GA3 content in young and mature antheridia of Chara tomentosa estimated by capillary electrophoresis

The content of gibberellic acid (GA3) in male sex organs of Chara tomentosa L. was estimated using capillary electrophoresis. Young antheridia contained 0.25 microg GA3 while mature ones 0.48 microg per antheridium. Although there are significant differences in GA3 content in antheridia between C. vulgaris and C. tomentosa, these values calculated per one spermatid are 2.4 and 3.3 pg, respectively. The present results compiled with the previous knowledge about regulation of GA3-dependent development of Characeae species allow an implication that the mechanisms controlling antheridia differentiation in both species can be similar.     

蕨类植物性别分化对环境的响应

蕨类植物是维管植物中唯一的孢子体和配子体都能独立生活的类群.同型孢子蕨类配子体的性别分化受到激素和环境因子的影响.生理学研究表明,成精子囊素与赤霉素能诱导雄配子体发育,抑制雌配子体发育;脱落酸阻止成精子囊素诱导的精子器形成;乙烯合成前体ACC促进赤霉素诱导的精子器形成,而乙烯合成抑制因子AOA通过抑制细胞分化来抑制精子器形成.光照对不同种类蕨类配子体分化的影响存在差异.糖类能够促进雄配子体形成,并可加速成熟雌配子体向两性分化.钙离子、钴离子和甲硫氨酸等分别参与了蓝光和赤霉素对配子体性别分化的调控过程.培养密度影响配子体生长及性别表达,高密度下雄性和无性配子体居多,而低密度下两性和雌性配子体居多.近年来的突变体表型分析与分子生物学研究表明,成精子囊素通过影响ANI1、HER、TRA、FEM和MAN等基因的表达调控配子体性别分化.综述了蕨类植物性别分化对环境响应的研究进展.     

Seasonal patterns of cell-to-cell communication in Chara corallina Klein ex Willd. II. Cell-to-cell communication during the development of antheridia

Cell-to-cell communication has been studied in lateral branches and developing antheridia of male Chara corallina plants. The moving cytoplasm is specialized to include essentially separate ascending and descending cytoplasmic streams within the inter-nodes. The neutral line which demarcates the ascending from the descending stream is established by the divisions of the nodal initial, which gives rise to both the node and internode. The ascending stream is located beneath the first-formed node-cells and the descending stream beneath the last-formed cells. The cells destined to develop into antheridia were always located on the same side as the descending internodal stream, and thus, were derived from the cells last formed during divisions of the nodal initial. Three stages of anther idial development have been defined: (1) young antheridia from the initial division of a node-cell to the formation of an octant structure; (2) maturing antheridia where differentiation into shield, manubria and capitular cells has occurred, including antheridia where an internal cavity has formed but contains filaments of less than 32 cells; and (3) mature antheridia where filaments contain more than 32 cells and spermatid production commences. Internodal cells of branches bearing young antheridia had similar characteristics to spring branches, including high plasmalemma potential differences (-217·7±31·5mV, [K⁺]_o 0·5 mol m^?3; pH 7·6) and extensive cell-to-cell communication (frequency of intercellular transport of 6 carboxyfluorescein 86%). The small probe 6 carboxy fluorescein moved into the entire young antheridium in 100% of injections. The molecular exclusion limit for internodes and the nodal complex lay between 874 and 1678Da whereas the exclusion limit for the young antheridium was smaller (between 750 and 874Da). Internodal cells of branches bearing maturing antheridia had similarly high PDs (–221·7±40mV; [K⁺]_o 0·5 mol m^?3; pH 7·6). Cell-to-cell communication between internodes bearing maturing antheridia was extensive (frequency of intercellular transport of 6 carboxyfluorescein 100%). The shield cells were isolated from the symplast of the thallus at this stage since they did not admit 6 carboxyfluorescein. Internodal cells of branches bearing only mature antheridia showed different characteristics. Intercellular communication between internodes was restricted to a level similar to that found in winter (frequency of intercellular transport of 6 carboxyfluorescein = 57%). The mature antheridium was entirely isolated from the symplast of the thallus. A period of extensive cell-to-cell communication and high PDs in internodal cells commences in vegetative lateral branches in spring, immediately before reproductive structures are initiated. These features persist throughout summer whilst reproductive structures develop, until the antheridial filaments contain 32 or more cells (mature stage), at which point spermatid production commences and the antheridium is isolated from the thallus. In autumn, following the stage of mature antheridia, no further antheridia are initiated. Internodes are subsequently vegetative throughout winter and their lateral branches are characterized by restricted cell-to-cell communication, low internodal PDs, and little obvious growth, all features consistent with winter dormancy.     

