深圳福田红树植物群落特征及金属元素分布状况

通过对深圳福田红树林群落特征的研究,对红树植物的区系组成、群落的外貌和结构、群落的主要类型和分布进行了概述,并对该红树林中的桐花树+秋茄+白骨壤+老鼠簕+海漆混交群落林地土壤和红树植物的金属元素分布进行分析。结果发现,该林地土壤金属元素含量分布具有一定规律性,元素K、Na、Ca、Mg在各层土壤中分布均匀;必需金属元素Fe、Mn在各层土壤中含量变化不明显;非必需重金属元素Cr、Ni、Pb、Hg、Cd和必需元素Zn、Cu含量从底层至表层逐步提高;金属元素在该林地红树植物中分布也具有一定规律性,元素K、Na、Ca、Mg在五种红树植物的不同部位均大量存在;必需金属元素Fe、Mn、Zn、Cu在各种红树植物中含量FeMnZnCu;非必需重金属元素Cr、Ni、Pb、Hg、Cd在各种红树植物中含量表现出差异性,秋茄和海漆中Ni含量较大,白骨壤中Pb含量最大,桐花树中Cr含量最大,老鼠簕Cu含量最大,Cd和Hg在五种红树植物中含量都最低;植物中金属元素含量分布和土壤中金属元素含量分布具有相关性。     

盐胁迫下白杨无性系苗木体内离子分配及比较

以白杨杂种无性系及其亲本当年生苗木为材料 ,分析了盐胁迫下无性系的离子含量 ,及 Na 、K 、Ca 在植物体内运输和分配特点 ,并对无性系间差异进行了比较。研究表明 ,随盐浓度提高 ,植物体内Na 含量迅速提高 ,K 、Ca 含量降低 ;盐分胁迫下 ,根部 Na 含量较高 ,叶片 Na 中含量最低 ,K 、Ca 含量则相反 ,特别是 Ca ,其分布顺序为叶 >茎 >根。杂种无性系 B430及其亲本新疆杨对 K 和 Ca 运输的选择性比毛白杨高 ,而对 Na 运输的选择性则比毛白杨低 ,从而导致根部存留的 Na 较多 ,叶片分配的 Na 数量较少 ,从而减轻 Na 对叶片的伤害。综合分析表明 B430和新疆杨耐盐能力最强 ,毛新杨其次 ,毛白杨最差。     

盐胁迫对高羊茅（Festuca arundinacea）幼苗生长和离子分布的影响

盐胁迫环境抑制植物的生长,影响植物组织的离子分布,不同的盐分组成对植物的抑制伤害存在差异,为了研究上海市临港新城滨海盐渍土的生态恢复和重建,模拟该地区的盐分组成,进行了高羊茅（Festuca arundinacea）幼苗的盐胁迫试验。高羊茅种子在非盐胁迫条件下萌发,出苗5d后,进行了不同浓度NaCl：0、50、100、150、200、300、400mmol/L处理,15d后测定生长情况、组织含水量和Na+、K+、Ca2+、Mg2+等离子含量。研究结果表明：盐分对高羊茅幼苗的抑制作用随NaCl浓度增加而加剧,低盐胁迫环境下,幼苗地上部分和根系的鲜重、干重和含水量都与对照没有显著性差异,但是高盐环境严重影响了高羊茅幼苗的生长,而且对地上部分的抑制作用大于根部;盐胁迫影响植物组织的离子分布,Na+浓度持续增加,Ca2+和K+浓度下降,Mg2+含量的影响不大;各组织中K/Na、Ca/Na和Mg/Na随盐胁迫增加而下降。     

