嫁接诱导大豆低镉富集性状及遗传稳定性

通过野外小区实验,从8个大豆品种中筛选出2个低镉富集品种作为砧木,2个高镉富集品种作为接穗植物,研究嫁接当代以及接穗子代镉富集性状的变化,探明嫁接诱导镉富集性状变异的机制及其遗传稳定性。结果表明:大豆的镉富集性状表现出显著的品种间差异,以低镉富集品种(铁丰29和东鲜1号)作砧木,可以使接穗大豆植株(青仁黑1号和中黄38)地上部分镉含量降低50%~70%;高通量测序和qRT-PCR分析显示,嫁接诱导了相关硫代谢基因的差异表达,与自根植株相比,嫁接植株的APX2、PAPRa、SAM1a和ATPs基因表达水平均显著下调,分别达72.53%、67.62%、42.37%和75.78%,APK4表达量则显著上调2.83倍;以阻控效果最好的青仁黑1号-东鲜1号为例,接穗子代遗传了接穗当代的低镉富集性状,对照亲本,子代籽粒镉含量的降低率仍有30%~50%。研究证明:嫁接可以通过调控含硫化合物的合成与代谢,影响作物地上部分的Cd富集性状,且这种性状可以在子代中稳定遗传。     

水分胁迫下嫁接对茄子生长及其生理生化指标的影响

以野生茄托鲁巴姆(Solanum torvum)为砧木,茄子品种西安绿茄为接穗进行嫁接,研究不同水分胁迫下嫁接对其生长和生理生化指标的影响.结果表明:土壤水分胁迫严重限制了嫁接茄和自根茄的生长,在对照(80％ ～85％)处理下差异不明显,在轻度(50％ ～55％)、重度(35％～40％)水分胁迫下差异显著;与自根茄相比,各处理嫁接茄的株高和茎粗显著增加(P＜0.05);地上部鲜重、根鲜重和地上部干重、根干重均呈显著增加趋势;叶片相对含水量和叶绿素含量也显著增加;而相对电导率和丙二醛( MDA)含量较自根茄显著下降;嫁接极显著地增加了叶片的脯氨酸和可溶性糖含量;随着胁迫时间的延长和程度的加大,嫁接茄叶片的超氧化物酶(SOD)和过氧化物酶(POD)活性与自根茄差异达显著水平(P＜0.05);嫁接增强了植株长势,能够调节自身渗透调节物质的含量和保护酶系统活性,来减轻干旱伤害,维持植物体的正常生理代谢功能,表现出较强的抗旱耐旱能力.     

嫁接茄的黄萎病抗性与根际土壤生物学活性的关系

以野生茄托鲁巴姆(Solanum torvum)和刺茄(S.surattense)为砧木,西安绿茄(smelongena)为接穗,研究了嫁接茄的抗黄萎病效果及其根际土壤微生物种群数量和酶活性变化,探讨了嫁接茄的抗病性与根际土壤生物学活性的关系.结果表明:嫁接茄的抗病效果明显,其根际微生物种群数量及所占比例、根际土壤酶活性均发生了改变,且不同生育时期存在一定的动态变化.总体看,嫁接茄的抗病性增强,与其根际放线菌数量增加、放线菌数量与真菌数量的比值提高,根际土壤脱氢酶、多酚氧化酶活性提高有关.     

茄子砧木Na^＋、K^＋含量、Sk,Na运输与耐盐性关系研究

为考察不同茄子砧木在茄子耐盐性的作用,以茄子嫁接生产中常用的托鲁巴姆（Solanum torvum）、赤茄（Solanum integgrifolium）、刺茄（Solanum texanum）和刚果茄（Solanum sisymbriifl ium）为试材,研究了盐害指数、根系和地上部Na^＋、K^＋含量、Na^＋/K^＋比、SK,Na运输及其与耐盐性的关系。结果表明,各种砧木的盐害指数均随着盐浓度的增大呈上升趋势,同一盐浓度下,盐害指数由大到小依次为刚果茄〉赤茄〉刺茄〉托鲁巴姆。根系Na^＋含量、地上部K^＋含量、根系Na^＋/K^＋比及SK,Na运输在各盐浓度下均表现为托鲁巴姆〉刺茄〉赤茄〉刚果茄。地上部Na^＋含量、根中K^＋含量及地上部Na^＋/K^＋比在各盐浓度下均表现为托鲁巴姆〈刺茄〈赤茄〈刚果茄。茄子砧木耐盐性与根中Na^＋含量、根中Na^＋/K^＋比、SK,Na运输呈正相关,与地上部Na^＋含量、根中K^＋含量、地上部Na^＋/K^＋比呈负相关。这些结果表明,Na Cl处理下耐盐性强的砧木通过限制Na^＋向叶片中运输,增加了叶片中K^＋含量,从而降低Na^＋/K^＋比来提高植株耐盐性。     

