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1.
为研究麦冬在水分胁迫和盐分胁迫条件下一些抗逆性生理指标的变化,本文以盆栽后以正常浇水处理为对照,设置了不同程度人工水分胁迫和钙离子胁迫处理研究可溶性糖含量、脯氨酸含量及丙二醛含量的变化情况.结果显示,轻度水分胁迫使可溶性总糖和游离脯氨酸含量减低.但随着时间的推移,胁迫程度加剧,可溶性总糖和游离脯氨酸含量开始回升,而MDA含量无显著变化.表明水分胁迫下.麦冬可积累可溶性糖和游离脯氨酸等渗透调节物质,从而改善自身水分状况,保护细胞膜及生理代谢过程,膜脂过氧化程度减轻.钙盐胁迫也可使可溶性总糖和游离脯氨酸含量升高.  相似文献   

2.
水分胁迫对白刺幼苗生物量和渗透调节物质积累的影响   总被引:18,自引:5,他引:13  
以PEG-6000模拟不同程度的水分胁迫对白刺幼苗进行处理,研究了其植株干重及其K 、Na 、丙二醛、游离脯氨酸、可溶性糖的含量变化.结果表明,15%PEG胁迫下白刺幼苗的生物量最高,丙二醛含量最低,且二者与对照的差异均显著;随着水分胁迫程度的增强,K 含量逐渐降低并与对照差异显著,Na 含量先减少后增加而其总积累量无显著变化;游离脯氨酸和可溶性糖含量随着水分胁迫程度的增强而显著增加.因此,轻度水分胁迫有利于白刺幼苗的生长,有机溶质游离脯氨酸和可溶性糖是白刺适应干旱环境的主要渗透调节物质.  相似文献   

3.
糜子幼苗生长于完全、缺钙、缺钾、缺钙并缺钾4种营养液中。水分胁迫下,各种幼苗相对含水量均下降,造性增强。其中,单缺钾及缺钙并缺钾时相对合水量比完全及单缺钙时下降较大,单缺钙时透性更易增强。水分胁迫下,完全营养苗游离脯氨酸含量明显高于对照,而其它3种苗的游离脯氨酸含量与其对照之间差异不显著。水分胁迫48h,缺钾苗和缺钙并缺钾苗叶肉细胞有质壁分离现象,叶绿体受到一定程度的损伤,单缺钾时超微结构损伤尤甚。另外,钙调蛋白抑制剂实验表明,干旱胁迫引起的幼苗体内游离脯氨酸含量的增加可能与钙调蛋白无关。  相似文献   

4.
水分胁迫下植物体内游离脯氨酸的累积及ABA在其中的作用   总被引:18,自引:0,他引:18  
无论是土壤干旱,还是NaCl或PEG所引起的水分胁迫,都使植物体内游离脯氨酸含量明显升高。不同小麦品种反应不一,如对干旱敏感的甘麦8号比抗旱的和尚头、定西24在NaCl和PEG胁迫下游离脯氨酸水平增高得更快,而后者持续的时间较长。土壤干旱胁迫下,小麦各品种之间脯氨酸含量无明显差异。中生植物倒挂金钟(Fuchsia hybrida)和沙生植物猪毛蒿(Artemisia scoparia)在水分胁迫下游离脯氮酸含量均有增高。把小麦幼苗放在5×10~(-5)M ABA溶液中浸根处理,无论在正常或胁迫情况下均能促进游离脯氨酸含量的增高。  相似文献   

5.
NaCl胁迫下羊草幼苗的生理反应及外源ABA的缓解效应   总被引:6,自引:0,他引:6  
对NaCl胁迫下羊草(Aneurolepidiumchinense)的生长、生理和代谢变化的研究表明,在Na+胁迫下,羊草幼苗生长受抑,叶片细胞膜相对透性增大,体内脯氨酸累积增加,无机Na+含量增多.叶绿素含量减少.外源ABA处理可促进羊草对K+吸收,抑制Na+吸收,减轻Na+毒害,增强膜稳定性、光合能力和渗透调节能力,并提高羊草生长代谢活性和叶绿素含量.  相似文献   

6.
以盆栽3年生红松和西伯利亚红松为材料,设置4种水分条件,土壤含水量分别为:29%~31%(C), 22%~24%(L), 15%~17%(M)和渍水组(W),研究不同水分条件下红松和西伯利亚红松当年生针叶和往年生针叶的脯氨酸含量和叶绿素含量变化。结果表明:1)脯氨酸含量在不同叶龄和不同树种之间存在差异。红松当年生针叶叶绿素含量高于往年生针叶,而西伯利亚红松则相反。总体上西伯利亚红松的脯氨酸含量高于红松;2)2树种在渍水条件下脯氨酸含量大量积累,红松在处理后一个月即出现胁迫反应,早于西伯利亚红松。土壤含水量在 15%~17%时已对2种红松的往年生针叶产生胁迫,但对红松的胁迫程度大于西伯利亚红松;3)叶绿素积累与2种红松的耐水分胁迫能力相关性不大;4)西伯利亚红松的水分适应范围大于红松;2种红松的当年生针叶的耐水分胁迫能力均大于往年生针叶。  相似文献   

