外源硒在魔芋不同生育时期不同器官中的含量变化研究

通过在土壤中添加不同浓度外源硒,了解硒对魔芋生长的影响,以及在魔芋生长的不同时期硒在不同器官中的吸收分布情况。试验选用杂交品种‘安魔128’芋鞭作为供试材料,采用盆栽的方式,通过在魔芋根部浇灌不同浓度的亚硒酸钠水溶液,测定各器官在不同生育时期的硒含量。结果发现：（1）在魔芋展叶期,随着硒浓度的增加,各器官硒含量均逐渐增加,表现为球茎>叶柄>叶片。（2）在球茎膨大期,各器官硒含量在不同硒浓度下达到最大值;当硒浓度超过16 mg/kg时,叶片及球茎中硒含量均显著降低,表明高硒处理对植株的生长发育造成了影响。（3）随着硒浓度的增加,叶片、叶柄及球茎中的硒含量均呈现先富集后减少的趋势,在硒浓度为16 mg/kg时达到最大;随着魔芋生长至成熟,叶片及叶柄硒含量均有向球茎转移的趋势。（4）不同生育时期叶片中硒含量是相互影响的,叶柄中硒含量最终由其他途径转移而来,且硒有从其他器官向球茎中转移的趋势。因此,我们认为适于魔芋生长发育及各器官硒含量积累的最适硒浓度范围为≤16 mg/kg,且在魔芋不同生育时期各器官中硒含量之间相互影响和转移。     

甘蔗对铅递进胁迫的生理响应

盆栽模拟试验研究了甘蔗长期受重金属铅胁迫的生理响应。在土壤铅（Pb）浓度为250mg／kg时,甘蔗生物量达到最大,甘蔗茎粗和茎节长较对照分别提高了9．63％和9．02％;叶片细胞质膜透性与土壤Pb浓度呈显著正相关;叶片中叶绿素a、叶绿素b、类胡萝卜素含量与土壤Pb浓度呈显著负相关,相关系数分别为0．994、0．994和0．985;叶片中蛋白质含量和过氧化氢酶（CAT）活力、蔗茎中可溶性糖含量均随着土壤Pb浓度的升高呈现先增高后降低的趋势,临界点的Pb浓度为250mg／kg左右。表明甘蔗具有植物修复Pb污染土壤的潜力。     

Pb胁迫下氮素形态对日本毛连菜生物量、叶绿素含量及抗氧化酶活性的影响

为揭示Pb胁迫下氮素形态及施氮量对日本毛连菜生长及生理生化特性的影响,采用盆栽试验方法,针对不同浓度Pb胁迫下铵态氮和硝态氮及其施氮量对日本毛连菜生物量、叶绿素含量和抗氧化酶活性的影响进行研究。结果表明,在Pb胁迫下,日本毛连菜的生物量随施氮量的增加总体呈先上升后下降的趋势。在低浓度Pb胁迫下,施用铵态氮肥时,日本毛连菜叶绿素含量和CAT活性随施氮量的增加呈先升后降的趋势,SOD活性逐渐增加,POD活性呈先降后升的趋势,施用硝态氮肥时,植株叶绿素含量和SOD活性的变化趋势为先升后降,POD和CAT的活性呈逐渐下降的趋势;在高浓度Pb胁迫下,施用铵态氮肥时,日本毛连菜叶绿素含量、POD活性随施氮量的增加呈先升高后降低的趋势,而SOD、CAT活性则呈先降低后升高的趋势,施用硝态氮肥时,CAT活性随施氮量的增加呈先上升后下降的趋势,其他指标则无明显的变化趋势。无论在何种Pb浓度胁迫下,适量的铵态氮肥更有利于日本毛连菜的生长,不仅能提高叶片叶绿素含量,还能增加其抗氧化酶活性,这对于增加日本毛连菜的生物量,提高其修复铅污染土壤的能力具有实际意义。     

