【作者】 苑博华；

【导师】 蒋继志；

【作者基本信息】 河北大学 ， 植物学， 2006， 硕士

【摘要】 全世界存在面积非常巨大的盐碱地，而且伴随着各种污染的加剧使得农业生产问题益发突出，因此提高植物耐盐性成为当前极为重要的课题。本文以盐敏感植物黄瓜为研究对象，进行了不同浓度盐胁迫和不同试剂浸种对黄瓜种子萌发及幼苗生长的影响的实验研究。测量了发芽率、发芽势、胚根长度、发芽指数、活力指数、一级侧根数、株高、干重、鲜重、相对含水量、保护酶活性、叶绿素、丙二醛（MDA）和脯氨酸含量等指标。结果表明，不同盐浓度胁迫下黄瓜种子和幼苗的生长指标均有不同的变化，其中以100mmol／L为阈值，在这个浓度以下对黄瓜的生长没有显著影响，超过这个浓度会严重影响它的各种指标、甚至使其死亡。随着胁迫浓度的增加，对种子萌发和幼苗生长的抑制作用明显增强，发芽势、发芽指数、活力指数和一级侧根数对NaCl胁迫的反应更敏感；幼苗叶绿素含量、蛋白含量和幼苗根系活力逐渐降低，MDA含量增加；超氧化物歧化酶（superoxide dismutase，SOD）、过氧化物酶（peroxidase，POD）、过氧化氢酶（Catalase，CAT）的活性先表现上升而后下降；渗透调节物质可溶性糖的含量和游离脯氨酸含量明显增加。不同外源试剂进行浸种处理对于黄瓜的耐盐性均有不同的影响，供试各种浓度的高锰酸钾（KMnO₄）均只在外在表现上减缓盐胁迫的伤害，对于黄瓜叶片的3种保护酶活性、MDA和脯氨酸等指标并没有显著的影响。适宜浓度的吲哚乙酸（IAA，20mg／L）、6-苄氨基嘌呤(6-BA，2×10^-7mol／L)和水杨酸（SA，500mg／L）能够相对促进黄瓜种子的萌发，提高幼苗干重和相对含水量，通过显著提高盐分胁迫条件下幼苗中脯氨酸、可溶性糖等渗透调节物质的含量，增强其渗透调节能力，同时提高幼苗体内SOD、POD保护酶的活性，抑制膜脂过氧化作用产物丙二醛MDA的积累，所有这些变化都有利于缓解盐害，提高黄瓜抗盐性。更多还原

【Abstract】 There are extremely giant saline-alkali soil all over the world, and agricultural production are more and more limited following intensity of various pollutions, therefore, enhancement of plant salt tolerance is the extremely important topic now. Effects of different concentrations of salt stress and seed soaking with different reagents on germination and seedling growth of cucumber were studied. We investigated germination rate, the germination tendency, stem length, germination index, vigour index, lateral root of the first order, dry weight, relative water content, activities of protective enzyme, chlorophyll, malondialdehyde （MDA） and proline content under different conditions. Results showed that the criterion of seed germination and seedling’s growth of cucumber has the different change under the different salinity stresses. The 100mmol/L was considered as a threshold value, and that below this density had not remarkable influence to cucumber growth. However, that above this density had seriously influence to cucumber growth, even possibly caused seedlings death. With the concentration of NaCl increasing, the inhibition on germination and seedling growth of cucumber increased significantly. The germination tendency, stem length, germination index, vigour index, and lateral root of the first order of cucumber seed were more sensitive to NaCl stress. The contents of chlorophyll, protein and root activity decreased, but MDA contents increased; the activities of peroxidase （POD）, superoxide dismutase （SOD）, and Catalase （CAT） increased in origin then declined. It could increase the contents of some osmotica, such as free proline and soluted suger.The different extraneous reagents had the different effects. The potassium permanganate （KMnO₄） possibly could only slow down the injury of seedlings in the external performance, while not significantly change activities of each kind of enzyme, contents of MDA, proline and some other targets in seedlings. Iindol-3-ylacetic acid （IAA）, 6-benzylaminopurine（6-BA）, and salicylic acid （SA） could alleviate the harm caused by salt stress, or even higher than that in comparison with the various physiological control. The results indicated that at the stage of seed germination, application of IAA （20mg/L）, 6-BA (2×10^-7mol/L), and SA （500mg/L） in appropriate concentrations could increase the germination rates, germination index and vigor index of cucumber. It was also found that at the stage of seedling growth, application of IAA, 6-BA, and SA could increase dry weight, relative water content and the contents of some osmotica, such as free proline and soluted suger content, and promote the activities of SOD and POD, and decrease the accumulation of MDA. Therefore, the injuries induced by the salt stresses were mitigated and salt resistance of cucumber was raised.更多还原