磷高效利用野生大麦基因型筛选及其根际土壤无机磷组分特征

通过土培盆栽试验,研究了16份野生大麦种质资源在相同供磷水平下磷素吸收利用的基因型差异,探讨磷高效野生大麦根际土壤无机磷组分特征.结果表明：拔节期和扬花期磷素干物质生产效率（CV=11.6%、12.4%）、成熟期磷素籽粒生产效率（CV=13.7%）基因型间差异较大.不同生育时期磷高效基因型IS-22-30和IS-22-25生物量、磷积累量和磷素干物质生产效率均显著高于低效基因型IS-07-07,且高效基因型的籽粒产量分别是低效基因型的3.10和3.20倍.不施磷、施磷30 mg·kg^-1条件下,不同磷素利用效率野生大麦根际土壤有效磷和水溶性磷含量均显著低于非根际土壤,且高效基因型较低效基因型根际土壤水溶性磷亏缺量更大.根际与非根际土壤无机磷组分含量为Ca₁₀-P＞O-P＞Fe-P＞Al-P＞Ca₂-P＞Ca₈-P.在拔节期和扬花期,施磷30 mg·kg^-1条件下,磷高效基因型根际土壤Ca₈-P含量显著高于低效基因型,而Ca₂-P含量显著低于低效基因型;不施磷条件下,高效基因型根际土壤Ca₂-P和Ca₈-P含量均显著高于低效基因型,且根际土壤Ca₁₀-P均减少.施磷30 mg·kg^-1条件下,根际土壤Fe-P和O-P含量均表现为高效基因型显著高于低效基因型,Al-P含量则呈现相反的趋势;不施磷条件下,高效基因型根际土壤Al-P、Fe-P和O-P含量均显著低于低效基因型.低磷胁迫下,高效基因型活化吸收Ca₂-P、Al-P的能力强于低效基因型.     

不同基因型小麦磷素营养阈值的研究

利用温室盆栽试验,对不同磷效率小麦基因型进行了磷素营养阈值的研究。结果表明,磷低效基因对缺磷反应敏感,在不施或施磷量较低时,籽粒产量及生物量均较低,随着施磷量增加,产量缓慢增加,表现出对磷肥效应较迟钝的钝的现象,而磷高效小麦基因型在不同施磷肥或施磷量较低条件下的产量与生物量相对较高,表现出明显的耐低磷特性及对土壤难溶性磷的高效活化、吸收能力。且随产丰施磷量增加,磷高效基因型的产量急剧增加,达到一定     

不同磷源对磷高效利用野生大麦根际土壤磷组分的影响

在土培盆栽条件下,以野生大麦磷高效利用基因型IS-22-30、IS-22-25和低效基因型IS-07-07为材料,研究不施磷(CK)、无机磷(KH₂PO₄,Pi)、有机磷(phytate,Po)及二者混合(KH₂PO₄+phytate,Pi+Po)的方式施磷30 mg·kg^-1时,磷高效基因型野生大麦对磷素吸收利用能力及土壤磷组分特征.结果表明： Pi处理野生大麦干物质量和磷素积累量最大,Pi+Po处理其次,Po处理最小,均显著高于CK处理,且磷高效基因型物质生产和磷素吸收能力显著高于磷低效基因型.土壤有效磷在不同磷源处理间差异显著,Pi处理时含量最高,Pi+Po处理次之,且磷高效基因型野生大麦根际有效磷含量显著高于磷低效基因型.磷高效基因型野生大麦根际有效磷呈现亏缺现象,在Pi和Pi+Po处理时亏缺程度较大.根际与非根际土壤无机磷组分含量为Ca₁₀-P>O-P>Fe-P>Al-P>Ca₂-P>Ca₈-P,且其含量随着Pi的增加而增加.各磷源处理下,磷高效基因型野生大麦根际土壤Ca₂-P、Ca₈-P出现亏缺;Pi处理磷高效基因型野生大麦根际土壤Al-P、Fe-P出现富集.土壤中有机磷各组分含量为中活性有机磷>中稳性有机磷、高稳性有机磷>活性有机磷.野生大麦根际土壤活性有机磷和中活性有机磷呈现富集,其富集量在Pi处理时最大;中稳性有机磷和高稳性有机磷呈现亏缺.各磷源处理下,磷高效基因型野生大麦根际土壤活性有机磷含量显著高于磷低效基因型,中稳性有机磷和高稳性有机磷在基因型间差异不显著.Pi缺乏时,磷高效基因型野生大麦活化吸收Ca₂-P、Ca₈-P、Al-P和活性有机磷的能力较强.     

