system in a factorially designed experiment of increasing complexity. Roots and mycorrhizas significantly enhance the rate of decomposition of the substrates. The mycorrhizal fungus Suillus luteus was the most active decomposer of all substrates. This root-induced enhancement of decomposition was suppressed in the presence of the saprotroph, Mycena galopus. Plant growth was influenced by the substrate, in that the nitrogen-containing substrates, hide powder and chitin, promoted greater growth than the pure carbohydrate, cotton. Presence of the saprotroph, Mycena galopus significantly enhanced tree growth. The data are discussed in relation to previous studies on the influence of roots and their mycorrhizas on decomposition.     

连作条件下地黄药用品质及土壤微生态特性分析

怀地黄是我国著名"四大怀药"之一,在其种植过程中存在着非常严重的连作障碍。本研究探讨了连作对地黄药用品质的影响,并从土壤微生态方面分析了连作障碍造成地黄药用品质下降的原因。从怀地黄道地产区河南省焦作地区和地黄主产区山西省临汾地区分别采集正茬地黄及其正茬土壤、重茬地黄及其重茬土壤和未种植地黄的对照土壤,利用生药学研究方法对两个产区正茬和重茬地黄的药用品质进行评价,并对4种土样的自毒作用潜力、土壤微生物群落和土壤酶活性指标进行测定分析。结果表明,道地产区与非道地产区地黄品质的差异达到显著水平(P<0.05,下同),但正茬与重茬地黄的品质差异显著高于产区之间差异;两产区地黄连作均显著抑制地黄幼苗生长;连作还造成根际土壤细菌数量减少,土壤真菌和放线菌数量增多,土壤微生物类型由"细菌型"向"真菌型"过渡;与正茬土壤相比,连作根际土壤中土壤脲酶、蔗糖酶和过氧化氢酶的活性显著下降,土壤多酚氧化酶、纤维素酶和蛋白酶的活性有所增加,但土壤磷酸酶活性在两个产区连作土壤中呈现相反的变化趋势。由此可见,连作会引起土壤酶活性和土壤微生态区系的变化,降低了地黄对营养物质的吸收利用,进而造成地黄药用品质下降。     

虫口密度和温度对乌蔹莓鹿蛾生长发育的影响

为探索乌蔹莓鹿蛾的人工饲养条件, 就幼虫饲养密度(每瓶1 头、3 头、5 头、7 头、9 头)和温度(25 ℃、28 ℃、31 ℃)对乌蔹莓鹿蛾的发育历期、存活率和取食等进行了研究。结果显示, 与群体饲养相比, 单头饲养的乌蔹莓鹿蛾幼虫的发育历期长, 成活率低, 取食量较大。在25~31 ℃的环境温度下, 乌蔹莓鹿蛾幼虫的发育历期随温度升高而缩短, 28~31 ℃较有利于幼虫生长发育, 28 ℃的存活率最高(79.47%), 31 ℃时幼虫取食量最大(2.45 g·头^-1)。在人工饲养条件下, 初龄幼虫以3~5 头群体饲养为宜, 3 龄以后以单头饲养为宜, 饲养温度以28~31 ℃为宜。     

植物根际钾富集及钾分布的基因型差异

Plant genotypic difference of potassium-enrichment capability and potassium (K) distribution at root-soil interface of different plant genotypes were studied by using seven plant species and eight varieties of tobacco (Nicotiana tabacum L.). The results indicated that K enrichment capability was: Ethiopian guizotia (Guizotia abyssinica Cass.)>feather cockscomb (Celosia argentea L.)>alligator alternanthera (Alternanthera philoxeroides (Mart.) Griseb.)> tobacco>sesbania (Sesbania cannabina (Retz.) Pers.)>wheat (Triticum aestivum L.)>broadbean (Vicia faba L.). Ethiopian guizotia showed very high K-enrichment capability at different soil K levels, and the K content in its dry matter was over 110 mg kg^-1 when soil K was fully supplied, and about 60 mg kg^-1 when no K fertilizer was applied. For alligator alternanthera, the capability to accumulate K was closely related with its growth medium. When it was grown on soils, both the K content and K uptake rate of the plant were similar to those of tobacco. Evident K depletion was observed in the rhizosphere of all plant species, and the depletion rate was related to the capability of K enrichment of plant.