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1.
低磷胁迫下马尾松无性系磷效率性状对氮沉降的响应 总被引:2,自引:0,他引:2
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田间玉米和蚕豆对低磷胁迫响应的差异比较 总被引:1,自引:1,他引:0
【目的】植物在长期进化过程中形成了一系列适应机制,以应对低磷胁迫。本文提出玉米主要通过根系形态变化适应低磷胁迫的假设,并通过与蚕豆植株在根系形态与生理方面对低磷胁迫反应的比较试验加以验证。【方法】在中国农业大学上庄长期定位试验田进行两年田间实验,玉米和蚕豆分别单作,重复3次。在玉米抽雄前的拔节至大喇叭口期和蚕豆的初花至盛花期两次取样(两年的两次取样时间间隔10~12天),比较研究了不供磷和供磷100 kg/hm2下玉米和蚕豆生长和磷素吸收、根系在0—40 cm土层中分布、以及根际p H值和酸性磷酸酶活性的差异。【结果】1)玉米植株的生物量和含磷量远远高于蚕豆;第一次取样时蚕豆的根冠比高于玉米,而且两种植物低磷下的根冠比高于供磷充足处理。两次取样时玉米的总根长大于蚕豆,两种植物的大部分根系分布在0—20 cm表层土壤,玉米根系在0—10 cm土层的分布更多。2)蚕豆根系的比根长明显大于玉米,但单位根长吸磷量低于玉米,两种植物间的上述差异不受取样时间和供磷水平的影响。3)两次取样时,蚕豆根表的酸性磷酸酶活性均明显高于玉米。玉米根表的酸性磷酸酶活性在两个供磷水平下没有差异。第一次取样时,缺磷蚕豆根表的酸性磷酸酶活性高于供磷充足的蚕豆植株。4)缺磷蚕豆的根际土壤p H值明显低于供磷充足蚕豆;但玉米根际土壤p H值在缺磷和供磷充足条件下无显著差异。【结论】低磷条件下两种植物的根冠比均明显增加。玉米根系单位根长的吸磷量高于蚕豆,并且在含磷量丰富的表层土壤分布有更多根系,但缺磷条件下玉米没有增加根系的质子和酸性磷酸酶的分泌,主要以根系形态变化来适应低磷胁迫。结果支持本文提出的玉米主要通过根系形态变化适应低磷胁迫的假设。但蚕豆在低磷条件下除了增加根系生长外,还具有通过增加质子分泌和根表酸性磷酸酶活性提高根际土壤有效磷浓度的潜力。 相似文献
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硫化氢促进缺磷条件下水稻根系细胞壁磷的再利用 总被引:2,自引:0,他引:2
在缺磷条件下,外源添加10 nmol/L H_2S供体Na HS可以显著提高水稻体内的有效磷含量。进一步研究发现,H_2S主要通过提高水稻根系细胞壁中的果胶含量和果胶甲酯酶的活性来增加水稻细胞壁磷的释放,从而确保水稻在缺磷条件下的存活。添加H_2S的清除剂亚牛磺酸后进一步验证了H_2S对水稻根系细胞壁磷再利用的调控作用。同时,测定3个负责水稻体内磷转运的磷转运子基因的表达,结果显示H_2S主要通过上调磷转运子OsPT6和OsPT8基因的表达来提高水稻体内磷从根部往地上部的转运。 相似文献
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低磷胁迫下箭筈豌豆和毛叶苕子根际过程的差异比较 总被引:2,自引:1,他引:1
采用我国北方两个豆科绿肥品种: 箭筈豌豆(Vicia sativa L.)与毛叶苕子(Vicia villosa Roth),在控制条件下通过不同供磷处理的营养液培养,研究了不同绿肥作物适应低磷胁迫根际过程的差异,并揭示其高效利用磷的机理。试验通过分次取样的方法,测定了两种豆科作物在缺磷与供磷条件下的生物量、根系质子释放速率、根系有机酸分泌速率以及根表酸性磷酸酶活性的动态。结果表明,箭筈豌豆与毛叶苕子在生长前期对低磷胁迫的响应存在明显差异。箭筈豌豆主要靠增大质子释放量和提高酸性磷酸酶活性来适应低磷胁迫; 而毛叶苕子主要通过提高根冠比、扩大根系生物量来对外界环境中的缺磷状况做出响应,在缺磷时其根表酸性磷酸酶的活性显著提高。箭筈豌豆与毛叶苕子可通过协调根系形态和生理的适应性变化提高对磷的吸收。 相似文献
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西瓜根系分泌酸性磷酸酶对有机肥营养的响应 总被引:1,自引:1,他引:0
有机肥营养对西瓜品质具有提升效果,但根系对有机肥中养分的吸收机制尚不完全清楚,尤其对磷素的利用机制。本研究关注西瓜根系分泌酸性磷酸酶活性对有机肥施用的响应。采用模拟西瓜根系分泌物的方法研究有机酸对有机肥中可溶性全磷和有效磷含量的影响;采用砂培的方法,研究有机肥中的磷替代化肥磷时西瓜根系分泌酸性磷酸酶活性的响应;采用田间试验研究有机肥替代化肥以及有机肥不同施用量对西瓜根际酸性磷酸酶活性、西瓜磷营养、产量和品质的影响。结果表明,有机肥中水浸提可溶性全磷含量为6.9 g?kg~(-1),可溶性无机磷含量为525.1 mg?kg~(-1),可溶性全磷中无机磷占7.6%,有机磷占92.4%,可溶性有机磷需经过水解后才能被根系吸收。有机肥中磷替代化肥磷时,西瓜根系和根际土壤酸性磷酸酶活性均显著提高,西瓜茎、叶中磷含量提高。施用三倍有机肥时西瓜根际土壤有效磷含量和西瓜产量提高。因此,有机肥中磷替代化肥磷时,西瓜通过提高根系分泌酸性磷酸酶的活性而提高利用有机磷的能力。 相似文献
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水培试验测试了澳洲坚果幼苗在6个供磷水平下排根的产生及对磷素利用情况, 结果表明: 随供磷量的升高(0.2~3.2 mol·L-1), 澳洲坚果幼苗排根产生量、植株干重和排根占根系干重的比例均呈下降趋势; 供磷量由0.2 mol·L-1升至1.6 mol·L-1, 非排根酸性磷酸酶活性呈升高趋势, 排根酸性磷酸酶活性变化与非排根相反, 排根酸性磷酸酶活性平均比非排根高72.86%; 全磷含量为叶片>根系>茎, 0.2 mol·L-1处理的澳洲坚果幼苗根系、茎秆和叶片全磷含量均高于其他处理; 与不施磷相比, 一定供磷量(0.2~0.4 mol·L-1)可降低非排根酸性磷酸酶活性, 提高排根产生量、植株干重、排根占根系干重的比例和排根酸性磷酸酶活性, 进而增加澳洲坚果幼苗根系、茎秆和叶片全磷含量, 最终提高植株磷含量。在0~1.6 mol·L-1供磷量下, 澳洲坚果幼苗排根产生量与植株干重、排根占根系干重的比例及茎秆、根系、植株磷含量呈显著和极显著正相关, 与排根酸性磷酸酶活性、叶片全磷含量呈90%以上正相关。 相似文献
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不同作物对低磷胁迫的适应机理研究 总被引:36,自引:3,他引:36
