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1.
试验研究Zn2 活度对不同耐低Zn水稻基因型生长及Zn吸收的影响结果表明,Zn2 活度较低时水稻生长发育受抑,其株高、叶片数、干物质积累量均随Zn2 活度的降低而下降,而根冠比、地上部和地下部Zn浓度之比则升高,且低Zn条件下耐低Zn水稻基因型“IR8192”的Zn转运能力、维持根系生长能力均高于Zn敏感水稻基因型“IR26”。  相似文献   

2.
试验采用营养液培养、同位素示踪方法,研究了HCO3-同化物在缺Zn敏感(IR26)和耐性水稻品种(IR8192-31-2)体内运输和分配的差异。研究结果表明,HCO3-同化物从敏感品种根部向地上部运输较少,在根部积累较多,而耐性品种HCO3-同化物向地上部运输较多,速率较快,而在根部积累较少;施Zn促进敏感品种HCO3-同化物从根部向地上部的运输。敏感品种离体根吸收的HCO3-高于耐性品种,并且HCO3-同化物从根尖向伸长区迁移的速率高于耐性品种。以上结果表明HCO3-同化物运输和分配差异是不同水稻品种对缺锌敏感差异的重要机制之一。  相似文献   

3.
水稻耐低锌基因型的生长发育和若干生理特性研究   总被引:11,自引:1,他引:10  
在不同Zn2+活度(pZn2+9.7,pZn2+11.0和pZn2+>11.5)的溶液培养条件下,研究了水稻耐低锌基因型的生长发育和若干生理特性。结果表明:水稻锌营养存在明显的基因型差异,降低锌离子活度会增加地下部于物质的积累,当Zn2+活度从pZn2+9.7下降到pZn2+11.0时,耐低锌品种的地上部干重虽下降,但因地下部干重显著增加,故总干重相近;锌敏感品种则地上部干重显著下降,而地下部干重增加不明显,总干重显著下降。当严重缺锌(pZn2+>11.5)时,所有基因型水稻的干重构极显著地下降,但锌敏感品种比耐低锌品种下降得更多。降低Zn2+活度使水稻秧苗的出叶速度减慢,在极度缺锌条件下,敏感品种只能生长到3.5叶,而耐低锌品种能生长到4.5叶左右。对叶绿素和根系氧化力的测定结果表明,轻度缺锌或缺锌初期会使叶绿素含量上升和根系氧化力下降,但严重缺锌时,则使叶绿素含量显著降低,而使根系氧化力明显增加。锌敏感品种比耐缺锌品种的变化更为明显。锌离子活度对秧苗的含水量也有明显的影响。因此,耐低锌基因型在低Zn2+活度条件通过保持较低的根氧化作用,促进根系生长以维持地上部新叶生长,达到低锌适应稳态。  相似文献   

4.
复合污染土壤中水稻根际元素特性及效应研究   总被引:1,自引:1,他引:0  
【目的】以广东大宝山重金属复合污染农田为生长介质,通过研究水稻不同部位生长量、 金属含量、 对金属的富集系数,及其与根际、 非根际土金属含量、 形态变化的相关关系,探讨根际效应可能对水稻体内金属积累转运以及生物量的影响。【方法】选取了广东大宝山稻田重金属复合污染(As、 Pb、 Fe、 Cu、 Zn)土壤及当地常见的20个水稻品种进行根际袋试验,即将根际袋内的土视为根际土,根际袋外的土视为非根际土,将供试水稻品种种植于根际袋土壤中60天后收获,测定水稻各部位的生长量、 不同金属的含量,根际土和非根际土中各金属有效态的含量。【结果】Fe、 Cu、 Pb、 Zn、 As在根部的富集系数均大于其在茎叶的富集系数,各金属在茎叶和根部的富集能力排序分别为Zn Cu As ≈ Pb ≈ Fe和Fe Zn As Cu Pb。根际土和非根际土中各种金属有效态含量均为Fe Cu Pb Zn As。研究还发现,有效态Fe、 Cu和Zn浓度对整株干重的影响显著,作用强弱顺序为Cu Zn Fe,对水稻生长影响作用显著的三种有效态金属Fe、 Cu和Zn均为植物生长所必需的元素。供试土壤中有效态Cu浓度对水稻的生长所起的作用最强。根际土有效态Fe浓度对根系Fe的积累作用效果显著,有效态As浓度显著抑制了根系Fe的积累,且有效态As浓度的作用强于有效态Fe。【结论】根际土中有效态Fe对株高、 根干重、 茎叶干重和整株干重均起着抑制作用,有效态Cu对水稻生长起到了促进作用。根际土有效态As和非根际土有效态Zn对根部Fe的积累起到了抑制作用,根际土有效态Fe和非根际土有效态Cu则起到了促进作用。非根际土有效态Fe和有效态Zn对水稻根长的增加均起到了促进作用。  相似文献   

