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1.
植物根内通气组织形成机理的研究进展   总被引:1,自引:0,他引:1       下载免费PDF全文
孔妤  王忠  顾蕴洁  汪月霞 《植物学报》2008,25(2):248-253
植物能否在湿地或淹涝环境中生长, 很大程度上取决于植物是否具有健全发达的通气组织。在结合形态学和分子生物学等方面研究的基础上, 概述了植物根内通气组织的形成过程, 主要涉及生理功能、诱导因子和相关酶等, 推测细胞程序性死亡是溶生性通气组织形成的机理, 乙烯在整体信号转导网络中起关键性中介作用。  相似文献   

2.
对山东滨海14种盐生植物的根及根中的通气组织进行了解剖学的比较研究。研究表明:除了少数植物的根中产生发达的机械组织、通气组织不发达以外,绝大多数植物的根中都具有发达的通气组织。这些通气组织的胞间隙非常明显,形成多个通气道,特别是一些根状茎、平卧茎发达的植物,如沙滩黄芩(Scutellaria strigillosa Heml.)、海边香豌豆(Lathyrus maritimus (L.)Bigel.)、肾叶打碗花(Calystegia soldanella(L.) R.Br.),其通气道较大。胞间隙的发生主要有二种情况:(1)裂生胞间隙;(2)溶生胞间隙,这是大多数胞间隙形成的方式。通气组织大多分布于靠近表皮的皮层和靠近周皮的次生韧皮部中,即位于保护组织的内侧。  相似文献   

3.
植物通气组织的形成过程和生理生态学意义   总被引:30,自引:1,他引:29  
文章从感受逆境信号、信号传递到细胞解体形成通气组织等几个过程介绍了植物通气组织形成过程的研究进展 ,并阐述了通气组织的生理生态学意义。  相似文献   

4.
山东滨海盐生植物根结构及通气组织的比较研究   总被引:7,自引:0,他引:7  
对山东滨海14种盐生植物的根及根中的通气组织进行了解剖不的比较研究。研究表明:除了少数植物的根中产生发达的机械组织,通气组织不发达以外,绝大多数植物的根中都具有发达的通气组织。这些通气组织的胞间隙非常明显,形成多个通气道,特别是一些根状茎,平卧茎发达的植物,如沙滩黄芩(Scutellaria strigillosa Heml.),海边香豌豆(Lathyrus maritimus(L.)Bigel.),肾叶打碗花(Calystegia,soldanella(L.)R.Br.),其通气道较大。胞间隙的发生主要有二种情况;(1)裂生胞间隙;(2)溶生胞间隙,这是大多数胞间隙形成的方式。通气组织大多分布于靠近表皮的皮层和靠近周皮的次生韧怪部中,即位于保护组织的内侧。  相似文献   

5.
对通气组织的解剖观察有助于了解湿地植物的生长、分布及对不同生境的适应。采用石蜡切片技术,在光学显微镜下对洞庭湖湿地沿水位高程梯度分布的4种优势植物——荻Miscanthus sacchariflorus、水蓼Polygonum hydropiper、红穗苔草Carex argyi、虉草Phalaris arundinacea的茎和叶解剖结构进行了比较研究。结果表明:茎通气组织的形成部位主要在皮层、维管束和髓腔,其中髓腔所占比例最大(〉77%)。茎通气组织大小为:水蓼(57.8%)〉红穗苔草(45.5%)≥虉草(41.7%)≥荻(37.8%)。4种湿地植物的叶均在叶肉组织和(或)维管束内形成通气组织,如荻、虉草的形成部位是维管束,水蓼的是叶肉组织,而红穗苔草在叶肉组织和维管束内均可以形成,但以叶肉组织中为主,占99%。红穗苔草叶通气组织最发达,为33.8%,其它3种植物相对不发达,仅为0.13%~1.68%。除虉草外,其它3种植物通气组织大小与其分布位置具有很好的一致性。可见,湿地植物通气组织与其分布有较好的相关性。  相似文献   