溶液培养和砂培试验研究表明 ,低磷条件下 ,作物主要通过减小根半径、提高根冠比、增加根系比表面积、提高体内有机酸总量及酸性磷酸酶活性等来实现对低磷胁迫的适应。不同作物对低磷胁迫的适应能力不同。不同作物根分泌物对难溶性磷的活化量及作物对难溶性磷的吸收量为象草 肥田萝卜 猪屎豆。难溶性磷对作物有效性大小为铝磷 铁磷 磷矿粉。难溶性磷的有效性越低 ,作物的根冠比越大 ,养分从作物根部转移到地上部的比例越小。缺磷胁迫明显诱导作物体内有机酸总量的增加和酸性磷酸酶活性的上升。作物不同部位有机酸总量与酸性磷酸酶活性大小为叶片 茎部 根系 相似文献
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不同价态无机砷胁迫下水稻秧苗的营养生理与分子响应 总被引:2,自引:0,他引:2
为揭示水稻秧苗响应砷胁迫的营养生理机制,以"汕优63"为受体材料,采用水培方法研究了水稻秧苗在不同价态无机砷胁迫下其形态学指标(根长、株高和干重)及植株中N、P、K含量等生理响应,并采用实时荧光定量PCR (FQ-PCR)分析了不同价态无机砷胁迫下水稻秧苗根和叶中与N、P、K吸收相关的4个关键酶基因的表达差异.结果表明,砷胁迫可显著降低水稻的根长、株高、干重,As(Ⅲ)的抑制作用大于As(Ⅴ);As(Ⅲ)主要抑制水稻秧苗对磷、钾的积累,而As(Ⅴ)主要抑制氮的积累;不同价态无机砷胁迫下,水稻秧苗根部,叶部与N、P、K吸收相关的基因表达均下调,且As(Ⅲ)主要影响磷酸根离子转运蛋白和钾离子转运蛋白的表达,而As(Ⅴ)则主要影响硝酸根离子转运蛋白和氨离子转运蛋白的表达.可见,不同价态无机砷胁迫对水稻营养生理机制的影响存在差异. 相似文献
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采用中间隔网的土培根箱试验,对旱作水稻或/和西瓜接种丛枝菌根真菌(简称AM真菌)幼套球囊霉(Glomus etunicatum Becker&Gerdemann),研究了旱作水稻/西瓜间形成菌丝桥并诱导水稻磷酸盐转运蛋白OsPT11的表达和对磷吸收的影响。结果表明:(1)根箱两侧均未接种AM真菌时,旱作水稻和西瓜根系均不形成菌根,水稻根系的磷酸盐转运蛋白OsPT11也不表达。(2)西瓜侧接种AM真菌时,西瓜与水稻间形成的菌丝桥引起水稻菌根的形成,并诱导水稻根系磷酸盐转运蛋白OsPT11表达。(3)菌丝桥侵染和直接接种侵染对旱作水稻和西瓜形成丛枝菌根能达到相同的效果,旱作水稻和西瓜的菌根侵染率分别为80%以上和70%以上。(4)在旱作水稻/西瓜间作系统中,当接种AM真菌时,水稻和西瓜根际有效磷含量显著高于对照处理,水稻地上部全磷含量降低,而西瓜地上部全磷含量升高。 相似文献
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运用~(15)N示踪及非损伤微测技术,研究了不同供磷水平(0 mmol×L~(-1)、1.0 mmol×L~(-1)、2.0 mmol×L~(-1)、3.0 mmol×L~(-1)、4.0 mmol×L~(-1)、6.0 mmol×L~(-1)、8.0 mmol×L~(-1)、12.0 mmol×L~(-1)和16.0 mmol×L~(-1) H_2PO_4~-)对平邑甜茶幼苗NO_3~--N吸收及利用特性的影响,为提高果园氮肥利用效率提供理论依据。结果表明,在低磷水平(0~1.0 mmol×L~(-1))时,平邑甜茶根系长度、根系总表面积较小,且根尖数较少。随着供磷水平的增加,在2.0~4.0 mmol×L~(-1)磷浓度处理时,平邑甜茶幼苗生物量、根系长度、根系总表面积及根尖数显著高于其他处理。而在6.0~16.0 mmol×L~(-1)时,过量供磷抑制了根系的生长,使平邑甜茶幼苗根系长度、表面积均大幅降低,根尖数量骤降。非损伤扫描离子选择电极测试表明,当生长介质磷浓度在3.0~6.0 mmol×L~(-1)时,平邑甜茶对NO_3~-有吸收作用,并在3.0 mmol×L~(-1)磷浓度时其吸收速率最高。而在0~2 mmol×L~(-1)及8.0~16.0 mmol×L~(-1)磷浓度处理下,平邑甜茶对NO_3~-有外排作用。随供磷水平的增加,各器官从肥料中吸收分配到的~(15)N量对该器官全氮量的贡献率(Ndff)及植株氮素利用率呈现先升高后降低的趋势,4.0 mmol×L~(-1)磷浓度时植株氮素利用率最大,为42.24%,超过4.0 mmol×L~(-1)植株氮素利用率显著降低。适当充足的供磷刺激了幼苗根系生长,从而促进平邑甜茶对氮素的获取,过量的NO_3~-抑制了平邑甜茶根系的生长,同时叶片硝酸还原酶的活性受到抑制,因此其氮素吸收和利用效率较低。因此,磷浓度在3.0~4.0 mmol×L~(-1)时最有利于平邑甜茶幼苗的生长及氮素的吸收利用。 相似文献
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Dynamics and availability of phosphorus in the rhizosphere of a temperate silvopastoral system 总被引:9,自引:0,他引:9
A field rhizosphere study was carried out over a period of 12 months on a 6-year-old silvopastoral trial in New Zealand. The trial comprised radiata pine (Pinus radiata) with lucerne (Medicago sativa) and perennial ryegrass (Lolium perenne) understoreys. The study was initiated because of the unique interrelationships between roots in silvopastoral systems and a paucity of understanding about the processes involved in phosphorus (P) dynamics in temperate silvopastoral systems. Improving our understanding in this area has important implications for nutrient management in silvopastoral systems. Rhizosphere soils were analysed to determine inorganic (Pi) and