辣椒胞质雄性不育系和保持系内源激素含量的比较

以2个辣椒品系(199807、199803)的胞质雄性不育系和相应保持系为实验材料,采用酶联免疫吸附法(ELISA)测定IAA、(Z ZR)、GA3和ABA等内源激素含量,用气相色谱分析仪测定乙烯(ETH)释放量,对辣椒胞质雄性不育系和相应保持系内源激素含量变化规律进行研究.实验结果表明:在四分小孢子之前,花药中的IAA含量不育系显著高于保持系,在四分小孢子时期花药和花蕾中的IAA含量出现转折,到花粉粒成熟期的花蕾和花药以及开花期叶片中的IAA含量均是不育系显著低于保持系;小孢子各发育时期花药以及花期叶片中GA3含量均是不育系高于保持系,但花粉粒成熟期化蕾中GA3含量为不育系低于保持系;小孢子不同发育时期的花药以及花期叶片中ABA含量始终足不育系显著高于保持系,而花粉粒成熟期花蕾中ABA含量不育系与保持系没有显著差异;花粉粒成熟期的花蕾和花期叶片中ETH释放量表现为不育系显著高于保持系.同时,花粉粒成熟期的花蕾、花药和叶片中IAA/ABA、(Z ZR)/ABA、GA3/ABA、IAA/GA3、(Z ZR)/GA3等5个激素的比值均有不育系低于保持系的趋势.本实验结果说明辣椒的育性表现与花器和叶片等组织中内源激素的含量变化有关,花药和花期叶片中IAA亏缺、GA3和ABA增加以及化蕾和叶片中ETH过度产生,都有可能导致辣椒雄性不育.     

Different Patterns of Intercellular Transport of Lucifer Yellow in Young and Mature Antheridia of Chara vulgaris L.

Intra- and intercellular movement of the fluorochrome Lucifer Yellow (LY), microinjected into the shield cells of male sex organs, was examined at different stages of spermatogenesis in Chara vulgaris L. Two distinct stage-associated types of probe movement were noted: (I) a fast and uniform spreading of fluorescence within the shield cell injected, followed by centripetal transport of LY into the adjoining manubrium and the capitular cells, and subsequent redistribution into the other manubria and shield cells in young antheridia (up to the stage of 4-cellular filaments), and (II) limited spreading of fluorescence, restricted to the triangle-shaped area of the impaled shield cell in more mature antheridia with multicellular filaments. These results confirm earlier electron microscopic observations on plasmodesmatal connections indicating an intensive solute movement between all cell types in young antheridia of Chara. Developmental changes appearing at later stages, during differentiation of sperm cells, strongly reduce the capacity for intercellular symplasmic transport.     

Autoradiographic studies on the role of plasmodesmata in the transport of gibberellin

Translocation of [¹⁴C]gibberellic acid into antheridial cells of Chara vulgaris L. was investigated in relation to the presence of symplasmic connections between the antheridium and the thallus. It was found that manubria, capitular cells, and antheridial filaments were about three-fold more strongly labelled in young antheridia connected to the thallus by plasmodesmata than in older antheridia in which spontaneous symplasmic isolation had occurred. Plasmolytically induced symplasmic isolation of young antheridia severely diminished the radioactivity of all the cells, down to the level characteristic for spontaneously isolated antheridia. It is concluded that plasmodesmata are the main channel of gibberellin transport into antheridia. The change in the character of symplasmic connections during the course of morphogenesis might, among other events, constitute a signal determining a shift of cell metabolism in a new direction, in response to a rapid change in gibberellin level.Abbreviations GA_(n) gibberellin (A_n) - GA₃ gibberellic acid - IAA indole-3-acetic acid This study was supported by the Polish Academy of Sciences research project CPBP 04.01.5.05.     

