NaCl对渗透胁迫下三角叶滨藜光合作用和水分状况的调节

以溶液培养的三角叶滨藜(Atriplex triangularis)为材料, 测定分析了在PEG诱导的渗透胁迫条件下, 适量的NaCl对其光合作用和水分吸收的影响, 以探讨环境溶液中NaCl对植物适应干旱的影响。结果表明, PEG诱导的渗透胁迫导致三角叶滨藜植株吸水困难、叶绿素含量降低、光合系统受损、生长受抑制、生物量减少; 而在PEG渗透胁迫的处理液中添加10–40 mmol·L^–1NaCl可以明显降低植株水势和叶片渗透势, 维持较高的细胞膨压, 减缓PEG渗透胁迫对光合系统的破坏作用, 保证相对较高的光合速率和生长速度, 从而有效增强了三角叶滨藜对渗透胁迫的适应能力。     

等渗盐分与水分胁迫对三角叶滨藜和玉米光合作用的影响

以溶液培养的三角叶滨藜(Atriplex triangularis)和玉米(Zeamays)为材料,测定了等渗的盐分和水分胁迫对2种植物光合作用的短期影响。结果表明:等渗的水分和盐分胁迫均会造成三角叶滨藜和玉米净光合速率(Pn)的降低,而且随着胁迫程度的增强,水分胁迫引起Pn下降的幅度要明显高于等渗的盐分胁迫;在较低渗透胁迫强度下,2种胁迫导致光合速率下降的主要原因是气孔限制;但在环境溶液渗透势为-1.0MPa时,水分胁迫对光合作用的影响逐渐转化成非气孔限制,而盐胁迫仍然是气孔限制起主要作用;由此可见,等渗透势的水分胁迫对2种植物光合系统的影响要明显大于盐分胁迫。     

不同光照强度下三角叶滨藜光合作用对盐激胁迫的响应

以溶液培养的三角叶滨藜植株为材料研究了不同光照条件下其叶片光合作用对盐(NaCl)激胁迫的即刻反应及变化规律.结果表明,三角叶滨藜光合作用对盐激胁迫的响应有8 min左右的滞后期.在光照强度为100umol·m-2·-1和100 mmol·L-1浓度NaCl共同作用下,三角叶滨藜叶片净光合速率略有上升;但随NaCl浓度和光照强度进一步增加,其净光合速率呈下降趋势,且光照越强,盐胁迫导致的净光合速率下降幅度越大.同时,弱光下或强光低浓度NaCl胁迫下,盐激胁迫导致的净光合速率下降主要是气孔限制引起的;而强光下,高浓度的NaCl胁迫导致的净光合速率下降在盐激胁迫处理的前30-40 min主要由气孔限制引起.40 min后则主要由非气孔限制引起.可见,不同光照强度和NaCl浓度胁迫下三角叶滨藜叶片光合作用响应规律不同,引起净光合速率下降机制各异.     

土壤盐分对三角叶滨藜抗旱性能的影响

本实验用不同浓度NaCl溶液浇灌后进行干旱处理,测定了不同处理条件下三角叶滨藜幼苗在干旱持续过程中植株生长状况、叶片光合作用、抗氧化酶活性以及植株水分状况等的变化,以分析土壤盐分对三角叶滨藜耐旱性的影响。结果显示,用0.1—0.4 mol/L NaCl溶液浇灌后进行干旱处理（“干旱 NaCl”）的三角叶滨藜幼苗在干旱持续期间植株生长量、叶片净光合速率均明显高于用水浇灌后进行干旱处理（“干旱”）的三角叶滨藜幼苗,且后者在干旱处理的后期导致了叶片光合机构的明显损伤,前者则无。同时,“干旱 NaCl”处理的植株叶片超氧化物歧化酶、过氧化物酶和过氧化氢酶活性的变化幅度明显小于“干旱”处理的,且前者的丙二醛含量显著低于后者。进一步分析各处理土壤和植株水分状况发现,与“干旱”处理相比,“干旱 NaCl”处理显著提高了土壤的保水能力,增加了植株对Na 的吸收和积累,降低了叶片渗透势。由此可见,土壤中适量盐分存在能够增加三角叶滨藜对Na 的吸收和积累、降低组织渗透势、维持较强的吸水和保水力,从而减弱因干旱脱水导致的过量活性氧自由基产生对细胞膜系统的损伤和对光合机构的破坏,有利于维持相对较高的物质生产能力和细胞的持续生长,最终表现为耐旱性能的增强。     

