不同有机肥影响菠萝生长的生理生化机制

以菠萝品种'澳大利亚卡因'为材料,研究了施用不同有机肥对菠萝长叶期和抽蕾期植株生长量、生理生化指标以及土壤酶活性、微生物等的影响,以探讨不同有机肥对菠萝生长的影响机理.结果显示:(1)在花生麸处理中菠萝株高、青叶数、地上部和根鲜重较对照(施用化肥)提高,而在鸡粪和水肥处理中株高、青叶数、地上部鲜重较对照降低.(2)花生麸处理的菠萝叶片细胞膜透性较对照降低,而叶绿素含量、根系活力以及叶片和根系的可溶性糖、可溶性蛋白含量、SOD活性均较对照提高;鸡粪和水肥处理的叶片细胞膜透性和根系SOD酶活性较对照提高,而叶绿素含量、根系活力、长叶期叶片和根系的可溶性糖含量、长叶期和抽蕾期叶片的可溶性蛋白含量、叶片SOD酶活性均比对照降低.(3)花生麸能提高土壤脲酶、转化酶和过氧化氢酶的活性及土壤微生物数量;鸡粪和水肥能降低土壤脲酶、蛋白酶活性,却能增强土壤转化酶、过氧化氢酶活性,鸡粪使土壤微生物数量增加,水肥使长叶期土壤微生物数量增加,但使抽蕾期的减少.研究表明,施用花生麸能提高菠萝叶绿素含量、根系活力以及叶片和根系的可溶性糖、可溶性蛋白含量,并增强根和叶的SOD活性,同时增加了土壤相关酶活性和微生物数量,从而有效促进菠萝植株生长.     

磁处理土壤对油菜品质的影响及土壤健康质量指示

用室外盆栽试验的方法,将土壤磁效应与生物磁效应相结合,以草甸土为供试土壤,油菜为供试作物,研究了盆栽条件下,磁处理土壤对油菜(Brassica napus L.)油菜生物学产量和品质的影响,进一步探讨了磁场处理对土壤健康质量的改善作用。研究结果表明,磁场强度处理土壤不仅可提高盆栽条件下油菜的生物学产量,还促使其维生素C含量得以增加,而且油菜叶柄和叶片内的硝酸盐含量也降低,说明磁处理可以使土壤健康质量得到改善。200mT磁场强度是适于油菜生长的最佳磁处理参数。     

土壤-小麦生态系统的磁化效应及其生态指示

应用室外盆栽试验方法,将土壤磁效应与生物磁效应相结合,研究了磁处理土壤对土壤-小麦系统健康的影响．结果表明,磁处理棕壤后土壤-小麦系统的健康状况得到较为明显的好转,包括使小麦种子提前出苗,出苗整齐一致;增加小麦幼苗的株高、主茎叶片数、分蘖数、单株根数和单株叶面积;使小麦根系的总吸收面积、活跃吸收面积、活跃吸收面积占总吸收面积的百分比提高;增加成熟小麦的有效穗数、结实小穗数、平均穗粒数、千粒重,减少不孕小穗数,提高小麦的生物学产量．在此基础上,对土壤-小麦系统磁化健康效应的生态指示进行了理论探讨,其中,200mT磁场强度是适于小麦生长的最佳磁处理参数．     

优康唑（S3307）对油菜幼苗某些生理特性的影响：简报

油菜以一定浓度的S－3307浸种后,幼苗根系干重、根冠比值、可溶性糖、可溶性蛋白质、叶绿素含量、SOD、CAT和NR活性均提高;光合产物向根部运输增加．根系活力和根系对32P的吸收增强;膜脂不饱和脂肪酸含量也有提高;石蜡切片显示,叶柄发育明显快于对照,根颈增粗,维管束发达,植株矮化,苗壮。     