干旱荒漠区旱生灌木根际土壤磷变化特征

以阿拉善干旱荒漠草地的7种旱生灌木白刺(Nitraria tangutorum)、霸王(Zygophyllum xanthoxylum)、红砂(Reaumuriasoongorica)、沙冬青(Ammopiptanthus mongolicus)、沙木蓼(Atraphaxis bractata)、梭梭(Haloxylon ammodendron)和驼绒藜(Ceratoides lateens)根际和非根际土壤为试验对象,对其根际与非根际土壤全磷、有效磷及不同磷的化学形态特征进行了分析研究。结果表明,7种灌木根际土壤有效磷含量高于非根际土壤;沙木蓼根际全磷含量、DHCl-Pi、HHCl-Pi含量高于非根际土壤,其余6种灌木根际全磷含量、DHCl-Pi、HHCl-Pi含量低于非根际土壤。另外,除梭梭外,其他6种灌木根际土壤H2O-P含量均低于非根际土壤;驼绒藜根际NaHCO3-Pi、DHCl-Pi和HHCl-Pi均显著低于非根际土壤。除沙冬青外,其余6种灌木根际NaOH-Po均低于非根际土壤,7种灌木根际HHCl-Po含量均低于非根际土壤。对根际、非根际土壤全磷,有效磷含量和pH进行相关分析,根际、非根际土壤有效磷和全磷含量相关性不显著,而根际、非根际土壤有效磷和pH相关性显著。     

烟草磷效率的基因型差异及其与根系形态构型的关系

以17个具有代表性的主要烟草基因型为材料,通过盆栽试验和培养基栽培试验,研究烟草磷效率的基因型差异及其与根系形态构型的关系,为磷高效烟草品种选育提供理论依据.结果表明,施磷肥能够显著增加各供试烟草基因型的生物量及氮、磷和钾的累积量;供试烟草的磷效率和氮、钾累积量存在显著基因型差异,土壤盆栽试验中,低磷条件下的'云烟85'生物量和磷累积量分别是'NC82'的4.06倍和3.34倍,氮和钾累积量分别是'K358'的4.06倍和3.75倍;供试烟草可划分为磷低效低产型、磷低效高产型、磷高效高产型、磷高效低产型等4种类型,其中的'云烟85'、'K326'、'云烟2号'、'RG11'和'红花大金元'属于磷高效高产型,是现代磷高效高产品种选育的理想材料.供试烟草基因型的根系形态构型与其磷效率显著相关,与磷低效低产型烟草'G28'和'许金1号'相比,磷高效高产型烟草'云烟85'和'K326'在高低磷条件下根系均较发达,总根长和根表面积均较大;磷有效性对烟草根构型具有调节作用,在缺磷条件下,磷高效基因型具有浅根根构型,而磷低效基因型具有深根根构型.     

白浆土—植物系统营养物质转化机制及其有效性研究：Ⅴ.有机物对？…

采用根盒试验研究了施用紫花苜蓿腐解物对白浆土－小麦根际Ｐ素形态转化,有效性及小麦植株Ｐ素吸收的影响,结果表明,施用有机物料使土壤有效磷显著上升,铝磷,铁磷含量也显著升高,且培养时间越长,效果越明显。小麦植株含Ｐ量明显上升,且与非根际土壤上升,且与非根际土壤铝磷,铁磷的变化显著相关．     

