共查询到18条相似文献,搜索用时 46 毫秒
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研究了缺水胁迫和缺铁胁迫对三叶期玉米(Zea mays)的光合作用特性和根生长的影响。玉米叶部的光合作用均受缺水胁迫和缺铁胁迫影响;短时间(≤2 h)缺水胁迫对光合作用造成的不利影响不能被短时间(24 h)的复水完全消除,而较长时间的缺铁胁迫(168 h)对光合作用造成的抑制作用可以被短时间(24 h)的补铁措施消除。短时间缺水(≤2 h)或短时间(≤72 h)缺铁不影响根系生长。较长时间的缺铁(168 h)严重限制根的生长并导致根生长畸形,短时间(24 h)补铁不能消除较长时间的缺铁对根的生长带来的不利影响。 相似文献
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营养胁迫与根系分泌物 总被引:34,自引:0,他引:34
根系不仅是活跃的吸收、代谢器官,而且是强大的分泌器官,营养元素是影响根系分泌的外界因素之一,在营养胁迫条件下,根系分泌物的组成、数量均发生变化。本文介绍了铝毒害及磷,铁。锌缺乏时,根系分泌物研究新进展。 相似文献
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缺铁水稻根表铁膜对硒的转运和吸收的影响 总被引:2,自引:0,他引:2
Under anaerobic conditions, ferric hydroxide deposits on the surface of rice roots and affects uptake and translocation of certain nutrients. In the present study, rice plants were cultured in Fe-deficient or sufficient solutions and placed in a medium containing selenium (Se) for 2 h. Then, FeSO4 was added at the various concentrations of 0, 10, 40, or 70 mg L-1 to induce varying levels of iron plaque on the root surfaces and subsequent uptake of Se was monitored. The uptake of Se was inhibited by the iron plaque, with the effect proportional to the amount of plaque induced. The activity of cysteine synthase was decreased with increasing amounts of iron plaque on the roots. This may be the important reason for iron plaque inhibition of Se translocation. At each level of iron plaque, Fe-deficient rice had more Se than Fe-sufficient rice. Furthermore, with plaque induced by 20 mg Fe L-1, plants from Fe-deficient media accumulated more Se than those from Fe-sufficient media, as the Se concentration was increased from 10 to 30 or 50 mg L^-1. We found that phytosiderophores, highly effective iron chelating agents, could desorb selenite from ferrihydrite. Root exudates of the Fe-deficient rice, especially phytosiderophores in the exudates, could enhance Se uptake by rice plants with iron plaque. 相似文献
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植物应答缺铁胁迫的分子生理机制及其调控 总被引:3,自引:0,他引:3
铁是植物生长发育中所必需的微量营养元素。虽然土壤中铁的丰度很高,但其生物有效性非常低,特别是在碱性石灰性土壤上,高pH和高重碳酸盐含量严重降低了土壤中铁的有效性。因此如何有效地提高植物对铁的利用效率及增强植物对缺铁胁迫的响应已成为目前该领域的研究热点。本文重点阐述了植物两种不同的铁吸收机制,以及对缺铁胁迫的应答反应;对目前所发现的植物中调控缺铁胁迫的相关基因进行了全面的综述,包括新发现的吞噬机理中所涉及的NRAMP基因;同时也介绍了感应铁缺乏的众多相关信号,包括植物激素、气体信号分子及microRNAs等;此外,还提出利用铁吸收相关基因的转导、控制铁吸收相关因子以及各种农艺措施的实施来提高植物铁的生物有效性从而有效缓解缺铁胁迫。最后对未来有关植物吞噬机制、铁缺乏感应信号及改善植物铁营养新途径等研究方向作了初步展望。 相似文献
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Keitaro Tawaraya Ryota Horie Akiko Saito Takuro Shinano Tadao Wagatsuma Kazuki Saito 《Journal of plant nutrition》2013,36(7):1138-1159
We applied a metabolite profiling technique to investigate root exudates under phosphorus (P) deficiency. Oryza sativa was grown in culture solution containing three P levels (0, 1, and 8 mg P L?1). Shoot extracts, root extracts, and root exudates were obtained from 18 and 23-day-old plants and their metabolites were determined by capillary electrophoresis/time-of-flight mass spectrometry. Eighty, 90, and 65 metabolites were identified in shoot extracts, root extracts, and root exudates, respectively. Sixty-three to eighty-four percent of the metabolites were exuded to the rhizosphere. More than 33% of the metabolites in the root exudates showed higher concentration at low P than at high P. On the other hand, only 14% of the metabolites in the root extracts showed lower concentration at low P than at high P. These results suggest that rice roots actively release many metabolites in response to P deficiency. 相似文献
