不定根及非连续通气组织对植物水淹耐受的影响

发布时间：2018-07-27 09:30

【摘要】：由于全球气候变化,在过去几十年里全球范围内频繁爆发强降雨和洪涝灾害,科学家们纷纷预测未来全球发生强降雨及洪涝灾害将会持续爆发,其强度和频率都会增大。全世界范围内频繁发生的洪涝灾害会影响陆地生态系统和湿地生态系统中物种的分布和多度以及生态系统的正常功能。基于以上背景,本论文致力于研究以下问题:(1)以喜旱莲子草为例,探讨植物在不同水淹情况下从环境中吸收氧气及其传递过程,尤其是植物不定根和通气组织对不同水淹环境的响应特性。(2)植物上述的响应特性对其生长和存活的影响。本研究中我们为了求证非连续茎髓腔在部分水淹植物中的功能以及对水淹植物水淹耐受性的影响,我们使用了髓腔阻塞法,使用氧微电极对受淹植物体内的氧气变化动态进行了,同时我们检测了髓腔阻塞后对部分水淹植物生长的影响。另外许多植物在水淹过程中会产生大量的不定根,为了探究不定根除了从水体中吸收营养物质和水分以外的其他功能(例如:从水体中吸收氧气),我们使用氧微电极,探测了不定根从水体中吸收氧气的能力;随后我们采取不定根去除的处理方式检测了不定根对水淹植物耐淹性的贡献。最后我们通过控制水体中溶解氧和营养盐浓度等实验方法来验证不定根对不同水环境的特定响应,及其对植物水淹耐受性的影响。主要研究结果如下:(1)许多植物茎和枝由节和节间构成,由实心的节隔板隔离开的非连续通气组织似乎无助于气体在植物体内的运输,但迄今为止此观点并无确切的研究数据证实。我们的实验结果证实,在部分水淹的情况下,仅仅阻塞茎内的一个节间的通气组织就会影响气体在茎中的输送,进而在被阻塞节间以下的毮腔和皮层中的氧气含量会急剧下降;髓腔阻塞会抑制遭受部分水淹的植物的生长、增强淹没茎段上不定根的生长。综上结果可以得出,虽然非连续通气组织被实心的节隔板隔开,但该组织仍然能帮助气体输送并有助于提高植物被淹器官中的氧气含量,从而对受淹植物生长和水淹耐受发挥积极作用。(2)许多植物受淹后会在受淹器官上长出不定根,不定根是否具有从水中吸收氧气的功能没有得到研究证实,也不清楚该功能对植物在长期水淹环境中生存和生长的贡献。、研究发现不定根可以从水体中直接吸收氧气并且可以将氧气运输到植物体的其他组织器官中;研究发现茎上长有不定根的被淹植株能够更加有效地利用其体内的碳水化合物储备,延长其在水淹环境中的存活时间。(3)不定根发生和生长会受水淹影响,但不定根产生及形态特征是否会受水体中溶氧水平和营养水平的影响并不清楚。我们的研究表明,水体中溶解氧和营养盐匮乏均会影响受淹喜旱莲子草的生长,同时会导致植物产生具有较高根表面积体积比的不定根。实验发现,水体中营养盐匮乏不会影响不定根中通气组织管道大小,而水体中低溶解氧含量会使植物产生的不定根中的通气组织管道增粗,因为通气组织管道增粗会降低气体运输阻力,提高不定根对营养物质的吸收能力,从而提高植物对水淹环境的耐受能力。(4)植物在遭受部分水淹的情况下,其水面上的茎段会将氧气输送到水下器官和组织中,氧气在受淹器官和组织中输送的过程中会逐渐消耗,所以离水面越远的被淹器官得到的氧气含量就越少,因此我们假设被淹植株茎内氧气含量逐渐降低的现象会影响离水面距离不同的茎部位上不定根的产生。在本论文研究中发现,水体中营养含量的多少会改变不定根在受淹喜旱莲子草茎段上生长的空间格局;随着水体中营养含量降低,喜旱莲子草的不定根产生会增强并且不定根会更多地在离水面较近的茎节上产生。总之,不定根和非连续茎髓腔均可以提高被水淹植物的体内的氧气含量,因此被淹植物的水淹耐受性会有所改善。但是针对不定根及非连续茎髓腔对不同环境条件在激素和分子方面的响应特性的研究究还很有限,建议未来应注重耐水淹植物在激素和分子方面的机制研究。
[Abstract]:As a result of global climate change, over the past few decades, heavy rainfall and flood disasters have been erupted around the world. Scientists have predicted that the intensity and frequency of heavy rainfall and flood will continue to increase in the future. Frequent flooding in the world will affect terrestrial ecosystems and wetland ecosystems. The distribution and abundance of species in the state system and the normal functions of the ecosystem. Based on the above background, this thesis is devoted to the following problems: (1) taking the lotus seed as an example, the absorption of oxygen and its transmission process in the environment under different flooding conditions, especially the response of plant adventitious roots and aeration tissues to different waterflooded environments, is discussed. Characteristics. (2) the effects of the response characteristics of plants on their growth and survival. In this study, in order to prove the function of the discontinuous medullary cavity in some waterflooded plants and the tolerance to water flooded plants, we used the medullary cavity blocking method, and the oxygen microelectrode was used to change the oxygen dynamics in the flooded plant. At the same time, we detected the effect of the intramedullary obstruction on the growth of some waterflooded plants. In addition, many plants produced a large number of adventitious roots in the water flooding process. In order to explore the function of the adventitious roots in addition to absorbing nutrients and water from the water body (for example: absorbing oxygen from the water), we used oxygen microelectrodes to detect the uncertainty. The ability of roots to absorb oxygen from water; then we used adventitious root removal to detect the contribution of adventitious roots to water flooded plants. Finally, we verified the specific responses of the adventitious roots to different water environments by controlling the dissolved oxygen and the concentration of nutrients in the water, and the tolerance to water flooding in plants. The