7.
水分胁迫对小麦捕光色素蛋白复合物的影响   总被引:14,自引:0,他引:14  
棉农4号春小麦幼苗(Triticum aestiuvum L.ev .Miannong No.4)经一0.5MPa PEG溶液渗透胁迫24、48和72h,使叶片分别受到轻蔗、中度和重度的水分胁迫。在渐进水分腔迫条件下,叶绿体类囊体膜中光系统Ⅱ捕光色素蛋白得合物(LCH Ⅱ)的各组分含量发生了不同变化。对类囊体纱蛋白复合物进行的温和电泳结果显示,在轻度水分胁迫(24h)时,明轻度水分胁迫对其有诱导作  相似文献   

8.
松嫩平原两种趋异类型羊草对干旱胁迫的生理响应   总被引:22,自引:4,他引:18  
采用盆栽实验,对灰绿和黄绿两种趋异类型羊草(Leymus chinensis(Trin.)Tzvel.)幼苗期用聚乙二醇(PEG)胁迫进行干旱生理指标测定,结果表明,在干旱胁迫下,灰绿型羊草和黄绿型羊草的电解质外渗率、脯氨酸、植株含水率、植株鲜重、SO4^2-、NO3^-之间均有显著或极显著差异,灰绿型羊草叶片电解质外渗率和叶绿素含量的b值均大于黄绿型羊草,而植株含水率的b值则小于黄绿型羊草,灰绿型羊草脯氨酸含量均大于黄绿型羊草,因子分析表明,脯氨酸是两种趋异类型羊草干旱胁迫生理反应的主要因子,两种趋异类型羊草在生理响应中均体现出耐旱能力,但灰绿型羊草的耐旱能力比黄绿型更强,两种趋异类型羊草在耐旱生理上有明显分化。  相似文献   

9.
不同种子预处理方法对提高三树种幼苗耐盐性的效应   总被引:10,自引:0,他引:10  
刺槐(RobiniapseudoacaciaLinn.)、湿地松(PinuseliotiEngelm.)和侧柏〔Platycladusorientalis(L.)Franco〕种子经03%CaCl2,250μg/gH3BO3和250μg/g多效唑(MET)浸种24h,然后测定幼苗的耐盐性。结果表明,在0.3%NaCl胁迫条件下,不同种子预处理方法对种子发芽率、平均苗高、根茎比、简易活力指数(SVIS)以及幼苗中Na+与K+的累积量、Na+/K+比及游离脯氨酸含量有较大影响。树种不同,处理效果也存在明显差异。湿地松以0.3%CaCl2,侧柏以250μg/gH3BO3浸种处理效果最好,显著提高种子发芽率、平均苗高、根茎比和SVIS,降低幼苗Na+吸收量和Na+/K+比,缓解盐胁迫逆境。3种种子预处理方法均降低刺槐种子发芽率、平均苗长和SVIS,但提高刺槐幼苗游离脯氨酸含量和幼苗根茎比,减少幼苗对Na+的吸收,降低Na+/K+比  相似文献   

10.
台湾桤木和四川桤木种源苗木对水分胁迫的生理响应   总被引:10,自引:0,他引:10  
采用PEG6000,研究了4种台湾桤木种源和2种四川桤木种源苗木对水分胁迫的生理响应。结果表明:(1)随着水分胁迫强度增加,叶片质膜相对透性增大,四川桤木种源质膜透性比台湾桤木种源增加幅度大。(2)在轻度的水分胁迫下,6个种源SOD活性均呈上升趋势,POD活性的增加只发生在PEG10%的水分胁迫强度以内,轻度水分胁迫下,MDA含量上升幅度小于重度胁迫强度;在PEG30%胁迫处理时,台湾桤木叶片MDA含量平均上升30.22%,而四川桤木上升了40.44%,表明台湾桤木种源膜脂过氧化程度较四川桤木种源轻,受害程度相对要小一些。(3)水分胁迫下,叶片脯氨酸含垃均有不同程度的增加.在PEG20%水分胁迫处理下,各种源脯氨酸积量增加的幅度为:台湾桤木苗栗种源(AF2)(68.9%)〉台湾桤木福建南平种源(AF4)(60.2%)〉台湾桤木台东种源(AF2)(54.7%)〉台湾桤木台中种源(AF1(47.6%)〉四川桤木广元种源(AC2)(39.7%)>金堂种源(AC1)(39.1%)。水分胁迫条件下,叶片可溶性糖含量呈下降趋势。6种种源苗木在水分胁迫条件下,由于脯氨酸的积累,有一定的渗透调节能力,但这种渗透调节能力又是十分有限的。(4)采用隶属函数法,对各种源的抗旱生理进行综合评价,其耐旱牛理强弱的顺序是:AF2、AF1、AF3、AF4、AC2、AC1,台湾桤木比四川桤木具有较强的耐旱生理适应性。从耐旱生理角度讲,凡是适合四川桤木生长的区域,基本上亦适合台湾桤木,在引种载培中,应选择抗旱性稍强一些的台湾桤木苗栗种源和台中种源。  相似文献   