5.
外源钾对铁胁迫下水稻元素吸收运输规律的影响   总被引:1,自引:0,他引:1  
以耐铁毒型水稻品种协优9308和铁毒敏感型品种Ⅱ优838为实验材料,采用水培法研究250mg/L Fe2+胁迫下,不同浓度的K+对水稻的生长特性以及不同器官和亚细胞的元素吸收运输规律的影响。结果表明,在250mg/L Fe2+胁迫下,两品种水稻生长均受到严重抑制,Fe含量显著上升,K、Na、Ca、Mg、Zn的吸收与运输受到抑制。施加外源钾可以不同程度的缓解铁毒,有效解除铁胁迫对水稻生长的抑制作用,降低水稻体内Fe含量,并促进营养元素K、Na、Ca、Zn的吸收,但对Mg元素的影响并不明显。在亚细胞分布中,Fe、K主要分布于细胞壁组分F1和以液泡为主的可溶性组分F5中。由此可知,高Fe2+胁迫抑制水稻生长,营养元素的吸收以及向地上部的运输,施加适宜浓度的外源钾有利于营养元素的吸收运输从而促进水稻生长,在一定程度上缓解铁毒。  相似文献   

6.
用溶液培养法研究不同Zn浓度对玉米缺Zn后恢复效果及胚乳在缺Zn中作用结果表明,不同基因型玉米缺Zn后恢复所需的适宜Zn浓度不同,敏感品种比非敏感品种要求更高的Zn浓度。缺Zn后恢复所需适宜Zn浓度高于正常培养所需适宜Zn浓度,低浓度Zn(0.1μmol/L)无恢复作用(生物量)。带上胚乳使敏感品种在缺Zn、低Zn下受抑程度(缺Zn与供Zn生物量差值)提高,而非敏感品种受抑程度反而减小。缺Zn与低Zn培养时体内P含量提高,胚乳可缓解这种影响。缺Zn后再供Zn可使体内Zn含量提高,而P含量降低,玉米对Zn产生奢侈吸收,使体内Zn含量超过正常供Zn水平,表明缺Zn后植物对Zn的要求提高。0.1μmol/L Zn恢复对“吉单120”玉米Zn含量无明显影响,但“辽单22”玉米Zn含量显著提高,这表明非敏感品种比敏感品种利用低Zn的能力更强。  相似文献   

7.
张琳  李光杰  施卫明 《土壤》2019,51(4):635-640
采用控制条件下的水培试验方法,研究了不同氮源条件下,外源供铁水平对粳稻品种中花11和籼稻品种扬稻6号的苗期生长特征、铵含量和铁、钾离子含量的影响。结果表明:外源铁浓度水平升高会显著缓解铵抑制的粳稻中花11的根系长度,但不缓解铵抑制的籼稻品种扬稻6号根长。外源铁浓度升高处理会显著增加两水稻品种根部铁离子含量,而显著降低两水稻品种铵态氮条件下水稻根部铵离子含量,且两品种间变化趋势相似。高量铵/铁共胁迫条件下,两水稻品种根部钾离子含量均显著降低,且两品种间变化趋势相似。粳稻中花11根系生长明显更耐铁毒害胁迫;硝态氮条件下,籼稻品种扬稻6号根部钾离子变化对铁毒害胁迫更敏感。上述结果显示外源铁浓度水平对根系铵毒害的缓解效果在不同水稻生态型之间存在差异,且这种差异可能与铁胁迫抗性之间存在关联。  相似文献   

