铁氰化钾在组织培养过程中对甜椒小孢子发育影响的ATP酶组织化学和扫描电镜初步研究

在组织培养条件下,用甜椒小孢子单核期的花药进行培养,研究低浓度铁氰化钾(0.1—1μg g~(-1))对甜椒花药化学杀雄的可能机理。通过ATP酶的组织化学染色及扫描电镜研究,本药剂对甜椒化学杀雄的作用可能与抑制绒毡层细胞中的ATP酶活性有关,因而抑制花药壁的形成。     

化学杀雄剂在组织培养过程中对黄瓜的杀雄作用的初步研究

选取黄瓜小孢子单核期的花药以组织培养方法检验铁氰化钾的杀雄效应,并初步探讨该试剂的杀雄机理。实验表明,该试剂在组织培养条件下,使用的浓度范围为0.1—10ppm 时,均显示有杀雄效应。表现为:处理的花药发育缓慢,小孢子变形或外粉壁不能形成。同时处理雌花则作用不明显。通过细胞形态观察,过氧化物酶、核酸、蛋白质及多糖组化定位及花粉壁的扫描电镜观察,初步认为:该试剂的杀雄效应与绒毡层、小孢子的过氧化物酶活性受抑制有关,故为生理性不育。     

南方红豆杉小孢子发生与雄配子体发育

采用石蜡切片法,对南方红豆杉小孢子发生及雄配子体发育过程进行了系统地观察。结果表明：南方红豆杉小孢子叶球于7月下旬分化,9月中旬形成造孢细胞,11月初形成小孢子母细胞;同一小孢子叶球中的小孢子母细胞表现出发育不同步现象;11中旬,进入减数分裂时期,形成游离小孢子后休眠越冬,于翌年1月下旬逐渐成熟,成熟花粉粒为单核;2月中下旬开始散粉,散粉时间持续15 d 左右。花粉落入胚珠后,经过3次分裂形成管细胞、柄细胞和2个精子;管细胞和柄细胞最终退化解体,未见花粉败育现象。认为南方红豆杉小孢子发生与雄配子体发育正常,不是致其濒危的主要原因。     

濒危植物水松小孢子发生和雄配子体发育的研究

水松(Glyptostrobus pensilis)是我国特有的单种属孑遗植物,是极度濒危物种,被列为国家一级重点保护植物。为了从生殖生物学方面探讨水松的濒危机制,采用石蜡切片法对水松小孢子发生及雄配子体发育过程进行了系统地观察研究。结果表明:水松雄球花于10月中旬开始分化,11月初小孢子囊壁形成,12月初小孢子母细胞形成,12月中旬减数分裂。翌年1月中旬形成四面体形和左右对称形四分体,1月下旬四分体解体,释放出游离小孢子。2月中旬花粉粒发育成熟,并以二细胞形态进行传粉,散粉期约为2周左右。3月萌发花粉管,3月下旬出现精原细胞、管核和不育核,5月下旬花粉管到达颈卵器顶部,精原细胞分裂成两个精细胞。水松小孢子和雄配子体发育过程中败育和变形现象很少,据此我们认为,水松小孢子发生与雄配子体发育正常,不是致其濒危的主要原因。     

小盐芥小孢子发生和雄配子体发育研究

在显微水平上研究了小盐芥的小孢子发生及雄配子体发育过程,以及不同阶段与花蕾外部形态的相关性.本实验报道的小孢子发生及雄配子体发育的研究结果表明:雄蕊为四强雄蕊,每个花药具4个花粉囊.小孢子母细胞减数分裂属同时型,小孢子在四分体中的排列方式属四面体型.成熟花粉粒属3-细胞型,有3个萌发沟.花粉囊壁发育属双子叶型,由4层细胞构成——表皮、药室内壁、中层和绒毡层.绒毡层为腺质绒毡层.植株花蕾肉眼可见时,雄性孢原细胞开始分化.花蕾露白即蕾长1.1~1.7 mm时,形成成熟的雄配子体,即3-细胞花粉粒.     

