Knowledge Resource Center for Ecological Environment in Arid Area
| 真盐生植物硝态氮吸收特性及调控研究 | |
| 其他题名 | Uptake and regulation of nitrate nutrition of euhalophyte |
| 原俊凤 | |
| 出版年 | 2009 |
| 学位类型 | 博士 |
| 导师 | 田长彦 |
| 学位授予单位 | 中国科学院新疆生态与地理研究所 |
| 中文摘要 | 盐生植物营养是盐生植物研究领域中的一个重要的研究课题，其中氮素营养在盐生植物生理中显得尤为重要，因为许多含氮化合物是盐生植物细胞质中重要的渗透调节物质，但有关盐生植物氮素营养生理生态的研究报道很少，对盐生植物硝态氮吸收特性、调控机制及其与盐生植物耐盐性关系仍不十分清楚。本论文选择新疆干旱区典型的真盐生植物囊果碱蓬（Suaeda Physophora Pall.）和梭梭（Haloxylon ammodendron (Mey.)Bge）为研究材料，研究了Na+对盐生植物NO3-吸收的影响，盐胁迫下盐生植物根系形态对硝态氮吸收的适应性变化，盐生植物NO3-的低亲和吸收特征以及不同生境的旱生盐生植物梭梭的氮吸收、利用差异和生态适应机制，从盐生植物营养学角度探索盐生植物氮素吸收的调控机制和提高盐生植物抵抗盐胁迫能力的关系，提高人们对盐生植物抗盐机理的认识，促进盐生植物资源利用和盐土农业的发展，并为盐碱地区盐生植物的栽培和生态系统的恢复提供理论依据。\n为了理解氮素营养状况与盐生植物耐盐性的关系，研究了盐、氮及其互作对囊果碱蓬的根系形态特征、氮营养状况及植物耐盐性的影响。结果表明：囊果碱蓬的根系发育与地上部的生长、氮素营养的累积存在密切关系。与低盐或低氮的对照相比，增加盐或者氮处理均显著增加囊果碱蓬的地上部和根部干重，并且根部干重的增加幅度显著高于地上部。不同的盐和氮水平下囊果碱蓬根系的初生根长、平均直径、比根长和根系密度没有显著影响，但显著增加了根系的侧根长、侧根数、平均侧根长、表面积、总吸收面积和活跃吸收面积。除了根系的平均直径和主根长外，地上部干重、有机氮、硝态氮和总吸氮量与根系的侧根长、侧根数、表面积、总吸收面积和活跃吸收面积均存在极显著的正相关。与1和150 mmol/L NaCl相比，300 mmol/L NaCl水平下，0.05和5 mmol/L NO3--N处理显著降低了盐胁迫下囊果碱蓬地上部的硝态氮含量，但10 mmol/L NO3--N处理下变化不大，说明囊果碱蓬地上部的需氮量随着盐分水平的增加而增加，而根系形态的变化为这种增加提供了保障。\n以陆地棉（Gossypium hirsutum L.）为对照，在不同氯离子和氮营养状况下，研究了盐生植物囊果碱蓬硝态氮低亲和吸收动力学特征，探讨了盐分胁迫下盐生植物NO3-高效吸收的调控机制。结果表明：两种植物NO3-的低亲和吸收动力学呈线性吸收，且囊果碱蓬NO3-的净吸收速率和硝酸还原酶的活性显著高于陆地棉；KNO3预处理后囊果碱蓬和陆地棉NO3-的净吸收速率分别比对照降低了46.6%和45.5%；NaCl长期胁迫显著抑制NO3-的吸收，且陆地棉NO3-的净吸收速率下降幅度显著大于囊果碱蓬；NO3-的净吸收速率与根系Cl-的含量呈显著性负相关；短期NaCl和KCl胁迫下陆地棉NO3-的净吸收速率分别比对照降低了43.8%和37.5%，但对囊果碱蓬NO3-的净吸收速率没有显著影响。研究发现，囊果碱蓬短期盐胁迫下介质中Cl-的浓度对NO3-的低亲和吸收系统影响较小，内部的高氮需求和Cl-的累积共同调控盐分下囊果碱蓬NO3-的吸收。\n研究了Na+对囊果碱蓬NO3-吸收和渗透调节的影响，结果表明：不同盐处理对囊果碱蓬的干重没有显著影响，但300 mmol/L NaCl和150 mmol/L NaCl+150 mmol/L KCl 处理显著增加了叶片的含水量和肉质化。叶片中Na+和NO3-含量在150 mmol/L NaCl +150 mmol/L KCl 处理下最高，而300 mmol/L KCl处理下最低。在150 mmol/L NaCl +150 mmol/L KCl 处理下NO3-，Na+，Cl-和K+的计算渗透势在实测渗透势中的贡献率为9.8%，31.0% 23.3%和14.5%，而300 mmol/L KCl处理下分别为1.6%，7.9%，11.9%和10.6%。与阳离子K+相比，Na+对囊果碱蓬NO3-的吸收具有一定的促进作用，这种刺激作用提高了囊果碱蓬盐胁迫下的渗透调节和营养平衡。\n以新疆旱生盐生植物梭梭为材料，研究硝态氮对盐胁迫下盐碱地和沙地两种生境下梭梭幼苗的生长、离子的累积和氮的吸收及渗透调节的影响。结果表明：盐胁迫下盐地梭梭地上部累积Na+和K+的能力显著高于沙地梭梭，盐地梭梭累积的Na+和K+含量分别是沙地梭梭的1.52和1.47倍。300 mmol/L NaCl胁迫下，0.05和1 mmol/L NO3--N处理时，沙地梭梭地上部有机氮和NO3-的含量显著下降，而盐地梭梭的变化不大。说明两种生境梭梭在适应环境过程中离子吸收能力和氮代谢均产生了差异，也反映出盐地梭梭长期进化过程中保留下来的一种对高盐低氮环境的适应性。梭梭地上部NO3-的计算渗透势在实测渗透势的贡献率仅为5%，显著低于对照，但梭梭地上部的干重和相对生长速率没有显著影响，说明盐分胁迫下梭梭NO3--N的营养功能大于其渗透调节作用。 |
| 英文摘要 | Nitrogen, in one form or another, accounts for about 80% of the total mineral nutrients absorbed by plants. Inadequate nitrogen is often the growth-limiting factor under salt stress. Nitrogen nutrition is the primary one for the reason that most of the osmotic adjustment substance in the plants cell cytoplasm are nitrogen containing compounds. The study of the nutrition ecophsiology of the halophyte is few, and the relationship between the nitrate uptake and the salt tolerance of the halophyte is scarely studied. The dissertation focus on the effects of nitrate on the root growth and salt tolerance of Suaeda physophora seedlings under NaCl stress, characterization of the low affinity transport system for NO3- uptake by S. physophora roots in the similar condition, effects of NaCl and NO3--N on ions uptake, nitrogen accumulation, and osmotic adjustment of Haloxylon ammodendron from different desert regimes, and the relationship between sodium-dependent nitrate uptake and osmotic adjustment of S. Physophora. The