Gibberellin-responding and non-responding dwarf mutants in foxtail millet

The sensitivity of foxtail millet (Setaria italica Beauv.) dwarf mutants to GA was studied. Seedlings of dwarf mutants, Aininghuang (ANH) and CH84113 were treated with GAs (GA1, GA4, GA9, GA19 and GA20) using the micro-drop method, or by soaking in GA3 solution. Plants were also sprayed with GA3 solution at the jointing stage. It was found that ANH was a GA-responding dwarf mutant, whose leaf blade, leaf sheath and internode length increased significantly after GA application, whereas CH84113 was a non-GA-responding dwarf mutant. However, the mesocotyl in etiolated seedlings of both ANH and CH84113 responded to exogenous GA3 in a similar way. With the help of an enzyme-linked immunosorbent assay, it was found that the endogenous GA1+3 level in leaves was lower in the GA-responding dwarf mutant ANH, but higher in the non-GA-responding dwarf mutant CH84113, compared with levels in normal cultivars.     

The Spontaneous Formation of Antheridia in Onoclea is not Blocked by Light

Onoclea sensibilis gametophytes were grown from spores on ashedsoil and agar to determine if the spontaneous formation of antheridiacan be blocked by light. Under most conditions, dark-grown gametophytesformed antheridia later than or at the same time as gametophytesgrown in the light. Under no circumstances was there a rapidonset of maleness in the dark. These results contradict thehypothesis that, in Onoclea, antheridiogen is required to inducemaleness because light inhibits the formation of antheridia.In the light, antheridia formed on heart-shaped thalli. In darkness,antheridia formed on filamentous gametophytes. The timing ofonset of maleness was affected by temperature and the presenceof sucrose. The effect of sucrose on the comparison betweenlight and dark treatments depended on both substrate and temperature Onoclea sensibilis, L., sensitive fern, fern gametophytes, sexuality, light-induced block     

外源赤霉素GA3对大豆光合作用的促进和叶片内源赤霉素GA1+3水平

在营养生长阶段大豆正在扩展和刚刚完全扩展的叶片（4-12天龄）观察到外源赤霉素GA3引起净光合速率增高,但是在成龄叶片（17-22天龄）观察不到这种效应（图1）。在扩展着的叶片（4-8天龄）中用免疫实验检测的内源赤霉素GA1 3含量低于成龄叶片中的含量（图2）。由这些结果得出结论：外源赤霉素GA3对大豆叶片光合作用的促进作用是以内源有生物活性的赤霉素含量低为前提的。     

Synthesis of glutaminic and aspartic acids in mitochondria of the visual analyzer of the dog brain during postnatal ontogenesis

It is revealed that glutaminic acid (GA) synthesis by direct reductive amination proves to be the most rapid in the mitochondria of the outer geniculate body (OGB) from the 1st till the 45th day of the postnatal development, and beginning from the 45th day till the 3-month age in visual cortex (field 17) (VC) and bigeminal bodies (BB). It is stated that GA synthesis by transamination in the mitochondria of VC, OGB, and BB proceeds less intensively than by a direct reductive amination at the early stage of postnatal development, being more rapid during the period from the 12-16th till the 45th day of postnatal development. Unlike GA synthesis in the mitochondria of the studied visual analyzer structures of canine brain AsA synthesis is more rapid in transamination reaction at the early stage of postnatal development. The high level of AsA synthesis was observed on the day when the puppies' eyes began to see clearly. The level of AsA synthesis by reductive amination and transamination in the mitochondria of VC, BB, and OGB at the early stage of postnatal development is lower than that of GA synthesis.     