镉、铅对板蓝根种子发芽及抗氧化系统的影响

研究了板蓝根种子在镉、铅污染下的发芽率及萌发时的抗氧化系统酶和蛋白质的变化。结果表明：镉浓度在5mg／L时能促进种子的发芽，而当镉浓度高于5mg／L时则显著抑制种子的发芽；铅胁迫下，随铅浓度的升高，对板蓝根种子发芽抑制作用加剧。但任何水平的镉、铅都对根伸长产生抑制作用。不同程度的重金属镉、铅胁迫下对种子发芽时POD、CAT、SOD活性均有显著影响，其中CAT、SOD酶活性都比对照低，只有过氧化物酶POD在Cd^2＋的浓度为10mg／L时，铅的浓度为200mg／L时POD活性比对照略高。当Cd^2＋的浓度为50mg／L、Pb^2＋d浓度为500mg／L时3种酶的活性都明显低于对照。镉、铅处理的种子，萌发时蛋白质含量的变化规律不同。     

铅（Pb）对西葫芦幼苗生理生化特性的影响

用不同浓度的1/2 Hoagland+Pb2+做胁迫试验,研究重金属铅(Pb)对西葫芦生理生化特性的影响.结果表明,随着Pb2+浓度的升高,西葫芦幼苗叶绿素含量下降,以及叶绿素a/b比值明显上升,叶片细胞膜透性显著增加,丙二醛(MDA)含量显著升高.随着Pb2+浓度的升高,超氧化物歧化酶( SOD)活性、过氧化物酶(POD)活性、过氧化氢酶(CAT)活性逐渐升高,达到一定浓度时,SOD、POD、CAT活性则显著下降.     

Cd、水分单一及复合胁迫对异叶天南星叶片抗氧化酶的活性影响

为探讨Cd、水分单一及复合胁迫条件下对异叶天南星叶片伤害及其抗氧化酶活性的响应,研究并比较了不同浓度Cd (200、400、800 mmol/L)和水分胁迫（PEG6000模拟,浓度分别为10%、20%、40%）条件下异叶天南星叶片的丙二醛(MDA)和超氧化物歧化酶(SOD)、过氧化氢酶(CAT)、过氧化物酶(POD)等抗氧化酶活性的影响。结果表明：在单一、复合胁迫条件下,相对于对照来说,MDA含量呈上升趋势,SOD、POD、CAT整体呈现先升高后降低趋势。同时,对于比较同水平浓度下单一因子胁迫而言,复合胁迫MDA含量体现出协同效应,SOD、POD、CAT则体现协同或拮抗效应。     

铅胁迫对甜瓜种子胚芽酶系统及MDA含量的影响

对不同浓度铅胁迫下甜瓜种子胚芽酶系统中抗氧化酶类及膜脂过氧化的影响进行研究,结果表明,在低浓度Pb2 胁迫下(0~50 mg/L),过氧化物酶(POD)、过氧化氢酶(CAT)、超氧化物歧化酶(SOD)的活性随Pb2 浓度增加而逐渐上升,并高于对照组,在高浓度Pb2 (100~400 mg)胁迫下,SOD、POD、CAT活性下降并低于对照组。丙二醛(MDA)含量恰好与其相反,先降低后升高。     

铬胁迫对薄荷生理特性的影响

为探讨薄荷（Mentha haplocalyx Briq.）耐受和富集重金属铬的生理机制,采用盆栽法研究不同质量浓度、不同时间Cr6+处理对薄荷根系活力、叶绿素含量、不同器官中抗氧化酶（SOD、POD、CAT）活性和丙二醛（MDA）含量的影响。结果表明,随着Cr6+质量浓度梯度和时间的增加,薄荷根系活力与对照相比,呈下降趋势;相反,MDA含量呈增加趋势。叶绿素a、叶绿素b和类胡萝卜素含量随Cr6+质量浓度的增加呈先升后降的趋势。SOD、POD、CAT 3种酶活性随Cr6+质量浓度的增加呈先升后降的趋势,在Cr6+质量浓度为40 mg/L时,三者均出现峰值,3种酶活性随时间呈增加趋势。在Cr6+质量浓度超过40 mg/L时,薄荷的抗氧化酶系统受到损害,无法对铬胁迫做出积极的响应,植株生长受到影响。     