organic (Po) P fractions, macroporous resin Pi and Po, phosphatase enzyme activity, microbial biomass carbon and pH. Concentrations of labile Pi were consistently greater and Po lower in tree rhizosphere soil compared to the companion understorey, indicating that radiata pine when grown with a productive understorey mineralised Po to a greater extent than either understorey species. Tree rhizosphere soil from under lucerne and lucerne rhizosphere soil contained the lowest concentrations of total Pi and Po compared with tree under ryegrass and ryegrass rhizosphere soils. This was partly attributed to higher levels of phosphatase enzyme activity in the lucerne rhizosphere soils. The results suggest the combination of lucerne with radiata pine may enhance greater utilisation of soil P, although this requires further investigation. Lower levels of labile Po, and higher levels of labile Pi and phosphatase enzyme activity, were determined in tree and understorey lucerne and ryegrass rhizosphere soils in spring compared with autumn. This data confirmed that overall rates of soil organic P mineralisation are greatest in spring. 相似文献
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Phosphatase activity in the rhizosphere and its relation to the depletion of soil organic phosphorus 总被引:23,自引:4,他引:23
Summary The distribution of phosphatase activity and of phosphate fractions of the soil in the proximity of roots was studied in order to evaluate the significance of phosphatases in P nutrition of various plants (Brassica oleracea, Allium cepa, Triticum aestivum, Trifolium alexandrinum). A considerable increase in both acid and alkaline phosphatase activity in all the four soil-root interfaces was observed. Maximum distances from the root surface at which activity increases were observed ranged from 2.0 mm to 3.1 mm for acid phosphatase and from 1.2 mm to 1.6 mm for alkaline phosphatase. The increase in phosphatase activity depended upon plant age, plant species and soil type. A significant correlation was noticed between the depletion of organic P and phosphatase activity in the rhizosphere soil of wheat (r = 0.99**) and clover (r = 0.97**). The maximum organic P depletion was 65% in clover and 86% in wheat, which was observed within a distance from the root of 0.8 mm in clover and 1.5 mm in wheat. Both the phosphatases in combination appear to be responsible for the depletion of organic P. 相似文献
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《Communications in Soil Science and Plant Analysis》2012,43(15):1995-2017
