黄腐酸浸种对PEG模拟干旱胁迫下紫花苜蓿种子萌发及幼苗生长的影响

以紫花苜蓿(Medicago sativa L.)为研究对象,采用不同PEG模拟干旱处理(CK、10%PEG、0.03%FA+10%PEG和0.05%FA+10%PEG)方法,探讨黄腐酸(FA)浸种对紫花苜蓿种子萌发、幼苗生长及抗逆性生理生化指标的影响。结果显示:(1)在PEG模拟干旱胁迫下,紫花苜蓿种子的发芽率、发芽势、发芽指数、活力指数、以及幼苗叶绿素含量、膜稳定指数(MSI)和根系活力较对照均呈下降趋势,株高和生物量的增长速率均显著低于对照;而幼苗叶片丙二醛(MDA)、过氧化氢(H2O2)、脯氨酸、可溶性糖含量均随处理时间呈上升趋势,过氧化氢酶(CAT)和谷胱甘肽还原酶(GR)活性则呈下降-升高-下降的趋势,超氧化物歧化酶(SOD)、过氧化物酶(POD)活性及超氧阴离子(O-·2)产生速率则均呈先升高后降低的趋势。(2)经黄腐酸浸种处理后,模拟干旱胁迫下紫花苜蓿种子的发芽率、发芽势、发芽指数、活力指数和幼苗株高、生物量、脯氨酸和可溶性糖含量均显著升高,并显著减小了模拟干旱胁迫引起的叶绿素含量、根系活力和MSI下降的幅度,相对提高了SOD、POD、CAT、GR活性,降低了MDA、H2O2含量和活性氧水平。研究表明,10%PEG模拟的干旱胁迫使紫花苜蓿的种子萌发及幼苗生长发育受到显著抑制,而黄腐酸浸种处理可通过提高渗透调节物质含量和保护酶活性来有效缓解干旱胁迫对紫花苜蓿幼苗造成的氧化伤害,增强植株的整体抗旱性,维持其正常生长发育,并以0.05%黄腐酸浸种对干旱胁迫下紫花苜蓿种子萌发及幼苗生长的保护效应较为显著。     

外源5-氨基乙酰丙酸对盐胁迫下菘蓝种子萌发及幼苗抗氧化酶活性的影响

采用砂培方式,研究了外源5-氨基乙酰丙酸(ALA)对盐胁迫下菘蓝种子的萌发、幼苗叶片的可溶性糖含量、丙二醛(MDA)含量及其抗氧化酶活性的影响,探讨ALA缓解菘蓝受盐胁迫伤害的响应机制。结果显示:(1)菘蓝种子萌发及幼苗生长在100 mmol·L^-1 NaCl胁迫下受到明显的抑制,种子发芽率、发芽势、发芽指数、活力指数与自然含水量均显著降低,丙二醛含量、可溶性糖含量以及超氧化物歧化酶(SOD)、过氧化物酶(POD)活性显著升高。(2)盐胁迫下适宜浓度的ALA处理显著提高了种子萌发率、自然含水量及SOD、POD和CAT活性,降低了可溶性糖和丙二醛的含量,并以16.7 mg·L^-1 ALA处理盐胁迫下菘蓝种子的发芽率、发芽势最大,其幼苗的SOD、POD、CAT活性最强。研究表明,盐胁迫显著抑制菘蓝种子的萌发及幼苗生长,适宜浓度的ALA能够有效缓解盐胁迫对菘蓝种子萌发及幼苗生长的伤害,提高植株的抗盐性,并以16.7 mg·L^-1 ALA处理效果最佳。     