8.
水稻根系生长对不同氮形态响应的动态变化   总被引:5,自引:2,他引:3  
赵学强  施卫明 《土壤》2007,39(5):766-771
土壤养分供应变异很大,植物根系生长对这种养分变异的响应非常敏感.为了探索水稻根系生长对N素供应响应的动态变化规律以及这种适应性变化与水稻N效率之间的关系,采用水培方法,以两个苗期不同N效率水稻品种桂单4号和南光为研究材料,比较了不同铵硝比、不同浓度NH4、不同浓度NO3-和不同浓度NH4NO3对水稻根系构型参数的影响.结果表明:NH4 和NH4NO3供应显著降低了总根长、总根表面积和总根体积,且有增加平均根直径的趋势;而NO3-供应在0~1 mmol/L浓度范围内,增加了总根长、总根表面积和总根体积,降低了平均根直径,但当NO3-供应超过1 mmo1/L后,NO3-却有降低总根长、总根表面积和总根体积的趋势,对平均根直径没有明显影响.苗期N高效基因型桂单4号总根长和总根表面积在各种N素营养条件下均显著高于N低效基因型南光.上述结果表明,NH4 和NH4NO3都抑制了水稻根系生长,而NO3-为低浓度诱导、高浓度抑制根系生长,根长和根表面积,对提高水稻N效率贡献较大.  相似文献   

9.
选用两个耐铝性差异较大的水稻品种武运粳7号(耐铝品种)和扬稻6号(铝敏感品种)作为实验材料,利用水培铝-磷交替处理试验研究了磷对水稻铝胁迫下苗期生长的影响及水稻耐铝性与磷效率之间的关系。结果表明,从水稻铝-磷交替处理下的生物量和根系形态等指标来看,P缓解了Al对两个水稻品种的毒害作用,且对敏感品种扬稻6号的缓解作用更加明显。铝-磷交替处理下,武运粳7号的体内磷含量显著高于扬稻6号的,而根部铝含量显著低于扬稻6号,因此武运粳7号体内的P/Al显著高于扬稻6号;同时,虽然两个品种间根表及根自由空间中Al浓度没有差别,而武运粳7号根表及根自由空间中P浓度显著高于扬稻6号,表现出耐铝品种更强的质外体解铝毒能力,这可能与武运粳7号较强的磷吸收效率有关。此外,与耐铝品种武运粳7号相比,铝敏感品种扬稻6号虽然磷吸收效率低,但利用效率高,即两个水稻品种的耐铝性与水稻的磷吸收效率和利用效率不一致,这为酸性土壤水稻育种提供了理论基础,即选育适应酸性土壤的水稻基因型不仅要关注其耐铝性还要关注其磷利用效率。  相似文献   

10.
铵态氮/硝态氮对水稻铝吸收的影响及其机制研究   总被引:2,自引:0,他引:2  
选用两个水稻品种武运粳7号(耐铝品种)和扬稻6号(铝敏感品种)作为实验材料,利用水培试验,通过长期和短期处理相结合的方式研究了NH4+-N和NO3--N对水稻Al吸收的影响及其作用机制。结果表明,与NH4+-N相比,NO3--N促进了水稻对Al的吸收。而且随着NO3--N浓度的提高,水稻根中Al含量显著增加,随着NH4+-N浓度的提高,水稻根中Al含量显著降低。这些结果表明NH4+-N和NO3--N对水稻Al吸收的影响具有浓度效应。当向Al溶液添加pH缓冲剂后,NH4+-N和NO3--N对根尖Al累积的影响变小,表明NH4+-N和NO3--N处理下溶液pH的变化可能是NH4+-N和NO3--N对水稻Al吸收影响不同的一个原因。  相似文献   