纤维素分解菌与无机磷细菌的相互作用

大多数土壤全磷含量较高 ,但由于其固定能力很强 ,不仅有效磷含量较低 ,而且施入的水溶性磷肥很快转化为无效形态。活化土壤中无效磷库 ,提高其有效性 ,是一个具有重要实践意义的研究课题。研究结果表明 ,土壤中存在许多具活化无效磷功能的微生物 ,尤其在根际土壤中解磷微生物的数量比非根际要多[8] ,这些微生物统称为解磷菌。增加土壤或根际解磷菌的数量 ,就能活化土壤中的无效磷 ,提高磷的利用率。但土壤中的解磷菌大多数是腐生性的 ,其生长繁殖需要碳源 ,而多数情况下 ,土壤碳源很少 ,且主要是农作物残体 ,其主要成分是纤维素和半纤维素 …     

三峡库区消落带典型植物根际土壤磷形态特征

三峡库区消落带生态系统演变对水库安全具有重要影响,其中植物群落演变与土壤氮磷形态转化及释放等广受关注。然而,消落带植物根际效应与土壤磷形态关系及潜在影响并不清楚。选择三峡库区澎溪河消落带为研究对象,分别在冲积潮土、紫色土和水稻土分布的消落区采集典型草本植物(狗牙根、香附子、苍耳)和农作物(玉米)根际、非根际土壤,分析无机磷和有机磷的形态特征,探讨了消落带典型植物生长对土壤磷形态的根际效应及潜在影响。结果表明,土壤类型对土壤磷含量及磷赋存形态具有显著影响,紫色土磷含量最高,且活性磷含量低于冲积潮土和水稻土,表现出磷库稳定性较高;4种植物根际土壤全磷、有效磷及不同形态无机、有机磷(弱吸附态磷WA-P、潜在活性磷PA-P、铁铝结合态磷Fe/Al-P、钙结合态磷Ca-P、残渣态磷R-P)含量均高于非根际,表现出明显的根际富集效应;不同植物根际土壤全磷和有效磷表现为狗牙根苍耳香附子玉米,但磷形态在不同植物根际富集水平不同:活性较高的WA-P、PA-P含量在玉米和苍耳覆盖区均高于狗牙根和香附子,而较稳定Ca-P_i、R-P_i、Fe/Al-P_o、Ca-P_o含量在狗牙根和香附子覆盖区更高,表明玉米和苍耳生长有利于稳定性磷的活化,提高消落带土壤磷流失风险。不同植物根际对不同形态磷富集率差异明显,且玉米根际对活性磷形态的富集率最高,表明农业活动可能加速土壤稳定性磷的活化。pH、土壤有机质、土壤容重与无机磷的赋存形态关系密切,而有机磷赋存形态受pH影响显著,植物根际有机质积累和有机酸分泌等是影响土壤磷形态变化的主要因素。消落带植物群落演变及恢复对土壤磷形态转化具有重要影响。     

酸性土壤上缺磷和铝毒对大豆生长的交互作用

以7个磷效率不同的大豆基因型为材料,通过土壤盆栽试验进行石灰和磷肥处理,研究酸性土壤上缺磷和铝毒对大豆生长的交互影响及其基因型差异.结果表明：缺磷和铝毒是酸性土壤上同时存在的影响大豆生长的主要障碍因子,其中铝毒对大豆生长的限制更为严重;缺磷和铝毒对酸性土壤上大豆生长的影响具有显著的交互作用.同时施用石灰（降低铝毒）和磷肥（提高磷有效性）比单施石灰或单施磷肥处理对大豆生长的促进效果更显著;缺磷和铝毒对大豆磷吸收的影响远大于对氮、钾吸收的影响.合理种植大豆对酸性土壤具有较好的改良作用.同时施用石灰［1.103 g Ca(OH)₂·kg^-1土］和磷肥（2.018 g KH₂PO₄·kg^-1土）可使酸性土壤pH值平均提高38.4%,交换性铝含量降低96.3%,有效磷含量提高3223.8％.种植磷高效大豆基因型比磷低效大豆基因型对酸性土壤的改良效果更好.     