不同水盐环境下荒漠植物群落抗逆性化学性状的种间、种内变异

叶片是植物获取资源的重要器官,研究荒漠植物抗逆性化学性状的种间、种内变异对环境变化的响应有助于揭示植物对极端环境的适应机制。以艾比湖自然荒漠植物群落为研究对象,通过野外调查与实验分析,解析不同土壤水盐环境下群落水平抗逆性化学性状（钾K;钙Ca;钠Na;镁Mg）的差异及其种间、种内变异特征,利用冗余分析、相关性分析,明析群落水平性状种间、种内变异与土壤环境因子间关系及其在不同水盐环境间的变化规律。结果表明：（1）高水盐环境下土壤pH及Ca、Na含量均显著高于低水盐环境;低水盐环境下群落水平K、Na、Mg含量显著高于高水盐环境。（2）高水盐环境下群落抗逆性化学性状的种间变异（Ca除外,P<0.05）、种内变异均低于低水盐环境。（3）高水盐环境土壤因子与群落种间、种内变异相关性较高（|r|>0.3）,其中与叶片Ca、Na种间变异普遍为负相关,与Na种内变异多为较强的正相关;低水盐环境种间、种内变异与土壤因子相关性总体较低,其中土壤盐分、水分与叶片Mg的种间变异呈负相关,与Na种内变异呈正相关。综上所述,水盐环境对荒漠植物群落水平的抗逆性化学性状有显著影响,各性状的种间、种内变异与土壤因子间关系在高水盐环境中更为密切,本研究为掌握胁迫环境下植物的适应策略提供依据。     

喀喇昆仑、昆仑山地区植物元素含量的区域分异和数量分析

对喀喇昆仑、昆仑山地区87种植物21个元素含量及区域分异的研究表明,Ca、Cr、Cd、Fe、V含量比高等植物含量偏高,Ph、P的含量偏低。同种植物在不同地点元素含量有差异。盐柴荒漠植物中Na、K、Mg、P含量较高;高山草甸、冰缘植被植物Ba、Ca、Fe、V、Ti含量较高。各植被类型植物元素含量Na/K差异最大,Ca/Mg较小,Fe/Al差异最小。其变异系数分别为153.5、20.5和15.9.%     

3种药赏两用植物对滨海盐碱土改良效应的比较

为比较种植药赏两用植物对滨海盐碱土的改良效应,采用实生栽培方法种植了薄荷(Mentha haplocalyxBriq.)、地榆(Sanguisorba officinalis L.)和枸杞(Lycium chinense Mill.)1年生植株,对不同土层的pH值以及可溶性盐和主要离子含量的变化进行了比较分析。结果表明:种植3种植物后,0～10、10～20和20～30 cm土层的pH值以及可溶性盐、K+、Na+、Ca2+、Mg2+、Cl-和SO42-含量均有不同程度的变化,且以0～10 cm土层的变化相对明显,并且各土层的离子组成也有所改变。种植3种植物后,0～10和10～20 cm土层的pH值以及0～10 cm土层的可溶性盐含量均低于对照,其中,地榆种植土壤pH值及枸杞种植土壤可溶性盐含量的降低效应最明显。种植3种植物后,各土层的Ca2+含量及10～20和20～30 cm土层的K+和Mg2+含量均极显著高于对照,各土层的Na+含量及0～10 cm土层的Cl-含量、10～20和20～30 cm土层的SO42-含量均极显著低于对照;不同土层的K+/Na+值均高于对照、(K++Na+)/(Ca2++Mg2+)值均低于对照、主要阳离子(Ca2+、K+和Mg2+)的交换量总和均明显增加。总体上,地榆和枸杞对土壤中K+及Ca2+和Mg2+含量、K+/Na+值、主要阳离子(Ca2+、K+和Mg2+)交换量总和的提高效应以及对Na+含量、(K++Na+)/(Ca2++Mg2+)值的降低作用均较强,而薄荷的作用均较弱。研究结果显示:供试的3种药赏两用植物对盐碱地均具有明显的改良作用,其中枸杞和地榆的改良效果较好。     

植物群落演替与土壤发展之间的关系

本文运用植物群落中植物优势种的重要值与相对应子群落的土壤特征值直接相关联的分析方法,对湖北宜昌大老岭的桦(Betula)、栎(Quercus)、栗(Castanea)七个群落类型的三个演替途径的土壤动态进行分析,结果表明:在植物群落的演替过程中,土壤中的Ca、pH值减少;离子代换量增加;Na、Mg、NH_4+-N、速效P、速效K、有机质的含量是随着物种的变化而呈不同的趋势。因此,植物群落的演替是生态系统的动态过程。     