Effect of Chelating Agents and Metal Ions on Growth and Fertility in the Male Clones of the Moss Microdus brasiliensis (Dub.) Ther

The male gametophores of Microdus brasiliensis become fertileafter 48 d on basal medium. EDDH A increases gametophore numberand percentage of fertile gametophores at lower concentrations(10^–8-10^–6 mol dm^–3), whereas EDTA enhancesboth the responses at all levels (10^–8-10^–4 moldm^–3). Their iron salts increase gametophore number aswell as the number of fertile gametophores, and the latter effectis more striking. The number of antheridia per head also increaseswith Fe-EDTA, and at higher concentrations antheridia are induced4 d earlier. EDTA and Fe-EDTA-stimulated antheridia] formationis associated with a corresponding increase in endogenous iron.Copper content increases only at higher levels of EDTA and Fe-EDTA,and there is no correlation with the antheridial induction response.Salicylic acid increases the number of gametophores and thepercentage of fertile gametophores only at lower concentrations(10^–8-10^–6 mol dm^–3), and ferric citrate doesso at all levels. With salicylic acid, antheridia are induced3 d earlier. The number of gametophores as well as the percentageof fertile gametophores increases with the increase in coppersulphate concentration. Co-addition of EDTA (10^–5 moldm^–3) and copper sulphate inhibits both the responsesat higher levels. Among the chelating agents tried, Fe-EDTAis most effective in enhancing antheridial production. Key words: EDDHA, EDTA, Salicylic acid     

ROLE OF ASYMMETRIC CELL DIVISION IN PTERIDOPHYTE DIFFERENTIATION. II. EFFECT OF CA2+ ON ASYMMETRIC CELL DIVISION,RHIZOID ELONGATION,AND ANTHERIDIUM DIFFERENTIATION IN VITTARIA GEMMAE

Gametophytes of Vittaria graminifolia reproduce vegetatively by means of gemmae. Each gemma consists of a linear array of six cells: four body cells and a knob-shaped terminal cell at each end. When gemmae are shed from the gametophyte onto Knop's mineral medium, the two terminal cells do not divide, but elongate to form primary rhizoids. The body cells undergo asymmetric cell division, and the smaller daughter cells differentiate into either secondary rhizoids or prothalli. When gibberellic acid is included in the medium, antheridia are formed as a result of asymmetric cell division instead of vegetative structures. We studied the effect of Ca²⁺ on asymmetric cell division, rhizoid elongation, and antheridium formation in gemmae cultured on Knop's mineral medium and variations of Knop's medium. Ca²⁺ inhibited the onset of cell division and rhizoid elongation, but was required for differentiation of antheridia. Treatments which lowered the Ca²⁺ content of gemmae (EGTA and dilute HCl extraction, culture on verapamil-containing and Ca²⁺-deficient medium) caused an early onset of cell division and rhizoid elongation. The stimulation of growth was most pronounced when gemmae were deprived of Ca²⁺ during the first 24 hr of culture. The proportion of cell divisions which differentiated into antheridia in response to GA was greatly reduced when the Ca²⁺ status of gemmae was lowered with verapamil and Ca²⁺-EGTA buffers.     

油菜生长发育期间内源激素含量的变化

初花期至盛花期华双3号、华杂4号、恢5900等3个品种花蕾的iPAs含量呈明显上升趋势,而秦油2号则刚好相反(表2)。对双低品种华双3号功能叶的研究表明：苗期至盛花期IAA含量始终最高,其后依次是GA1 3;、iPAs、ABA。功能叶IAA的含量在越冬期处于整个生育期的最低水平,蕾薹期达到高峰,随后下降：GA1 3和iPAs含量随生育进程逐渐升高,并在初花期达到峰值;ABA在苗期及抽薹后一直处于很低水平,但在越冬期达到最高值(图1、2)。蕾薹期IAA主要分布在幼嫩和正在生长的器官中并起重要作用,而在功能叶中相对要少;幼叶GA1 3和iPAs含量最高,功能叶其次,花蕾最低(表1)。角果皮与籽粒的内源激素含量差异极显著,在开花后第39天,籽粒中IAA、GA1 3;、iPAs的含量大大超过角果皮(表3)。结果 表明iPAs在促进籽粒的充实饱满、物质积累转化方面发挥重要作用。     