dissertation provide more information on the salt tolerant mechanism of the halophyte, promote the utilization of halophyte and the halophyte agriculture development, and provide the theory direction for the culture of the halophyte in the saline region and resume of the ecosystem in the area. \nThe main conclusions are followed as:\nNO3--N plays both a nutritional role and an important osmotic role in the euhalophyte S. physophora under high salinity with adequate NO3--N supply. The effects of salinity and nitrate on root morphologic characteristics and nitrogen accumulation in shoot of S. physophora were investigated in this study in order to elucidate relationship between nitrate and salt tolerance. S. physophora seedlings were grown under solutions which were salinized by four salinity treatments (1, 150, 300 or 450 mmol/L NaCl) and enriched with three NO3--N levels (0.05, 5 or 10 mmol/L NO3--N) making nine combination treatments. The results showed that dry weight of the shoot and root were increased with increasing salinity or nitrate levels. Meanwhile, salinity and nitrate obviously increased the lateral root length, number of laterals, mean length of lateral root, surface area, absorbing area and active absorbing area of root in addition to primary root length, root average diameter, specific root length and root density of S. physophora. Dry weight and nitrogen uptake of shoot had significant positive correlations with lateral root length, number of laterals, surface area, absorbing area and active absorbing area of root.The concentrations of organic nitrogen and nitrate in shoot of S. physophora reduced significantly by 53% and 75% at 0.05 mmol/L NO3--N levels, and the values were 36% and 57% at 1 mmol/L NO3--N levels, with an increase in salinity from 1 to 300 mmol/L NaCl. However, there were no adverse effects at 10 mmol/L NO3--N treatment. Results suggested that nitrogen demand in shoot of S. physophora was increase with an increase in salinity and changes of root morphologic characteristics especially root active absorbing area meet the demand.\nThe low affinity transport system（LATS）contributes significantly to the uptake rate at external nitrate higher than 1 mmol/L. However, the LATS for nitrate uptake in halophyte and the effects of nitrate or salt ions on the system have been scarcely studied. Results showed the rates of NO3- uptake by roots of S. physophora and Gossypium hirsutum L. increased linearly with 1 to 50 mmol/L KNO3 in the uptake solution medium. Meanwhile, net NO3- uptake rate and nitrate reductase activity were progressively higher in S. physophora roots than that G. hirsutum. This implied that S. physophora had a higher demand of nitrate than that of G. hirsutum. NO3- pre-treatments decreased the net NO3- uptake rates by 46.6% and 45.5% of G. hirsutum and S. physophora roots, respectively. The result suggested that the LATS of the two species were under negative feedback control by N status of the plants. The LATS was also inhibited when G. hirsutum and S. physophora seedlings were pretreated with NaCl solution. And net NO3- uptake rate exhibited a negative correlation with Cl- concentration in roots of G. hirsutum and S. physophora. Different salt additions to uptake solutions had little effect on net NO3- uptake of S. physophora, while it decreased by 43.8% and 37.5% of G. hirsutum with 150 mmol/L NaCl and 150 mmol/L KCl addition, respectively. The differences in the characterization of LATS for NO3- uptake between G. hirsutum and S. physophora are discussed in relation to the N demand, N status, internal and external Cl- concentration brought on by salinity stress.