紫穗槐幼苗根系生理特性和解剖结构对PEG-6000模拟干旱的响应

Abstract

PDF HTML阅读 XML下载 导出引用 引用提醒 紫穗槐幼苗根系生理特性和解剖结构对PEG-6000模拟干旱的响应 DOI: 10.5846/stxb201610312216 作者: 作者单位: 作者简介: 通讯作者: 中图分类号: 基金项目: 中央高校基本科研业务费专项（2572014CA27） Response of physiological characteristics and anatomical structure of roots in Amorpha fruticosa seedlings exposed to simulated drought with PEG-6000 Author: Affiliation: Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:采用PEG-6000模拟干旱胁迫处理，测定了紫穗槐幼苗根系的可溶性糖、可溶性蛋白质、丙二醛、游离脯氨酸含量及SOD、POD酶活性变化以及解剖结构特征，旨在比较不同干旱程度对紫穗槐幼苗根系生理指标、内部解剖结构的影响，探索紫穗槐幼苗对水分胁迫的适应能力，揭示紫穗槐幼苗根系对土壤水分胁迫的响应和调控机制。结果表明：丙二醛含量变化显示当PEG-6000溶液浓度超过50g/L以后，紫穗槐幼苗根的膜系统开始受到损伤，并在PEG-6000溶液浓度达到250g/L受损程度显著增强，达到了对照的1.6倍，同时启动渗透调节作用（游离脯氨酸含量显著增加），达到了对照的3.8倍，在PEG-6000溶液浓度低于200g/L时，紫穗槐幼苗根系中至少没有启动以游离脯氨酸为主的渗透调节过程。可溶性糖和可溶性蛋白质含量及SOD、POD酶活性的变化印证了胞内发生的生理代谢变化，在PEG-6000溶液浓度为200g/L时，可溶性糖含量仅为0.121mg/g，达到最低点，随后上升，当PEG-6000溶液浓度进一步增加到250g/L时，紫穗槐幼苗根系中的可溶性糖含量则迅速回升到0.64mg/g，为对照组的63.37%。可溶性蛋白质含量在低浓度PEG-6000溶液（50g/L）处理下即有明显反应，下降到对照的61.5%，随后呈波动性变化。SOD和POD活性对PEG-6000模拟干旱胁迫的响应规律类似，均对PEG-6000模拟干旱胁迫处理迅速响应且活性增加。当PEG-6000溶液浓度达到50g/L至100g/L时，抗氧化酶的合成量最高，而后活性下降。60d的PEG-6000模拟干旱胁迫处理影响了紫穗槐幼苗根系的生长发育，随着PEG-6000溶液浓度增加，维管柱的直径变大，木质部厚度增大，导管直径变小、但导管密度增加，当PEG-6000溶液浓度达到250g/L时，导管密度比对照组增加了41.3%，木质部厚度比对照组增加了91.5%。以上结果表明，PEG-6000模拟干旱胁迫处理下，不同胁迫程度紫穗槐内部生理和根系解剖结构变化不同，通过改变自身生理代谢和根系内部解剖结构，以适应土壤水分胁迫的逆境条件，来满足自身生长和发育的需求平衡。 Abstract:In this study, we used the PEG-6000 to simulate drought stress, and determined the content of soluble sugars, soluble protein, MDA(Malondialdehyde), and free proline, and changes in enzyme activities of SOD(Superoxide dismutase) and POD(Peroxidase) in roots of Amorpha fruticosa seedlings and in their anatomical features. Our objectives were to examine the effects of different levels of drought on the physiological indices and internal anatomical structures of seedlings of Amorpha fruticosa. Furthermore, we explored the adaptability response and regulation mechanism to water stress of Amorpha fruticosa seedlings. The results indicated that MDA appeared when the concentration of PEG-6000 was more than 50g/L, and the membrane system of Amorpha fruticosa seedling roots began to suffer damage. When the PEG-6000 concentration reached 250g/L, the extent of damage was significantly enhanced, reaching 1.6 times that of the the control group, and at the beginning of osmotic adjustment (free proline content increased significantly), it reached 3.8 times that of the control group. When the concentration of PEG-6000 solution was less than 200g/L, the osmotic adjustment process was not initiated in the roots of Amorpha fruticosa seedlings with free proline. The physiological metabolism of the cell was verified through changes in soluble sugar and soluble proteincontent, and SOD and POD activity. When the concentration of PEG-6000 was 200g/L, the soluble sugar content was 0.121mg/g, reached its lowest point, and then increased. As the PEG-6000 solution concentration further increased to 250g/L, the soluble sugar content in the roots of Amorpha fruticosa seedlings rapidly increased to 0.64mg/g, which was 63.37% of that of the control group. Soluble protein content in the low concentration of PEG-6000 solution (50g/L) treatment decreased to 61.5% of that of the control group, followed by fluctuating changes. SOD and POD activities were similar to PEG-6000 simulated drought stress, and rapidly responded to PEG-6000 simulated drought stress treatment. Simultaneously, the enzyme activity of POD and SOD were increased. When the concentration of PEG-6000 was 50g/L to 100g/L, the synthesis of antioxidant enzyme was the highest, and then it decreased. SOD amplitude activity differed by more than six fold. Changes in POD activity were relatively small, and the difference in amplitude was less than a multiple of one. The 60-、day PEG-6000 solution simulating the drought stress affected the growth and development of the root system of the Amorpha fruticosa seedlings. With the increasing concentration of PEG-6000, the diameter of the vascular bundles increased. At the same time, the diameter of the catheter decreased, but its density increased. When the concentration of PEG-6000 reached 250g/L, the catheter density increased by 41.3% compared with that of the control group, and xylem thickness increased by 91.5% compared with that of the control group. The results showed that under different levels of drought stress treatments, the internal physiology and root anatomical structures of Amorpha fruticosa varied. The stress conditions of water and self-、growth and development balance needs were satisfied by altering their physiological metabolism and the internal anatomical structure of the roots. 参考文献 相似文献 引证文献