玉米根、叶质膜透性和叶片水分对土壤干旱胁迫的反应

利用大型活动式防雨旱棚 ,人工控制不同土壤含水量 ,全生育期系统研究了轻度及严重土壤干旱胁迫对夏玉米根系活力、叶片相对含水量、离体叶片保水力和根、叶质膜透性的影响 .结果表明 :土壤干旱胁迫下 ,玉米叶片相对含水量下降、离体叶片保水力降低 ;叶片及根系质膜透性上升 ,并且根的质膜透性比叶片上升快 ,根系活力下降 ;在干旱胁迫下 ,根系、叶片质膜透性与叶片相对含水量呈负相关 ,而根系、叶片质膜透性与离体叶片保水力呈显著正相关 ,根系膜透性与叶片膜透性也呈显著正相关 ,维持根系活力与保持较高的叶片含水量有密切关系 .另外 ,由于严重水分胁迫处理的上述特性和充分供水处理差异显著 ,而轻度胁迫和充分供水不显著 ,因此可以认为轻度水分胁迫 ,即土壤含水量为田间持水量的 6 0± 5 %为夏玉米正常生长发育的下限指标 ,可作为制定节水栽培措施的理论依据 .     

Ca^2＋对盐胁迫下黄瓜幼苗中CaM,MDA含量和质膜透性的影响…

添加ＣａＣｌ２可提高黄瓜幼苗中ＣａＭ含量,降低ＭＤＡ（丙二醛）和质膜透性,减轻盐害,添加ＣａＭ抑制剂ＣＰＺ（氯丙嗪）、ＴＦＰ（三氟拉嗪）则取得相反效果,添加外源ＣａＭ在体内合成,起到降低盐害作用。     

盐胁迫下Ca~(2 )对小麦根无机离子分布和膜脂脂肪酸的影响

用扫描电镜、X—射线能谱仪和等离子耦合吸收光谱(ICP)分析发现,培养在含NaCl培养液中,小麦柜吸收大量Na~ 和Cl~-,K~ 和Ca~(2 )的吸收降低,质膜相对透性提高,K~ 、Na~ 和Cl~-的相对外渗百分率增加。培养在补充CaCl_2含NaCl培养液的,Na~ 和Cl~-含量明显减低,K~ 和Ca~(2 )提高,质膜相对透性下降,K~ 、Na~ 和Cl~-相对外渗百分率减少。由气相色谱分析可知,用含NaCl或补充CaCl_2培养液培养的幼苗,根的膜脂脂肪酸组分没有变化,但培养在补充CaCl_2的培养液中的根,亚麻酸含量和脂肪酸不饱和指数下降。     

三角叶滨藜的组织培养和植株再生

1　植物名称　三角叶滨藜 (Atriplextriangu laris)。2　材料类别　无菌苗的子叶。3　培养条件　培养基 :( 1 )MS + 6 BA 1mg·L- 1(单位下同 ) + 2 ,4 D 1 ;( 2 )MS + 6 BA 1 +NAA 1 ;( 3)MS + 6 BA 1 +IBA 1 ;( 4 )MS + 6 BA 1 +IAA1 ;( 5 )MS + 6 BA 0 .5 +IAA 0 .1 +GA 0 .2 ;( 6)MS + 6 BA 0 .5 +IAA 0 .4+GA 2 ;( 7)MS + 6 BA1 +IAA 0 .2 +GA 2 ;( 8)MS + 6 BA 1 +IAA 0 .4+GA 2 ;( 9) 1 /2MS +IAA 2 ;( 1 0 ) 1 /2MS。上述培养基 ( 1 )～ ( 4 )加CH(水解酪蛋白 ) 2 0 0、45 g·L- 1 蔗糖 ,( 5 )～ ( 8…     