干旱胁迫对远志种子萌发及幼苗生长和生理特性的影响

以远志(Polygala tenuifolia Willd.)为研究对象,采用不同浓度(2.5%~25%)聚乙二醇(PEG-6000)模拟不同程度的干旱胁迫,探讨干旱胁迫对远志种子萌发及幼苗生理生化特性的影响。结果表明:(1)随着干旱胁迫强度的增加,远志种子的发芽启动时间推迟,发芽率、发芽势、发芽指数和活力指数降低,但种子发芽率在2.5%~15%PEG胁迫下与对照无显著性差异,而在20%PEG胁迫下均显著低于对照,在25%PEG胁迫下种子不能萌发;在干旱胁迫条件下,远志幼苗生物量降低,胚芽生长受到显著抑制,胚根长度则先伸长后缩短。(2)远志幼苗叶绿素含量在2.5%~10%PEG范围内随胁迫强度的增加和时间的延长而持续上升,在15%和20%PEG胁迫下则表现为先上升后下降,在10%PEG胁迫处理第15天时含量最高,为对照的1.34倍。(3)幼苗叶片的游离脯氨酸、可溶性糖和可溶性蛋白含量随PEG胁迫强度的增加和时间的延长而增加,各指标均在20%PEG胁迫处理第15天时含量最高,分别为对照的1.99倍、1.53倍和1.50倍。(4)随着PEG胁迫时间的延长,远志幼苗叶片超氧化物歧化酶(SOD)和过氧化氢酶(CAT)活性先上升后下降,并在10%PEG胁迫处理第10天时活性最强;过氧化物酶(POD)活性随着胁迫时间的延长表现出先上升后下降又上升的特性,并在20%PEG胁迫处理第5天时活性最强;叶片丙二醛(MDA)含量在15%和20%PEG胁迫处理下持续上升,在2.5%~10%PEG胁迫范围内先上升后又有所下降。研究发现,远志种子在轻、中度干旱胁迫下仍可正常萌发,而且幼苗能通过调节自身生长、渗透调节物质含量和抗氧化酶活性主动适应干旱环境,对干旱环境表现出较好的适应能力。     

外源Ca2+浸种对Cd2+胁迫下红三叶种子萌发和幼苗生长及其生化特性的影响

用不同浓度Ca2 溶液浸种处理红三叶种子后、用0.1 mmol·L-1Cd2 溶液培养,探讨外源Ca2 对Cd2 胁迫下红三叶种子萌发、幼苗生长及其保护酶活性和子叶叶绿素含量的影响.结果显示:(1)0.1 mmol·L-1Ca2 浸种处理能显著缓解Cd2 胁迫的影响,可使红三叶种子发芽势、发芽指数及活力指数显著升高,全苗长、胚根长和胚根/胚芽显著增加(分别增加21.38%、44.06%和38.63%),并显著提高叶绿素含量(14.59%);(2)0.11、.0 mmol·L-1Ca2 浸种预处理均能显著提高Cd2 胁迫下红三叶幼苗子叶SOD活性(43.17%、218.95%)和POD活性(34.00%、14.28%),并显著降低其CAT活性(17.43%、29.19%)和MDA含量(21.92%、24.51%).结果表明,0.1mmol·L-1外源Ca2 浸种处理能显著缓解Cd2 (0.1 mmol·L-1)胁迫对红三叶种子萌发及幼苗生长及其保护酶活性的抑制作用,可明显提高红三叶幼苗对Cd2 胁迫的抵抗能力,缓解效果最优.     