不同作物两苗同穴互作育苗的生理生态效应

为了探明不同作物两苗同穴互作育苗提高目的作物幼苗素质的机理,本试验在塑料温棚20-30℃、自然光照条件下,采用532mm×280mm具有200方形孔的塑料育苗盘,用土壤作基质,分别以小麦、玉米、谷子、高粱和目的作物棉花、油菜、番茄、花生、牡丹、烟草同穴播种,研究了互作育苗对育苗土壤微生物、酶活性及根系分泌物的影响,以及对目的作物幼苗根系活力、叶片可溶性糖含量和ATP含量的影响,结果表明:随互作苗的加入,育苗土壤中细菌数量显著增加52.80％-102.76％、放线菌数量显著增加34.11％-76.48％、真菌数量显著降低44.33％-56.14％;所测土壤酶活性显著提高,其中脱氢酶活性显著提高30.57％-66.37％、中性磷酸酶活性显著提高38.17％-54.37％、转化酶活性显著提高23.74％-35.04％、脲酶酶活性显著提高60.25％-85.47％;所测根系分泌物积累量显著减少,其中2,4-二叔丁基苯酚显著减少32.80％-51.65％、2,6-二叔丁基苯酚显著减少36.60％-56.59％、邻苯二甲酸二丁酯显著减少10.42％-49.99％、9-16碳烯酸甲酯显著减少25.62％-55.59％;目的作物则表现为根系活力、叶片可溶性糖含量和ATP含量显著提高,增加了目的作物幼苗根重、苗重和侧根数,离床存活期延长,栽后缓苗期缩短,表现互作促进.在所有互作处理中,以棉花+小麦、棉花+谷子、油菜+谷子、番茄+小麦、番茄+谷子、花生+小麦、花生+谷子、牡丹+谷子、烟草+谷子处理中目的作物幼苗素质表现较好.不同作物两苗同穴互作育苗改善了育苗土壤微生物数量和结构,这可能是提高土壤酶活性和降低土壤有害根系分泌物积累的主要原因,进而提高了目的作物幼苗素质.     

壳聚糖包衣对油菜种子萌发及幼苗耐盐性影响

以不同浓度的壳聚糖对油菜种子进行包衣处理,考察其对油菜种子萌发及幼苗耐盐性的影响,并在不同盐浓度胁迫条件下对种子萌发时的发芽势、发芽率、生物量（鲜重、干重、根长、芽长）等指标进行测定,同时分析油菜幼苗叶绿素含量、可溶性蛋白及可溶性糖含量的变化。结果表明,一定浓度的壳聚糖包衣处理可提高油菜种子发芽率、发芽势、生物量、幼苗的耐盐指数、叶绿素含量、可溶性蛋白及可溶性糖的含量,其中浓度为0.25 g·L^-1壳聚糖包衣处理对油菜种子萌发的促进效果较好,而浓度为0.50 g·L^-1壳聚糖包衣处理对提高油菜幼苗耐盐性具有较好的促进作用。     

薯蓣皂素对油菜种子萌发及幼苗生长的影响

薯蓣皂素对油菜种子萌发及幼苗生长的作用随处理浓度的不同而有差别。0．5mg／L对种子萌发和幼苗生长有明显的促进作用,处理后的油菜幼苗下胚轴伸长,干鲜重增加,并且子叶中可溶性蛋白、可溶性总糖、过氧化物酶和过氧化氢酶、Ca2 -ATP酶的活性都高于对照,这表明适度的薯蓣皂素有利于油菜生长和代谢。     

冬小麦幼苗根系适应土壤干旱的生理学变化

采用盆栽试验对冬小麦幼苗根系适应土壤干旱的生理学变化进行了初步研究。结果表明，随干旱胁迫的加剧，洛麦9133和济麦21幼苗根水势、根相对含水率和根系活力均降低，饱和亏、可溶性糖含量、脯氨酸含量、质膜透性以及SOD、POD活性均呈增加趋势。这说明，在干旱胁迫下，冬小麦幼苗根系通过降低水势、相对含水率和根系活力，增加渗透调节物质可溶性糖、脯氨酸含量和增强SOD、POD活性等生理上的变化以提高抗旱性，从而使冬小麦幼苗适应干旱逆境。     

突变哈茨木霉H-13对小白菜生长和品质的影响

用N＋离子束诱变哈茨木霉,得到促生长突变型哈茨木霉H-13,用不同浓度的哈茨木霉H-13发酵液浸种处理小白菜种子,对幼苗进行灌根处理发现,发酵液稀释100倍和200倍处理,提高了种子的活力指数、植株鲜重和叶绿素含量,增加了植株体内可溶性还原糖和可溶性蛋白的含量,降低了植株体内硝酸盐和亚硝酸盐的含量.     

