低磷胁迫下杉木根系形成通气组织与磷利用效率的关系研究

发布时间：2018-06-28 14:37

本文选题：杉木 + 半同胞家系　；参考：《福建农林大学》2015年硕士论文

【摘要】：杉木(Cunninghamia lanceolata)为我国特有速生树种,也是我国南方最重要的用材造林树种之一。但随着杉木人工林栽培面积不断增大及多代连栽现象的出现,杉木生长的南方林地因有效磷匮乏而严重制约了杉木人工林长期生产力的维持。由于不同植物或同种植物不同基因型对养分胁迫逆境的适应能力存在较大差异。近年来,有研究表明不同杉木无性系的磷素吸收和利用效率存在明显差异。磷高效利用杉木无性系可通过增强光合效率、提高叶片和根际酸性磷酸酶活性、增加根系分泌有机酸的种类及数量等生理指标的改变,以调整根系表型、根构型等形态特征指标对低磷胁迫逆境作出响应。然而,植物根系在低磷环境下大量增生会增加体内有限磷营养的消耗。根据Lynch提出有关根系觅养行为的“成本-收益”理论,当植物体内磷资源不足以满足根系大范围拓展的养分需求时,根系生长明显受阻,这意味着植物通过根系从土壤中捕获养分的机会大大减少。那么,植物在低磷胁迫环境中如何平衡有限磷养分的吸收与消耗,以维持正常的生长状态?有学者发现低磷胁迫可诱导一些植物根系皮层细胞溶解形成空腔,这些空腔迅速被空气占据成为通气组织,一方面减少胁迫环境中根部老组织的呼吸消耗,缓解老幼组织对同化物的竞争,对保证幼嫩组织的正常生长有一定作用；另一方面,皮层溶解析出的磷营养等化合物被运往植物其它部位,用以满足植物对磷等化合物的需求,这种养分的循环高效利用有利于植物的生长发育。鉴于上述前人的研究经验,本研究认为低磷环境中不同杉木无性系在一系列生理指标的调控下,之所以有些无性系通过根系大量增生,提高觅磷机会以适应低磷环境,而有些无性系根系增生不明显,但通过加速体内磷素循环仍能维持较高生产力,这可能与根系皮层组织溶解程度及释放磷含量的不同有关。为验证这一假设,本文以导师课题组遴选出低磷胁迫下根构型差异较大的13个半同胞杉木家系幼苗作为研究对象,通过室内模拟磷胁迫环境,观测不同磷处理条件下杉木根尖、根端皮层组织溶解变化规律,同时测定不同供磷水平处理前后杉木的苗高、地径、根系生长等情况,比较不同磷处理条件下杉木各器官生物量的积累与分配,研究低磷胁迫环境下杉木根、茎、叶的磷含量、磷素累积量以及全株磷利用效率的变化规律,分析了磷胁迫环境条件下根系皮层组织溶解度与上述指标变化的相关性,阐明低磷环境中杉木磷利用效率与根系皮层组织磷溶解之间的关系,为深入探讨磷高效利用杉木基因型对低磷胁迫内在响应机制提供理论依据,为筛选优产、速生杉木基因型的研究提供形态解剖及生理学理论与实践依据。主要研究结果如下：(1)不同供磷水平处理对参试杉木家系根系皮层溶解形成通气组织的影响存在明显差异。正常供磷条件下,所有杉木家系根尖、根端皮层组织细胞均生长正常,无溶解现象；在中度磷胁迫条件下,仅32号家系根尖皮层组织出现少量的溶解现象,而根端皮层组织除20号、25号、40号、41号杉木家系尚未出现溶解现象外,其余参试苗木的根端皮层组织均出现不同程度的溶解现象；在重度磷胁迫条件下,15号、20号、25号、38号、41号家系根系未出现通气组织,其余家系的溶解度从大到小依次为28号、30号、27号、40号、4号、23号、32号和36号,根端皮层组织除41号家系根端皮层组织未出现溶解,其余家系均有溶解现象。相比于正常供磷和中度磷胁迫,重度磷胁迫条件下根端皮层组织溶解面积更大,皮层溶解度从大到小表现为4号、32号、36号、15号、30号、28号、40号、23号、27号、25号、20号和38号家系。(2)低磷胁迫下杉木根系皮层形成通气组织与苗高、地径、根系生长的相关性显著。不同磷处理条件下所有参试杉木家系苗高、地径的平均增量大小为：正常供磷中度磷胁迫重度磷胁迫。对杉木根系生长来说,20号、25号、38号、40号、41号家系随着磷胁迫程度加剧,根系形态指标的生长量逐渐增加；相反的,4号、32号、36号家系总体上表现为随着磷胁迫程度的加重,根系生长量逐渐减少。从皮层溶解度与杉木的苗高、地径、根系生长的相关性分析发现,随着磷胁迫程度的加重,根端皮层组织溶解度与苗高呈正相关性,并且相关性也逐渐显著,这与地径和皮层溶解度的相关性相反；而根系体积、总根长、根表面积、根平均直径在磷胁迫环境下与根系皮层组织溶解度呈负相关关系,并且随着胁迫程度的加深,这种负相关性也逐渐显著。(3)低磷胁迫下杉木根系皮层形成通气组织与各器官生物量积累分配的关系明显。随着磷胁迫程度的加重,20号、25号、38号、40号、41号杉木家系的茎、叶生物量均呈递减趋势,而根生物量和根冠比则逐渐增大；其它家系茎、叶的生物量随磷胁迫程度加剧而逐渐增加,根生物量和根冠比却变小。从皮层溶解度与其相关性分析表明：胁迫环境下根系皮层组织溶解度与根冠比呈负相关关系,同时,茎和叶生物量与根系皮层组织溶解度相关性系数逐渐增大。随着胁迫程度的加重,根尖和根端皮层组织溶解度与茎、叶生物量的相关性系数也逐渐增大,而根生物量与根系皮层组织溶解度呈负相关关系。(4)低磷胁迫下杉木根系皮层形成通气组织与各器官的磷含量、磷素累积量及全株磷利用效率均有明显的相关性。在不同磷处理条件下,所有参试杉木家系根、茎、叶的平均磷素含量以及平均磷素积累量均表现为正常供磷中度供磷重度供磷。从根系皮层组织溶解度与其相关性来看,胁迫条件下根系皮层组织溶解度与根磷含量及根磷素积累量均呈负相关关系。随着胁迫程度的加重,磷利用效率虽然与根系皮层组织溶解度相关性不明显,但随着皮层组织溶解度的加大,两者的相关性逐渐增大。(5)综上所述,低磷环境中杉木根系皮层组织发生溶解的家系与其磷利用效率具明显相关性。如皮层组织溶解明显的4号家系,随着磷胁迫程度的加重,其根系生长量逐渐减少,根的生物量、磷含量、磷素积累量虽然同样存在这样的规律,但地上部分茎、叶的生物量、磷含量、磷素累积量则随着胁迫程度加剧而逐渐增加,苗高、地径、磷利用效率也表现出相同的规律。对于皮层组织溶解不明显的41号家系,尽管皮层组织细胞未出现溶解,但在磷胁迫条件下,随着胁迫程度的加重,其根系增生明显,且维持了较高的磷利用效率。可见不同杉木家系对低磷胁迫的适应性策略差异较大,但均以能够维持植株的正常生长为目的。
[Abstract]:Cunninghamia lanceolata (Cunninghamia lanceolata) is a special fast-growing tree species in China and also one of the most important timber forestation species in the south of China. However, with the increasing cultivation area of Chinese fir plantation and the emergence of multi generation continuous planting phenomenon, the long-term productivity of Chinese fir plantation is severely restricted by the lack of effective phosphorus in the South forestland grown by Chinese fir. In recent years, there have been obvious differences in the phosphorus absorption and utilization efficiency of different