11.
Abstract

Effects of bicarbonate (10 mM as NaHCO3) and high pH (pH 8 buffered with HEPES) separately on root growth and accumulation of organic acids in the roots of zinc (Zn)‐efficient (IR36) and Zn‐inefficient (IR26) rice genotypes (Oriza sativa L.) were investigated in this study. The results indicated that shoot dry matter yields were decreased more by bicarbonate than by high pH for the Zn‐inefficient genotype, but not affected for the Zn‐efficient genotype. Root dry weights, especially root length, was significantly decreased by bicarbonate and high pH treatments for the Zn‐inefficient genotype, whereas was considerably enhanced by only bicarbonate treatment for the Zn‐efficient rice genotype. The reduction in root growth of the Zn‐inefficient rice genotype and the enhancement of root length in the Zn‐efficient genotype were greater when plants grown with bicarbonate than with high pH treatment. Accumulation of malate, citrate, and fumarate in roots of the two genotypes increased considerably due to both high pH and bicarbonate treatments, but to a greater extent for the Zn‐inefficient than for the Zn‐efficient cultivars. After an 8‐day treatment, more organic acids accumulated in the roots of the Zn‐inefficient genotype (IR26) when plants grown with bicarbonate than at high pH, but this was not the case for the Zn‐efficient genotype. The influence of root growth by bicarbonate appeared to be one of the major factors for the sensitivity of rice genotypes to Zn deficiency in calcareous soils. The greater inhibitory effect of bicarbonate than high pH on root growth of the Zn‐inefficient genotype might result from an excessive accumulation and inefficient compartmentation of organic acids, particularly citrate and malate, in the root cells.  相似文献   

12.
Two barley cultivars (‘Sahara’ = Zn-efficient and ‘Clipper’ = Zn-inefficient) were grown at different soil Zn fertilization (0, 0.2, 0.8, 1.6 and 3.2 mg Zn kg?1 soil). Root exudates were collected 16 and 28 days after sowing. At Zn = 0, shoot dry matter was decreased in both genotypes, but more distinctly in ‘Clipper’. At 0.2 mg Zn kg?1, the ‘Sahara’ shoot concentrations of Zn was 130% higher and shoot Zn content 44% greater compared with ‘Clipper’. Low-molecular-weight organic acid anions (=carboxylates) (malate, maleate, fumarate and cis-aconitate) and amino acids (alanine, valine, proline, aspartic acid and glutamic acid) were detected in root exudates, with the highest concentration at Zn = 0.2 mg kg?1 soil. Higher concentrations of organic acid anions as well as amino acids were noted in the rhizosphere of ‘Sahara’ than ‘Clipper’. The genotypic differences in Zn acquisition from soil may be linked to differential carboxylate and amino acid composition of root exudates.  相似文献   