不同浓度5-氨基乙酰丙酸(ALA)浸种对NaCl胁迫下番茄种子发芽率及芽苗生长的影响

为探讨外源5-氨基乙酰丙酸(ALA)对NaCl胁迫下番茄种子发芽率及芽苗生长的影响,以‘中杂九号’番茄种子为试材,不同浓度ALA(0、0.1、0.5、1.0、5.0、10.0mg/L)浸种24h后,在0、25、50、100mmol/L NaCl胁迫下,28℃,黑暗培养7d,研究ALA对番茄种子发芽参数(发芽率、发芽势、发芽指数、活力指数、芽苗总鲜重)及胚芽和胚根中的抗氧化酶(超氧化物歧化酶SOD、过氧化物酶POD、过氧化氢酶CAT)活性和丙二醛(MDA)含量的影响.结果表明:非盐胁迫下,ALA浸种使番茄种子的发芽势、发芽指数、活力指数、芽苗总鲜重增加,胚根中SOD、POD活性降低,MDA含量减少;25 mmol/L NaCl胁迫能够提高发芽率、活力指数、芽苗总鲜重,而50-100mmol/L NaCl胁迫极显著的降低发芽率、发芽势、发芽指数、活力指数;0.1-0.5mg/L ALA浸种能够提高NaCl胁迫下番茄种子的发芽率、发芽指数、活力指数、芽苗总鲜重和抗氧化酶活性,降低MDA含量,而高浓度ALA(10.0mg/L)浸种导致发芽率、发芽指数、活力指数降低.总之,ALA浸种能够促进番茄种子萌发和芽苗生长,浸种浓度不宜超过5.0mg/L,NaCl胁迫下以0.1 mg/L ALA浸种处理效果最佳.     

外源5-氨基乙酰丙酸对干旱胁迫下甘草种子萌发及幼苗生理特性的影响

以药用植物甘草种子和幼苗为材料,在20%PEG-6000模拟干旱胁迫条件下,测定了不同浓度外源5-氨基乙酰丙酸(ALA)处理甘草种子的发芽势(Gv)、发芽率(Gr)、发芽指数(Gi)和活力指数(Vi)的变化,以及ALA处理幼苗叶片的质膜透性、丙二醛(MDA)含量、可溶性糖含量、游离脯氨酸含量和超氧化物歧化酶(SOD)、过氧化物酶(POD)、过氧化氢酶(CAT)活性。结果显示:(1)在20%PEG-6000胁迫下,甘草种子萌发受到显著抑制,而各项萌发指标经过不同浓度的ALA进行恢复处理后均有明显提高,且均以10 mg.L-1ALA处理的各项指标值最大,其种子发芽势(75%)、发芽率(91%)比干旱胁迫对照显著提高了35%和30%,发芽指数(36.2)和活力指数(709.7)分别提高至干旱胁迫的2.6和3.5倍。(2)各ALA处理较对照均显著提高了干旱胁迫下甘草幼苗总生物量、可溶性糖的含量及脯氨酸含量,却显著降低了甘草叶片的MDA含量和质膜透性,同时显著提高了干旱胁迫下甘草叶片中的SOD、POD和CAT的活性,且以10 mg.L-1ALA处理后的酶活性最强。研究表明,适宜浓度(10 mg.L-1)的ALA能显著提高干旱胁迫下甘草种子的萌发能力,通过调节渗透调节物质含量和保护酶活性来有效减缓干旱胁迫对甘草幼苗的伤害,提高甘草种子及幼苗的抗旱能力。     

豌豆种子萌发及幼苗生长对NaCl胁迫的响应

以“陇豌一号”和“S4008”2个豌豆品种为材料, 利用不同浓度的NaCl溶液处理种子进行发芽实验, 研究豌豆种子萌发及幼苗生长对NaCl胁迫的响应。结果表明: 10 mmol·L–1NaCl胁迫可促进种子萌发, 2 个豌豆品种的发芽率、发芽势、胚芽和胚根长、幼苗鲜重和干重、相对含水率、叶绿素含量均显著高于对照(P<0.05); 25 mmol·L–1NaCl处理略高于对照, 但差异不显著; 发芽指数总体随着盐浓度增高而降低, 10、25 mmol·L–1处理与对照差异不显著; 高浓度NaCl(50、100、200 mmol·L–1)则显著抑制了发芽率、发芽势、胚芽和胚根长、幼苗鲜重和干重、相对含水率以及叶绿素含(P<0.05), 且胚根下降趋势大于胚芽; 极高浓度NaCl (300 mmol·L–1)胁迫下种子基本不发芽。细胞膜透性随着盐浓度增加显著上升(P<0.05); 丙二醛含量随NaCl浓度的增加先升高后降低, 100 mmol·L–1处理达到最大值; 而脯氨酸含量则先降低后升高(P<0.05), 25 mmol·L–1处理达到最小值。胚根是对盐分胁迫较敏感的部位, S4008抗盐能力>陇豌一号。     