荒漠盐生植物根际土壤盐分和养分特征

中国西北地区是我国干旱、盐碱化土壤分布面积较广、土壤积盐较重的地区,这里发育着丰富的盐生植物。目前对于干旱荒漠区盐生植物根际特征的研究相对较少,而不同盐生植物的根际特征对于研究盐生植物适应盐渍环境的机制有着重要意义。本研究利采用盆栽根袋法对7种不同类型的荒漠盐生植物的根际盐分和养分特征进行了初步探索。结果表明:盐分在盐生植物根际发生富集,稀盐盐生植物和泌盐盐生植物根际土壤中总盐和8种主要盐分离子的含量都有所增加,而在拒盐盐生植物根际中增加不显著,其中Cl-和Na 的富集程度相对其它6种离子的富集程度要高。稀盐盐生植物和泌盐盐生植物根际土中的SO42-/Cl-比土体有显著的降低,表明在稀盐盐生植物和泌盐盐生植物根际土壤中Cl-的富集程度比SO42-高,拒盐盐生植物根际土盐分SO42-/Cl-比略有提高。7种盐生植物根际土中的Na /K ,Na /Ca2 ,Na /Mg2 比均较土体有显著的增加,芦苇根际土中的增加最小。在所有研究植物中,根际土壤中全N含量比土体的含量高,但全P和全K含量却比土体的含量低;根际土壤中有效态养分的变化则与全态相反,根际土壤中的有效N含量比土体中的都显著降低,除芦苇外,其他六种盐生植物根际土壤中有效P和有效K的含量都高于土体,但有效P的富集不及有效K富集的程度高。在研究的七种植物中,钠猪毛菜根际土壤的有效N亏缺量最高,有效P和速效K富集也最少。7种植物,尤其是稀盐盐生植物和泌盐盐生植物的地上部分的主要盐离子含量比地下部分高,如Cl-、Na 、Ca2 和K ,在根际富集程度最高的Cl-和Na ,在植株的地上部分也增加的最多。     

五种沙生植物根际土壤的盐分状况

以根袋模拟法,研究了古尔班通古特沙漠5种常见沙生植物梭梭(Haloxylon ammodendron Bge)、白梭梭(Haloxylon persicum Bge)、刺沙蓬(Salsola Rathenica Iljin)、骆驼蓬(Peganum harmala Linn)和骆驼刺(Alhagi sparsifolia Shap)根际土壤的pH值和盐分状况,结果表明:5种植物根际土壤的pH值均小于非根际土壤,其中梭梭根际土壤和非根际土壤差值最大,达0.3个单位;5种供试植物根际土壤的电导率均高于非根际土壤,除刺沙蓬外其它供试植物均差异显著(p<0.05);可溶性总盐含量在根际土壤中均出现了聚集的现象,主要是SO2-4、Ca2+和Mg2在根际的聚集,Cl-主要在骆驼刺根际中出现了聚集现象,在其他植物根际和非根际中没有显著变化;5种供试植物中骆驼刺根际土壤盐分聚集最为明显;从Cl- / SO2-4、Na+/ K+、Na+/ Ca2+和Na+/ Mg2+的值可以看出,沙生植物根际土壤主要是硫酸钙、镁盐的聚集,而非氯化钠的聚集.以上结果说明,沙生植物能够通过根际调节降低根际土壤的pH值,从而促进植物对土壤中养分以及水分的利用,同时沙生植物根际土壤中盐分聚集的现象为植物根际的"盐岛"效应的发生提供了很好的依据.     

英罗港红树植物群落不同演替阶段植物元素分布及其与土壤肥力的关系

 根据广西英罗港红树植物群落的演替过程, 研究了5个主要演替阶段红树植物群落优势种地上部分的7种元素 （N、P、K、Ca、Mg、Na、Cl）含量、群落元素积累量及其与土壤肥力的关系。结果表明：1）红树植物不同器官元素含量大小为：N、P、K均为花果＞叶＞枝＞皮＞干,Ca为皮＞枝、叶＞花果＞干,Mg为花果＞叶＞皮＞枝＞干, Na、Cl为叶、花果＞皮＞枝＞干;2）同一器官中各元素含量均以Cl、Na最多, 其次是N、Ca、K, 然后是Mg, 最少是P;3）随着进展演替, 红树植物群落优势种的N、P、K含量呈明显减少     