6.
为了探究乙烯和α-萘乙酸(α-NAA)是否是水淹环境条件下植物体内通气组织形成的直接原因,对三峡库区岸生植物野古草(Arundinella anomala)和秋华柳(Salix variegata) 在无水淹环境条件下施加乙烯利和α-NAA后茎中通气组织的形成情况进行了研究。实验分3种处理:单独用乙烯利溶液处理(浓度分别为0、250和500 mg●L-1)、单独用α-NAA溶液处理(浓度分别为0、50和100 mg●L-1)和二者混合处理(250 mg●L-1乙烯利溶液 +50 mg●L-1 α-NAA溶液)。处理5 d后,采用切片法制备其茎中部横切面切片,用E80i Nikon显微镜进行观察,并运用ACT-2U和Simple PCI软件分析野古草和秋华柳茎中通气组织的形成情况。结果显示:在这3种处理条件下,野古草和秋华柳茎中通气组织形成均有明显增强,并且较高浓度的乙烯利溶液促使茎通气组织形成更多,施加的α-NAA浓度越高,形成通气组织的能力越强;混合溶液处理与单独施加250 mg●L-1乙烯利或单独施加50 mg●L-1 NAA的处理相比,对通气组织形成的增强效应无明显差异。研究表明,在水淹条件下植物体内通气组织的发生与乙烯和生长素含量的增加有直接关系。  相似文献   

7.
 为了探究乙烯和α-萘乙酸(α-NAA)是否是水淹环境条件下植物体内通气组织形成的直接原因,对三峡库区岸生植物野古草(Arundinella anomala)和秋华柳(Salix variegata) 在无水淹环境条件下施加乙烯利和α-NAA后茎中通气组织的形成情况进行了研究。实验分3种处理:单独用乙烯利溶液处理(浓度分别为0、250和500 mg●L-1)、单独用α-NAA溶液处理(浓度分别为0、50和100 mg●L-1)和二者混合处理(250 mg●L-1乙烯利溶液 +50 mg●L-1 α-NAA溶液)。处理5 d后,采用切片法制备其茎中部横切面切片,用E80i Nikon显微镜进行观察,并运用ACT-2U和Simple PCI软件分析野古草和秋华柳茎中通气组织的形成情况。结果显示:在这3种处理条件下,野古草和秋华柳茎中通气组织形成均有明显增强,并且较高浓度的乙烯利溶液促使茎通气组织形成更多,施加的α-NAA浓度越高,形成通气组织的能力越强;混合溶液处理与单独施加250 mg●L-1乙烯利或单独施加50 mg●L-1 NAA的处理相比,对通气组织形成的增强效应无明显差异。研究表明,在水淹条件下植物体内通气组织的发生与乙烯和生长素含量的增加有直接关系。  相似文献   

8.
洪水条件下湿地植物的生存策略   总被引:18,自引:1,他引:17  
洪水是自然界存在的一种普遍现象。湿地植物由于所处生境的特殊性,会经常受到周期性或永久性的洪水胁迫。在长期的适应进化过程中,湿地植物形成了一些特殊的生存策略,以适应水文条件的大幅度变化。主要的生存策略如下:1)生活史方面,植物可通过改变生长时间、繁殖方式、种子特征等避免洪水的直接伤害或利用洪水的流动起到传播扩散的作用;2)形态学特征方面,植物可通过调整根系形态、分布等将根系生长到氧气相对充足的土壤表层或形成不定根增强根系通气功能;3)解剖学方面,植物可通过改善组织孔隙度形成通气组织等改善空气传导到根系的"气体通道";4)生理生化方面,植物可通过增加碳水化合物含量以延长生存时间,释放出一些生长激素(乙烯等)以调节植物缺氧条件下的生理活动或形态、解剖方面的变化。在今后的研究中,不定根的形成机理、乙烯在通气组织形成中的作用及其过程、放射氧损失(ROL)的形成机理及其释放速率的调控等一些机理性的工作还需进一步加强。  相似文献   

9.
生态适应性在植物水生诱导上的运用   总被引:6,自引:0,他引:6  
本文通过论述植物普遍存在的生态适应性与环境变化对适应性形成及进化上的影响,以及植物生态适应性形成过程中胁迫环境的重要性,分析了植物水生诱导过程中相关的生理生化及生态方面的变化规律,提出了利用人工环境模拟技术来促进植物通气组织形成的技术路线,形成一套完整可操作的植物水生诱变操作流程,并展现了植物水生诱变技术在生产、生活、生态上的广阔应用前景。  相似文献   

