【作者】 魏秋平；

【导师】 章文华；

【作者基本信息】 南京农业大学 ， 植物学， 2007， 硕士

【摘要】 盐胁迫可以引起植物组织中多胺水平变化,同时外源多胺处理可以增强植物对盐胁迫的抗性,但是外源多胺的作用机理尚不清楚。本文选用拟南芥(Arabidopsisthiliana)为研究对象,比较了不同浓度、不同种类外源多胺对拟南芥幼苗盐害的缓解效应;同时采用不同浓度盐胁迫下拟南芥幼苗内源多胺含量的测定和外源精胺处理缓解拟南芥盐害相结合的方法,研究了多胺和拟南芥耐盐性之间的关系。研究结果如下:100 mmol/L NaCl胁迫下拟南芥幼苗的生长受到明显的抑制,相同条件下比较了不同浓度的4种外源多胺-腐胺(Put)、尸胺(Cad)、亚精胺(Spd)、精胺(Spm)对拟南芥幼苗盐害的缓解效应,发现外加0.01 mmol/L Spd、0.01 mmol/L Spm在不同程度上都能增加幼苗根的伸长和干鲜重,其中以0.01 mmol/L Spm效果更显著;但是1mmol/L Put和0.05 mmol/L Cad作用相对不明显。对不同浓度NaCl处理下的拟南芥幼苗体内三种形态多胺含量进行测定,结果显示,50 mmol/L NaCl刺激高氯酸可溶性结合态Spd积累,除此之外,随着盐浓度的增加,游离态和高氯酸可溶性结合态Spd含量显著下降,而Spm含量逐渐升高;150mmol/L NaCl处理7天,游离态Put比同期对照有所降低,在其它浓度和时间处理条件下,三种形态Put含量基本不变。三种形态Cad含量在所有处理条件下均没有明显变化。与游离态和高氯酸可溶性结合态相比,高氯酸不溶性结合态多胺较稳定,受盐处理影响较小。随着处理时间的延长,总多胺含量呈下降趋势。外源施用0.01 mmol/L Spm对100 mmol/L NaCl胁迫下拟南芥幼苗的伤害有显著的缓解效应,不仅可以有效地抑制叶片中MDA含量的上升和质膜透性的增加,还降低植株体内Na~+含量,增加K~+的累积,降低植株体内Na~+/K~+,结果表明外源精胺通过对离子平衡的调节缓解了盐胁迫对拟南芥幼苗的伤害。更多还原

【Abstract】 Salt stress could cause changes in polyamines levels in plant tissues,and exogenous polyamines enhanced salt tolerance of plant.However the mechanism of the effect of exogenous polyamines still remains unclear.In the paper,we chose Arabidopsis thaliana as a studying material,the alleviative effects on salinity of different polyamines at different concentrations were compared.In addition,endogenous polyamine contents of Arabidopsis seedlings under different NaCl concentrations were determined,combining with exogenous spermine treatment for Arabidopsis salinity,the relationships between polyamine metabolism and Arabidopsis salt tolerance were studied.The main results were as follows:The growth of Arabidopsis seedlings was obviously suppressed under 100 mmol/L NaCl treatment,and the alleviative effect on Arabidopsis salinity of four exogenous polyamines(putrescine,Put;cadaverine,Cad;spermidine,Spd;spermine,Spm) at different concentrations were investigated.After applying 0.01 mmol/L Spd and 0.01 mmol/L Spm respectively,the length of root elongation and the dry and fresh weight of per plant increased to some different extent,and 0.01 mmol/L Spm had the best alleviative effect on the salt damage of Arabidopsis.However,the effect of 1 mmol/L Put and 0.05 mmol/L Cad appeared not to be significant compared with Spd and Spm.Three forms of endogenous polyamine contents of Arabidopsis under different NaCl concentrations were determined,it showed that the PCA soluble Spd content was provoked by 50 mmol/L NaCl treatment.Besides,free form and PCA soluble Spd contents obviously decreased while Spm content increased with the rising of NaCl concentrations in Arabidopsis seedlings.The free Put content decreased under 150 mmol/L NaCl treatment for 7 days,under the other concentration and time treatment,three forms of Put contents did not mainly change.There was no distinct changes in three forms of Cad caused by salt stress.Comparing with the free polyamines and PCA soluble polyamines,the PCA insoluble polyamines changed unconspicuously under salt stress.The contents of total polyamines reduced significantly as the treatment time was prolonged. The Arabidopsis was treated with 0.01 mmol/L exogenous Spm,which significantly ameliorated Arabidopsis damage caused by 100 mmol/LNaCl stress.The increase of MDA content and electrolytic leakage of leaves were restrained effectively,the content of Na~+ decreased and the content of K~+ increased,resulting in the decrease of the ratio of Na~+/K~+ in Arabidopsis seedlings.It is suggest that exogenous Spm alleviated the salt damage of Arabidopsis through regulating the ion balance of Arabidopsis.更多还原