荒漠植物不同功能群性状特征及其与土壤环境的关系

研究不同功能群植物性状差异及其与土壤环境关系对于充分掌握植物的环境适应策略至关重要。以艾比湖流域为研究区,利用荒漠植物的植物高度、叶片碳、氮、磷、硫、钾、钙、钠、镁含量等9个性状,将高、低土壤水盐环境下的植物划分为5个功能群,分析不同功能群的植物组成、性状差异及其与土壤环境的关系。结果表明：(1)不同土壤水盐环境下,其植物功能群组成不同;其中白刺、胡杨和罗布麻在两个土壤水盐环境下的功能群中均存在。(2)植物的功能性状在不同土壤水盐环境下也发生了适应性的变化。高土壤水盐环境下3个功能群的植物高度、叶片碳、氮、磷和钙含量显著高于低土壤水盐环境功能群(P<0.05);低土壤水盐环境下2个功能群的植物叶片硫、钠和镁含量高于高土壤水盐环境功能群。(3)土壤含水量(SVWC)、电导率(EC)、pH以及土壤磷含量对荒漠植物功能性状影响较大。在高土壤水盐环境下,EC、pH与植物高度,叶片钾、钙含量正相关,与叶片硫含量负相关;在低土壤水盐环境下,SVWC、EC与植物高度呈显著正相关(P<0.05)。研究有助于理解荒漠植物对极端环境的适应对策,为保护荒漠地区生物多样性提供理论依据。     

Vegetation-soil relations in the lowlands of south-west Tasmania

A geographic survey of 14 south-west Tasmanian sedgeland-heaths revealed that soil organic matter is related to: water content: total nitrogen (N): total and exchangeable sodium (Na), calcium (Ca) and magnesium (Mg); exchangeable potassium (K) cation exchange capacity; and total exchangeable bases. However, total and available phosphorus (P), total K and Iron (Fe). pH level and percentage base saturation were found to be Independent of organic content. Most of the soil nutrient capital is contained In the A₀ horizon, the depth of which was found to be positively related to the time elapsed since the last fire. There is no clear relationship between rock type and soil fertility, but there is evidence of soil-vegetation interaction. The sedgeland-heath species have lower concentrations of P, Ca and Mg in their foliage and are more efficient In the withdrawal of P and K upon tissue senescence than the surrounding scrub and forest species. Over a vegetation transition from sedgeland-heath to forest on uniform geology there was a change in soil type. The forest was found to have more fertile soils and a higher concentration of nutrients in the above-ground biomass than the adjacent sedgeland-heath. The ecotone was burnt between 20–30 years prior to sampling, but the fire did not kill all the forest trees, and the structural differences suggest a mare rapid recovery of forest species. Soil fertility appears to be an important factor in controlling the rate of recovery and succession following a fire, especially if the nutrient-rich organic layer is burnt.     

中微量元素和有益元素对水稻生长和吸收镉的影响

采用盆栽试验,研究了中微量元素和有益元素对水稻生长和吸收镉的影响。结果表明,在所有测试的元素和施用方法中,硅酸钠叶面喷施显著增加稻谷产量,而碳酸钙、硼酸、硅酸钠土施和亚硒酸钠显著降低了稻谷产量。镁、锌、铁的盐酸盐形态对水稻籽粒的增产效果优于硫酸盐形态,而钙、铜的硫酸盐形态增产效果略高于盐酸盐形态。在钙、镁、硫三种中量元素中,钙增加了水稻籽粒中的Cd浓度和吸收量,而镁和硫则降低了籽粒中的Cd浓度和吸收量,以硫磺粉处理为最低。稻草中的Cd浓度和总量均以氯化镁处理为最高,硫磺粉处理最低。镁能有效抑制Cd从秸秆向籽粒的转移,其盐酸盐优于硫酸盐。在微量元素中,锌对水稻Cd的吸收抑制作用最为显著,其次是铜,而有益元素肥料硅酸钠叶面喷施则显著增加了稻谷中的Cd浓度和吸收量。硫酸亚铁、氯化锰、氯化铜、硼酸和硼砂处理都能有效地抑制Cd从秸秆向籽粒的转移,而硅酸钠叶面喷施和锌处理则促进了Cd的转移,表明硅酸钠抑制水稻吸收Cd的机制很可能发生在土壤中,而非在植株体内或地上部分。在Cd污染土壤上选用适宜的中微量和有益元素肥料及其施用方法,能有效降低水稻对镉的吸收和稻米中的Cd含量。     