多菌灵胁迫下嫁接对茄子生长和抗氧化酶活性的影响

以野生茄托鲁巴姆(Solanum torvum)为砧木,以栽培品种西安绿茄(S.melongena)为接穗进行嫁接,测定不同施入频次多菌灵条件下嫁接茄子和自根茄子果实中的农药残留、生长发育状况和抗逆生理指标。结果表明,经过多菌灵施药1次、2次、3次处理后,嫁接茄果实中农药残留量比自根茄分别降低了12.7%～49.6%、11.4%～63.1%、13.5%～44.1%;嫁接茄株高、茎粗、植株鲜重和鲜果重相对于自根茄明显增加;嫁接茄根系活力比自根茄增加了6.8%～29.3%、8.7%～24.5%、11.1%～28.6%;嫁接茄叶片过氧化氢酶(CAT)活性、过氧化物酶(POD)活性、谷胱甘肽过氧化物酶(GSH-PX)活性相对于自根茄明显增加,而相对电导率比自根茄降低了16.3%～27.3%,19.7%～31.9%、20.5%～36.1%;嫁接茄丙二醛含量比自根茄降低了21.4%～31.6%、24.6%～37.9%、23.7%～39.0%。试验结果显示,施药2次和3次,各指标变化相对于施药1次明显。因此,在多菌灵胁迫下,嫁接茄子果实中的农药残留降低,植株长势明显增强,有关酶的代谢活性显著提高,从而缓解了多菌灵胁迫对茄子造成的危害。     

镉胁迫下春小麦中镉的分布、富集及转移规律

采用盆栽试验,研究了镉胁迫下重金属镉(Cd)在春小麦中的分布、富集及转移规律。结果表明:Cd胁迫下,小麦根、茎、叶和籽粒中Cd积累量随外源Cd的增加而增加,小麦不同部位Cd积累量为根叶茎籽粒;籽粒中Cd含量与土壤中Cd显著相关;小麦不同部位对Cd的富集能力差异显著,且随外源Cd处理浓度的增加,各部位富集系数逐渐降低,低Cd浓度时各部位更易富集Cd;小麦植株地上部的转移系数亦呈递减趋势为茎、叶籽粒;在春小麦全生育期,土壤中Cd含量无明显变化,根对外源Cd的富集吸收于生育期70d左右达峰值,小麦植株中的Cd也在80d左右达到峰值后逐步减少,表明植株中的Cd,随籽粒的成熟逐步转移至籽粒。     

肉桂酸和香草醛对嫁接茄子根系生长及生理特性的影响

以“托鲁巴姆”茄子为砧木,“西安绿”茄子为接穗,采用盆栽试验研究了自毒物质肉桂酸和香草醛对嫁接、自根和砧木茄子根系生长及抗氧化酶活性、渗透调节物质含量的影响.结果表明：肉桂酸、香草醛对茄子根系生长及生理代谢的化感作用基本表现为“低促高抑”,两物质对自根茄子根系表现促进、抑制效应的临界浓度点分别为0.1和0.5 mmol·kg^-1;对嫁接、砧木茄子表现促进、抑制效应的临界浓度点分别为0.5和1 mmo·kg^-1.茄子根系对自毒物质耐性大小依次为：砧木茄>嫁接茄>自根茄;在较高浓度肉桂酸(0.5～4 mmol·kg^-1)和香草醛(1～4mmol·kg^-1)作用下,与自根茄子相比,嫁接茄子根系SOD活性提高了8.50%～24.50%,脯氨酸含量增加了9.39%～27.64%,可溶性糖含量增加了12.77%～81.81%,可溶性蛋白含量、根系鲜、干物质量和根系活力显著高于自根茄.表明嫁接换根使茄子根系具有了砧木抗自毒物质的特性,缓解了自毒物质给茄子根系生长带来的不良影响.     