云南松小孢子发生及雄配子体形成

本文详述了云南松花粉母细胞的减数分裂、小孢子发生及雄配子体形成过程。在研究中发现:花粉母细胞在减数分裂中有明显的不同步现象;有少数发育畸形的小孢子;在减数分裂后期Ⅰ有染色单体桥及染色体片断出现;雄配子体发育过程中核分裂的方向异常;染色体数目2n=24与其它报道一致。     

扁豆雄配子体发育超微结构的观察

扁豆雄配子体发育超微结构的观察叶宝兴,席湘媛（山东农业大学基础部,泰安２７１０１８）间期小孢子母细胞质中有许多质体,线粗体和核糖体,线粒体和质体的内部结构都不明显,质体呈长棒形或长梭形,基质深。小孢子母细胞之间及小孢子母细胞与绒毡层细胞之间均有胞间连...     

矮沙冬青小孢子发生和雄配子体发育的观察

对矮沙冬青（Ammopiptanthus nanus）小孢子发生及雄配子体发育过程进行了观察,结果表明：花约具4个花粉囊,花药壁发育为基本型,由表皮、药室内壁、中层（2—3层）和绒毡层组成,绒毡层为腺质型。小孢子母细胞减数分裂后胞质分裂为同时型,四分体为四面体型排列,成熟的花粉粒为二细胞型。在矮沙冬青小孢子发生及雄配子体发育过程中没有发现异常现象,认为矮沙冬青濒危不存在雄性生殖结构与发育过程异常的内在因素。     

罗汉松雄球花及其雄配子体发育的形态结构

该研究采用光学显微镜和扫描电镜,观察罗汉松雄球花、小孢子及其配子体发育过程的形态结构特征,以揭示罗汉松小孢子的发生和雄配子体的发育规律,为罗汉松的生殖和杂交组合提供胚胎学证据。结果发现：(1)罗汉松花芽于每年的7月开始分化,至次年5月花粉成熟散粉,雄球花由单生的卵圆形转为2~3个葇荑花序并生,小孢子叶螺旋状着生于圆柱状的花序轴上,每一小孢子叶远轴面基部并列着生2个小孢子囊。(2)小孢子囊壁发育过程中由外及里出现各由1层薄壁细胞组成的表皮、药室内壁、中层和绒毡层,至散粉前,后两者基本被分解吸收。(3)同一小孢子囊内的造孢细胞发育在时间上存在差异,小孢子母细胞减数分裂后形成的四分体有四面体型和十字交叉型两种排列方式,成熟的雄配子体包括生殖细胞和粉管细胞,发育过程中出现的第一和第二原叶细胞大部分被分解消失。(4)电镜下罗汉松花粉粒为典型的松花型花粉,两侧各具1个气囊,远极面具一萌发沟,花粉粒表面具纹理或皱褶。     

玉米体细胞培养中胚状体的发生

在植物细胞和组织培养中,高等植物发生胚状体的现象比较普遍。单子叶植物从花粉小孢子和体细胞形成胚状体的有水稻、小麦、黑麦、玉米、甘蔗、大麦、无芒雀麦、珍珠谷等。我们对玉米雌、雄幼穗进行培养,获得了体细胞胚状体和胚性细胞团,并建立起细胞无性系。现将试验结果报道如下。     

Anesthetic effects of clove oil and lidocaine-HCl on marine medaka (Oryzias dancena)

Fish may be anesthetized for various experimental and practical purposes, primarily to immobilize them in order to facilitate handling. Marine medaka (Oryzias dancena) is a teleost fish used in marine ecotoxicology studies. Despite the importance of anesthesia in handling experimental fish, the effects of anesthesia in marine medaka have not yet been investigated. In this study, the authors evaluated the anesthetic effects (time required for anesthesia to take effect and recovery time) of two anesthetic agents, clove oil and lidocaine-HCl, on marine medaka. They anesthetized fish at different water temperatures (23 °C, 26 °C and 29 °C) and using different concentrations of clove oil (50 ppm, 75 ppm, 100 ppm, 125 ppm, 150 ppm and 175 ppm) or lidocaine-HCl (300 ppm, 400 ppm, 500 ppm, 600 ppm, 700 ppm and 800 ppm). The time required for anesthesia to take effect decreased significantly as both anesthetic concentration and water temperature increased for both clove oil and lidocaine-HCl. To anesthetize marine medaka within approximately 1 min, the optimal concentrations for clove oil were 125 ppm at 23 °C, 100 ppm at 26 °C and 75 ppm at 29 °C and for lidocaine-HCl were 800 ppm at 23 °C and 700 ppm at both 26 °C and 29 °C. The authors also compared anesthetic effects in marine medaka of different sizes. Both anesthetic exposure time and recovery time were significantly shorter for smaller fish than for larger fish. These results provide a useful foundation for the laboratory handling of marine medaka.     

