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真盐生植物肉质化器官对水盐的响应
Alternative TitleThe response on euhalophytes’s succulence organ of watering and salinity treatments
马风兰
Subtype博士
Thesis Advisor田长彦
2019-06-30
Degree Grantor中国科学院大学
Place of Conferral北京
Degree Discipline理学博士
Keyword真盐生植物 盐胁迫 干旱 肉质化 Euhalophytes Salt tolerance Drought Succulence
Abstract真盐生植物是新疆等盐碱地区环境修复和发展盐地农业的优良植物资源, 其之所以能在高盐条件下正常生长, 在形态方面主要源于器官肉质化, 储存大量盐分并对其进行区格化从而保护植物本身不受伤害。由于肉质化是真盐生植物面对土壤盐渍胁迫的一种适应性策略, 因此, 从理论上来说盐生植物器官肉质化特征应该与不同的盐渍环境直接相关, 然而相关研究相对薄弱, 阻碍了对真盐生植物耐盐机理的进一步理解。本文以新疆比较典型的两种真盐生植物: 盐角草(茎肉质化)和盐地碱蓬(叶肉质化)作为研究对象,设置室内盆栽试验,并结合田间调查,利用扫描电镜(SEM)和超高透射电镜(TEM) 等方法, 就不同水-盐交互作用对两种真盐生植物生长和肉质化程度、 形态结构等的影响进行了研究, 以期加深对真盐生植物肉质化生态学意义的理解, 并为更为高效的利用真盐生植物实现盐碱地改良提供理论依据。取得的主要结果如下:(1) 在一定的范围内, 提高土壤盐分可增加真盐生植物的肉质化程度。 田间条件下, 随着种植年限的增加(土壤含盐量逐渐降低) , 两种真盐生植物的肉质化程度呈降低趋势。 盆栽试验进一步证实, 盐角草和盐地碱蓬肉质化程度最高的 NaCl 供应量分别为 340 mM 和 170 mM, 超过这一阈值会降低肉质化程度。此外, 苗期是两种真盐生植物肉质化程度最高的时期, 随着生育期的推进, 肉质化程度逐渐降低。 相关性分析发现, 两种真盐生植物的肉质化程度与植物干重呈极显著线性关系。(2) 水分亏缺不会增加真盐生植物的肉质化程度。 与干旱处理(40%田间持水量, 40% field capacity, 40%FC) 相比, 充足供水条件下(80%田间持水量,80%FC),盐角草和盐地碱蓬的肉质化程度明显更高。而且 80%FC 和适宜的 NaCl供应(盐角草 340 mM, 盐地碱蓬 170 mM) 可实现肉质化程度的最大化。(3) 真盐生植物肉质化程度与表皮细胞面积大小呈极显著线性关系。 肉质化程度增加, 表皮细胞大小也增加, 但气孔密度会降低。 而且两种真盐生植物肉质化器官内部超微特征较肉质化器官表皮形态特征对水、 盐胁迫的响应更为敏感,肉质化器官细胞内叶绿体和线粒体的形态则都在170mM NaCl和80%FC处理下,形态饱满、 结构完整, 但是, 干旱和高盐都会破坏内部结构。(4) 植物肉质化器官中 Na+、 Cl-含量随着 NaCl 处理浓度的增加而增加。随着土壤深度的增加, Na+、 Cl-浓度逐渐降低。 比较不同土层溶质势与肉质化器官溶质势差, 发现 20-30 cm 深度土壤溶质势与肉质化器官溶质势梯度差最大,是提供植物吸水的动源。 在 80%FC 条件下, 盆栽底部溶质势约为-0.6 MPa, 植物干重、 表皮细胞大小均最大。(5) 适宜的水分供应可提高真盐生植物的光饱和强度。 真盐生植物的净光合速率、蒸腾速率与气孔导度显著正相关, 表明光合能力下降主要由于气孔限制。在 0~1600μmol·m-2·s-1的光强范围内和 80%FC 水分供应条件下, 盐角草和盐地碱蓬苗期的净光合速率随着光照强度的增加而增大。 但是, 当供水条件为 40%FC水分时, 净光合速率下降, 饱和光强从 1600 降为 1400μmol·m-·s-1, 说明干旱会降低光饱和点。综上所述, 真盐生植物生长和肉质化的变化主要由肉质化器官的细胞大小决定, 且在适宜水分条件下主要受随盐分供应强度的驱动。 在不破坏植物的情况下测定真盐生植物的肉质化程度, 能够直接、 简单、 快速高效率的反应植物的生长情况。 说明测定肉质化程度可作为真盐生植物生长有意义的生态指标。
Other AbstractEuhalophyte has the greatest potential for improving of saline-alkali land, and itone of the most excellent plant species for the restoration and development ofsaline-alkali agriculture in Xinjiang. From the morphological aspect, the reason whyeuhalophytes is refrained from harm while restoring much salts is because of organsucculence which is normally considered to associated with environment. However,with few considerations on succulence of euhalophytes and the mechanism ofadaptation to environmental salt - drought stress. Terefore, in-depth study on theresponse of organ succulence of euhalophytes to NaCl and water supply treatment,that is the key point in understanding the mechanism of salt tolerance.In this study, two typical euhalophytes in Xinjiang were selected for fieldexperiment and simulated pot experiment. Salicornia europaea L (stem succulent)and Suaeda salsa Pall (leaf succulent) were grown in pots of sand soil supplied withfour NaCl treatments and two levels of water supply (80% and 40% of fieldcapacity).To study the effects of different water and salt treatments on the twoeuhalophytes’ growth and succulence, In combination with the study of ion content,solute potential and photosynthetic physiology in soil and succulent organs, themechanism of succulence from salt tolerance and drought was discussed.Also, wecollected for analysing the succulence organ's surface cell size and internalultrastructure by using Scanning Electron Microscope (SEM) and TransmissionElectron Microscope (TEM).The main results and conclusions are as follows:1.The degree of succulence of euhalophytes can increase with the increase of soilsalinity under a certain range. In field experiment, the degree of succulence wasdecreased with the increase of planting years under soil samples (soil salinity isgradually reduced) with different salt content. Pot experiment, further confirmed thatthe highest succulent NaCl supply of Salicornia europaea and Suaeda salsa was340mM and 170mM, respectively. Exceeding this threshold, the degree of succulencewitnessed a reduction trend. In addition, the