13.
Background, aim, and scope  The Zn content in the human body is tremendously higher than that in the plant. It is vulnerable to Zn nutrition deficiency in the human body. Those who consume less animal products are subject to Zn deficiency and mainly live in the developing regions. The preventive measures against Zn deficiency in the human body, for example, Zn supplements from chemicals and Zn-fortified food, are expensive and often unattainable. We have been working on finding solutions to Zn malnutrition by screening Zn-efficient varieties of crops which can absorb more Zn from Zn-deficient soils and transfer more Zn to the edible part of crops. Pakchoi is a popular vegetable in many parts of the world. The Zn deficiency in the human body could be rectified by consuming Zn-efficient pakchoi cultivars. Rhizosphere is the ‘hotspot’ for plant–soil–microbe interactions, and the rhizospheric interactions play a key role in the micronutrient acquisition. However, little attention has been paid to the rhizosphere effects of different plant genotypes on the expression of nutrient efficiency. The aim of this study was to examine the difference of rhizosphere effect between two pakchoi cultivars with different Zn efficiencies. Materials and methods  A Zn-deficient calcareous purple soil was collected from central China. There were two Zn treatments, one with Zn addition (5 mg kg−1 soil) and the other, which acts as a control, with no Zn addition. Two pakchoi cultivars were Wuyueman of Zn-efficient and Heiyoubaicai of Zn-inefficient plants. Ten seeds of each pakchoi cultivar were sown in the rhizobag. The plastic pot was filled with 0.8 kg soil with 37% of the soil in the rhizobag. The seedlings were harvested on day 45 after planting. The rhizosphere and bulk soil samples were analyzed for their physical and chemical properties, microbial biomass, and Zn concentrations. Zn in the plants was also determined. Results  The cultivar Wuyueman demonstrated a much higher depletion rate of available Zn in the rhizosphere than did the cultivar Heiyoubaicai. The available Zn in the rhizosphere of Wuyueman was lower in the rhizosphere soil (0.47 mg kg−1) compared with that in the bulk soil (1.08 mg·kg−1), and the depletion rate of available Zn was 56.5% under Zn deficiency. This was closely associated with the capacity of cultivar Wuyueman to take up more Zn from the soil, especially under Zn-limiting conditions. The rhizosphere pH of pakchoi cultivars was lower than that in the bulk soil, while the microbial biomass carbon in the rhizosphere was significantly higher than that in the bulk soil. Under Zn-deficient conditions, the rhizosphere pH of the cultivar Wuyueman was lower but the microbial biomass carbon was higher than those of the cultivar Heiyoubaicai. Discussion  Soil-available Zn was substantially depleted in the rhizosphere of two pakchoi cultivars, with the greater depletion rate being found in the cultivar Wuyueman rather than in the cultivar Heiyoubaicai, especially under Zn-deficient conditions. This was related to the mobilization of Zn induced by the plants with different Zn efficiencies and, thus, Zn bioavailability in the rhizosphere. The pH decrease and the increase of microbial biomass carbon in the rhizosphere of the cultivar Wuyueman might have contributed to the translocation of Zn in its rhizosphere, which allows Zn to be absorbed more easily by Wuyueman than by Heiyoubaicai. This suggests that root-induced changes in the rhizosphere of pakchoi have a certain effect on the expression of zinc efficiency. Conclusions  Root-induced changes mobilized Zn in the rhizosphere of two pakchoi cultivars and increased its bioavailability. The rate of Zn mobilization was higher in the rhizosphere of the Zn-efficient cultivar than that of the Zn-inefficient cultivar at low Zn levels. Recommendations and perspectives  Root-induced changes in the rhizosphere are important factors for the nutrient dynamics and, thus, also for the mineral nutrition of plants. Soil conditions near the roots are different from those in the bulk soil. Many results have shown that these differences depend on soil properties, fertilizer application, plant species, and other factors. Further research should focus on the environmental effects of the rhizosphere on nutrient availability.  相似文献   

14.
锌离子活度对水稻幼苗锌吸收分配的影响及基因型差异   总被引:1,自引:1,他引:1  
采用卜HEDTA螯合缓冲营养液,在4个锌水平(pZn2+即-log[Zn2+])分别为11.4、11.0、10.3和9.7下对锌营养效率不同的4个水稻基因型[IR8192、IR26、BY(碧玉早糯)、Z921(浙农921)]进行营养液培养试验,研究水稻幼苗对Zn吸收、转运和利用规律。结果表明,随着锌离子活度下降,各水稻基因型的锌累积量下降,锌从地下部向地上部的转运率提高,锌利用效率提高,且各基因型间差异显著。在锌离子活度较低时,耐低锌基因型(IR8192)锌养分利用效率和提高养分利用率的能力要远远高于锌敏感基因型IR26和子粒富锌基因型BY;在锌离子活度较高时,水稻子粒富锌基因型BY有较强的锌富集能力,具有较高的秧苗锌累积量,这可能是其子粒富锌的主要机理之一;利用苗期营养性状筛选子粒富锌水稻基因型效果可能较好。  相似文献   

