【作者】 徐呈祥；

【导师】 徐锡增；

【作者基本信息】 南京林业大学 ， 森林培育学， 2005， 博士

【摘要】 盐碱是枣（Ziziphus jujuba Mill.）树成活生长、枣果产量提高的重要逆境。国内外对枣树耐盐生理与调控技术的研究甚少。硅是土壤中仅次于氧的第2 大元素,但对植物的可利用性往往很低。硅在植物中的生理功能近年很受关注。本文以2 年生嫁接苗为试材,在盆栽比较4 个枣优良品种耐盐性差异的基础上,通过电子显微分析技术、能谱分析技术、叶绿素荧光分析技术等着重研究了硅与金丝小枣（Z.jujuba cv.jinsixiaozao）耐盐性的关系。主要结论如下: 1)随盐（NaCl）胁迫加重,4 个枣品种盐害发生的速度加快、等级提高,生长量减少,生物量下降,叶生理状况恶化,但不同品种各自的表现差异显著。综合评价,金丝小枣耐盐性最强,其次是梨枣（Z.jujuba cv.lizao）和大瓜枣（Z.jujuba cv.daguazao）,冬枣（Z.jujuba cv. dongzao）耐盐性最弱。2)土壤含盐量0.1﹪不抑制金丝小枣生长,但含盐量0.3﹪以上生长受到显著抑制,生物量低于对照的50﹪。在含盐量0.3﹪和0.5﹪土壤上生长的金丝小枣,萌发前给土壤施硅（Si,0.4‰,w/w）的植株与不施硅植株的生长和生理状况有明显差异:施硅植株叶相对含水量提高,叶片细胞质膜透性（ PMP）降低,光系统II（PSII）的潜在光化学活性（Fv/Fo）和最大光化学效率（Fv/Fm）提高,CO₂ 同化速率（Pn）和水分利用效率（ WUE）提高,气孔调节能力增强,枣头枝长度及生物量显著增大。施硅改善了盐胁迫下金丝小枣树的生长与生理。3)应用电子探针技术对根尖和叶片横切面上离子微域分布状况的分析结果表明,外源硅使受盐胁迫（ 0.3﹪）金丝小枣细胞中的K⁺ 相对含量大幅升高,根系各组织细胞中的Na⁺ 和Cl-相对含量大幅降低,叶片栅栏组织细胞中的Na⁺ 和Cl-相对含量大幅降低,枣树体内的离子平衡与光合细胞中的离子稳态得到了良好维持。4)0.3﹪NaCl 短期（ 30 d）胁迫对金丝小枣叶片超微结构的伤害轻微,但长期（165 d）胁迫伤害效应显著为大;0.5﹪NaCl 短期（30 d）胁迫对金丝小枣叶片超微结构产生显著伤害,长期（165 d）胁迫则使之近乎完全破坏。给土壤施硅（Si）明显缓解前述各处理下盐分离子对金丝小枣叶片超微结构的伤害,叶绿体片层结构得到了较好保持,较大程度上维护了膜系统及其结构的正常和更多还原

【Abstract】 Salt and alkali is one of the key stress factors inhibiting survival rate, growth, fruit yield and quality of Ziziphus jujuba Mill. The information on salt tolerance and control technology of jujube were very little in world wide. The availability of silicon in soils for plants is usually low though it is the second abundant element in soils. Some people reported that silicon could alleviated ion toxicity of plants, including Na~+ and Cl-. Nevertheless, the relation between silicon and salt tolerance of plants is still not understood well. The differences of salt tolerance among four super jujube cultivars were investigated in this dissertation. The main objects of the this study were focused on the relation between silicon and salt tolerance of Z.jujuba cv.jinsixiaozao, a very famous jujube variety in China, and its mechanism. X-ray electron probe microanalysis, ultra-structure observation and analysis, chlorophyll fluorescence technology and other scientific methods were used to release the secretary. Salt and silicon source was sodium chloride and silicate potassium, respectively. The test material were 2-year old grafting seedlings. The main results of the dissertation were presented as follows: 1) Salt injure grade and speed of 4 jujube varieties, such as inhibition of growth, reduction of biomass, declining of leaf physical status, became more and more heavier with the increase of soil salt content. However, salt tolerances of 4 jujube varieties were significantly different. According to synthetic evaluation, salt tolerance of Z.jujuba cv. jinsixiazao was the strongest in the 4, second and third was Z.jujuba cv. lizao and Z.jujuba cv.Dongzao, respectively.The weakest tolerance to salt stress was Z.jujuba cv.daguazao. 2) The experimental results also showed that salt ions had distinctively toxic effects on jinsi jujube plants grown on soils containing 0.3﹪(w/w, dw) or 0.5﹪NaCl for more than 6 months while added silicon ameliorated the toxicity of salt on jinsi jujube. The differences of growth and physiological status between the plants added and no added silicon (0.4 ‰Si, w/w, dw)under the two salt stresses were significant. Silicon increased the relative water content of leaf blade and decreased the plasma membrane permeability. The photo-system II activity of potential chemistry (Fv/Fo), maximum efficiency of photo-chemistry (Fv/Fm), net photosynthetic rate (Pn) and the water use efficiency were all promoted by added silicon. The leading stem length, a key growth index of Z.jujuba under salt stress, was much larger by added silicon. Silicon improved the growth and physiology of Z.jujuba under salt stress. 3) The analysis results of ion micro-distribution status on the across sections of root tip and leaf blade of Z. jujuba cv jinsixiaozao clearly showed that added silicon enhanced the relative content of K+ in almost all cells of the root tip and leaf blade under salt stress while the relative weight of Na+ and Cl-in palisade tissue of leaf blade was decreased significantly . Therefore, the ion balance in the plants and the ion homeostasis in photosynthetic cells were better maintained. 4) The experimental results showed that 0.3﹪NaCl stress for 30 d lightly wounded while significantly wounded the ultra-structure of leaf blade stressed for 165 compared with that of salt stress. Same was 0.5﹪NaCl stress for 30 d and 165 d, respectively. However, added Si alleviated injure of leaf blade ultra-structure under 0.3﹪and 0.5﹪NaCl whether it was for 30 d or 165 d. The main effects of silicon on this respect were keeping with the stability and integrity of ultra-structure of membrane system under salt stress, suppressing aging of chloroplast and des-integrity of the lamellae. Silicon also increased the production of osmiophilic granule, starch grain, and other vesicles. Therefore, silicon is benefit to maintain the photosynthetic efficiency and osmotic regulation capacity of Z.jujuba.cv.jinsixiaozao under salt stress. 5) The effect of silicon on fatty acid content and composition of root and leaf membrane lipid of the fruit tree under salt stress were significantly different. In root of the plant, the content of saturated fatty acid decreased by exogenous silicon compared with no silicon addition under salt stress. Both the content of unsaturated fatty acid and the index of unsaturated fatty acid of root membrane were all promoted due to addition of silicon under salt stress. The effects of silicon on fatty acid content and composition of leaf membrane lipid were adverse to those of root under salt stress, which implied that the physiological function of silicon in alleviating the injure of salt stress to Z. jujuba cv. jinsixiaozao was closely correlated with the physiological function and growth characteristics of the tree,s organs.更多还原