highest degree of succulence were foundin seedling stage for both species. And the degree of succulence in the two euhalophytes showed a decreasing trend during growth stage. We found a significantlinear relationship between succulence and dry mass of them.2. Water deficits do not increase the degree of succulence of euhalophytes. Thedegree of succulence at 40% FC water supply did not increase; By contrast, the 80%FC treatment is more succulent than the 40% FC water supply. Moreover , thecombination of sufficient water (80% FC) treatment and optimal NaCl treatment(Salicornia europaea at 340 mM NaCl treatment, Suaeda salsa at 170 mM NaCl) canmaximize the degree of succulence.3. The correlation analysis showed that there was a striking linear relationshipbetween succulence and epidermal cell size (P<0.001); The increase of degree ofsucculence will followed by the increase of epidermal cell size. But, the density ofstomata decreases. Moreover, the internal ultrastructure more sensitive to drought andNaCl interaction treatments than external ultrastructure the epidermis of thesucculence organs. In our experiment, the morphology of chloroplasts andmitochondria in the cells of the succulent organs not affected when treated by 170mM NaCl and 80% FC. Their shape is normal and the structure is complete. However,their internal structures have all been destroyed by drought and high salt.4. The concentration of Na+ and Cl-increased with the increment of NaClsupplyin succulence organ of the two euhalophytes. As the soil depth increases, theconcentration of Na+ and Cl-in soil decreased gradually. The most likely source ofwater for plant growth from within the pot is indicated by comparing the solutepotential of the soil (at the 3 depths in the pot) and the solute potential of the shoots.Water can be expected to flow most readily across plant membranes from soil at20-30cm in the pot into plants down the largest solute potential gradient.Both species had curvilinear growth responses to the solute potential of the soilsolution, with a shoot dry mass optimum and cell size optimum occurring at about-0.6 MPa when watered to the equivalent of 80% field capacity, and about -1.2 MPawhen watered to the equivalent of 40% field capacity. Tissue hydration was alsoresponded in a curvilinear manner by the solute potential of the soil solution. Itindicates that the degree of succulence is related to its growth.5. A optimal water supply increases the light saturation intensity of truehalophytes. There was a striking linear relationship between net photosynthetic rateand stomatal conductance, transpiration rate and stomatal conductance of Salicornia europaea and Suaeda. salsa(P<0.05). The result showed that the decrease inphotosynthetic capacity was mainly caused by stomatal limitation.In the light intensity range of 0-1600 μmol·m-2 ·s-1, the net photosynthetic rate ofSalicornia europaea and Suaeda. salsa increased with the increase of light intensityincreaseunder the 80% FC water supply condition. However, when the water supply isreduced to 40% FC water supply, the net photosynthetic rate decreased with theincrement of salinity, and the saturated light intensity decreases from 1600 to 1400μmol·m-2·s-1. It revealed that the interaction of drought and NaCl will reduce the lightsaturation point (LSP).In conclusion, the variation in growth of euhalophytes and their tissue hydrationwere both caused mostly by the same factor – variation in cell size with salinity.Therefore, succulence can be regarded as an index of growth in euhalophytes; this isthe direct approach without destroying plants and simple to the measure growth ofeuhalophytes.
Subject Area生态学
Language中文
Document Type学位论文
Identifierhttp://ir.xjlas.org/handle/365004/15347
Collection中国科学院新疆生态与地理研究所
研究系统
Affiliation中国科学院新疆生态与地理研究所
First Author Affilication中国科学院新疆生态与地理研究所
Recommended Citation
GB/T 7714
马风兰. 真盐生植物肉质化器官对水盐的响应[D]. 北京. 中国科学院大学,2019.
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