10.
红树植物自然条件下生长于河口、海岸潮间带。受潮汐作用影响,红树植物在生理、形态、结构上对渍水环境产生了相应的适应机制。其中红树植物通气组织的发达程度与其耐淹水的能力具有很高的相关性,是衡量红树植物耐淹浸能力的重要依据。利用测定孔隙率和石蜡切片面积比两种方法揭示了华南地区5种红树植物优势种:白骨壤 (Avicennia marina)、红海榄 (Rhizophora stylosa)、木榄 (Bruguiera gymnorrhiza)、秋茄 (Kandelia candel)和桐花树 (Aegiceras corniculatum)在自然条件和人工生境下根通气组织的发育规律,并用石蜡切片研究了茎和叶的通气组织发育状况。结果表明:两种方法测得根的通气组织发育程度的结果相关性显著(P<0.05)。5种红树植物通气组织主要产生于根部,茎和叶发育较少,除了潮汐生境中白骨壤根的通气组织为根、茎、叶总和的48.16%、非潮汐生境中桐花树根为43.81%,其余树种根部通气组织占总体的50%以上。自然潮间带生境中,桐花树、木榄、白骨壤、秋茄、红海榄,通气组织分别为(14.98±3.34)%、(27.83±2.3)%、(29.64±3.17)%、(3009±4.12)%、(42.12±3.14)%,通气组织比例与其在潮间带上的分带性和演替序列较为吻合。非潮汐人工生境下,红海榄、木榄、秋茄、桐花树和白骨壤根部通气组织较自然生境下均有所增加,说明各树种对非潮汐淹浸条件具备一定的适应力。根据非潮汐生境下通气组织的比例可判定它们对恒定水位的适应能力依次为:桐花树>白骨壤>秋茄>木榄>红海榄。红树植物对非潮汐淹浸条件的适应有利于在沿海地区开展人工生境下红树林的栽培与推广应用,研究结果对提高栽培成活率,更大限度地发挥红树林的生态服务价值,具有重大的实践意义。  相似文献   

11.
Flooded plant roots commonly form aerenchyma, which allows gas diffusion between shoots and roots. The programmed cell death involved in this induced aerenchyma formation is controlled by the plant hormone ethylene, as has been shown for maize (Zea mays). However, the role of ethylene is uncertain in wetland species that form constitutive aerenchyma (also under nonflooded conditions). The aim of this study is to shed light on the involvement of ethylene in constitutive aerenchyma formation in Juncus effusus. Plants of J. effusus and maize were treated with ethylene and inhibitors of ethylene action to determine the consequences for aerenchyma formation. Neither treatment with high ethylene concentrations nor with ethylene inhibitors resulted in changes in root aerenchyma in J. effusus. By contrast, ethylene increased aerenchyma development in maize unless ethylene action inhibitors were applied simultaneously. Similarly, root elongation was insensitive to ethylene treatment in J. effusus, but was affected negatively in maize. The data show that aerenchyma in J. effusus is highly constitutive and, in contrast to the inducible aerenchyma in maize, is not obviously controlled by ethylene.  相似文献   

12.
In roots of gramineous plants, lysigenous aerenchyma is created by the death and lysis of cortical cells. Rice (Oryza sativa) constitutively forms aerenchyma under aerobic conditions, and its formation is further induced under oxygen‐deficient conditions. However, maize (Zea mays) develops aerenchyma only under oxygen‐deficient conditions. Ethylene is involved in lysigenous aerenchyma formation. Here, we investigated how ethylene‐dependent aerenchyma formation is differently regulated between rice and maize. For this purpose, in rice, we used the reduced culm number1 (rcn1) mutant, in which ethylene biosynthesis is suppressed. Ethylene is converted from 1‐aminocyclopropane‐1‐carboxylic acid (ACC) by the action of ACC oxidase (ACO). We found that OsACO5 was highly expressed in the wild type, but not in rcn1, under aerobic conditions, suggesting that OsACO5 contributes to aerenchyma formation in aerated rice roots. By contrast, the ACO genes in maize roots were weakly expressed under aerobic conditions, and thus ACC treatment did not effectively induce ethylene production or aerenchyma formation, unlike in rice. Aerenchyma formation in rice roots after the initiation of oxygen‐deficient conditions was faster and greater than that in maize. These results suggest that the difference in aerenchyma formation in rice and maize is due to their different mechanisms for regulating ethylene biosynthesis.  相似文献   

13.
Aerenchyma is widely known to be lysigenous, schizogenous or, more recently, expansigenous. The interpretation and understanding of its function is questionable, given the lack of extensive knowledge on the development and cellular changes of this tissue. The aerenchyma of Pistia stratiotes roots reportedly originates from packet lysigeny. However, our observations suggest schizogenous development. Our objective was to analyse ontogeny of aerenchyma in P. stratiotes roots and evaluate the morphological and chemical changes in the cell wall during the formation of aerenchyma. The aerenchymatous inner cortex of schizogenous origin was observed under light and electron microscopy. Lacunae are formed by the separation, division and stretching of cells, which remain alive until maturity. Analyses using monoclonal anti‐glycan antibodies show that formation of that type of aerenchyma apparently proceeds through the same mechanisms as the genesis of intercellular spaces. However, the greatest changes occur when cells undergo stretching, including the loss of methyl‐esterification and detection of arabinans, which are not directly involved in cell separation. Thus, other factors may account for the formation of schizogenous aerenchyma.  相似文献   