Cunninghamia lanceolata clones. The high efficiency of Chinese fir clones can increase the activity of acid phosphatase in leaf and Rhizosphere by increasing photosynthetic efficiency and increasing the activity of acid phosphatase in the leaves and rhizosphere. The changes in physiological indexes such as the variety and quantity of organic acids in the root system can be used to adjust the morphological characteristics of root system and root configuration to respond to low phosphorus stress. However, the large proliferation of plant roots in low phosphorus environment will increase the consumption of limited phosphorus nutrition in the body. According to Lynch, the "cost - harvest" of root foraging behavior is put forward. When the phosphorus resources in the plant are not sufficient to meet the nutrient needs of the roots, the growth of the roots is significantly hindered, which means that the opportunity for plants to capture nutrients through the roots is greatly reduced. Long state? Some scholars have found that low phosphorus stress can induce some plant root cortex cells to dissolve and form cavity, and these cavities are rapidly occupied by air into aeration tissue. On the one hand, it reduces the respiratory consumption of old tissues in the root of stress environment, alleviates the competition of the old and young tissues to assimilates, and has a certain effect on the normal growth of young young tissues. On the other hand, the phosphorus nutrients and other compounds dissolved in the cortex are transported to the other parts of the plant to meet the plant's demand for phosphorus and other compounds. The cycling and efficient utilization of this nutrient is beneficial to the growth and development of plants. In view of the previous experience of the previous studies, this study suggests that the different Chinese fir clones in the low phosphorus environment are in a series of physiology. Under the control of the index, some clones increase the opportunity for phosphorus seeking to adapt to the low phosphorus environment through the proliferation of root systems, and some clones have no obvious growth in the root system, but they can still maintain high productivity by accelerating the phosphorus cycle in the body. This may be related to the difference in the degree of dissolution of the cortex and the release of phosphorus in the root system. On the assumption that 13.5 Chinese fir families with relatively large root configuration differences under low phosphorus stress were selected as the research object by the tutor topic group. Through indoor simulated phosphorus stress environment, the changes of the root tip of Chinese fir root and root end cortex in different phosphorus treatment conditions were observed, and Chinese fir was measured before and after different phosphorus supply levels. The accumulation and distribution of the biomass of various organs of Chinese fir under different phosphorus treatment conditions were compared with the conditions of seedling height, ground diameter and root growth. The changes of phosphorus content, phosphorus accumulation and total phosphorus utilization efficiency under the environment of low phosphorus stress were studied. The solubility of