\nThe effect of Na+ on nitrate uptake and osmotic adjustment of halophyte S. physophora was investigated under glasshouse conditions. Seedlings were exposed to 1 mmol/L NaCl, 300 mmol/L NaCl, 150 mmol/L NaCl plus 150 mmol/L KCl or 300 mmol/L KCl treaments for 30 d. Dry weight was not affected greatly by various salts, but water content and succulence in shoots of S. physophora were significantly increased at 300 mmol/L NaCl, 150 mmol/L NaCl plus 150 mmol/L KCl treaments. The concentrations of Na+, NO3- and proline in shoots of S. physophora were higher at 300 mmol/L NaCl, 150 mmol/L NaCl plus 150 mmol/L KCl treaments than that at 300 mmol/L KCl level. And the estimated contribution of NO3- to osmotic potential (CNO3) in leaves of S. physophora was 9.8% at 150 mmol/L NaCl plus 150 mmol/L KCl, and the CNa ,CCl and CK were 31.0%, 23.3% and 14.5%, respectively. However, the CNO3, CNa, CCl and CK were 1.6%, 7.9%, 11.9% and 10.6% at 300 mmol/L KCl level, respectively. Our data indicated that the results are discussed with respect to the Na+ stimulates NO3- absorption. The characteristic may explain the high nitrogen content in leaves of the desert plant under NaCl salinity.\nStudies on effects of salinity and nitrate on ion uptake, nitrogen accumulation and osmotic adjustment of Haloxylon ammodendron growing in sandy and saline deserts were conducted under greenhouse conditions. Plants grown in pots filled with quartz sand were irrigated nutrient solutions with 1 (as control) or 300 mmol/L NaCl and NO3--N supplied at concentrations of 0.05, 1 or 10 mmol/L. Salinity progressively increased the concentrations of Na+ and Cl- in shoots of H. ammodendron from both deserts. However, H. ammodendron from saline desert was more significantly salt-tolerant as a consequence of their capacity to allocate Na+, K+ and organic nitrogen in the shoot than that from sandy desert. At 0.05 and 1 mmol/L NO3--N, 300 mmol/L NaCl treatment had no adverse effects on the concentrations of NO3- and organic nitrogen in shoots of H. ammodendron from saline desert, but these values were reduced significantly in H. ammodendron from sandy deserts. These results implied the adaptation of low nitrogen environment in saline desert ecosystems of H. ammodendron. The contribution of NO3- to osmotic potential of H. ammodendron was significantly reduced at 300 mmol/L NaCl (about 5%), but the shoot biomass and relative growth rate were little influenced. It was suggested that nitrate performed more nutritional than osmotic adjustment function in H. ammodendron under salt stress. |
| 中文关键词 | 囊果碱蓬 ; 梭梭 ; 盐生植物 ; 根系形态 ; 低亲和吸收系统 ; 渗透调节 ; NaCl ; NO3- |
| 英文关键词 | Suaeda physophora Haloxylon ammodendron halophyte root morphology low affinity nitrate transport sys |
| 语种 | 中文 |
| 国家 | 中国 |
| 来源学科分类 | 生态学 |
| 来源机构 | 中国科学院新疆生态与地理研究所 |
| 资源类型 | 学位论文 |
| 条目标识符 | http://119.78.100.177/qdio/handle/2XILL650/286806 |
| 推荐引用方式 GB/T 7714 | 原俊凤. 真盐生植物硝态氮吸收特性及调控研究[D]. 中国科学院新疆生态与地理研究所,2009. |
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