玉迪安对蚯蚓三种抗氧化酶活性的影响

摘要：采用急性毒性方法,测定了不同浓度玉迪安溶液处理的赤子爱胜蚓半致死浓度(LC50),用测定酶活性方法检测了中毒后赤子爱胜蚓抗氧化酶活性的变化。（1）玉迪安对赤子爱胜蚓48h LC50为81.371 mg L-1。（2）玉迪安药物对动物SOD、CAT、POD活性影响均为显著(p＜0.05)。低浓度药物60.342~75.044 mg L-1处理动物SOD、CAT活性呈上升趋势;当浓度增加至83.691mg L-1,SOD、CAT活性开始表现为不同程度的降低,POD与SOD、CAT活性变化趋势相反,酶活性呈现先下降再上升的现象。拌种农药玉迪安流失到自然土壤中,在一定浓度范围内对蚯蚓造成胁迫,影响动物正常行为以至危害生命,并直接或间接地影响土壤生态系统及以蚯蚓为食物的下一级消费者。     

3个陆地棉种质(系)重金属镉的积累、转运和富集特性分析

以2个转基因陆地棉种质系(ZD-90和SGK3)和陆地棉标准系TM-1为材料,于2009-2010年进行盆栽试验,对镉胁迫下棉花植株不同器官镉的累积、转运和富集特性进行了研究。结果表明,3个棉花种质(系)不同器官镉的累积量随镉胁迫浓度的增加而增加,其中纤维中镉累积量最低,叶柄中镉累积量最高;营养器官镉累积量远高于种子和纤维。各器官累积镉能力的顺序为:纤维<种仁<棉子壳<根<叶片<茎秆<铃壳<叶柄。3个棉花种质(系)各器官的镉转运能力和富集系数与镉累积能力顺序一致,但品种间有显著差异,SGK3和ZD-90的镉累积能力和镉富集系数高于TM-1。棉花具有较强的吸收、转运和聚集重金属镉的能力,体内存在较好的镉运输机制,具备作为超富集植物的基本特征,可以作为超富集植物来治理土壤镉污染。     

Location of a high-lysine gene and the DDT-resistance gene on barley chromosome 7

Summary The high-lysine gene in Risø mutant 1508 conditions an increased lysine content in the endosperm via a changed protein composition, a decreased seed size, and several other characters of the seed. The designation lys3a, lys3b, and lys3c, is proposed for the allelic high-lysine genes in three Risø mutants, nos 1508, 18, and 19. Linkage studies with translocations locate the lys3 locus in the centromere region of chromosome 7. A linkage study involving the loci lys3 and ddt (resistance to DDT) together with the marker loci fs (fragile stem), s (short rachilla hairs), and r (smooth awn) show that the order of the five loci on chromosome 7 from the long to the short chromosome arm is r, s, fs, lys3, ddt. The distance from locus r to locus ddt is about 100 centimorgans.     

Biological Activity and Quantification of Suspected Allelochemicals from Alfalfa Plant Parts

Autotoxicity restricts reseeding of alfalfa (Medicago sativa L.) after alfalfa until autotoxic chemical(s) breaks down or is dispersed into external environments. A series of aqueous extracts from leaves, stems, roots and seeds of alfalfa ‘Vernal’ were bioassayed against alfalfa seedlings of the same cultivar to determine their autotoxicity. The highest inhibition was found in the extracts from the leaves. Extracts at 40 g dry tissue l^?1 from alfalfa leaves were 15.4, 17.5 and 28.7 times more toxic to alfalfa root growth than were those from roots, stems and seeds, respectively. A high‐performance liquid chromatography (HPLC) analysis with nine standard compounds showed that the concentrations and compositions of allelopathic compounds depended on the plant parts. In leaf extracts that showed the most inhibitory effect on root growth, the highest amounts of allelochemicals were detected. Among nine phenolic compounds assayed for their phytotoxicity on root growth of alfalfa, coumarin, trans‐cinnamic acid and o‐coumaric acid at 10^?3 m were most inhibitory. The type and amount of causative allelochemicals found in alfalfa plant parts were highly correlated with the results of the bioassay, indicating that the autotoxic effects of alfalfa plant parts significantly differed.     