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水稻品种对石灰性土壤缺Zn耐性机理的研究 总被引:14,自引:1,他引:13
选用缺Zn敏感水稻品种IR26和耐缺Zn水稻品种IR8192-31-2,采用营养液培养的方法,研究了水稻品种耐石灰性土壤Zn与HCO^-3关系的生理生化机制。在低锌浓度下,HCO^-3严重抑制敏感品种根系生长,而对耐性品种影响很小;HCO^-3增加增加了两种水稻品种根中的苹果酸和柠檬酸浓度,但敏感品种增加的幅度大,以上结果表明HCO^-3对敏感品种根生长的抑制,并诱发缺Zn是由于根中有机酸过度积累导致的,HCO^-3显著提高敏感品种根中PEP羧化酶活性可能是HCO^-3增加其有机酸只累,从而影响根生长及Zn有效性机理的重要过程。 相似文献
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植物根系分泌物对污染胁迫响应的研究进展 总被引:3,自引:1,他引:3
根系分泌作用是植物实现对外交流的重要形式,研究根系分泌物对环境胁迫的响应是明确植物环境适应性机制的重要途径。本文综述了植物根系分泌物对重金属污染和有机物污染的响应特点,分析了根系分泌物应对重金属和有机物污染胁迫的机制,对污染胁迫下根系分泌作用的研究和应用进行了展望,并讨论了需要进一步研究的问题。 相似文献
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HCO3-同化物在水稻体内的运输分配及其与石灰性土壤水稻耐缺锌的关系 总被引:2,自引:0,他引: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
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不同树龄茶树根层土壤化学特性及其对微生物区系和数量的影响 总被引:31,自引:2,他引:31
研究了红壤茶园中不同树龄茶树根层土壤微生物区系分布和种群结构的变化及其生态学因子。结果表明 ,随着树龄的增长 ,茶树根层土壤的酸度增加 ,pH值下降 ,土壤交换性酸组成从交换性H 为主转变为以交换性Al3 为主 ;同时 ,土壤有机碳、可溶性酚总量和全氮含量随树龄而增加。细菌、放线菌以及微生物总量以树龄 1 0年的茶树根层土壤中数量最多 ,4 0年和 90年树龄的茶树根层土壤中的较接近 ;树龄 1 0年和 90年的茶树根层土壤中真菌数量相当 ,其大于 4 0年树龄的茶树根层土壤真菌数量 ;而芽孢杆菌数量以 4 0年树龄茶树根层土壤最多 ,而 1 0年和 90年树龄茶树的接近 ;茶树根层土壤微生物生物量碳随树龄增长而增加 ,但与茶树根层土壤可培养微生物总量无显著相关。茶树根层土壤微生物生物量碳与土壤pH、有机碳、可溶性酚和全氮分别呈显著 (p<0 0 5 )或极显著 (p<0 0 0 1 )相关。 相似文献
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Maribela Pestana Pedro José Correia Teresa Saavedra Florinda Gama Susana Dandlen Gustavo Nolasco 《Journal of plant nutrition》2013,36(13):2035-2047
In the present experiment, we studied the interaction between copper (Cu) and iron (Fe) in strawberry plants grown in nutrient solutions containing different concentrations of Fe. Plants grown in the absence of iron (Fe0) had the characteristic symptoms of Fe deficiency, with smaller chlorotic leaves, less biomass, acidification of the nutrient solution, and roots that were smaller and less ramified, while no symptoms of Fe deficiency were observed in plants grown with Fe. A greater amount of Cu was found in roots of chlorotic plants than in those grown with Fe, while plants grown with 20 μM of Fe (Fe20) in the nutrient solution had a greater amount of Fe compared with plants from the other treatments. Chlorotic plants (Fe0) and plants grown with the greatest level of Fe (Fe20) had a greater root ferric chelate reductase (FC-R; EC 1.16.1.17) activity compared with the other treatments with 5 or 10 μM Fe in the nutrient solution. The same pattern was obtained for relative FC-R mRNA concentration and for the sum of Fe and Cu contents in shoots (leaves plus crowns). The DNA obtained from amplification of the FC-R mRNA was cloned and several of the inserts analysed by single strand confirmation polymorphism (SSCP). Although there were different SSCP patterns in the Fe20 treatment, all the inserts that were sequenced were very similar, excluding the hypothesis of more than one FC-R mRNA species being present. The results suggest that Cu as well as Fe is involved in FC-R expression and activity, although the mechanism involved in this regulation is unknown so far. Both small contents of Fe and Cu in plants led to an over-expression of the FC-R gene and enhanced FC-R activity in strawberry roots. 相似文献
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柑桔根系对缺铁的生理反应 总被引:1,自引:0,他引:1
柑桔在缺铁条件下,幼苗根系分泌H+和还原Fe3+的能力增加,与植株吸收铁素营养的能力相一致。摘除缺铁失绿的新叶和顶芽,抑制根系分泌H+和Fe3+还原物;但随着新叶的重新长出,根系分泌H+和Fe3+还原物的速率逐渐提高。说明缺铁失绿的组织能调控根系分泌H+和Fe3+还原物。在营养液中加入0.1nmol/L生长素(IAA),能解除因缺少失绿组织对根系分泌H~+产生的抑制作用。此外,在缺铁条件下,吸铁能力较强的酸橙根尖发生膨胀,有利于铁的接触吸收。 相似文献