菌根形成对不同成熟度的森林优势树种磷吸收的影响

研究了不同成熟度的森林中主要优势树种菌根侵染程度、植物养分与根际土壤磷酸酶活性的变化规律, 试图探讨自然生态系统中菌根真菌影响下的磷循环特征。结果表明, 1)土壤磷酸酶活性在土壤有效磷含量低的森林群落高于土壤有效磷含量高的森林群落。季风常绿阔叶林0-10 cm 和10-20 cm 土层的土壤有效磷含量皆低于马尾松林, 该林型非根际土壤的磷酸酶活性(6.66 ± 0.69 molg^–1h^–1)则显著高于马尾松林(3.97 ± 1.05 molg^–1h^–1)。2)磷酸酶活性在根际和非根际土壤中存在差异, 群落中优势树种根际土壤磷酸酶活性高于非根际土壤。3)由于植物缺磷往往表现为成熟叶片磷含量低, 成熟叶片磷含量与根际土壤磷酸酶活性的显著负相关关系(R²=0.5416, P<0.0001)表明, 磷限制可能是诱导磷酸酶产生的驱动力之一。菌根形成对于促进菌根共生体分泌磷酸酶, 缓解土壤磷限制, 提高植物磷吸收效率具有重要作用。     

稻、麦根系H~ 的分泌与介质磷水平的关系

水稻、小麦根系H~ 的分泌量随供磷水平的降低而增加,并存在明显的昼夜变化。在自然光照下H~ 分泌量随光强度增加而增多,同时强光比黑暗时H~ 分泌对磷供应水平更为敏感。磷供应不足还诱导水稻根系柠檬酸分泌量增加,而苹果酸则差异不明显。难溶性磷的溶解率与根系H~ 和柠檬酸分泌所导致的根际pH下降有密切联系。因此,在有效磷不足的条件下可明显提高稻、麦根际土壤中难溶性磷的利用率,其中丰产型小麦和粳稻品种对土壤中磷利用的根际效应更为显著。     

根际酸化作用对杨树无性系磷营养效率的影响

应用土培盆栽技术,研究了杨树P营养效率的无性系差异与根际酸化作用的关系。P处理设4个水平,分别为0、40、80和120mg·kg^-1(P2O5),每个处理重复3次。各用土40kg,随机排列．结果表明,在缺P胁迫下,P营养高效型无性系S17、S19和105的根际pH值明显降低,最大为1．32个单位。降幅均在10％以上;而P营养低效型无性系106、797、I-69、1388和3244的根际pH值的降低则很小。最大的仅为0．21个单位,降幅均在2．5％以下。高效型无性系的根际pH值。随缺P胁迫的增加而逐渐降低。一旦缺P胁迫缓和,根际pH值随之增高,低效型无性系则不具有这种反应机理。S17、S19和105在缺P胁迫环境下,根际有效磷分别为2．64、3．27和3．28mg·kg^-1,根际有效磷的积累率均在60％以上;而无性系106、797、I—69、1388和3244的根际有效磷均不足2．00mg·kg^-1,根际有效磷的积累率不足10％。高效型无性系在缺P胁迫环境下对P的吸收量显著高于低效型无性系,统计分析也证明,缺P胁迫条件下。无性系根际有效磷的积累与根际pH值降低呈显著相关。说明根际酸化作用是根际有效磷增加的原因。     

Effects of liming and mycorrhizal colonization on soil phosphate depletion and phosphate uptake by maize (Zea mays L.) and soybean (Glycine max L.) grown in two tropical acid soils