Simultaneous Determination of Four Phenolic Acids in Radix Salviae Miltiorrhizae Formula Granules by QAMS

[Objectives]This study aimed to establish a QAMS(quantitative analysis of multi-components by single-marker)method for simultaneous determination of four phenol...     

Changes in Seed Yield and Quality with Maturity in Onion (Allium cepa L., cv. 'Early Cream Gold')

Development of onion (Allium cepa L., cv. ‘Early Cream Gold’) seed under cool climate conditions in Tasmania, Australia occurred over a longer duration than previously reported, but similar patterns of change in yield components were recorded. In contrast to previous studies, umbel moisture content declined from 85 to 67 % over 57 days while seed moisture content decreased from 85 to 31 %. Seed yield continued to increase over the duration of crop development, with increasing seed weight compensating for seed loss resulting from capsule dehiscence in the later stages of maturation. Germination percentage was high and did not vary significantly from 53 to 77 days after full bloom (DAF), but mean germination time declined and uniformity of germination increased significantly over the same time period. The percentage abnormal seedlings declined with later harvest date, resulting in highest seed quality at 77 DAF. The results of this study suggest that the decision to harvest cool climate onion seed crops before capsule dehiscence will result in a loss of potential seed yield and quality.     

Water Extraction Process of Chinese Herbal Compound Man Gan Ning

[Objectives]To optimize the water extraction process of Chinese Herbal Compound Man Gan Ning and establish a method for its extraction and content determination...     

Present status and future strategy in breeding faba beans (Vicia Faba L.) for resistance to biotic and abiotic stresses

Progress is being made, mainly by ICARDA but also elsewhere, in breeding for resistance to Botrytis, AScochyta, Uromyces, and Orobanche; and some lines have resistance to more than one pathogen. The strategy is to extend multiple resistance but also to seek new and durable forms of resistance. Internationally coordinated programs are needed to maintain the momentum of this work.Tolerance of abiotic stresses leads to types suited to dry or cold environments rather than broad adaptability, but in this cross-pollinated species, the more hybrid vigor expressed by a cultivar, the more it is likely to tolerate various stresses.     

Pollen and pollination experiments. III. The viability of apple and pear pollen as affected by irradiation and storage

Summary Apple and pear pollen was irradiated with doses of 0, 50, 100, 250 and 500 krad (gamma rays) and stored at 4°C and 0–10% r.h. From the in-vitro germination percentages an average LD 50 dose of about 220 krad was estimated. For both irradiated and untreated pollen a close and corresponding lineair relationship existed between germination percentage and pollen tube growth.Irradiated pollen was much more sensitive to dry storage conditions than untreated pollen, resulting in less germination and more bursting. Apparently, irradiation caused the pollen cell membrane to lose its flexibility faster than normal. Rehydration of dry-stored, irradiated pollen in water-saturated air restored germination percentages up to their initial levels. The importance of this procedure in germination trials is stressed.     

Optimization of Extraction Technology and Determination of Content of Total Phenols of Leaves in Acanthopanax giraldii Harms

[Objectives] To determine the optimum extraction technology for total phenols of leaves in Acanthopanax giraldii Harms.[Methods]The single factor test and ortho...     

Cytoplasmic male sterility,resistance to gall mite and mildew,and season of leafing out in black currants

