胡杨叶片表皮角质膜与抗旱性关系的研究

发布时间：2018-03-10 00:37

本文选题：胡杨　切入点：异形叶　出处：《中央民族大学》2016年博士论文　论文类型：学位论文

【摘要】：本文研究对象为胡杨(Populus euphratica Oliv.),又称幼发拉底河杨树或沙漠杨树,属于杨柳科杨属,是第三纪以来古地中海地区形成的最古老的植物。目前胡杨主要分布在中亚、西亚、北非到南欧(大约在北纬30°～50°之间)。胡杨是中亚和中国西北干旱荒漠地区唯一天然分布的乔木树种,中国是世界上胡杨分布面积最广、数量最多的国家,胡杨在我国主要分部在新疆维吾尔自治区塔里木盆地、轮台县和内蒙古阿拉善盟额济纳地区。胡杨生长期漫长,由于风沙和干旱的影响,很多胡杨树造型奇特、诡异,有句古语形容它“活三千年不死,死三千年不倒,倒三千年不朽”。’在我国少数民族文化中,胡杨被视为“神木”或“圣树”,并作为死亡和复活的象征总是和鲜血与凤凰紧密相连。胡杨在生长发育过程中表现出显著的异形叶特征。胡杨幼树叶形均为细长状,随着生长发育,植株上部的叶片逐渐变短变宽,最后形成两侧带锯齿状的阔叶形。成年胡杨同一植株上的叶形有披针形、椭圆形、卵圆形、阔卵形、锯齿阔卵形等多种形状,这是一种植物适应异质环境的叶片表型可塑性,是胡杨长期适应干旱地区生长环境的结果。本研究以胡杨叶表皮角质膜为切入点,通过对内蒙古额济纳地区八道桥(较为干旱)和七道桥(较为湿润)胡杨异形叶片的形态特征、渗透调节、水分利用效率等生态特征、蜡质晶体的形态结构、胡杨长叶阔叶叶片表皮角质膜中蜡质、角质的成分含量等生态及生理生化特征的比较,分析了胡杨异形叶对干旱环境的适应能力。同时,对不同水分条件下胡杨异形叶表皮蜡质相关代谢基因的表达情况进行了对比分析。主要研究结果如下：(1)通过对比观察干湿两地的胡杨叶片形态我们发现,胡杨幼树均为长叶,成树叶形多变,同种形态的叶片,在湿润环境下,其表面积和体积均较大,叶片较薄；从叶形来讲,长叶叶片单位体积的表面积更大,阔叶叶柄长度更大。从树冠分布位置来看,长叶主要分布在树冠中下层,阔叶主要分布在树冠中上层。根据叶片表皮渗透性实验,我们发现不论是在干旱环境还是相对湿润环境,胡杨的长叶比阔叶表现出更高的叶绿素渗出速率和失水速率,说明长叶表皮比阔叶具有更高的渗透性,长叶的保水能力相对较弱,阔叶的保水能力相对较强。(2)胡杨不同形态叶片的表皮角质膜微观结构存在较大差异,同时叶表皮蜡质形态、晶体排列、分布以及叶片气孔形态、数量与叶形和生长环境中的水分条件具有密切关系。与湿润环境相比,干旱环境下的胡杨长叶具有更多的直立状鳞片状蜡质晶体,而且排列更为密集、有序,而阔叶表皮蜡质晶体融合成更多更厚的蜡被。在相同水分条件下,胡杨阔叶表皮蜡质晶体融合成的蜡被比长叶面积更大,厚度更高。阔叶和干旱环境下的叶片气孔有较明显的下陷,而蜡被增厚造成气孔位置相对下降是形成气孔下陷的主要原因。相同水分条件下,胡杨阔叶表皮气孔密度比长叶大；相同形态的叶片,干旱环境下叶片表皮的气孔密度比湿润环境大；相同类型的叶片远轴面表皮气孔密度比近轴面大。胡杨叶片表皮蜡质晶体形态和气孔形态、密度的差异是长期以来对干旱环境适应的结果。(3)通过对两地胡杨异形叶表皮角质膜中的蜡质和角质含量及成分进行对比分析,我们发现同一地点的胡杨阔叶比长叶表皮蜡质和角质含量高,干旱环境下生长的胡杨比湿润环境下生长的胡杨叶片表皮蜡质和角质含量高,而蜡质和角质的组分比例也会随着叶形和水分条件不同发生变化。总体来讲,成树阔叶的总蜡质含量是长叶的1.3倍,而在干旱环境下,成树阔叶的总蜡质含量是成树长叶的1.6倍。其中烷烃是蜡质中差异最大的组分,在干旱环境下烷烃组分的含量远高于其它组分,阔叶表皮蜡质中烷烃含量达50%以上；在干旱环境下长叶的烷烃含量比湿润环境下高出1.4倍,而干旱环境下阔叶的烷烃含量比在湿润环境下高出1.2倍。我们在胡杨异形叶中共发现了7种角质单体组分,其中最主要的成分是10,16-diOH C16:0酸,在所有检验样本中占角质单体总量一半以上,其它检测到的组分包括：16-OHCi6：o酸C16：o酸C18:idioic酸,18-OHC18：1酸,C16:0dioic酸和18-OH C18:2酸。在湿润环境下和干旱环境下,成树阔叶比长叶分别多产生2.1倍和0.9倍角质。长叶在干旱环境下比在湿润环境下的角质总含量多1.1倍,其中10,16-OH C16：0酸高出79.8%；阔叶在干旱环境下比在湿润环境下的角质总含量多31.5%,其中10,16-OHC16：0酸高出26.5%。另外,在两种水分条件下阔叶角质中C16：o酸和C18：1 dioic酸含量也高于长叶。(4)通过对不同水分条件下胡杨异形叶表皮蜡质代谢基因的表达分析我们发现,在干旱环境下胡杨叶中烷烃合成相关基因CER1以及ABC转运蛋白和延长酶基因WBC11,WBC12比在湿润环境下表达水平更高,从叶形上比较,阔叶CER1,CER4,KCS1和ATT1的表达量都高于长叶2倍以上(l0g2倍数),从环境水分条件来看,干旱环境下长叶CER1, WBC11、WBC12和WIN1的表达量都高于湿润环境下长叶2倍以上(l0g2倍数)。相对而言,干旱环境下阔叶CER1, CER26和MAH1的表达量高于湿润环境下的阔叶2倍以上(log2倍数)；干旱环境下,CER1, WBC11, WBC12和WIN1的表达量在长叶和阔叶中的表达量均较湿润环境下有所提高。在两种水分条件下,蜡质代谢相关基因在阔叶中表达水平普遍较高,而且两种叶形的叶片在干旱环境下蜡质代谢相关基因表达水平普遍较高。在干旱环境下,胡杨叶片具有产生更多蜡质的潜能。上述结果表明,胡杨叶片角质膜在不同水分条件下、不同叶形叶片间的差异是胡杨对干旱环境适应性的重要体现。本研究为自然生境下的胡杨林及其生态环境的保护提供了有价值的数据,同时为角质膜和异形叶与植物的抗旱性关系研究提供了启示。
[Abstract]:The study object of this article is Populus (Populus euphratica Oliv.), also called euphrates poplar or desert to poplar, Populus, is the formation of the ancient Mediterranean region since the third century of the oldest plants. The Populus mainly distributed in Central Asia, West Asia, North Africa to southern Europe (approximately at latitude 30 degrees to 50 degrees between Central Asia and China). Poplar is the northwest arid desert region is the only natural distribution of tree species, Populus China is the most widely distribution area in the world, the largest number of countries, in our country the main branch of Populus euphratica in the Tarim Basin in the Xinjiang Uygur Autonomous Region, Luntai county and Inner Mongolia Alashan Ejina area. The growth period is long, due to the impact of wind and drought a lot of poplar, strange shapes, strange, there is an old saying to describe it "live three thousand years dead, dead three thousand years, down three thousand years" immortal ". In China's ethnic culture, Hu Yang is regarded as "Shenmu" or "sacred tree", and as a symbol of death and resurrection is always closely connected with Phoenix and blood. Populus showed obvious characteristics of