The effects of liming and inoculation with the arbuscular mycorrhizal fungus, Glomus intraradices Schenck and Smith on the uptake of phosphate (P) by maize (Zea mays L.) and soybean (Glycine max [L.] Merr.) and on depletion of inorganic phosphate fractions in rhizosphere soil (Al-P, Fe-P, and Ca-P) were studied in flat plastic containers using two acid soils, an Oxisol and an Ultisol, from Indonesia. The bulk soil pH was adjusted in both soils to 4.7, 5.6, and 6.4 by liming with different amounts of CaCO₃.In both soils, liming increased shoot dry weight, total root length, and mycorrhizal colonization of roots in the two plant species. Mycorrhizal inoculation significantly increased root dry weight in some cases, but much more markedly increased shoot dry weight and P concentration in shoot and roots, and also the calculated P uptake per unit root length. In the rhizosphere soil of mycorrhizal and non-mycorrhizal plants, the depletion of Al-P, Fe-P, and Ca-P depended in some cases on the soil pH. At all pH levels, the extent of P depletion in the rhizosphere soil was greater in mycorrhizal than in non-mycorrhizal plants. Despite these quantitative differences in exploitation of soil P, mycorrhizal roots used the same inorganic P sources as non-mycorrhizal roots. These results do not suggest that mycorrhizal roots have specific properties for P solubilization. Rather, the efficient P uptake from soil solution by the roots determines the effectiveness of the use of the different soil P sources. The results indicate also that both liming and mycorrhizal colonization are important for enhancing P uptake and plant growth in tropical acid soils.     

Soluble inorganic tissue phosphorus and calcicole-calcifuge behaviour of plants

BACKGROUND AND AIMS: Natural and semi-natural, non-fertilized calcareous soils are consistently low in soluble and easily exchangeable phosphate. An over-utilization, or possibly an immobilization, of inorganic P in the tissues of calcifuge plants may take place, if such plants are forced to grow on a calcareous soil, though this has not been experimentally demonstrated. The objectives of this study are, therefore, to elucidate if calcifuge plants, when forced to develop on a calcareous soil, not only have lower total P (Ptot) concentrations in their leaves than calcicole plants grown on such soil, but also a lower proportion of Ptot as water-soluble, inorganic phosphate. Such differences may be of importance in understanding the calcicole-calcifuge behaviour of plants. MATERIALS AND METHODS: Plants of five calcicole and five calcifuge herbs and three calcicole and three calcifuge grasses were cultivated in a glasshouse on a moderately acid Cambisol and a calcareous Rendzic Leptosol using seeds of wild populations from southern Sweden. The calcifuges were: Corynephorus canescens, Deschampsia flexuosa, Holcus mollis, Digitalis purpurea, Lychnis viscaria, Rumex acetosella, Scleranthus annuus and Silene rupestris. The calcicoles were: Melica ciliata, Phleum phleoides, Sesleria caerulea, Arabis hirsuta, Sanguisorba minor, Scabiosa columbaria, Silene uniflora ssp. petraea and Veronica spicata. KEY RESULTS: At harvest, calcifuges had much lower leaf tissue concentrations of Ptot and Pi than calcicoles when grown on the calcareous soil, and biomass production of the calcifuges was poor on this soil. Moreover, the calcifuge herbs had, on average, a lower proportion of their Ptot as Pi than had the calcicole herbs. The calcifuge herbs were also unable to avoid excessive uptake of Ca from the calcareous soil. The calcifuge grasses maintained a similar proportion of Ptot as Pi as the calcicole grasses, but their growth was still poor on the calcareous soil. CONCLUSIONS: On calcareous soil, very little Pi in the tissues of calcifuge herbs is, at any time, available for use in various physiological functions. This is of importance to their photosynthesis, growth, competition and final survival on such soils.     

Buckwheat (Fagopyrum esculentum Moench) has high capacity to take up phosphorus (P) from a calcium (Ca)-bound Source

Two experiments were carried out in a growth chamber to investigate the phosphorus (P)-uptake efficiency of Fagopyrum esculentum Moench (buckwheat) and Triticum aestivum (spring wheat) from a Ca-bound form. The first experiment was based on a sand-culture system with either rock phosphate (RP) or CaHPO₄ (CaHP) as the P source and nitrate or ammonium nitrate as nitrogen source. A highly calcareous soil was used in the second experiment. Buckwheat was shown to be highly efficient in taking up Ca-bound P compared to spring wheat. When plants were supplied with nitrate, the total P uptake by buckwheat from RP was nearly 10-fold higher than that of spring wheat (20.1 compared with 2.1 mg P pot^–1). Changing nitrogen source from nitrate only to ammonium nitrate increased P uptake by spring wheat substantially, but not buckwheat. High P-uptake efficiency of buckwheat was also demonstrated using the field soil, but to a lesser extent, which may be related to the difference in Zn supply between sand culture and field soil. It is suggested that buckwheat may be included in intercropping or crop rotation systems to activate P sources in calcareous soils. The principal mechanism of P uptake efficiency of buckwheat may be its ability to acidify the rhizosphere; however, further study is needed to unravel the regulation of root excretion of H⁺ and its molecular basis in order to exploit buckwheat's genetic capability to utilise sparingly soluble P from soil.     