To evaluate phosphorus (P)–stress–induced relative growth responses, P-efficiency characteristics, P remobilization, and redesign in root architectural systems, Brassica cultivars were grown with sparingly soluble rock phosphate and calcium phosphate [Ca3(PO4)2] or with low/high P supply in solution and sand culture experiments. Tested cultivars showed considerable genetic diversity in biomass accumulation, concentration and contents of P, P-stress factor (PSF), and P-efficiency characteristics [P-utilization efficiency (PUE), P efficiency (PE), and P-efficiency ratio (PER)]. Statistically significant correlations were observed between P efficiency and growth parameters. Elongation rates of primary roots decreased but the length of lateral roots and branched zone elongation rates increased under P starvation. Cultivars remobilized P from metabolically inactive to active sites in P-stressed plants that may have helped low-P-tolerant cultivars to establish a better rooting system, which provided basis for enhanced P-use efficiency and tolerance against P stress. Cultivars depicting high P efficiency and low PSF values were more tolerant and are a better choice to grow under P-stress environments. 相似文献
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镉诱导拟南芥根尖过氧化氢积累导致植物根生长抑制 总被引:3,自引:0,他引:3
以模式植物拟南芥为材料研究了植物主根对不同浓度镉胁迫的响应。结果表明,随镉浓度的升高,植物主根生长受到明显抑制,胎盘兰染色表明高剂量的镉造成主根根尖细胞死亡。进一步二氨基联苯胺(DAB)染色发现镉胁迫诱导植物根尖大量积累过氧化氢,而在胁迫培养基中加入维生素C可显著改善植物根的生长、降低过氧化氢积累,并减少镉诱导的根尖细胞死亡。上述结果表明,镉胁迫诱导的拟南芥主根生长抑制很可能是由于根尖细胞过氧化物积累所致。 相似文献
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Several ectomycorrhizal fungi, including Hebeloma cylindrosporum, actively release large quantities of phosphatase enzymes into their growth medium. We fractionated the phosphatase activity of the ectomycorrhizal association between H. cylindrosporum and its host plant, Pinus pinaster, with the aim to quantify its spatial and temporal variation in response to contrasting soil phosphorus conditions. Seedlings were grown in mini-rhizoboxes and the phosphomonoesterase activity of rhizosphere soil, released by roots, surface-bound to roots or mycelium was determined spectrophotometrically with the p-nitrophenyl phosphate method or microscopically with the ELF-method as a function of culture time. We showed that acid phosphatase activity of the soil and the root increased with mycorrhizal association. We also observed that the phosphatase activity associated with ectomycorrhizal plants was related to soil type. All phosphatase fractions decreased over culture time, except the proportion of hyphae exhibiting phosphatase activity in the extramatrical mycelium, which increased over time. The specific fractions of phosphatase activity associated with the mycorrhizal plants were clearly related to the soil phosphorus type and content. Soils showed an increase in acid phosphomonoesterase activity with mycorrhizal association, supporting a role for this enzyme in the degradation of soil bound phosphorus. The gradually increasing proportion of hyphae in the extramatrical mycelium exhibiting alkaline phosphatase activity, particularly under low phosphorus conditions, indicates an induction of alkaline phosphatase activity by phosphorus limitation. 相似文献