黄萎病菌胁迫下野生茄子托鲁巴姆防卫反应的生理生化分析

以野生茄子托鲁巴姆(Solanum torvum Swartz)和苏崎茄(Solanum melongena L.)为主要材料,通过比较两种茄子在大丽轮枝菌(Verticillium dahliae Kleb)侵染过程中体内的生理生化指标变化,分析托鲁巴姆对黄萎病的抗性响应机制。结果表明:(1)与苏崎茄植株相比,托鲁巴姆植株表现出很强的自我防御和自我修复能力。(2)托鲁巴姆体内存在的活性氧清除系统(如SOD、POD、CAT等酶的活性)高于苏崎茄;在侵染后,托鲁巴姆体内各种酶的活性快速增加,其幅度高于苏崎茄;MDA的变化则恰恰相反。这个结果提示,黄萎病菌胁迫可能激活了托鲁巴姆体内活性氧清除系统,从而加快了某些防御物质(如木质素和抗菌物质绿原酸等)的形成,同时减缓或降低MDA等有害物质在植株体内的积累。(3)黄萎病菌侵染后各生理指标的响应时间表现出差异。托鲁巴姆中POD、PAL的活性和可溶性蛋白含量在侵染后的12h内就迅速作出响应(POD增加、PAL和可溶性蛋白减少);而SOD、PPO、CAT的活性和MDA的含量则在处理后初始阶段(至少12h)进行了一些调整,随后才进入持续性的增加或减少阶段。由此可见,托鲁巴姆对黄萎病病菌侵染的响应具有时序性,其体内POD酶、PAL酶和可溶性蛋白首先参与植物的防卫反应以应对黄萎病的胁迫,其它酶随后参与响应,它们的共同作用形成对黄萎病菌的有效防卫。     

嫁接对盐胁迫下西瓜幼苗体内离子和内源激素含量与分布的影响

以小型西瓜‘秀丽’为接穗、耐盐砧木瓠瓜‘超丰抗生王’为砧木,以自根嫁接苗为参照,分析了砧木嫁接对NaCl胁迫下西瓜幼苗根、茎、叶中离子和内源激素含量的影响。结果表明:(1)盐胁迫下,自根嫁接苗Na+主要积累在地上部,K+含量和K+/Na+比下降幅度大;砧木嫁接苗大部分Na+积累在根系中,K+含量和K+/Na+比下降幅度小且在不同部位皆高于自根嫁接苗。(2)盐胁迫下,自根嫁接苗吲哚-3-乙酸(IAA)以及玉米素和玉米核苷的总量(Z+ZR)在根系和接穗茎中显著增加,在叶片中明显下降,赤霉素(GA3)含量在不同部位保持不变或明显增加;而砧木嫁接苗不同部位IAA和(Z+ZR)的含量均显著增加,GA3含量在不同部位保持不变或明显下降。(3)盐胁迫下,两种嫁接组合根系和茎中脱落酸(ABA)含量均明显下降,叶片中ABA含量则显著增加。(4)盐胁迫下,自根嫁接苗和砧木嫁接苗根系和接穗茎中IAA/(Z+ZR)的比值均明显上升,叶片中明显下降,但砧木嫁接苗上升和下降幅度均远大于自根嫁接苗。研究表明,瓠瓜根系对进入根系的Na+具有截留作用;采用瓠瓜砧木嫁接可有效防止Na+在西瓜接穗地上部尤其是在叶片中的大量累积,从而防止离子毒害的发生;瓠瓜砧木嫁接植株体内具有较高的K+含量和K+/Na+比,可有效维持盐胁迫下西瓜嫁接植株体内的离子稳态;瓠瓜砧木嫁接植株体内具有较高的IAA和(Z+ZR)含量,IAA/(Z+ZR)比值较高,对提高西瓜嫁接植株盐胁迫耐性起到了积极的作用。     

Generalized accumulation of neutral glycosphingolipids with G M2 ganglioside accumulation in the brain

Analyses have been made of glycosphingolipids from visceral organs and brain of a patient with an unusual lipid storage disorder diagnosed initially as classical Tay-Sachs disease. Levels of the lipids from fresh-frozen sections of gray and white matter, kidney, spleen, liver, and heart from this patient were compared with those of normal juvenile controls, and the fatty acid composition of accumulated glycosphingolipids was compared with reference compounds. This patient was found to have abnormally high concentrations of a globoside in liver, kidney, and spleen, asialo G(M2) ganglioside in brain and liver, and G(M2) ganglioside in the brain. On the basis of these findings along with the clinical manifestations of Tay-Sachs disease with visceral involvement (hepatosplenomegaly) and demonstration of total deficiency of both A and B components of beta-N-acetylhexosaminidase activity, this glycosphingolipidosis is the same as two previously reported cases of G(M2) gangliosidosis with globoside accumulation and total beta-N-acetylhexosaminidase deficiency.     