the root cortex tissue and the above indexes under the condition of phosphorus coercion were analyzed. The relationship between the phosphorus utilization efficiency of Chinese fir in the low phosphorus environment and the relationship between the phosphorus dissolution of the cortex tissue in the root system, which provides the theoretical basis for the internal response mechanism of low phosphorus stress in the efficient use of Chinese fir genotypes, provides the theory and practice of morphological and physiological theory and Practice for screening the best yield and fast-growing Chinese fir genotypes. The main results are as follows: (1) there is a significant difference in the effect of different phosphorus supply levels on the aeration tissue of the root cortex of Chinese fir families. Under normal phosphorus supply, the root tip of the root tip of all Chinese fir families grows normal and does not dissolve. Under moderate phosphorus stress, only the root tip skin of No. 32 family is root. There was a small amount of dissolution in the layer tissue, and the root end cortex tissues of the root end cortex were not dissolved, except for No. 20, No. 25, No. 40 and No. 41, and the root end cortex tissues of the rest of the seedlings were dissolving in varying degrees. Under the condition of severe phosphorus stress, the root system of No. 15, 20, 25, 38 and 41 had no aeration. The solubility of the family was 28, No. 30, No. 27, No. 40, No. 40, No. 4, 23, 32 and 36. The root end cortical tissue of the root end was not dissolved, and the other families had dissolving. Compared to normal phosphorus supply and moderate phosphorus stress, the root end cortex tissue dissolved in larger area and cortical dissolution under severe phosphorus coercion. Grade 4, No. 32, No. 36, No. 15, No. 15, No. 30, 28, No. 40, 23, 27, 25, 20 and 38. (2) the correlation between the formation of aeration tissue in the cortex of Chinese fir root system under low phosphorus stress and the height of seedling, ground diameter and root growth was significant. The average increment size of all the Chinese fir families under different phosphorus treatments was normal. The average increment size of the ground diameter was normal. For the growth of root growth of Cunninghamia lanceolata, 20, No. 25, No. 38, No. 40 and 41 increased with the degree of phosphorus stress, and the growth of root morphological indexes increased gradually. On the contrary, the number of families of 4, 32 and 36 gradually decreased with the degree of phosphorus coercion, and the growth of root system decreased gradually. From cortex dissolving. The correlation analysis of the height, ground diameter and root growth of Cunninghamia lanceolata showed that with the increase of the degree of phosphorus stress, the solubility of the root cortex was positively correlated with the height of the seedlings, and the correlation was gradually significant, which was opposite to the correlation between the ground diameter and the cortical solubility, and the root volume, the total root length, the root surface area and the root mean diameter were in the phosphorus stress. There was a negative correlation with the cortical tissue solubility in the environment, and the negative