Antimicrobial Activity of Essential Oil Components Against Potential Food Spoilage Microorganisms

The antimicrobial activity of six essential oil components against the potential food spoilage bacteria Aeromonas (A.) hydrophila, Escherichia (E.) coli, Brochothrix (B.) thermosphacta, and Pseudomonas (P.) fragi at single use and in combination with each other was investigated. At single use, the most effective oil components were thymol (bacteriostatic effect starting from 40 ppm, bactericidal effect with 100 ppm) and carvacrol (50 ppm/100 ppm), followed by linalool (180 ppm/720 ppm), α-pinene (400 ppm/no bactericidal effect), 1,8-cineol (1,400 ppm/2,800 ppm), and α-terpineol (600 ppm/no bactericidal effect). Antimicrobial effects occurred only at high, sensorial not acceptable concentrations. The most susceptible bacterium was A. hydrophila, followed by B. thermosphacta and E. coli. Most of the essential oil component combinations tested showed a higher antimicrobial effect than tested at single use. Antagonistic antimicrobial effects were observed particularly against B. thermosphacta, rarely against A. hydrophila. The results show that the concentration of at least one of the components necessary for an antibacterial effect is higher than sensorial acceptable. So the use of herbs with a high content of thymol, carvacrol, linalool, 1,8-cineol, α-pinene or α-terpineol alone or in combination must be weighted against sensorial quality.     

红光,远红光和植物激素对水稻幼苗生长及CAT,POX活性的影响

红光(R)和远红光(Fr)都抑制水稻胚芽的生长,但对胚芽鞘来说,红光抑制其生长,远红光表现出部分逆转效应。一定浓度单一生长素(IAA)促进水稻胚芽鞘的生长,而赤霉素(GA_3)与生长素作用相反。对于水稻的过氧化氢酶(CAT)、过氧化物酶(POX),红光促进两种酶的活性,远红光则表现出逆转效应。单一10~(-2)ppmIAA、10~(-2)ppmGA_3都促进其活性。照光时,在10~(-2)ppm IAA存在的条件下,红光表现为促进,远红光则表现为抑制;但在10~(-2)ppm GA_3存在的条件下,红光反而对两种酶的活性有抑制作用,远红光则表现为促进作用。     

Protective<Emphasis Type="Italic">in vivo</Emphasis> effect of curcumin on copper genotoxicity evaluated by comet and micronucleus assays

Curcumin is a phytochemical with antiinflammatory, antioxidant and anticarcinogenic activities. Apparently, curcumin is not genotoxic in vivo, but in vitro copper and curcumin interactions induce genetic damage. The aim of this study was to test if in vivo copper excess induces DNA damage measured by comet and micronucleus assays in the presence of curcumin. We tested 0.2% curcumin in Balb-C mice at normal (13 ppm) and high (65, 130 and 390 ppm) copper ion concentrations. The comet and micronucleus assays were performed 48 hr after chemical application. Comet tail length in animals treated with 0.2% curcumin was not significantly different from the control. Animals exposed to copper cations (up to 390 ppm) exhibited higher oxidative DNA damage. Curcumin reduced the DNA damage induced by 390 ppm copper. We observed statistically significant increase in damage in individuals exposed to 390 ppm copper versus the control or curcumin groups, which was lowered by the presence of curcumin. Qualitative data on comets evidenced that cells from individuals exposed to 390 ppm copper had longer tails (categories 3 and 4) than in 390 ppm copper + curcumin. A statistically significant increase in frequency of micronucleated erythrocytes (MNE/10000TE) was observed only in 390 ppm copper versus the control and curcumin alone. Also cytotoxicity measured as the frequency of polychromatic erythrocytes (PE/1000TE) was attributable to 390 ppm copper. The lowest cytotoxic effect observed was attributed to curcumin. In vivo exposure to 0.2% curcumin for 48 hr did not cause genomic damage, while 390 ppm copper was genotoxic, but DNA damage induced by 390 ppm copper was diminished by curcumin. Curcumin seems to exert a genoprotective effect against DNA damage induced by high concentrations of copper cations. The comet and micronucleus assays prove to be suitable tools to detect DNA damage by copper in the presence of curcumin.     