heteromorphic leaves during the growth of Populus euphratica. Leaf were slender, with the development of the upper leaves gradually become shorter and wider, the final form of on both sides with a jagged shape. Leaf leaved Populus euphratica in the same plant having lanceolate, elliptic, ovate, broadly ovate, serrated broad oval shape, this is the phenotypic plasticity of leaf of a plant to adapt to the heterogeneous environment, Hu Yang is long-term adaptation to arid area growth environment results in this study. Populus euphratica leaf epidermal cuticle as the breakthrough point, through to the Inner Mongolia Ejina area eight (drought) bridge and seven bridge (more humid) morphological characteristics of Populus euphratica leaf shaped osmotic adjustment, water use efficiency and ecological characteristics, The morphological structure of waxy crystal, waxy leaf leaf cuticle of Populus euphratica broadleaf film, ecological and physiological and biochemical characteristics of cutin composition, analyzes the adaptability of Populus euphratica heteromorphic leaves to drought environment. At the same time, the expression of Populus euphratica heteromorphic leaves of epicuticular wax related metabolic genes under different water conditions were analyzed the main results are as follows: (1) through the observation of Populus euphratica leaf morphology of wet and dry places we found that Populus euphratica were long leaf, a tree leaf blade is changeable, the same form, in the moist environment, the surface area and volume are larger, thinner leaves; from the leaf, leaf length per unit volume the surface area is larger, more broad leaf petiole length. From the view of crown distribution, mainly distributed in the lower leaf canopy, mainly distributed in the upper broadleaf canopy. According to leaf epidermal permeability. Check, we found both in the arid environment is still relatively moist environment, long leaf broad-leaved Populus showed chlorophyll exudation rate and water loss rate higher, long leaf epidermis has higher permeability than hardwood, leaf water retention capacity is relatively weak, broad leaf water retention capacity is relatively strong (2). There is a big difference between the cuticle microstructure morphology of Populus euphratica in different leaf, and leaf epicuticular wax morphology, crystal structure, distribution and leaf stomatal morphology, water conditions and the number of leaf and growth environment have close relationship. Compared with the moist environment, the arid environment of Populus euphratica leaf with crystal zhilizhuang flake more wax moreover, arranged more orderly, intensive, while broad-leaved epicuticular wax crystals merged into more thick wax. In the same water condition, Populus broad-leaved epicuticular wax crystals merged into the wax is longer than leaves The area is larger, the thickness is higher. Leaf stomata and broadleaf arid environment has obvious subsidence, and wax thickening caused by stomatal position relative decline is mainly due to the formation of sunken stomata. The same water condition, the stomatal density of Populus euphratica broadleaf than leaves; the same leaf morphology, stomatal density of leaf epidermis of drought under the moist environment than leaves; the same type of abaxial stomatal density than the adaxial surface. Leaf epidermis wax crystal morphology and pore morphology, density difference is to adapt to drought environment long-term results. (3) through the analysis and comparison of wax and cutin content and composition of two poplar shaped the leaf epidermal angle in plasma membrane, we found the same location than the leaf epicuticular wax of Populus euphratica broadleaf