摘  要：氮肥是影响植物生长及抗盐性的一个重要因素。本文研究了不同pH控制条件下氮源对狗牙根抗盐性的影响。结果表明，NH4-N处理下营养液pH下降，而NO3-N处理下升高。盐胁迫下枝条生长受到抑制，根系生长、叶片和根系的Na含量、钠钾选择性运输能力、Na和K分泌量增加，而植株K含量的影响较小。两种氮源相比较，NO3-N处理的植株具有更高的植株生长量、根系Na含量，更低的叶片Na含量及Na和K分泌量。盐胁迫下用2-(N-吗啡啉)乙磺酸（MES）缓冲营养液pH值后，植株的生长受到一定促进，表明狗牙根的抗盐性增加。其中NH4-N处理的叶片Na和K含量显著增加，Na和K分泌量显著减少，而对NO3-N处理的钠钾离子调控没有显著影响。77615

毕业论文关键词：盐胁迫，氮素形态，pH，狗牙根，离子调控

Abstract: Nitrogen fertilizer is one of the important factors that affect the growth and salt tolerance of plants。 In this study, we researched the effects of different nitrogen sources under pH control on salt tolerance in bermudagrass。 The results showed that the pH of nutrient solution decreased under the treatment of NH4-N, while it increased under NO3-N treatment。 Under salt stress, shoot growth was decreased, while root growth, Na content and Na/K in leaf and root, Na and K selective transport capacity, Na and K secretion rate, and Na/K ratio in secretion was increased。 The number of shoot branches, leaf and root K content was less affected by salt treatment。 Comparison of two kinds of nitrogen sources, the plant of NO3-N treatment had higher shoot and root growth and Na content in root, and lower leaf Na content and Na and K secretion rate。 When nutrient solution pH value buffered with 2-(N-methyl morpholine) ethanesulfonic acid (MES), plant growth was promoted in some degree, which indicated salt tolerance was increased in bermudagrass。 The content of Na and K in leaves of MES treated with NH4-N increased significantly under salt stress, while the Na and K secretion rate was significantly decreased, however, the sodium and potassium content was not significantly affected by NO3-N treatment。 

Keywords: Salt stress，nitrogen form，pH，bermudagrass，ion regulation

目  录

1  前言 4

2  材料与方法 4

2。1  实验材料 4

2。2  材料培养与处理 4

2。3  数据测定 5

2。4  数据分析 6

3  结果分析 6

3。1  营养液pH变化 6

3。2  植株生长 6

3。3  离子含量 9

结  论 15

参 考 文 献 17

致  谢 19

1  前言

狗牙根(Cynodon Rich。)属于禾本科虎尾草亚科植物，是一种世界上温暖区域广泛使用的暖季型草，主要用于运动场、公路、公园、厂区及庭院绿化等，也是一种重要的水土保持植物和牧草[1]。

盐对植物的伤害有渗透性影响、离子伤害及营养元素缺乏[2]，而离子伤害中主要是钠和氯的危害最重，易造成单盐毒害及对其它营养离子(例如钾、硝酸根) 的吸收产生拮抗作用，使植物发生营养缺乏 [3,4]。盐胁迫下植株体内离子平衡破坏的常见指标是钠离子含量增加，钾离子含量降低，钠钾比增加[5]。