活性炭对苦荞幼苗根系和叶片生理特性的影响

以山西省主栽苦荞品种‘黑丰1号’温室盆栽幼苗为材料,设置土壤活性炭含量分别为0(CK)、2.5(B2.5)、5.0(B5.0)、7.5(B7.5)、10(B10)g/kg共5个水平,研究土壤中施加活性炭后对苦荞幼苗根系及碳氮代谢、保护酶活性等指标的影响.结果显示:(1)随着活性炭施用比例的增加,苦荞幼苗根系生长指标和根系活力指标均呈先增后减的趋势,根平均直径呈先减后增的趋势,其中B5.0、B7.5处理的幼苗根系总长度、总表面积、总体积、活跃吸收面积、根尖数均显著高于对照,但B10处理的根系发育减弱.(2)随活性炭施用比例的增加,苦荞幼苗叶片蔗糖酶活性变化呈先增后减的趋势,同一处理水平条件下随苦荞的生长而逐渐下降;B2.5、B5.0处理苦荞幼苗叶片蔗糖酶活性和可溶性糖含量均比CK极显著增加,B7.5处理略有提高,B10处理差异不显著.(3)苦荞幼苗叶片谷氨酰胺合成酶(GS)活性随活性炭的增加基本呈上升趋势,而同一处理水平下随苦荞的生长而下降;叶片GS活性在B5.0、B7.5处理时比CK极显著提高,可溶性蛋白质含量在B7.5处理时也显著提高.(4)叶片保护酶SOD、POD、CAT活性随活性炭浓度的升高呈先升后降的变化趋势,而同一处理水平下各时期间变化不大;B2.5处理叶片的SOD、POD和CAT活性比对照显著增强.研究发现,适量施用活性炭(2.5～7.5g/kg)能有效促进苦荞幼苗碳氮代谢和保护酶活性,增强其根系活力.     

Characterisation of hemp (Cannabis sativa L.) roots under different growing conditions

Hemp (Cannabis sativa L.) is mainly grown for its fibre and is considered a desirable crop for sustainable production systems. In a field trial carried out over two years in Northern Italy the root system of a hemp crop, cultivated at contrasting plant densities, was sampled and analysed with an image analysis software. Root length density (RLD) was highest in the first 10 cm of soil, almost 5 cm cm^?3; it decreased progressively until the depth of 130 cm, a part from a peak at 90–100 cm in response to a perched water table. Roots were found to 130 cm of depth in one year and to 200 cm in the other. Root diameter was finer (190 μm) in the upper soil layer, it increased with depth until 100 cm, and remained constant at 300 μm thereafter. Following the same trend of RLD, root biomass was highest in the first soil layer; 50% of the root biomass was found in the first 20 cm or 50 cm when taproot biomass was considered or not. Total root biomass was 3.21 t ha^?1 and 2.41 t ha^?1 in the two years of trial, but the ratio between aboveground and below ground biomass was constant at 5.46. None of the root parameters were significantly affected by plant population, which seems to confirm the plastic behaviour that hemp shows for aboveground development. The high root biomass production measured in this study, especially in deeper soil layers, provides additional evidence of the positive role that hemp can play in sustainable cropping systems.     

Differential recovery of above‐ and below‐ground rich fen vegetation following fertilization

Abstract. For seven years we studied the recovery of vegetation in a Belgian P limited rich fen (Caricion davallianae), which had been fertilized with nitrogen (200 g.m^?2) and phosphorus (50 g.m^?2) in 1992. The vegetation in this fen has low above‐ground biomass production (< 100 g m^?2) due to the strong P limitation. Above‐ground biomass was harvested from 1992 to 1998 and P and N concentrations measured. In 1998, below‐ground biomass was also harvested. The response to fertilization differed markedly between below‐ and above‐ground compartments. Above‐ground, P was the single most important factor that continued to stimulate growth 7 yr after fertilization. Below‐ground, N tended to decrease live root biomass and increase dead root biomass and seemed to have a toxic effect on the roots. In the combined NP treatment the stimulating effect of P (an increase of live root biomass) was countered by N. The 1998 soil analysis showed no difference in soil P in the plots. Thus, Fe hydroxides are not capable of retaining P in competition with fen vegetation uptake. However, higher capture of P in root Fe coatings from N plots may partially explain this negative N effect. The results suggest that N root toxicity will be amplified in strongly P limited habitats but that its persistence will be less influenced by P availability. This mechanism may be a competitive advantage for N₂ fixing species that grow in strongly P limited wetlands.     

