摘 要

以一年生喜树苗为材料，以无盐正常供水为对照，研究了在盐渍、涝渍和盐涝复合胁迫条件下喜树苗高、地径、生物量及生理生化相关指标的变化。结果表明：（1）涝渍、盐渍和盐涝复合胁迫均不同程度地影响了喜树的生长及生物量的积累。涝渍对喜树苗高和地径生长及生物量积累的抑制作用小于盐渍，而盐渍与盐涝复合胁迫对喜树苗高和地径生长及生物量积累的影响相对较大。（2）涝渍所造成的MDA含量的增加及膜透性的升高的幅度较盐渍和盐涝处理低，表明喜树具有较强的耐涝性，而对盐渍胁迫则较为敏感。（3）盐涝胁迫下喜树的SOD活性高于对照，且整个过程的变化相对平稳；盐渍和盐涝胁迫下SOD活性变化剧烈，尤其在后期急剧下降，且MDA含量及膜透性同步升高，表明喜树植株受害程度加剧。上述研究结果表明，喜树具有一定的耐涝性，而对盐渍较为敏感。盐渍及盐涝胁迫后期的SOD活性显著降低、MDA含量升高及膜透性增加是造成喜树后期生长被明显抑制的生理原因之一。

关键词：喜树；盐渍；涝渍；盐涝；生理响应

The Different Physiological Responses of Camptotheca Acuminata Seedlings’ Growth to Salt-water Stress

ABSTRACT

The changes of annual growth Camptotheca acuminata seedlings’ height, collar diameter, and biomass, relevant physiological and biological indexes under conditions of salt stress, waterlogging as well as salt and water compound stress were researched in comparison with those under salt-free and normal water supply circumstance. It turned out that firstly, salt stress, waterlogging as well as salt and water compound stress all influenced the growth and biomass accumulation of Camptotheca acuminata to varying degrees. Waterlogging had less inhibiting effect on seedlings’ height, collar diameter and biomass accumulation than salt stress. Namely, salt stress and compound stress played a relatively smaller part. Secondly, compared with salt stress and water-salt stress, under waterlogging condition, the increase of MDA content and the increasing amplitude of membrane permeability were relatively lower, which implies that Camptotheca acuminata has a rather strong waterlogging tolerance, and in the meantime is fairly susceptible to salt stress. Thirdly, seedlings’ SOD activity under salt-water stress is higher than control group and the change in the whole process is relatively steady. While under the condition of salt stress and salt-water stress, the SOD activity change dramatically especially at later period when it dropped sharply. Meanwhile the MDA content and membrane permeability went up simultaneously. All of these changes indicates that under salt stress and water-salt stress, seedlings’ suffering degree was aggravated. To sum up, Camptotheca acuminata has certain waterlogging resistance and susceptibility to salt stress. The remarkable drop of SOD activity and rise of MDA content and membrane permeability during the late period partly contributed to the inhibition of Camptotheca acuminata’s growth physiologically.

Key words: Camptotheca acuminata; salt stress; water stress; water-salt stress; physiological response

目 录

引言 1

1 研究概况 2

1.1 盐渍和水渍单一作用对植物的影响 2

1.2 盐渍和水渍联合作用对植物组织离子浓度的影响 3

1.3 盐渍和水渍联合作用对植物生理的影响 3

1.3.1 对通气组织和内皮层的影响 3

1.3.2 对气孔导度的影响 4

1.3.3 对泌盐作用的影响 4

1.4 盐渍和水渍联合作用对植物发育的影响 5

1.4.1 对叶片发育的影响 5

1.4.2 对植物存活和萌发的影响 5

1.5 喜树的研究进展 5

2 材料与方法 7

2.1 材料 7

2.2 方法 7

2.2.1 苗高、地径的测定 7

2.2.2 生物量和根系的测定 7

2.2.3 质膜透性的测定 7

2.2.4 超氧化物歧化酶（SOD）的测定 8

2.2.5 丙二醛含量的测定 8

2.3 数据处理 8

3 结果与分析 9

3.1 盐涝胁迫对喜树苗高的影响 9

3.2 盐涝胁迫对喜树地径的影响 9

3.3 盐涝胁迫对喜树苗生物量的影响 10

3.4 盐涝胁迫对喜树苗膜透性的影响 10

3.5 盐涝胁迫对喜树苗丙二醛含量的影响 11

3.6 盐涝胁迫对喜树苗叶SOD活性的影响 12

4 讨论 14

5 结论 15

致谢 16

参考文献 17

引 言

现实生态环境中植物很少遭受单一的环境胁迫，而更多的是同时或先后受多种逆境环境胁迫，因此研究联合逆境胁迫对植物体生理特性的影响就显得十分必要。我国沿海滩涂面积大，滩涂水位的不断变化以及海潮的侵蚀直接影响着沿海滩涂的水分和盐分状况，在地下水位较浅的滨岸地区，植物生长会受到水分和盐分双重胁迫影响，而植物对水分和盐分的响应则可以通过形态特征变化、叶绿素含量变化以及抗氧化酶活性等表现出来。喜树为珙桐科喜树属植物，生长迅速，高大雄伟，树干通直圆满，姿态优美，具有很高的观赏价值，是绿化、美化环境的优良树种，也是造林的优良树种。喜树的叶、根、皮、茎和种子中的次生代谢产物——喜树碱具有显著抗癌活性，因而其备受人们的关注。目前有关喜树抗逆生理的研究多集中在Cu² 胁迫、不同pH值、涝渍、低温胁迫等方面。对喜树幼苗的盐胁迫以及涝胁迫的研究很少，而对盐涝双重胁迫的研究更加少见。为此，拟对喜树幼苗在盐涝双重胁迫下的幼苗生长和生理特性进行研究，以期探讨喜树的耐盐耐涝机理，为喜树在滨海地区的应用提供理论依据。

1 研究概况