【作者】 油天钰；

【导师】 兰海燕；

【作者基本信息】 新疆大学 ， 生物化学与分子生物学， 2010， 硕士

【摘要】 藜是世界广泛分布的一种藜科植物,具有很强的适应性和较强的耐盐性。对其进行盐胁迫下的响应研究,为深入探讨其耐盐机制,进一步认识和利用其改良土壤创造条件。本论文通过石蜡切片、扫描电镜、体视显微镜观察以及各种生理指标的检测,对藜在不同盐浓度短期和长期胁迫下的形态结构和生理响应进行研究,获得了以下主要结果:1.在盐短期胁迫下,藜植株含水量、相对电导率和丙二醛含量在不同盐浓度处理不同时间下没有显著变化。其中可溶性糖含量在较短时间内随着盐浓度的升高有所增加。而脯氨酸和甜菜碱含量在均无显著升高。以上结果显示短期盐胁迫下,各指标在高低盐浓度之间差异较小,藜生长状态并未受到明显影响。2.在盐长期胁迫下,藜的株高和茎粗随盐浓度的升高而降低,生长受到抑制,但对叶面积的影响较小,且叶无肉质化现象。叶解剖结构也并未因盐胁迫而产生显著差异。然而茎的解剖结构显示,随着盐浓度的升高,茎的形成层和髓射线增厚且密度增大;随着盐浓度的升高,根的木质化程度增强,导管密度降低,直径减小。另外观察到叶片表面有大量囊泡,其密度随盐浓度升高无显著增加;叶和茎的很多细胞中都含有簇状结晶,茎中较多,未观察到结晶数量随盐浓度增加而上升的趋势。这些结果显示盐的长期胁迫在一定程度上改变了藜的形态结构。3.在长期盐胁迫后对藜的生理指标检测显示,随着盐浓度的升高,其含水量和叶绿体色素含量直到花期才显著降低。其相对电导率则在苗期和花期都有显著地升高,但是丙二醛含量在苗期和花期都没有显著变化。在盐胁迫下渗透调节物质糖、脯氨酸和甜菜碱含量均显著升高;但是可溶性糖含量在花期又恢复至对照水平,而脯氨酸和甜菜碱含量始终保持较高水平。由此显示,藜在长期高盐胁迫下从生理水平进行了适应性调节。通过分析短期与长期盐胁迫对藜的形态及生理方面的影响显示,藜在盐短期胁迫下,只有可溶性糖含量有所增加,其他生理指标变化不显著;而长期盐胁迫使藜的形态和各项生理指标都有显著变化,尽管生长受到明显抑制,藜却能从生理水平上进行调节以适应盐胁迫环境,并能正常完成生活史。研究表明,藜是一种比较耐盐的藜科植物,其耐盐性至少部分是通过形态的改变及生理过程的调节来实现的。更多还原

【Abstract】 Chenopodium album, belonging to genus Chenopodium, widely distributes all over the world. It is meaningful to investigate comprehensive responses to NaCl stress at different levels in Chenopodium so as to make a better understanding of the salt-tolerance mechanisms of the salt-tolerant species. The present study focused on the morphological, physiological changes in C. album under short- and long-term stress of different salt concentrations, by using paraffin sections, SEM, stereomicroscope methods, and measurement of various physiological parameters. The key results are as follows:1. Under short-term salt stress, the contents of relative water, electrolyte, MDA and betaine were not significantly affected under different concentrations of NaCl. However, the contents of soluble sugar and free proline were increased with the increasing of salinity. The results showed that there was no significant difference of various parameters between low and high salt concentrations treatments. The growth and development of plant were not affected over a short period of NaCl stress.2. After a long-term of salt stress, the height of plant and diameter of stem decreased with the increasing salinity. The leaf area and anatomic structure were not affected, while the thickness of meristem and medulla in stem anatomic structure were increased; in root, the trachea density was reduced while lignification was strengthened. Furthermore, large number of salt bladders were observed on leaves, the number of which seemed not to increase with the increasing salinity. Crystals were observed in leaf and stem cells. The results indicated that during a long-term salt stress, the morphological structure of C. album was changed in some extent.3. During a long-term salt stress, the chlorophyll and relative water content of C. album were decreased more significantly in anthesis than at seedling stages. Marked increments were observed in relative electric conductance, proline and betaine contents at both seedling and anthesis stages. The content of soluble sugar was notably elevated during seedling stage, but decreased to the control level at anthesis stage. The content of MDA was not affected at both anthesis and seedling stages. The results suggested that during a long-term salt stress, C. album adjusted itself at physiological level to adapt the stress.By analysis of the responses of C. album to short- and long-term salt stress on the morphological and physiological levels, suggesting that the physiological parameters were not significantly changed except for soluble sugar with which an increment was observed under short-term salt stress; while exposed to long period NaCl stress, significant changes were observed in both structural and physiological levels. Although the growth of C. album was suppressed under long term of high salt stress, C. album could adjust itself at both morphological and physiological levels to adapt the stress, and completed the life cycle. Taking together, it imply that C. album is a salt-tolerant species, and such salt-resistant property was attributed, at least partially, to the changes in structure and the adjustment at physiological levels.更多还原