main results are as follows: (1) many plant stems and branches are composed of nodes and internodes, and the discontinuous ventilatory tissue that is separated from solid septum septum does not seem to be helpful to the transport of gas in the plant, but so far this view has not been confirmed by exact data. The ventilatory tissue in one Internode in a blocked stem will affect the delivery of gas in the stem, and then the oxygen content in the cavity and cortex below the blocked internodes will decrease sharply; the medullary obstruction inhibits the growth of partially flooded plants and increases the growth of the adventitious roots on the submerged stems. The results can be concluded, although discontinuous. Ventilatory tissue is separated by a solid partition board, but the tissue can still help gas transport and help improve the oxygen content in the submerged organs of plants, thus playing an active role in the growth and flooding tolerance of flooded plants. (2) many plants will grow adventitious roots on the flooded organs, and whether the adventitious roots can absorb oxygen from the water. The function has not been confirmed, nor is it clear that the function contributes to the survival and growth of plants in a long-term waterflooded environment. The study found that the adventitious roots can absorb oxygen directly from the water and transport oxygen to other tissues and organs of the plant. (3) the occurrence and growth of adventitious roots and growth will be affected by water flooding, but the effects of the formation and morphological characteristics of the adventitious roots and their morphology are not clearly affected by the level of dissolved oxygen and the nutrient level in the water. Our study shows that both dissolved oxygen and nutrients are scarce in the water body. It is found that the lack of nutrients in water does not affect the size of the aerated tissue pipes in the adventitious roots, and the low dissolved oxygen content in the water body makes the aerated tissue pipe in the adventitious roots produced by the plant grow thicker because of the fact that the water in the plant is produced by the low dissolved oxygen content. The thickening of gas tissue pipes will reduce the resistance of gas transportation and increase the absorptive capacity of the adventitious roots to nutrients, thus improving the tolerance of plants to water flooded environment. (4) in the case of partial flooding, the plants will transport oxygen to the subaqueous organs and tissues on the surface of the water, and oxygen is transported in the flooded organs and tissues. It is gradually consumed in the process, so the less oxygen content is obtained from the submerged organs from the water, so we assume that the gradual reduction of oxygen content in the stems of the flooded plants will affect the production of the adventitious roots on the stem parts of different distances from the water. The spatial pattern of the growth of the stem segments of the flooded lotus seed grass; with the decrease of the nutrient content in the water body, the adventitious roots of the lotus root will be enhanced and the adventitious roots will be produced more on the stem nodes near the water. The tolerance of plants to water flooding will be improved. However, the response characteristics of adventitious roots and discontinuous stem medullary cavity to different environmental conditions in different environmental conditions are still limited. It is suggested that the mechanism of water tolerant plants should be paid more attention to in the future.
【学位授予单位】：西南大学
【学位级别】：博士
【学位授予年份】：2016
【分类号】：Q945

【相似文献】