Biogeography and variability of eleven mineral elements in plant leaves across gradients of climate, soil and plant functional type in China

Understanding variation of plant nutrients is largely limited to nitrogen and to a lesser extent phosphorus. Here we analyse patterns of variation in 11 elements (nitrogen/phosphorus/potassium/calcium/magnesium/sulphur/silicon/iron/sodium/manganese/aluminium) in leaves of 1900 plant species across China. The concentrations of these elements show significant latitudinal and longitudinal trends, driven by significant influences of climate, soil and plant functional type. Precipitation explains more variation than temperature for all elements except phosphorus and aluminium, and the 11 elements differentiate in relation to climate, soil and functional type. Variability (assessed as the coefficient of variation) and environmental sensitivity (slope of responses to environmental gradients) are lowest for elements that are required in the highest concentrations, most abundant and most often limiting in nature (the Stability of Limiting Elements Hypothesis). Our findings can help initiate a more holistic approach to ecological plant nutrition and lay the groundwork for the eventual development of multiple element biogeochemical models.     

Bioconcentration of some macrominerals in soil,forage and buffalo hair continuum: A case study on pasture irrigated with sewage water

The present study aimed to evaluate the bioaccumulation of some macrominerals in grazing buffaloes fed forage irrigated with sewage water or canal water. In particular, the transfer of sodium (Na), magnesium (Mg), potassium (K) and calcium (Ca) from soil to plant and in turn to animals was evaluated under sub-tropical environmental conditions. Samples of soil, forage and buffalo hair were collected and digested by wet method. Sodium and K concentrations were significantly higher in the soil but lower in the forages; however, Mg and Ca concentrations in both soil and forages were higher. The correlation between soil, forage and hair showed an imbalanced flow of Na, Mg and K and a balanced flow of Ca from soil to forage and then to animals. Based on the findings, the highest rates of transfer of minerals were found for sewage water treatment, whereas lowest rates were found for canal water treatment, except for Na. As the transfer of minerals depends on their bioavailability, the highest values may be due to the high rates of mineral uptake by plants. Thus, the high transfer rate of some elements by plants could become toxic in future causing detrimental effect to grazing livestock.     

Indirect estimation of the underground standing crop of individual plant species of natural grassland communities

The estimation of underground standing crop of individual plant species in a natural grassland ecosystem without direct measurement of screened plant material is described. A mathematical formulation techinque has been designed by correlating the variables fresh weight, dry weight, ash weight and also nitrogen, phosphorus, potassium, sodium, calcium, sulphur and magnesium content of the plant species.     

Nutrient dynamics and plant assemblages of Macrotermes falciger mounds in a savanna ecosystem

Termites through mound construction and foraging activities contribute significantly to carbon and nutrient fluxes in nutrient-poor savannas. Despite this recognition, studies on the influence of termite mounds on carbon and nitrogen dynamics in sub-tropical savannas are limited. In this regard, we examined soil nutrient concentrations, organic carbon and nitrogen mineralization in incubation experiments in mounds of Macrotermes falciger and surrounding soils of sub-tropical savanna, northeast Zimbabwe. We also addressed whether termite mounds altered the plant community and if effects were similar across functional groups i.e. grasses, forbs or woody plants. Mound soils had significantly higher silt and clay content, pH and concentrations of calcium (Ca), magnesium (Mg), potassium (K), organic carbon (C), ammonium (NH₄⁺) and nitrate (NO₃⁻) than surrounding soils, with marginal differences in phosphorus (P) and sodium (Na) between mounds and matrix soils. Nutrient enrichment increased by a factor ranging from 1.5 for C, 4.9 for Mg up to 10.3 for Ca. Although C mineralization, nitrification and nitrification fraction were similar between mounds and matrix soils, nitrogen mineralization was elevated on mounds relative to surrounding matrix soils. As a result, termite mounds supported unique plant communities rich and abundant in woody species but less diverse in grasses and forbs than the surrounding savanna matrix in response to mound-induced shifts in soil parameters specifically increased clay content, drainage and water availability, nutrient status and base cation (mainly Ca, Mg and Na) concentration. In conclusion, by altering soil properties such as texture, moisture content and nutrient status, termite mounds can alter the structure and composition of sub-tropical savanna plant communities, and these results are consistent with findings in other savanna systems suggesting that increase in soil clay content, nutrient status and associated changes in the plant community assemblage may be a general property of mound building termites.     