Distribution of selected elements within flax plants as affected by FeEDDHA

Summary Flax growing on a calcareous soil in the greenhouse developed Mn toxicity symptoms. The toxicity was eliminated by application of 2 ppm FeEDDHA-Fe. FeEDDHA had major effects on distribution of Mn, Zn, Fe and P among selected plant parts. Application of the chelate reduced Mn concentration in older leaves, the tissue most susceptible to Mn toxicity, associated stem tissue, plant tops, and roots from 2295 to 133 ppm, 62 to 7 ppm, 550 to 34 ppm, and 42 to 34 ppm, respectively. Analysis of older leaves is recommended for diagnosing Mn toxicity in flax.FeEDDHA reduced Zn concentration in plant tops and this was chiefly reflected in greatly reduced leaf concentrations, especially in older leaves. FeEDDHA increased plant Fe concentration and the effect was greatest in root and older leaf tissues. The overall effect of FeEDDHA on P concentration was small but large increases occurred in younger leaf tissue due to application of the chelate. Relative distributions of K, Na, Ca, and Mg among plant parts were only slightly affected by FeEDDHA.     

Effect of phosphorus and zinc on nodulation and nitrogen fixation in chickpea (Cicer arietinum L.)

A green house study was conducted on the effect of P and Zn on nodulation and N fixation in chickpea (Cicer arietinum L.) in a loamy sand (Typic Torripsamments) using treatment combinations of five levels of P (0, 25, 50, 100 and 250 ppm), and six levels of Zn (0, 5, 10, 20, 40 and 100 ppm). The number, dry matter and leghaemoglobin content of nodules, and amount of N fixed generally increased with Zn alone upto 19 ppm and P alone upto 50 ppm, and decreased with their higher levels. Application of 25 to 50 ppm P and 5 to 10 ppm Zn counteracted to a greater extent the adverse effect of 40 and 100 ppm Zn, and 250 ppm P, resp. Maximum nodulation and N fixation (91 to 145% over zero P and Zn, at maturity) was recorded with 25 to 50 ppm P applied along with 5 to 10 ppm Zn. At 64 days, depletion in soil-N was noted, particularly when P was applied, whereas at maturity there was a gain in soil-N, ranging from 10.5 to 44.5 kg/2×10⁶ kg soil depending upon P and Zn treatments. The increase in nodulation and N fixation with balanced P and Zn nutrition might be attributed to an increase in leghaemoglobin, and K and Fe concentration in nodules, and increased plant growth, resulting into enhanced activity of N fixing organisms. The results showed that balanced P and Zn nutrition is essential not only for plant growth but also for maximum activity of Rhizobium for N fixation. Work done at Harvana Agricultural University, Hissar, India.     

Cα and Cβ Carbon-13 Chemical Shifts in Proteins From an Empirical Database

We have constructed an extensive database of 13C Cα and Cβ chemical shifts in proteins of solution, for proteins of which a high-resolution crystal structure exists, and for which the crystal structure has been shown to be essentially identical to the solution structure. There is no systematic effect of temperature, reference compound, or pH on reported shifts, but there appear to be differences in reported shifts arising from referencing differences of up to 4.2 ppm. The major factor affecting chemical shifts is the backbone geometry, which causes differences of ca. 4 ppm between typical α- helix and β-sheet geometries for Cα, and of ca. 2 ppm for Cβ. The side-chain dihedral angle χ1 has an effect of up to 0.5 ppm on the Cα shift, particularly for amino acids with branched side-chains at Cβ. Hydrogen bonding to main-chain atoms has an effect of up to 0.9 ppm, which depends on the main- chain conformation. The sequence of the protein and ring-current shifts from aromatic rings have an insignificant effect (except for residues following proline). There are significant differences between different amino acid types in the backbone geometry dependence; the amino acids can be grouped together into five different groups with different φ,ψ shielding surfaces. The overall fit of individual residues to a single non-residue-specific surface, incorporating the effects of hydrogen bonding and χ1 angle, is 0.96 ppm for both Cα and Cβ. The results from this study are broadly similar to those from ab initio studies, but there are some differences which could merit further attention.     