西洋参根残体对自身生长的双重作用

无论在自然生态环境还是在人工农田环境下,植株残体进入土壤后都会对土壤的物理化学性质以及后茬植物的生长产生重要影响。西洋参（Panax quinquefolium L.）为人参属多年生名贵药材,在栽培生产中存在严重的连作障碍问题。为了探明秋后残留在土壤中的须根降解产物对来年植株生长的影响,以及收获后残留在田间的根茬对连作西洋参生长的作用,本实验以3年生西洋参苗为研究对象,采用室内水培试验以及田间盆栽试验,通过添加西洋参根的粉碎物模拟根残体,测定其对西洋参生长的影响。水培试验中全营养液中分别添加0.02 mg/mL、0.1 mg/mL、0.5 mg/mL西洋参根粉碎物,处理后每隔5天测定植株叶片展开情况、株高、冠幅等生长指标。盆栽试验在土壤中添加0.1 mg/g根粉碎物,于栽种后1-2个月测定西洋参叶片展开情况、株高、冠幅等生长指标;水培及盆栽试验均于展叶期、现蕾期、结果期测定地上部及地下部生物量。采用高效液相色谱法（HPLC）测定根围土壤中8种酚酸类化合物的含量。试验结果表明,水培溶液中添加0.02-0.5 mg/mL根残体,可显著抑制西洋参自身地上部分生长,推迟展叶期,结果期生物量降低14.9%-45.0%;对地下部分的影响主要表现为在展叶期显著促进须根生长(p<0.05)。与水培试验相比,盆栽土壤中添加0.1 mg/g根残体同样导致西洋参展叶期推迟;不同的是处理组的地上、地下部及须根的平均生物量均高于对照。另外,添加根残体后盆栽西洋参根围土壤中丁香酸、香草醛、p-香豆酸、阿魏酸等酚酸类化感物质含量下降49.1%-81.4%,但作为逆境信号物质的水杨酸含量升高59.9%。以上结果可以初步确认根残体对西洋参早期生长具有自毒和促进的双重作用,表现为抑制地上部分生长,导致生物量显著下降;同时在生长早期促进须根生长;但在田间环境下,自毒作用可能受根残体降解速度以及土壤对降解产物吸附的影响有所减弱,使促进作用更为明显。     

Effect of soil waterlogging on below‐ground biomass allometric relations in Norway spruce

Abstract

An increasing importance is assigned to the estimation and verification of carbon stocks in forests. Forestry practice has several long‐established and reliable methods for the assessment of above‐ground biomass; however, we still miss accurate predictors of below‐ground biomass. A major windthrow event exposing the coarse root systems of Norway spruce trees allowed us to assess the effects of contrasting soil stone and water content on below‐ground allocation. Increasing stone content decreases the root/shoot ratio, while soil waterlogging leads to an increase in this ratio. We constructed allometric relationships for below‐ground biomass prediction and were able to show that only soil waterlogging significantly impacts model parameters. We showed that diameter at breast height is a reliable predictor of below‐ground biomass and, once site‐specific parameters have been developed, it is possible to accurately estimate below‐ground biomass in Norway spruce.     

高原鼢鼠对高寒草甸植被特征及生产力的影响

本研究结果表明,高原鼢鼠栖息10年的斑块,植物群落的物种数减少,植物物种多样性指数下降,地上、地下总生物量显降低,单子叶和可利用双子叶植物生物量极显减少,但不可利用双子叶植物生物量显增加。高原鼢鼠去除5年后,斑块内植物群落的单子叶植物物种数增加,而双子叶植物下降,植物群落物种多样性指数下降,地上、地下总生物量显增加,单子叶和可利用双子叶植物生物量增加极显,不可利用双子叶植物生物量显降低。高原鼢鼠栖息10年的斑块,净初级生产量较未栖息地区减少68.98%。高原鼢鼠去除5年后,净初级生产量增加,但仅达到未栖息地区的58.69%。     

Seasonal storage of nutrients by perennial herbaceous species in undisturbed and disturbed deciduous hardwood forests

Question: Pollution and eutrophication of surface water is increasingly a problem in agricultural landscapes. Do intact (relatively undisturbed) and degraded forests differ in seasonal nutrient storage and therefore potential to ameliorate nutrient pollution? Location: United States, Midwestern region. Methods: We used three sets of paired plots, where intact plots were located close to disturbed woodlands. Herbaceous perennials located in eight 0.25 m² quadrats in the plots were harvested (in spring and mid‐summer), dried, separated into above‐ and below‐ground plant parts, and weighed to determine biomass. Nitrogen, phosphorus and potassium content of the plant tissues were then determined, and these data combined with biomass to estimate nutrient storage. Results: In spring, intact sites had 62% greater above‐ground biomass than disturbed sites and 75% greater below‐ground biomass. In summer, below‐ground biomass of intact plots was still much greater than that of disturbed plots (73 percent), but above‐ground biomass was similar. Nutrient tissue concentration generally did not differ, nor did soil nutrient levels. The disturbed sites were largely missing one group of species, the spring ephemerals, and this accounted for the difference in biomass and nutrient storage between sites. Conclusions: Relatively undisturbed woodlands in our study had a much greater capacity to store nutrients, and therefore ameliorate nutrient pollution, in early spring. This is significant because spring is also the time of highest potential leaching of nutrients into surface water.     