Heme-oxygenase-mediated iron accumulation in the liver

Heme oxygenase (HO) isozymes, HO-1 and HO-2, catalyze the conversion of heme to iron, carbon monoxide, and biliverdin. The present study was aimed at elucidating the role of the HO system in iron accumulation and oxidative stress in the liver. We have also studied the regulation of an iron exporter, ferroportin-1 (FPN-1), as an adaptive response mechanism to increased iron levels. Sprague-Dawley rats were treated with HO inducer hemin or HO inhibitor tin-protoporphyrin IX (SnPPIX) for 1 month. A portion of liver tissues was subjected to RT-PCR for HO-1, HO-2, and FPN-1 gene expression as well as an HO activity assay. Paraffin-embedded tissues were stained for iron with Prussian blue. Hepatic iron concentration was measured by High Resolution-Inductively Coupled Plasma-Mass Spectrometry. 8-hydroxy-2'-deoxyguanosine (8-OHdG) stain, a sensitive and specific marker of oxidative DNA damage, was performed to assess oxidative stress. Hemin treatment led to augmented HO expression and activity in association with increased iron accumulation and oxidative stress. FPN-1 expression was also found to be upregulated. SnPPIX treatment reduced HO activity, intracellular iron levels, and oxidative stress as compared to controls. Our data provides evidence of increased HO activity as an important pro-oxidant mechanism leading to iron accumulation in the liver.     

Estimating the species accumulation curve using mixtures

As a significant tool in ecological studies, the species accumulation curve or the collector's curve is the graph of the expected number of detected species as a function of sampling effort. The problem of estimating the species accumulation curve based on an empirical data set arising from quadrat sampling is studied in a nonparametric binomial mixture model. It will be shown that estimating the species accumulation curve not only is independent of the unknown number of species but also includes estimating the number of species as a limiting case. For the purpose of interpolation, moment-based estimators, associated with asymptotic confidence intervals, are developed from several points of view. A likelihood-based procedure is developed for the purpose of extrapolation, associated with bootstrap confidence intervals. The proposed methods are illustrated by ecological data sets.     

Zinc accumulation in the telencephalon of lizards

The zinc concentration in the brains of two species of lizard was determined by atomic-absorption spectrophotometry. The zinc concentration was found to be highest in the telencephalon of Lacerta galloti (21.1 micrograms/g fresh weight) and Podarcis hispanica (16.77 +/- 0.8 micrograms/g) while the mesencephalon and brain stem exhibited lower zinc concentrations, i.e., 7.0 micrograms/g in Lacerta galloti and 6.08 +/- 0.4 micrograms/g in Podarcis hispanica. This high telencephalic concentration of zinc is paralleled by intense and well-defined Timm reactivity used for demonstrating the presence of zinc-containing boutons at the light-microscope level. Volumetric-densitometric studies of these Timm-reactive zones were performed using serial transverse sections of the same lizard brains.     

Zinc accumulation in the telencephalon of lizards

Summary The zinc concentration in the brains of two species of lizard was determined by atomic-absorption spectrophotometry. The zinc concentration was found to be highest in the telencephalon of Lacerta galloti (21.1 g/g fresh weight) and Podarcis hispanica (16.77±0.8 g/g) while the mesencephalon and brain stem exhibited lower zinc concentrations, i.e., 7.0 g/g in Lacerta galloti and 6.08±0.4 g/g in Podarcis hispanica. This high telencephalic concentration of zinc is paralleled by intense and well-defined Timm reactivity used for demonstrating the presence of zinc-containing boutons at the light-microscope level. Volumetricdensitometric studies of these Timm-reactive zones were performed using serial transverse sections of the same lizard brains.     

beta-Casomorphins alter the intestinal accumulation of L-leucine

Everted sacs of the rat jejunum change the accumulation of [3H]leucine when beta-casomorphins (BCMs) or synthetic analogs, in a concentration range of 10(-8) mol/l, are coincubated with the amino acid. BCM5 (BCM fragment 1-5, Tyr-Pro-Phe-Pro-Gly) and [D-Ala2]-BCM5-NH2 (Tyr-D-Ala-Phe-Pro-Gly) increase, whereas [D-Pro4]-BCM5 (Tyr-Pro-Phe-D-Pro-Gly) decreases the leucine accumulation and [Arg8]-vasopressin has no effect. No effect of BCM5 could be observed on the accumulation of the space marker [14C]inulin. Specific binding sites for casomorphins were detected microautoradiographically, exclusively at the epithelial cell layer using [3H][D-Pro4]-BCM5 in competition studies as a model. HPLC analysis revealed that under the experimental conditions about 50% of the studied [D-Pro4]-BCM5 was enzymatically degraded and no intact peptide is accumulated within the samples of everted sacs. From the results we postulate a brush-border receptor contact of the BCMs which induces an alteration of the amino acid uptake. A contraluminal binding of the chemical signals is not likely, because there is no evidence for a transepithelial transport of intact BCMs. The observed effects of the BCMs demonstrate as yet unknown peptide-receptor interactions, probably at the brush-border membrane, with subsequent effects on the nutrient supply. Furthermore, the results support the general hypothesis of distinct peptide-receptor interactions in those types of epithelia in which the cells are connected by tight junctions.