Citric acid excretion and precipitation of calcium citrate in the rhizosphere of white lupin (Lupinus albus L.)

Abstract. White lupin ( Lupinus albus L.) was grown for 13 weeks in a phosphorus (P) deficient calcareous soil (20% CaCO₃, pH(H₂O)7.5) which had been sterilized prior to planting and fertilized with nitrate as source of nitrogen. In response to P deficiency, proteoid roots developed which accounted for about 50% of the root dry weight. In the rhizosphere soil of the proteoid root zones, the pH dropped to 4.8 and abundant white precipitates became visible. X-ray spectroscopy and chemical analysis showed that these precipitates consisted of calcium citrate. The amount of citrate released as root exudate by 13-week-old plants was about 1 g plant⁻¹, representing about 23% of the total plant dry weight at harvest. In the rhizosphere soil of the proteoid root zones the concentrations of available P decreased and of available Fe, Mn and Zn increased. The strong acidification of the rhizosphere and the cation/anion uptake ratio of the plants strongly suggests that proteoid roots of white lupin excrete citric acid, rather than citrate, into the rhizosphere leading to intensive chemical extraction of a limited soil volume. In a calcareous soil, citric acid excretion leads to dissolution of CaCO₃ and precipitation of calcium citrate in the zone of proteoid roots.     

杉木、马尾松及其混交林根际土壤磷素特征

2007-2010年,在福建省南平市延平区太平试验林场比较分析了杉木、马尾松纯林及其混交林根际土壤的磷素特征.结果表明:在杉木、马尾松纯林中,根际土壤的有效磷含量均大于非根际土壤.与非根际土壤相比,杉木、马尾松纯林及其混交林的根际土壤pH值均出现下降趋势;根际土O-P的数量低于非根际土,而Al-P和Fe-P则高于非根际土;3种林型中,根际土壤对磷的吸附量小于非根际土壤;而根际土壤磷解吸量和解吸率均高于非根际土壤.杉木、马尾松纯林中,马尾松根际土壤的有效磷、Fe-P、Al-P、解吸量和解吸率均高于杉木,而O-P、磷吸附量则低于杉木.杉木与马尾松混交后,二者根际土壤磷的活化作用进一步加强,且杉木的增幅更大.杉木与马尾松混交有利于杉木根系磷素营养的改善.     

Copper uptake and phytotoxicity as assessed in situ for durum wheat (Triticum turgidum durum L.) cultivated in Cu-contaminated, former vineyard soils

This work assessed in situ, copper (Cu) uptake and phytotoxicity for durum wheat (Triticum turgidum durum L.) cropped in a range of Cu-contaminated, former vineyard soils (pH 4.2–7.8 and total Cu concentration 32–1,030 mg Cu kg⁻¹) and identified the underlying soil chemical properties and related root-induced chemical changes in the rhizosphere. Copper concentrations in plants were significantly and positively correlated to soil Cu concentration (total and EDTA). In addition, Cu concentration in roots which was positively correlated to soil pH tended to be larger in calcareous soils than in non-calcareous soils. Symptoms of Cu phytotoxicity (interveinal chlorosis) were observed in some calcareous soils. Iron (Fe)–Cu antagonism was found in calcareous soils. Rhizosphere alkalisation in the most acidic soils was related to decreased CaCl₂-extractable Cu. Conversely, water-extractable Cu increased in the rhizosphere of both non-calcareous and calcareous soils. This work suggests that plant Cu uptake and risks of Cu phytotoxicity in situ might be greater in calcareous soils due to interaction with Fe nutrition. Larger water extractability of Cu in the rhizosphere might relate to greater Cu uptake in plants exhibiting Cu phytotoxic symptoms.