NaCl胁迫下外源亚精胺和二环己基胺对滨藜内源多胺含量和抗盐性的影响

受高浓度NaCl胁迫的滨藜叶中内源腐胺（Put)、叶绿素、丙二醛（ＭＤＡ）的含量,腐胺／多胺（Put/PA)值以及相对电导率明显增加,内源亚精胺（Spd)、精胺（Spm）、蛋白质的含量和含水量显著下降。,外施亚精胺可以逆转NaCl的胁迫效应,外施二环己基胺（ＤＣＨＡ）的作用与外施亚精胺的相反。     

三角叶滨藜根吸水特点与其抗盐性的关系

采用压力室和冰点渗透压计测定了三角叶滨藜在不同浓度NaCl的根系环境溶液中根木质部的压力势和伤流液的渗透势,并利用原子吸收分光光度计测定了植株和伤流液以及环境溶液中Na 含量。结果表明:随着根环境溶液NaCl浓度的增加,三角叶滨藜植株和木质部伤流液中Na 含量虽呈上升趋势,但根系的过滤系数和体内Na 相对累积量逐渐降低,说明三角叶滨藜根细胞对盐分有很强的过滤作用;木质部伤流液的渗透势随着环境溶液渗透势的降低而降低,但根木质部溶液的水势则逐渐高出根外环境溶液的渗透势;表明三角叶滨藜能够利用较低的木质部负压来抵抗根外溶液的低渗透势而反渗透吸水,并利用根细胞对盐分的过滤作用来避免从环境摄取过量的盐分。     

不同耐盐品种棉花根系主要指标对盐分胁迫的响应

以盐敏感品种‘中棉所45’(CCRI45)、弱耐盐品种‘新陆早17号’(XLZ17)、中等耐盐品种‘新陆早13号’(XLZ13)和耐盐品种‘中棉所35’(CCRI35)为试验材料,利用根系分析系统研究盐分胁迫下棉花根系形态特征及其与棉株耐盐性的关系.结果表明:盐分胁迫显著降低棉花根和叶的干质量以及K^+/Na^+,其中耐盐品种CCRI35和中等耐盐品种XLZ13的根干质量、叶干质量以及根中K^+/Na^+分别比盐敏感品种CCRI45提高了69.3%~104.4%、24.8%~45.3%和25.0%~45.8%;盐分胁迫显著抑制棉花根系生长发育,其中CCRI 35和XLZ13的总根长、根系总表面积、根系总体积以及0~10 cm土层中直径为0~1.2 mm内的根长、根表面积和根体积均显著高于CCRI45,分别增加了15.2%~85.8%、12.0%~68.5%、31.7%~217.8%、27.2%~73.9%、39.6%~74.3%和99.0%~309.7%.主成分分析表明,比根长、浅层根长比例和细根比例受基因型差异的影响较为明显,是区分不同耐盐品种棉花根系形态差异的主要指标.逐步回归分析显示,比根长、0~10 cm土层的粗根根长、细根根表面积、粗根根表面积、粗根体积、中根比例,以及10~20 cm粗根根长、粗根表面积、粗根体积等根系参数对盐分响应敏感.耐盐棉花品种可通过维持表层根长比例、细根比例和比根长的增加来适应盐分胁迫.     

Life history and population dynamics of Atriplex triangularis

The dynamics of a population of the stoloniferous Potentilla anserina was studied during four years. The mortality of established ramets followed a log-linear pattern superimposed on a seasonal fluctuation with an increased mortality during the period of vegetative spread. The major external mortality factors were unfavourable weather conditions such as drought and freezing. The turnover rate of the population was slow (31.6 yr). Vegetative spread dominated the recruitment to the population. Seedlings occurred but were exposed to a much higher mortality than vegetative daughter ramets. The juvenile period of seedlings is at least 4 yr in the field. This contrast to vegetative daughter ramets which are potentially flowering and stoloniferous the year after they are established, even if age affects both reproduction and vegetative spread. The density of most of the population is below the level where intraspecific regulative effects operate. However, in very dense stands both stolon and flower production were negatively density dependent.Nomenclature follows Lid (1974), Norsk og Svensk Flora, 2nd ed. Oslo.I am indebted to Lenn Jerling, Peter Torstensson, Anders Telenius and Gudrún Jónsdóttir for their help, and inspiring criticism throughout this study.     