Summary Cytoplasmic male sterility (cms) is described in the F₁ hybrids Ribes × carrierei (R. glutinosum albidum × R. nigrum) and R. sanguineum × R. nigrum. In backcrosses to R. nigrum, progenies with R. glutinosum cytoplasm were either all male sterile, or segregated for full male fertility (F) and complete (S) and partial (I) male sterility. Ratios of F:I+S suggested that two linked genes controlled cms, F plants being dominant for one (Rf ₁) and recessive for the other (Rf ₂).Segregation for cms in relation to three linded genes, Ce (resistance to the gall mite, Cecidophyopsis ribes), Sph ₃(resistance to American gooseberry mildew, Sphaerotheca mors-uvae) and Lf ₁(one of two dominant additive genes controlling early season leafing out) indicated that Rf ₁and Rf ₂were in this linkage group. The gene order and approximate crossover values appeared to be: % MathType!MTEF!2!1!+-% feaafiart1ev1aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn% hiov2DGi1BTfMBaeXafv3ySLgzGmvETj2BSbqef0uAJj3BZ9Mz0bYu% H52CGmvzYLMzaerbd9wDYLwzYbItLDharqqr1ngBPrgifHhDYfgasa% acOqpw0xe9v8qqaqFD0xXdHaVhbbf9v8qqaqFr0xc9pk0xbba9q8Wq% Ffea0-yr0RYxir-Jbba9q8aq0-yq-He9q8qqQ8frFve9Fve9Ff0dme% aabaqaciGacaGaamqadaabaeaafaaakeaacaWGdbGaamyzamaamaaa% baGaaiiiaiaacccacaGGWaGaaiOlaiaacgdacaGG0aGaaiiiaiaacc% caaaGaaiiiaiaacccacaGGGaGaamOuaiaadAgaliaaigdakmaamaaa% baGaaiiiaiaacccacaGGGaGaaiiiaiaaccdacaGGUaGaaiOmaiaacs% dacaGGGaGaaiiiaiaacccacaGGGaGaaiiiaaaacaWGsbGaamOzaSGa% aGOmaOWaaWaaaeaacaGGGaGaaiiiaiaacccacaGGGaGaaiiiaiaacc% cacaGGGaGaaiiiaiaacccaaaGaamitaiaadAgaliaaigdakmaamaaa% baGaaiiiaiaacccacaGGGaGaaiiiaiaacccacaGGGaGaaiiiaiaacc% cacaGGGaGaaiiiaiaacccacaGGGaaaaiaadofacaWGWbGaamiAaSGa% aG4maaaa!6E4D!\[Ce\underline { 0.14 } Rf1\underline { 0.24 } Rf2\underline { } Lf1\underline { } Sph3\]. Crossover values of 0.36 for Ce-Lf ₁, and 0.15 for Lf ₁-Sph ₃were estimated from the relative mean differences in season of leafing out between seedlings dominant and recessive for Ce and Sph ₃.It is suggested that competitive disadvantage of lf ₁-carrying gametes and/or zygotes at low temperatures may be implicated in the almost invariable deficit of plants dominant for the closely linked mildew resistance allele Sph ₃. Poor performance of lf ₁- (and possibly lf ₂-) carrying gametes and young zygotes during periods of low temperature at flowering might also account for the liability of some late season cultivars and selections to premature fruit drop (running off).     

Screening techniques and sources of resistance to parasitic angiosperms

Parasitic angiosperms cause great losses in many important crops under different climatic conditions and soil types. The most widespread and important parasitic angiosperms belong to the genera Orobanche, Striga, and Cuscuta. The most important economical hosts belong to the Poaceae, Asteraceae, Solanaceae, Cucurbitaceae, and Fabaceae. Although some resistant cultivars have been identified in several crops, great gaps exist in our knowledge of the parasites and the genetic basis of the resistance, as well as the availability of in vitro screening techniques. Screening techniques are based on reactions of the host root or foliage. In vitro or greenhouse screening methods based on the reaction of root and/or foliar tissues are usually superior to field screenings and can be used with many species. To utilize them in plant breeding, it is necessary to demonstrate a strong correlation between in vitro and field data. The correlation should be calculated for every environment in which selection is practiced. Using biochemical analysis as a screening technique has had limited success. The reason seems to be the complex host-parasite interactions which lead to germination, rhizotropism, infection, and growth of the parasite. Germination results from chemicals produced by the host. Resistance is only available in a small group of crops. Resistance has been found in cultivated, primitive and wild forms, depending on the specific host-parasite system. An additional problem is the existence of pathotypes in the parasites. Inheritance of host resistance is usually polygenic and its transfer is slow and tedious. Molecular techniques have yet to be used to locate resistance to parasitic angiosperms. While intensifying the search for genes that control resistance to specific parasitic angiosperms, the best strategy to screen for resistance is to improve the already existing in vitro or greenhouse screening techniques.