and cutin content is high, the leaf growth of Populus euphratica than humid environment in arid environment Epicuticular wax and cutin and wax and cutin content is high, the component ratio also with leaf shape and moisture change. Overall, a total wax content of broad-leaved tree is 1.3 times the length of leaves, while in the arid environment, the total wax content of broad-leaved tree is 1.6 times as Shuchang leaves. Which is the biggest difference in paraffin wax composition, content of component alkane in the arid environment is much higher than that of other components of epicuticular wax in broad-leaved alkane content reached more than 50%; the content of alkanes in the arid environment leaves is 1.4 times higher than that of the moist environment, and alkane content environment than broad-leaved drought in the moist environment is 1.2 times higher. We found 7 kinds of cutin monomer components in Populus euphratica heteromorphic leaves of the Communist Party of China, one of the most important components of 10,16-diOH C16:0 acid in all test samples accounted for more than half of the total cutin monomers, the other detected component package Including: 16-OHCi6:o acid C16:o acid C18:idioic acid, 18-OHC18:1 acid, C16:0dioic acid and 18-OH acid C18:2. In the moist environment and arid environment, tree leaves were more than broad-leaved produce 2.1 times and 0.9 times of cutin. Long leaf under drought conditions than the total cutin content in the moist environment of more than 1.1 times, including 10,16-OH C16:0 acid 79.8% higher; broad leaved in the arid environment than the total cutin content in the moist environment of more than 31.5%, which is higher than the 26.5%. 10,16-OHC16:0 acid, in addition, in the two water conditions in C16:o acid and C18:1 leaf cutin dioic acid content is higher than that of leaf. (4) the expression of Populus euphratica heteromorphic leaves of epicuticular wax metabolic genes under different water conditions analysis we found that in the arid environment of Populus euphratica leaf alkanes in synthesis related genes CER1 and ABC transporters and elongase gene WBC11, WBC12 expression level more than in the moist environment. High, from the leaf on the broad leaved CER1, CER4, expression of KCS1 and ATT1 were higher than that of leaves more than 2 times (l0g2 times), from the point of view of water condition, leaf CER1, arid environment WBC11, expression of WBC12 and WIN1 were higher than that in the moist environment leaves more than 2 times (l0g2 times number). In contrast, the arid environment of broad-leaved CER1, expression of CER26 and MAH1 was higher than that of the moist environment of hardwood is more than 2 times (log2 times); the arid environment, CER1, WBC11, WBC12 and WIN1 expression in leaf and broadleaf in volume were increased in the moist environment. The two water conditions, the expression level of higher wax metabolism related genes in the broad-leaved, and leaves of two leaf wax in the arid environment of metabolism related gene expression level is generally high. In the arid environment, has produced more leaf wax potential. The results showed that P. Leaf cuticle under different water conditions, the difference between the leaves of different leaf is an important manifestation of Populus to drought environment adaptability. This study provides valuable data for the protection of natural habitats of Populus euphratica forest and its ecological environment, at the same time as the cuticle and heteromorphic leaves provided the inspiration and research of drought resistance in plants.

【学位授予单位】：中央民族大学
【学位级别】：博士
【学位授予年份】：2016
【分类号】：S792.11

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