施用泥炭对风沙土改良及蔬菜生长的影响

通过盆栽试验比较了施用不同剂量的泥炭(0％、2％、5％、8％及10％)对风沙土改良的效果和对白菜生长及产量的影响。结果表明,泥炭能增强风沙土的持水能力,降低土壤的pH值,增加土壤中有机质、全氮、速效氮和速效磷等的含量;白菜根系长度、生物量、高生长和地上部分的生物量均有增加,其中8％泥炭处理为最佳,其根系长度、根鲜重、干重、高生长、地上部分鲜重、干重依次比对照增加71％、402％、464％、107％、847％和1001％;同时施用泥炭还有利于提高白菜干物质的积累及其品质。     

Above- and below-ground responses of C3–C4 species mixtures to elevated CO2 and soil water availability

We evaluated the influences of CO₂[Control, ～ 370 µ mol mol ^{? 1}; 200 µ mol mol ^{? 1} above ambient applied by free‐air CO₂ enrichment (FACE)] and soil water (Wet, Dry) on above‐ and below‐ground responses of C₃ (cotton, Gossypium hirsutum) and C₄ (sorghum, Sorghum bicolor) plants in monocultures and two density mixtures. In monocultures, CO₂ enrichment increased height, leaf area, above‐ground biomass and reproductive output of cotton, but not sorghum, and was independent of soil water treatment. In mixtures, cotton, but not sorghum, above‐ground biomass and height were generally reduced compared to monocultures, across both CO₂ and soil water treatments. Density did not affect individual plant responses of either cotton or sorghum across the other treatments. Total (cotton + sorghum) leaf area and above‐ground biomass in low‐density mixtures were similar between CO₂ treatments, but increased by 17–21% with FACE in high‐density mixtures, due to a 121% enhancement of cotton leaf area and a 276% increase in biomass under the FACE treatment. Total root biomass in the upper 1.2 m of the soil was not influenced by CO₂ or by soil water in monoculture or mixtures; however, under dry conditions we observed significantly more roots at lower soil depths ( > 45 cm). Sorghum roots comprised 81–85% of the total roots in the low‐density mixture and 58–73% in the high‐density mixture. CO₂‐enrichment partly offset negative effects of interspecific competition on cotton in both low‐ and high‐density mixtures by increasing above‐ground biomass, with a greater relative increase in the high‐density mixture. As a consequence, CO₂‐enrichment increased total above‐ground yield of the mixture at high density. Individual plant responses to CO₂ enrichment in global change models that evaluate mixed plant communities should be adjusted to incorporate feedbacks for interspecific competition. Future field studies in natural ecosystems should address the role that a CO₂‐mediated increase in C₃ growth may have on subsequent vegetation change.     

Linking above-ground and below-ground effects in autotrophic microcosms: effects of shading and defoliation on plant and soil properties

Although factors affecting plant growth and plant carbon/nutrient balance – e.g., light availability and defoliation by herbivores – may also propagate changes in below‐ground food webs, few studies have aimed at linking the above‐ground and below‐ground effects. We established a 29‐week laboratory experiment (～one growing season) using autotrophic microcosms to study the effects of light and defoliation on plant growth, plant carbon/nutrient balance, soil inorganic N content, and microbial activity and biomass in soil. Each microcosm contained three substrate layers – mineral soil, humus and plant litter – and one Nothofagus solandri var. cliffortioides seedling. The experiment constituted of the presence or absence of two treatments in a full factorial design: shading (50% decrease in light) and artificial defoliation (approximately 50% decrease in leaf area in the beginning of the growing season). At the end of the experiment a range of above‐ground and below‐ground properties were measured. The shading treatment reduced root and shoot mass, root/shoot ratio and leaf production of the seedlings, while the defoliation treatment significantly decreased leaf mass only. Leaf C and N content were not affected by either treatment. Shading increased NO ₃–N concentration and decreased microbial biomass in humus, while defoliation did not significantly affect inorganic N or microbes in humus. The results show that plant responses to above‐ground treatments have effects which propagate below ground, and that rather straightforward mechanisms may link above‐ground and below‐ground effects. The shading treatment, which reduced overall seedling growth and thus below‐ground N use and C allocation, also led to changes in humus N content and microbial biomass, whereas defoliation, which did not affect overall growth, did not influence these below‐ground properties. The study also shows the carbon/nutrient balance of N. solandri var. cliffortioides seedlings to be highly invariant to both shading and defoliation.