15.
To elucidate physiological mechanisms of zinc (Zn) efficiency in rice (Oryza sativa L.), comparative studies on root morphology, ultrastructure, and oxidative enzyme activities were investigated using Zn-efficient rice genotype (‘IR8192’) and Zn-inefficient rice genotype (‘Erjiufeng’). The results showed that moderate Zn-deficient conditions increased root length, root surface, and root tips in both genotypes, but a greater extent occurred in ‘IR8192’. Under moderate Zn deficient conditions, many swollen mitochondria were observed in the root tip cells of ‘Erjiufeng’, whereas most root cells in ‘IR8192’ remained intact. Disturbances in the ultrastructure of these organelles were accompanied with elevated oxidative stress in both genotypes and the increases were less in ‘IR8192’ than in ‘Erjiufeng’. This may result from the differences that existed in the activities of antioxidative enzymes between these two genotypes. These results suggest that Zn efficiency in ‘IR8192’ is closely associated with its high root tolerance to Zn-deficiency by maintaining a relatively higher efficient antioxidative system and intact root tip cell and functions.  相似文献   

16.
Genotypic variation to zinc (Zn) deficiency in barley indicates that selection for Zn efficiency is possible. Sahara (Zn-efficient) and Clipper (Zn-inefficient) were evaluated at different Zn nutrition in soil and chelator-buffered nutrient. Zinc deficiency symptoms appeared first in Clipper and later in Sahara. At 0.8 mg Zn/kg soil, shoot and root Zn concentration and content were higher in Sahara than Clipper. The root:shoot dry matter ratio of genotypes increased as Zn application decreased. The 4th and 5th leaf elongation were depressed greater in Clipper than Sahara by Zn deficiency. The genotypes responses to Zn in solution and soil were consistent in all parameters except root growth. In contrast to soil, root drymatter was greater in Clipper than Sahara in solution under Zn deficiency. Shoot Zn concentration and content can be used in assessment of barley genotypes, and may be useful criteria in screening large genotypes aimed at developing molecular markers for Zn efficiency.  相似文献   

17.
蚕豆枯萎病是土传病害,其发生与蚕豆根系分泌物有密切关系。本文以3个枯萎病不同抗性蚕豆品种——‘89-147’(高抗)、‘8363’(中抗)和‘云豆324’(感病)为材料,通过水培试验收集根系分泌物,测定根系分泌物对镰刀菌孢子萌发和菌丝生长的影响,分析对枯萎病表现出不同抗性的蚕豆品种根系分泌物中糖、氨基酸和有机酸的含量,分离鉴定了根系分泌物中氨基酸和有机酸的组分。结果表明,抗病品种的根系分泌物抑制了尖孢镰刀菌的孢子萌发和菌丝生长,在加入5 mL中抗品种根系分泌物时,显著促进尖孢镰刀菌孢子萌发,但对菌丝生长无显著影响;而在加入1 mL感病品种根系分泌物时,就能显著促进尖孢镰刀菌孢子萌发和菌丝生长。不同抗性蚕豆品种根系分泌物中氨基酸总量和总糖含量随抗性的降低而升高,有机酸分泌总量则随蚕豆品种对枯萎病的抗性增加而升高。感病品种和中抗品种中检出15种氨基酸,而高抗品种中检出14种,组氨酸只存在于中抗品种中,脯氨酸仅在感病品种中检出,3个蚕豆品种根系分泌物中均未检出精氨酸。蚕豆根系分泌物中天门冬氨酸、谷氨酸、苯丙氨酸、酪氨酸和亮氨酸含量高,可能会促进枯萎病的发生,而蛋氨酸、赖氨酸和丝氨酸含量高可能抑制枯萎病发生。酒石酸仅在抗病品种中存在,根系分泌物中有机酸种类丰富,有助于提高蚕豆对枯萎病的抗性。蚕豆对枯萎病的抗性不同,根分泌物对镰刀菌孢子萌发和菌丝生长的影响也不同,而这种抗病性差异与蚕豆根系分泌物中糖、氨基酸、有机酸的含量和组分密切相关。  相似文献   

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