CdCl2对豌豆种子萌发和幼苗生长的影响

以豌豆为实验材料,采用水培方法研究了Cd2 单盐胁迫对豌豆种子萌发与生长的影响。结果显示:(1)Cd2 质量浓度≤1 mg/L时,促进种子萌发,Cd2 质量浓度达到5 mg/L时抑制种子的萌发。(2)随Cd2 质量浓度的增加Cd2 对幼苗根生长的抑制作用逐渐增强;Cd2 质量浓度≤5 mg/L时,促进茎的生长,≥10 mg/L时,抑制茎的生长;且Cd2 对幼苗根生长的抑制作用大于茎。(3)低浓度Cd2 能促进幼苗叶绿素合成,当Cd2 质量浓度高于1 mg/L时,则对幼苗叶绿素合成有抑制作用,且随Cd2 质量浓度增加叶绿素含量逐渐下降。(4)Cd2 诱发的胚根细胞核、染色体畸变率随着Cd2 质量浓度增加而增大。(5)过氧化物酶(POD)同工酶的活性随着Cd2 质量浓度升高而明显增强,Cd2 质量浓度为1 mg/L时POD活性最强,但当Cd2 质量浓度达10 mg/L时,POD的灰度值明显下降。     

盐胁迫下黄芩种子萌发及幼苗对外源抗坏血酸的生理响应

以黄芩(Scutellaria baicalensis)种子为材料,用氯化钠(Na Cl)模拟盐胁迫条件,采用纸上发芽,研究外源抗坏血酸(As A)对盐胁迫下黄芩种子萌发及幼苗的影响。结果表明,在80 mmol·L-1 Na Cl胁迫下,黄芩种子萌发及幼苗生理指标受到显著抑制;0.50 mmol·L-1 As A处理可显著提高盐胁迫下黄芩种子的发芽势(GE)、发芽率(GR)、发芽指数(GI)、简化活力指数(SVI)以及根系总黄酮、可溶性糖和脯氨酸(Pro)含量,同时也可显著提高幼苗根系活力和超氧化物歧化酶(SOD)活性,显著降低丙二醛(MDA)含量。这说明适宜浓度的抗坏血酸能提高黄芩种子的萌发能力和幼苗对盐胁迫的适应能力,从而起到缓解盐胁迫对种子萌发及幼苗生长的抑制作用。     

干旱胁迫对鹿角杜鹃种子萌发和幼苗生理特性的影响

为探明鹿角杜鹃种子萌发和幼苗生长期的耐旱性,以鹿角杜鹃干种子和90d苗龄幼苗为材料,采用聚乙二醇(PEG-6000)模拟不同程度的干旱胁迫,研究干旱胁迫对其种子萌发、早期幼苗生长及幼苗的细胞膜透性、MDA含量、有机渗透调节物质和抗氧化酶活性的影响,并对种子萌发率、早期幼苗生长量与PEG胁迫浓度间进行了回归分析。结果表明:(1)5%~25%PEG胁迫范围内,随着干旱胁迫程度的增加,鹿角杜鹃种子的发芽启动时间推迟,发芽持续时间延长,发芽率、发芽势、发芽指数、活力指数和幼苗生长量显著降低;重度干旱胁迫(25%PEG)下,鹿角杜鹃种子完全未萌发。(2)发芽率、发芽势、发芽指数、活力指数以及幼苗生长量的变化均与干旱胁迫程度呈极显著负相关关系,回归分析求得鹿角杜鹃种子萌发的半致死PEG干旱胁迫浓度为15.68%、半致矮PEG干旱胁迫浓度为15.37%。(3)随着PEG胁迫浓度的增加,鹿角杜鹃幼苗叶片SOD活性呈先升后降的趋势,但各胁迫处理仍显著高于CK(0%PEG);细胞膜透性、MDA、脯氨酸、可溶性糖含量、POD和CAT活性则在中度(15%~20%PEG)和重度胁迫下显著升高,与干旱胁迫程度呈极显著正相关关系。研究表明,干旱胁迫显著抑制了鹿角杜鹃种子萌发和早期幼苗生长,使其细胞膜受到损伤,同时鹿角杜鹃可通过体内渗透调节物质和抗氧化酶活性的增加来适应干旱环境,使得自身受抑制、损伤程度降到最低。     