Physical and gene mapping of chloroplast DNA from Atriplex triangularis and Cucumis sativa.

A rapid and simple method for constructing restriction maps of large DNAs (100-200 kb) is presented. The utility of this method is illustrated by mapping the Sal I, Sac I, and Hpa I sites of the 152 kb Atriplex triangularis chloroplast genome, and the Sal I and Pvu II sites of the 155 kb Cucumis sativa chloroplast genome. These two chloroplast DNAs are very similar in organization; both feature the near-universal chloroplast DNA inverted repeat sequence of 22-25 kb. The positions of four different genes have been localized on these chloroplast DNAs. In both genomes the 16S and 23S ribosomal RNAs are encoded by duplicate genes situated at one end of the inverted repeat, while genes for the large subunit of ribulose-1,5-bisphosphate carboxylase and a 32 kilodalton photosystem II polypeptide are separated by 55 kb of DNA within the large single copy region. The physical and genetic organization of these DNAs is compared to that of spinach chloroplast DNA.     

Regulation of metabolomics in Atriplex halimus growth under salt and drought stress

Forty-day-old Atriplex halimus seedlings were treated with either NaCl (50, 300 and 550?mM) for the subsequent 30?days or PEG for the following 3, 6 and 10?days. Shoot fresh and dry weights were significantly increased by 50?mM NaCl; nevertheless, the other concentrations had no effect. However, the growth was reduced by drought only after 10?days. Meanwhile, Na⁺ was accumulated in treated plants; the magnitude of accumulation was highest with high NaCl concentration or PEG for 10?days. The metabolite profiles showed discrimination particularly up-regulation of the amino acids proline, valine, isoleucine, and methionine. Moreover, the macro analysis revealed that NaCl- and PEG-treated plants shared 10?% of the metabolites in the positive mode, however, 87?% were unique to NaCl and 46?% were unique to PEG whereas in the negative mode, 8?% were in share while 90 or 53?% were restricted to NaCl or PEG, respectively. Additionally, sucrose in particular was significantly increased up to threefold and fivefold by 300 and 550?mM NaCl, respectively and up to 2.5-fold by drought for 10?days, nevertheless, the other sugar fractions remained largely unchanged. Also, proline was significantly increased by only the high NaCl concentrations and the long-term drought, nonetheless, the other treatments led, if any, to decreases. These results conclude that NaCl affects the metabolite profiles more than PEG and these metabolites might contribute to osmotic adjustments to act as osmoprotectants rather than osmolytes. These changes of metabolomics might function in many resistance and stress responses.     

Responses of Atriplex spongiosa and Suaeda monoica to Salinity

The growth and tissue water, K⁺, Na⁺, Cl⁻, proline and glycinebetaine contents of the shoots and roots of two Chenopodiaceae, Atriplex spongiosa and Suaeda monoica have been measured over a range of external NaCl salinities. Both species showed some fresh weight response to low salinity mainly due to increased succulence. S. monoica showed both a greater increase in succulence (at low salinities) and tolerance of high salinities than A. spongiosa. Both species had high affinities for Na⁺ and maintained constant but low shoot K⁺ contents with increasing salinity. These trends were more marked with S. monoica in which Na⁺ stimulated the accumulation of K⁺ in roots. An association between high leaf Na⁺ accumulation, high osmotic pressure, succulence, and a positive growth response at low salinities was noted. Proline accumulation was observed in shoot tissues with suboptimal water contents. High glycinebetaine contents were found in the shoots of both species. These correlated closely with the sap osmotic pressure and it is suggested that glycinebetaine is the major cytoplasmic osmoticum (with K⁺ salts) in these species at high salinities. Na⁺ salts may be preferentially utilized as vacuolar osmotica.