11.
Paramyxoviruses: different receptors - different mechanisms of fusion   总被引:1,自引:0,他引:1  
Paramyxovirus-mediated membrane fusion usually requires an interaction between the viral-attachment and -fusion proteins. The mechanism by which this interaction regulates fusion differs between paramyxoviruses that bind to sialic acid-containing receptors and those that recognize specific proteins. The recently solved structure of the globular head of the measles virus hemagglutinin suggests that this difference might be related to the location of the receptor-binding sites on the attachment proteins of the two classes of paramyxoviruses.  相似文献   

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Papillomaviruses (PVs) infect stratified squamous epithelia in vertebrates. Some PVs are associated with different types of cancer and with certain benign lesions. It has been assumed that PVs coevolved with their hosts. However, recently it has been shown that different regions of the genome have different evolutionary histories. The PV genome has a modular nature and appeared after the addition of pre-existent blocks. This order of appearance in the PV genome is evident today in the different evolutionary rates of the different genes, with new genes--E5, E6 and E7--diverging faster than old genes--E1, E2, L2 and L1. Here, we propose an evolutionary framework aiming to integrate genome evolution, PV biology and epidemiology of PV infections.  相似文献   

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This study evaluates the antimicrobial effects of ethanolic extract of five herbal plants; Guava (Psidium guajava), Sage (Salvia officinalis), Rhamnus (Ziziphusspina Christi), Mulberry (Morusalba L.), and Olive (Oleaeuropaea L) leaves against several microbial population representing Gram positive, Gram negative and Mollicutes; S. aureus, E. coli, Pasteurella multocida, B. cereus, Salmonella Enteritidis and M. gallisepticum using standard agar disc diffusion technique and minimal inhibitory concentration (MIC). Different extracts reveal variable results against the microorganism under study. All extracts have no antibacterial potency for Mycoplasma gallisepticum except Psidium guajava. The results of minimal inhibitory concentration (MIC) and Minimum bactericidal concentration (MBC) of the extracts against the six bacteria ranged from 625 to 5000 μg/ml. The used herbal extract could inhibit the selected microorganism under study with variable minimal inhibitory concentration (MIC) and minimum bactericidal concentration (MBC).  相似文献   

16.
J. PEOPLE 《Austral ecology》2006,31(2):271-281
Abstract Artificial structures, such as seawalls, pilings and pontoons, are common features of urban estuaries. They replace natural structures or add to the amount of hard substratum in an area and provide habitats for many fish and invertebrates. Previous work has concentrated on fish or on the invertebrates that occupy the primary substratum of artificial structures. Mussels often grow on different types of structures (pontoons, pilings, seawalls and natural reefs) and provide a secondary substratum for other organisms to inhabit. Counting and identifying organisms associated with mussel beds is traditionally done to species level, which is very time‐consuming. To save time, organisms in this study were identified to coarse levels of taxonomic resolution (a mix of taxa, such as class, order, family and genus), which showed similar patterns to those when particularly speciose and abundant groups were identified to species. This study tests hypotheses that the distribution and abundance of mobile and sessile organisms that inhabit mussel beds will differ among natural and various types of artificial structures. When the associated assemblages of mussel beds from different types of structures and from different locations were examined, assemblages varied according to the type of structure they inhabited and its location. Assemblages associated with mussels on pontoons differed consistently from those on other types of structures. Patterns in the assemblages were also consistent through time. These data show that the types and amounts of artificial structures added to an environment can affect the types, distribution and abundances of organisms living in biogenic habitats.  相似文献   

17.
Ras signalling has classically been thought to occur exclusively at the inner surface of a relatively uniform plasma membrane. Recent studies have shown that Ras proteins interact dynamically with specific microdomains of the plasma membrane as well as with other internal cell membranes. These different membrane microenvironments modulate Ras signal output and highlight the complex interplay between Ras location and function.  相似文献   

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Six polymorphic protein systems in 15 chicken breeds have been investigated. In the Silkie breed another variant of G3 proteins (G3 AF Silkie) has been observed characterized by higher electrophoretic mobility than G3 A. The frequencies of individual alleles in various lines and different generations have been determined in two breeds (White Leghorn and White Cornish).  相似文献   

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