correlation was also significant with the deepening of stress. (3) the relationship between the aeration tissue of the root cortex formation and the biomass accumulation and distribution of various organs under low phosphorus stress was obvious. With the increase of phosphorus stress, No. 20, No. 25, No. 38, No. 40, 41 Cunninghamia lanceolata The biomass of the stems and leaves of the lines all decreased, but the root biomass and the root cap ratio increased gradually. The biomass of the stems and leaves of other families increased with the degree of phosphorus stress, and the root biomass and the root cap ratio became smaller. The analysis of the cortical solubility and the correlation between the root and the roots showed that the solubility of the root cortex and the root crown ratio were negative under the stress environment. At the same time, the correlation coefficient of stem and leaf biomass and root cortical tissue solubility increased gradually. With the aggravation of stress, the correlation coefficient of the tissue solubility of root tip and root end cortex and stem and leaf biomass also increased gradually, and the root biomass was negatively correlated with the solubility of root cortex tissue. (4) low phosphorus stress under the low phosphorus stress. The average phosphorus content and the average phosphorus accumulation of all the Chinese fir roots, stems and leaves and the average phosphorus accumulation in all the Chinese fir families were normal phosphorus supply phosphorus. There was a negative correlation between the solubility of the tissue and the content of root phosphorus and the accumulation of root phosphorus under stress conditions. With the aggravation of the stress, the correlation between the efficiency of phosphorus utilization and the solubility of the cortex tissue was not obvious, but the correlation gradually increased with the increase of the solubility of the skin tissue. To sum up. (5) to sum up, the family line of dissolving of the cortex of Chinese fir root in the low phosphorus environment has obvious correlation with the utilization efficiency of phosphorus. For example, the root growth of the No. 4 family, which is obviously dissolved in the cortical tissue, gradually decreases with the increase of phosphorus stress, and the root biomass, phosphorus content and phosphorus accumulation have the same rules. Law, but the biomass, phosphorus content and phosphorus accumulation of the parts of the ground increased with the intensification of the stress degree. The height, the ground diameter and the utilization efficiency of phosphorus also showed the same rule. For the No. 41 family, which did not dissolve obviously in the cortex, the cortical tissue cells did not dissolve, but under the condition of phosphorus stress, with the stress degree. It is obvious that the root growth of the root system is obvious and the phosphorus utilization efficiency is high. It can be seen that the adaptation strategies of different Chinese fir families to low phosphorus stress are different, but all of them can maintain the normal growth of the plant.
【学位授予单位】：福建农林大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：S791.27

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