14.
In waterlogged soil, deficiency of oxygen triggers development of aerenchyma in roots which facilitates gas diffusion between roots and the aerial environment. However, in contrast to other monocots, roots of rice (Oryza sativa L.) constitutively form aerenchyma even in aerobic conditions. The formation of cortical aerenchyma in roots is thought to occur by either lysigeny or schizogeny. Schizogenous aerenchyma is developed without cortical cell death. However, lysigenous gas-spaces are formed as a consequence of senescence of specific cells in primary cortex followed by their death due to autolysis. In the last stage of aerenchyma formation, a ‘spoked wheel’ arrangement is observed in the cortical region of root. Ultrastructural studies show that cell death is constitutive and no characteristic cell structural differentiation takes place in the dying cells with respect to surrounding cells. Cell collapse initiation occurs in the center of the cortical tissues which are characterized by shorter with radically enlarged diameter. Then, cell death proceeds by acidification of cytoplasm followed by rupturing of plasma membrane, loss of cellular contents and cell wall degradation, while cells nuclei remain intact. Dying cells releases a signal through symplast which initiates cell death in neighboring cells. During early stages, middle lamella-degenerating enzymes are synthesized in the rough endoplasmic reticulum which are transported through dictyosome and discharged through plasmalemma beneath the cell wall. In rice several features of root aerenchyma formation are analogous to a gene regulated developmental process called programmed cell death (PCD), for instance, specific cortical cell death, obligate production of aerenchyma under environmental stresses and early changes in nuclear structure which includes clumping of chromatin, fragmentation, disruption of nuclear membrane and apparent engulfment by the vacuole. These processes are followed by crenulation of plasma membrane, formation of electron-lucent regions in the cytoplasm, tonoplast disintegration, organellar swelling and disruption, loss of cytoplasmic contents, and collapse of cell. Many processes in lysing cells are structural features of apoptosis, but certain characteristics of apoptosis i.e., pycnosis of the nucleus, plasma membrane blebbing, and apoptotic bodies formation are still lacking and thus classified as non-apoptotic PCD. This review article, describes most recent observations alike to PCD involved in aerenchyma formation and their systematic distributions in rice roots.  相似文献   

15.
The influence of naphthylacetic acid, abscisic acid, gibberellic acid and kinetin on the formation of aerenchyma in seedling roots of Zea mays L. cv. Capella has been studied in relation to reported changes of their concentration in poorly aerated roots, which readily form aerenchyma, and to the effects of these hormones on the production of ethylene, a major factor promoting aerenchyma formation. Because the absence of nitrate accelerates aerenchyma formation in aerated roots, their influence on these roots was compared. The growth regulators were added to roots growing in non-aerated and aerated nutrient solutions, and aerenchyma formation and the production and endogenous concentration of ethylene were measured. Naphthylacetic acid prevented aerenchyma formation in both aerated roots without nitrate and in non-aerated roots although it enhanced the ethylene concentration of the roots. Abscisic acid also prevented aerenchyma formation, but without affecting the ethylene concentration. Gibberellic acid promoted aerenchyma formation in aerated roots only, but ethylene production in both aerated and non-aerated roots. Kinetin promoted aerenchyma formation in both aerated and non-aerated roots. It stimulated ethylene production in aerated roots, but slightly inhibited it in non-aerated roots. Co2+ and Ag+, which suppress ethylene production and action, respectively, reduced the promoting effects of gibberellic acid, but not those of kinetin. It is concluded that the effects of the plant growth regulators on aerenchyma formation in maize roots were, with a possible exception for gibberellic acid, not the result of altered ethylene concentrations in the roots. Their influence on aerenchyma formation is discussed in relation to their reported actions on cell membranes.  相似文献   

16.
Maize (Zea mays L.) is generally considered to be a plant with aerenchyma formation inducible by environmental conditions. In our study, young maize plants, cultivated in various ways in order to minimise the stressing effect of hypoxia, flooding, mechanical impedance or nutrient starvation, were examined for the presence of aerenchyma in their primary roots. The area of aerenchyma in the root cortex was correlated with the root length. Although 12 different maize accessions were used, no plants without aerenchyma were acquired until an ethylene synthesis inhibitor was employed. Using an ACC-synthase inhibitor, it was confirmed that the aerenchyma formation is ethylene-regulated and dependent on irradiance. The presence of TUNEL-positive nuclei and ultrastructural changes in cortical cells suggest a connection between ethylene-dependent aerenchyma formation and programmed cell death. Position of cells with TUNEL-positive nuclei in relation to aerenchyma-channels was described.  相似文献   