Influence of selenium on the efficiency of fungicide action against certain fungi

Aspergillus funiculosus was isolated from rotted banana fruits, whereas Alternaria tenuis and Fusarium sp. were isolated from rotted tomato fruits. The isolated fungi tolerated relatively high levels of the fungicide, Dithane, up to 2560 ppm on solid medium, but grew well at 40 ppm when supplemented with liquid medium. They are able to tolerate selenite up to 2% (w/v) sodium selenite. A. funiculosus showed no growth in the presence of mixture of 2.5 ppm selenium and 20 ppm Dithane, whereas Fusarium sp. failed to grow at 2.5 ppm selenium and 10 ppm Dithane, or at 10 ppm of each. Nevertheless, Alternaria tenuis is more tolerant; it showed growth in the presence of relatively high levels of selenium and Dithane; up to 10 ppm selenium and 40 ppm Dithane, however, its growth was inhibited by the presence of a mixture of both. The results suggested new form of highly active fungicides. Selenium as an essential nutrient at such very low concentrations, as well as the application of very low concentrations of the fungicide, would certainly reduce the hazardous effect of such pollutant in the environment.     

Vinyl chloride mutagenesis in Drosophila melanogaster.

In inhalation experiments, Drosophila males were exposed to vinyl chloride at concentrations of 200, 850, 10,000 30,000 or 50,000 ppm for 2 days, and to 30 or 850 ppm for 17 days. VCM was mutagenic in the recessive-lethal test both after short-term and long-term exposures. The lowest effective concentration (LEC) was 850 ppm after 2 day exposure, and this value could be lowered to 30 ppm by prolonging the exposure time to 17 days. With the concentration levels tested, the mutation frequency increased with concentrations and reached a plateau at 10,000 ppm. This indicates a substrate saturation effect. In contrast with the recessive lethal assay, negative results were obtained when tests on dominant lethals, translocations, entire and partial sex-chromosome loss were carried out with VCM at 30,000 ppm for 2 days. This finding of a false negative seems a logical consequence of the observed saturation effect, and strengthens the concept that there exist two effective concentrations for point mutations vs the induction of chromosome breakage events. Vinyl chloride monomer provides another example to support our view that chromosome breakage is not a reliable measure of mutagenic activity.     

The Effect of Micro-organisms on the Absorption of Inorganic Nutrients by Intact Plants: II. UPTAKE AND UTILIZATION OF PHOSPHATE BY BARLELY PLANTS GROWN UNDER STERILE AND NON-STERILE CONDITIONS

The uptake of phosphate by barley plants grown under sterileand non-sterile conditions has been compared from solutionsranging in concentration between 0.001 to 10.0 ppm P. If specialprecautions are not taken to exclude microorganisms their activityon or in plant roots greatly modifies the absorption and utilizationof phosphate in plants, especially when the external concentrationis low. More phosphate is incorporated into nucleic acids, phospholipids,and phosphoproteins in the roots; at 0.001 ppm P these compoundsaccount for over 60 per cent of the phosphate absorbed comparedwith about 15 per cent in plants grown under sterile conditionsand even at 1.0 ppm P there is a twofold difference. The immobilizationof phosphate in the roots reduces its transfer to the shoots;at 0.001 ppm P, 2 as compared with 20 per cent of the phosphateabsorbed is transferred to the shoots. This effect decreaseswith increasing concentration but small differences are stillapparent up to about 0.5 ppm P. A further effect of micro-organisms is apparent when plantsare transferred from dilute solutions to phosphate-free solutions.Under non-sterile conditons there is an almost tenfold increasein the loss to these solutions of previously absorbed phosphate. It is evident that conclusions on the mechanism of absorptionof phosphate, based on experiments in which the actions of micro-organismshave been ignored, require reinvestigation.