白蚁与动物及微生物的共生类型及其机制

综述了白蚁螱客的主要种类、共生关系及相关机制的研究进展。白蚁螱客中,已报道的动物种类达170种。在与动物的共生关系中存在偏利共生（宾主共栖和异种共栖）、互利共生和无关共生三种;在与微生物的共生关系中,存在与内生菌（原生动物、细菌、真菌和放线菌）和外生菌（蚁巢伞菌等）间的互利关系。指出了白蚁与螱客研究中存在的问题,给出了解决方案,并提出了今后可能的研究热点或方向,为白蚁的综合利用（如纤维素酶）及今后研究物种间的协同进化提供了基础资料。     

New amino-dithiaphospholanes and phosphoramidodithioites and their rhodium and iridium complexes

New sulfur derivatives of phosphoramidite ligands were synthesized and the impact of the sulfur unit on the spectroscopic properties of their rhodium and iridium complexes was investigated. The new ligands Bn₂NPSCH₂CH₂S^a(P-S^a) (Bn = benzyl, 4), Bn₂NPSCHCHS^a(CH₂)₃C^aH₂(P-S^a)(C^a-S^a) (6) and Bn₂NP(4-XC₆H₄OMe)₂ (X = S, 7a; X = O, 7b) were converted to the rhodium and iridium complexes trans-[Rh(CO)Cl(L)₂] (L = 4, 6, 7), [RhCl(COD)(L)] (L = 4, 6, 7), [IrCl(COD)(7a)] and [IrCl₂Cp∗(6)]. For comparison, some phosphoramidite complexes of these formulations also were synthesized. The new metal complexes were spectroscopically analyzed. For the carbonyl complexes, the ν_CO IR stretching frequencies were lower than for the corresponding phosphite and phosphoramidite ligands. The ¹J_PRh coupling constants for the rhodium complexes with the new ligands were also smaller than for the respective phosphoramidite and phosphite complexes. Finally, the ¹J_PSe coupling constants of the selenides of the new ligands were lower than those of the phosphoramidite ligands but higher than for PPh₃. The spectroscopic data reveal that the new thio ligands 4, 6 and 7a are more electron donating than phosphites and phosphoramidites but less electron donating than PPh₃.     

Astrocytes and Synaptosomes Transport and Metabolize Lactate and Acetate Differently

Astrocytes transport the monocarboxylate acetate, but synaptosomes do not. The reason for this is unknown, because both preparations express monocarboxylate transporters (MCT). The transport and metabolism of lactate, another monocarboxylate, was examined in these two preparations, and the results were compared to those for acetate. Lactate transport is more rapid in astrocytes than in synaptosomes, but of lower affinity (Kms of 17 and 4 mM, respectively). Lactate (0.2 mM) is metabolized to CO2 more rapidly in synaptosomes than in astrocytes (rates of 0.37 and 0.07 nmol x mg protein(-1) x min(-1), respectively). The reason for this is unclear, but cellular differences in lactate dehydrogenase isotype expression may be involved. Acetate is metabolized to CO2 more rapidly in astrocytes than in synaptosomes (rates of 0.43 and 0.02 nmol x mg protein(-1) x min(-1), respectively). This is likely due to cellular differences in the expression of monocarboxylate transporter subtypes.     