17.
张小萍  曾波  陈婷  叶小齐  罗芳丽  刘巅 《生态学报》2008,28(4):1864-1871
野古草(Arundinella anomala var. depauperata Keng)在三峡库区长江及其支流江(河)岸有广泛分布,对水淹有很好的耐受能力.有研究表明许多植物在水淹时通气组织发生增强,通气组织的产生改善了植株通气状况,提高了植物对水淹的抵御能力.为了研究水淹是否会影响野古草的通气组织发生以及野古草通气组织发生对水淹的反应,考察了不同水淹深度、不同水淹时间和不同水淹方式处理时野古草茎中通气组织的发生情况.实验中共设置3个水淹深度:不进行水淹(对照)、植株地下部分淹没、植株完全淹没于水下2m深处;5个淹没时间:植株被淹没的时间长度分别为5、10、20、30d和60d;2种水淹方式:连续水淹和间歇水淹.实验结果表明:(1)在无水淹情况下野古草茎中可以产生通气组织,通气组织产生随植株的生长而增强;水淹加快了野古草通气组织发生的进程,促进了野古草通气组织的提前发生.(2)野古草茎中通气组织并不会因为水淹的时间越长而产生越多,植株通气组织的大小达到一定程度后不再因水淹时间的增长而继续增大.(3)淹没深度对通气组织发生有一定影响,总的看来,地下部分淹没野古草植株的通气组织发生要强于完全淹没植株.(4)不同水淹方式对野古草通气组织发生的影响因水淹深度不同而有差异.在完全淹没情况下,连续水淹植株的通气组织比间歇水淹植株的通气组织发达;在地下部分淹没情况下,除水淹初期外,随水淹时间的延长,连续水淹植株通气组织发生与间歇水淹植株没有差异.  相似文献   

18.
? To adapt to waterlogging in soil, some gramineous plants, such as maize (Zea mays), form lysigenous aerenchyma in the root cortex. Ethylene, which is accumulated during waterlogging, promotes aerenchyma formation. However, the molecular mechanism of aerenchyma formation is not understood. ? The aim of this study was to identify aerenchyma formation-associated genes expressed in maize roots as a basis for understanding the molecular mechanism of aerenchyma formation. Maize plants were grown under waterlogged conditions, with or without pretreatment with an ethylene perception inhibitor 1-methylcyclopropene (1-MCP), or under aerobic conditions. Cortical cells were isolated by laser microdissection and their mRNA levels were examined with a microarray. ? The microarray analysis revealed 575 genes in the cortical cells, whose expression was either up-regulated or down-regulated under waterlogged conditions and whose induction or repression was suppressed by pretreatment with 1-MCP. ? The differentially expressed genes included genes related to the generation or scavenging of reactive oxygen species, Ca(2+) signaling, and cell wall loosening and degradation. The results of this study should lead to a better understanding of the mechanism of root lysigenous aerenchyma formation.  相似文献   

19.
? Gas spaces (aerenchyma) form as an adaptation to submergence to facilitate gas exchange. In rice (Oryza sativa), aerenchyma develop by cell death and lysis, which are poorly understood at the cellular level. ? Aerenchyma formation was studied in rice stems by light microscopy. It was analyzed in response to submergence, ethylene and hydrogen peroxide (H(2)O(2)) treatment, and in the MT2b::Tos17 mutant. O(2)·(-) was detected with nitroblue tetrazolium and an epinephrine assay. H(2)O(2) was detected with 3,3'-diaminobenzidine. ? Aerenchyma develop constitutively in all internodes of the deep-water rice variety Pin Gaew 56, but are absent from the nodes. Constitutive aerenchyma formation was also observed in two lowland rice varieties, albeit to a lesser degree. A larger number of aerenchyma are present in older internodes, and at the top of each internode, revealing developmental gradients. Submergence or treatment with the ethylene-releasing compound ethephon promoted aerenchyma formation in all genotypes analyzed. Pre-aerenchymal cells contain less starch, no chloroplasts, thinner cell walls and produce elevated levels of O(2)·(-) and H(2)O(2) compared with other parenchymal cells. Ethephon promotes O(2)·(-) formation and H(2)O(2) promotes aerenchyma formation in a dose-dependent manner. Further-more, genetic downregulation of the H(2)O(2) scavenger MT2b enhances aerenchyma formation. ? Aerenchyma formation is mediated by reactive oxygen species.  相似文献   

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