Metabolic regulation in C4 photosynthesis: Phosphoenol pyruvate carboxylase and 3C intermediates of the photosynthetic carbon reduction cycle

Summary Gibberellins and auxins were extracted from embryos and suspensors of Phaseolus coccineus L. at two stages of development: A) heart-shaped embryo and B) cotyledonary embryo with suspensor in the initial stage of degeneration. The time interval between the two stages was 5–6 days.In both embryos and suspensors, gibberellin (GA)-like activity was found in three fractions: F-1 (ethyl acetate fraction at pH 8.0), F-2 (free GAs) and F-3 (bound GAs). At stage A, the total GA activity in the suspensor was about 30 times greater than in the embryo and the bound GAs contributed by about 90% to the total GA content. A dramatic decrease in level of bound GA-like substances was found in suspensors at stage B, when the level of total GAs in the embryo had increased to 10 times that at stage A. This might suggest a transport of GAs from the suspensor to the embryo. In both embryo and suspensor, qualitative changes in GAs with shift in activity of the fractions tested occurred at the two developmental stages.The methanolic extracts of stage A suspensors showed two inhibitors, one much more active than the other, and two large peaks of growth promoting activity at Rf 0.4–0.7; in stage A embryos, the general activity of the extracts was lower and the promoting effect was spread over Rf 0.3–0.9.The present results seem to support the view that the suspensor plays a role in embryogenesis by acting as a site of synthesis of growth regulators needed by the embryo.Abbreviations F-1 ethyl acetate fraction at pH 8.0 - F-2 free gibberellins - F-3 bound gibberellins - GA gibberellic acid - Stage A heart-shaped embryo - stage B cotyledonary embryo with suspensor in the initial stage of degeneration     

Prediction of gestational age by ultrasonic fetometry in llamas (Lama glama) and alpacas (Lama pacos)

Fetal biparietal diameter (BPD) and thorax height (TH) were measured by ultrasound during intrauterine growth in pregnant llamas (Lama glama) and alpacas (Lama pacos). The goal was to establish representative curves that allows estimation of gestational age (GA) from real-time ultrasonic measurements of these fetal structures at any stage of gestation. Llamas and alpacas were mated under controlled conditions. Ultrasound exams were conducted to determine pregnancy status 1 month later. Measurements of fetal BPD and TH were conducted from the second month of pregnancy until term. Observation and assessment of fetal TH was difficult during the last 3 months of pregnancy, specially in llamas. Regression curves were calculated from the data as a function of GA, with the best fit represented by the following equations: llama GA=(BPD-0.002399)43.02293,r=0.98,P<0.001; llama GA=(TH-0.07137)46.94485, r=0.95,P<0.001; alpaca GA=(BPD-0.11376)47.23287, r=0.98,P<0.001; alpaca GA=(TH-0.36436)52.87663, r=0.96,P<0.001, where GA was measured in days and BPD and TH in centimeters. Results indicate that ultrasonic measurement of these fetal biometric variables constitute a valuable tool to estimate GA at any stage of pregnancy in these domestic South American camelids.     