Rapporteur report: Basics and technology and metrology and standards

The first and second sessions of the Workshop focussed on the basics of ultrasound and infrasound, their applications in both industry and medicine, and metrology and protection standards for ultrasound applications.     

Relative and combined effects of ethanol and protein deficiency on strontium and barium bone content and fecal and urinary excretion

To elucidate accumulation of minerals in human iliac arteries with aging, the content of minerals was analyzed by inductively coupled plasma atomic emission spectrometry. Bilateral common, internal, and external iliac arteries of 16 men and 8 women, ranging ages from 65 to 93 yr, were examined. It was found that an extremely high accumulation of calcium and phosphorus occurred in the common iliac artery at old age, being higher than that of the internal and external iliac arteries. It should be noted that the accumulation of calcium and phosphorus is the highest in the common iliac artery among the human arteries examined to date. Regarding sexual differences, the content of calcium and phosphorus in the common and internal iliac arteries was higher in women than in men, whereas their content in the external iliac artery was lower in women than in men.     

Prostaglandin and thromboxane production by human and guinea-pig macrophages and leucocytes

The ability of partially purified human and guinea-pig haematogenous cell populations, when cultured in vitro, to metabolise arachidonic acid (AA) has been studied. Supernatants from 24 hour cell culture have been subjected to analysis for products of AA metabolism by gas chromatography with electron-capture detection.The cell types studied were human peripheral blood monocytes (both glass adherent and non-adherent), neutrophils, eosinophils and leukemic leucocytes; thoracic duct lymphocytes and lung alveolar macrophages. From the guinea-pig, induced and non-induced macrophage or neutrophil enriched peritoneal exudate populations, lymph node cells, peritoneal eosinophils and peripheral blood platelets were examined. Supernatants were assayed for the presence of PGE₂, PGD₂, PGF_2α, TXB₂ and 6-keto-PGF_1α. In all types studied PGE₂ and TXB₂ were the major products formed. The identification of PGE₂ and TXB₂ was confirmed by GC/MS with multiple ion monitoring.The results have been compared with other reports and their possible significance discussed in relation to the proposed role of prostaglandins as mediators and modulators in immunopathology.     

Chemokines and cytokines: axis and allies in asthma and allergy

Allergic asthma can be precipitated by many factors. For the atopic person, fungus, pollen, dust mites, cockroach antigens, and diesel exhaust are all agents that may trigger an allergic attack. Cytokines and chemokines are integral mediators of fungal asthma. From the earliest time points, they recruit and activate the cells required for the clearance of fungus as well as being critical factors involved in the immunopathology of this disease. In the final analysis, it is clear that these mediators can act to the benefit or the detriment of the host.     

Oxidation and nitration of ribonuclease and lysozyme by peroxynitrite and myeloperoxidase

In spite of the many studies on protein modifications by reactive species, knowledge about the products resulting from the oxidation of protein-aromatic residues, including protein-derived radicals and their stable products, remains limited. Here, we compared the oxidative modifications promoted by peroxynitrite and myeloperoxidase/hydrogen peroxide/nitrite in two model proteins, ribonuclease (6Tyr) and lysozyme (3Tyr/6Trp). The formation of protein-derived radicals and products was higher at pH 5.4 and 7.4 for myeloperoxidase and peroxynitrite, respectively. The main product was 3-nitro-Tyr for both proteins and oxidants. Lysozyme rendered similar yields of nitro-Trp, particularly when oxidized by peroxynitrite. Hydroxylated and dimerized products of Trp and Tyr were also produced, but in lower yields. Localization of the main modified residues indicates that peroxynitrite decomposes to radicals within the proteins behaving less specifically than myeloperoxidase. Nitrogen dioxide is emphasized as an important protein modifier.