湖南烟区土壤交换性钙、镁含量及对烤烟品质的影响

分析了湖南烟区主要土壤类型交换性钙、镁元素含量状况及其对烟叶品质的影响,结果表明:(1)土壤交换性钙、镁含量在不同土壤类型间存在显著性差异,交换性钙含量平均为8.87cmol/kg,以红壤含量最高;交换性镁含量平均为1.16cmol/kg,以黄棕壤含量最高;交换性钙镁比值大小依次为:红壤(11.74)>水稻土(10.25)>黄壤(6.84)>黄棕壤(6.14),在烟叶实际生产中,应重视镁肥在红壤和水稻土中的施用;(2)烟叶钙含量偏高(21.93g/kg±4.37g/kg),烟叶镁含量偏低(2.52g/kg±1.26g/kg),两者均存在广泛的变异性;(3)整体来看,烟叶钙含量随土壤中交换性钙含量的升高和镁含量的降低而显著升高;烟叶镁含量随土壤交换性镁含量的升高而升高,与土壤交换性钙含量的相关性不显著;(4)典型相关分析表明,土壤中交换性镁含量的降低可能引起烟叶钾含量的提高,从而使得烟叶钾素和镁素含量达到较好的平衡;(5)土壤交换性钙、镁含量与烟叶其它化学成分指标的相关分析表明,土壤交换性钙有利于烟株对硼和氯素的吸收,对氮、锌和锰素的吸收则有显著的抑制作用;而土壤交换性镁有利于烟叶总糖、硼素和锰素的积累,对氮、磷、铁和锌素的吸收具有显著的抑制作用。     

种植星星草对盐碱草地土壤养分状况的改良作用

对人工种植在碱斑草地上的星星草在不同年份相同生育期的土壤养分状况进行研究, 并与天然状况的星星草地在各个生育期的土壤养分相比较。种植星星草后, 随着星星草种植年限的增加, 0~10cm 土壤中:有机质含量和土壤全氮含量呈上升趋势, 土壤全磷含量略有增加, 土壤全钾含量变化不明显;而土壤全钠含量、全钙含量以及土壤全镁含量都有不同程度的降低。     

Development and use of a short-term nutrient-absorption technique for evaluating soil magnesium status

Summary A greenhouse investigation was undertaken to study and evaluate the use of a short-term nutrient-absorption technique for evaluating soil magnesium status. Barley (Hordeum vulgare), variety Arivat, was used as the test plant. The investigation included four experiments with the following objectives: (1) to determine the need for base applications of nitrogen and phosphorus in a soil-magnesium study using a short-term nutrient absorption technique; (2) to study the effect of base applications of N and P on Mg-uptake by plants under three time periods of root-soil contact; (3) to study the effect of increasing soil moisture from 75 to 100 per cent of the soil moisture equivalent on the plant uptake of Mg; and (4) to evaluate the short-term nutrient-absorption technique in determining the magnesium status in six different soils: Gila silt loam, Tours silty clay loam, Cajon clay loam, La Palma fine sandy loam, Yavapai sandy clay loam, and Casa Grande loam. Magnesium was applied in the form of MgSO₄ and Sul-PO-Mag.Plant growth, potassium, calcium, and magnesium uptake were increased by the base application of nitrogen and phosphorus using a 7-day period of root-soil contact.Plant growth was not affected by soil moisture level. Potassium and calcium concentrations in the plant were decreased with increasing soil moisture, but the total plant uptake of these nutrients was not affected. Total plant uptake and concentration of magnesium were increased by increasing soil moisture level.The results obtained in this study agree with previous observations that soil response to Mg does not depend upon the amount of exchangeable magnesium in the soil.Published as Arizona Agr. Expt. Station Technical Publication No.848.