甘蔗节间伸长过程赤霉素生物合成关键基因的表达及相关植物激素动态变化

以甘蔗(Saccharum officinarum)优良品种桂糖42号(GT42)为研究材料, 分别于未伸长期(9-10叶龄以前) (Ls1)、伸长初期(12-13叶龄) (Ls2)和伸长盛期(15-16叶龄) (Ls3)取甘蔗第2片真叶(自顶部起)对应的节间组织, 测定其赤霉素(GA)、生长素(IAA)、油菜素甾醇(BR)、细胞分裂素(CTK)、乙烯(ETH)和脱落酸(ABA)的含量, 并通过实时荧光定量PCR (qRT-PCR)分析赤霉素合成途径关键基因GA₂₀氧化酶基因(GA20-Oxidase1)、赤霉素受体基因(GID1)和DELLA蛋白编码基因(GAI)的差异表达。结果表明, 在甘蔗伸长期间, GA和IAA含量呈现上升趋势, CTK和ABA含量呈下降趋势, ETH含量先上升后下降, BR含量则变化不明显; GA20-Oxidase1和GID1的表达呈上升趋势, 而GAI的表达则呈下降趋势, 这与相关植物激素的变化基本一致。综上, 甘蔗节间伸长过程主要与GA和IAA相关, 其次为CTK和ABA, 而ETH受到IAA的调控影响节间伸长; 植物激素间通过相互作用调控GA20-Oxidase1、GID1和GAI的表达, 影响GA含量和GA的信号转导过程, 进而影响甘蔗节间的伸长。该研究揭示了甘蔗节间伸长过程中赤霉素生物合成途径和信号转导关键基因的差异表达及植物激素含量的动态变化规律。     

低温处理青花菜萌动种子对花芽分化的促进作用

低温(0～2℃)处理萌动种子可使青花菜的花芽分化提前.种子萌动时期经低温处理10 d(T10)和20d(T20)的青花菜植株花芽分化开始时的节位分别比对照(CK)低0.86个节位和1.03个节位.花芽分化临界期、第1级侧花茎原基分化期和第2～3级侧花茎原基分化期经低温处理10d和20 d均分别比对照提前5 d和6d.当进入花芽分化临界期时,叶片中GA3、可溶性蛋白质含量以及POD和转化酶活性均开始剧增,在第1级侧花茎原基分化期和第2～3级侧花茎原基分化期,叶片中POD、转化酶活性和GA3均有一高峰值.萌动种子经一段时间的低温处理后,首先诱导了GA3的合成,从而提高POD和转化酶等酶的活性,而这两种酶活性的升高对花芽分化有利.     

甘蔗节间伸长过程赤霉素生物合成关键基因的表达及相关植物激素动态变化

以甘蔗(Saccharum officinarum)优良品种桂糖42号(GT42)为研究材料, 分别于未伸长期(9-10叶龄以前) (Ls1)、伸长初期(12-13叶龄) (Ls2)和伸长盛期(15-16叶龄) (Ls3)取甘蔗第2片真叶(自顶部起)对应的节间组织, 测定其赤霉素(GA)、生长素(IAA)、油菜素甾醇(BR)、细胞分裂素(CTK)、乙烯(ETH)和脱落酸(ABA)的含量, 并通过实时荧光定量PCR (qRT-PCR)分析赤霉素合成途径关键基因GA₂₀氧化酶基因(GA20-Oxidase1)、赤霉素受体基因(GID1)和DELLA蛋白编码基因(GAI)的差异表达。结果表明, 在甘蔗伸长期间, GA和IAA含量呈现上升趋势, CTK和ABA含量呈下降趋势, ETH含量先上升后下降, BR含量则变化不明显; GA20-Oxidase1和GID1的表达呈上升趋势, 而GAI的表达则呈下降趋势, 这与相关植物激素的变化基本一致。综上, 甘蔗节间伸长过程主要与GA和IAA相关, 其次为CTK和ABA, 而ETH受到IAA的调控影响节间伸长; 植物激素间通过相互作用调控GA20-Oxidase1、GID1和GAI的表达, 影响GA含量和GA的信号转导过程, 进而影响甘蔗节间的伸长。该研究揭示了甘蔗节间伸长过程中赤霉素生物合成途径和信号转导关键基因的差异表达及植物激素含量的动态变化规律。     

受精前后梨子房(幼果)中钙与内源激素含量的关系

受精促进子房(幼果)对钙的吸收,受精完成后的黄花子房(幼果)中钙含量迅速上升,未受精的子房(幼果)中钙含量远低于同期受精的果实.受精前后钙含量变化与其中IAA和GA3含量变化相似;NAA、GA3处理促进钙的吸收.IAA和GA3可能同时参与受精前后树体中的钙向幼果(子房)的运输过程.