GA_3对老化花椰菜种子活力和几种相关生理生化性状的影响

用10、50、100、150和200mg·L-15种浓度赤霉素（GA3）溶液处理于10℃冰箱中贮藏5年的花椰菜老化种子。结果表明,100mg·L-1GA3浸种22h的效果最佳,老化种子的发芽率、发芽势、活力指数、根长均有提高,畸形苗率下降;过氧化物酶（POD）、过氧化氢酶（CAT）和脱氢酶活性提高,可溶性蛋白和叶绿素含量也提高,种子浸出液的电导率和丙二醛（MDA）含量则下降。另外,100mg·L-1GA3处理后的种子在温度为25℃条件下贮藏时间不宜超过25d。     

植物组合及水体营养梯度对三种功能性植物生物量累积与分配的影响

设置4个营养水平(I: 0.5 mg N·L^-1, 0.1 mg P·L^-1; II: 1.5 mg N·L^-1, 0.3 mg P·L^-1; III: 4.5 mg N·L^-1, 0.9 mg P·L^-1; Ⅳ: 13.5 mg N·L^-1, 2.7 mg P·L^-1), 研究了水体营养水平、物种组合及其交互作用对入侵漂浮植物凤眼莲、本地扎根浮叶植物黄花水龙和沉水植物苦草生物量累积与分配的影响.结果表明：随营养水平的升高,4个营养水平的凤眼莲和黄花水龙单种和混种的总生物量及茎叶生物量都呈上升趋势,凤眼莲和黄花水龙的总生物量在Ⅲ、Ⅳ处理下平均比Ⅰ、Ⅱ处理下分别增加了54.47%和102.63%;不同植物组合下,苦草各部分生物量呈下降趋势,Ⅲ、Ⅳ处理的总生物量比Ⅰ、Ⅱ处理平均降低了45.88%;经双因素分析,水体营养水平对凤眼莲和黄花水龙生物量有极显著的正影响（P<0.01）,对苦草生物量有极显著的负影响（P<0.01）;而植物组合的影响随目标植物的不 同呈现出差异.     

Studies on Desiccation and Storage of Mango Seeds

Mango (Mangifera indica L.) seed is recalitrant which taken from ripened fruits con,ained as high as 69.2'–75.5% moisture content (The moisture content of embryonic axis is 73.8–86.3%). When seeds were naturally dried for 8 days, the moisture content declined to 39.1% (in embryonic axis the moisture content declined to 46.5%) and the viability of seeds completely lost. Embryonic axis lost water slower than whole seed because of the prevention of desiccation by the large cotyledons. During natural desiccation, the conductivity of leachate increased rapidly from 2.2 μΩ·cm-1·g-1 (the same unit below) to 56.7, whereas the activities of dehydrogenase and acid phosphatase decreased drastically. When seeds were rapidly dried for 42 hours, the moisture content declined from 75.5 to 29.9%, the conductivity of leachate increased from 1.8 to 36.9 and the percentage germination changed from 100% to 10%. Desiccation damaged the cell membrane and decreased the activities of enzymes. Rapid drying was better for maintaining longevity than natural (slow) drying because the former did less damage to the cell membrane than natural (slow) drying as shown in the conductivity changes. The moisture content of excised embryonic axis decreased to 11.8% when they were dried for 8 hours by silicagel. The survival percentage of these embryonic axis was 80% when they were incubated in MS+0.2 mg/L BA+2.0 mg/L NAA+500 mg/L gln+3% sucrose+0–9% agar medium. Seeds with 51.0% moisture content (rapidly dried for l0 hours by electric fan blowing) had 65% viability after 7 months wet storage with the polyethylene bag at 15℃.     

Ion exchange during heavy metal bio-sorption from aqueous solution by dried biomass of macrophytes

In this study, potentials of oven dried biomass of Eichhornia crassipes, Valisneria spiralis and Pistia stratiotes, were examined in terms of their heavy metal (Cd, Ni, Zn, Cu, Cr and Pb) sorption capacity, from individual-metal and multi-metal aqueous solutions at pH 6.0+/-0.1 (a popular pH of industrial effluent). V. spiralis was the most and E. crassipes was the least efficient for removal of all the metals. Cd, Pb and Zn were efficiently removed by all the three biomass. Cd was removed up to 98% by V. spiralis. Sorption data for Cr, Ni and Cd fitted better to Langmuir isotherm equation, while, the sorption data for Pb, Zn and Cu fitted better to Freundlich isotherm equation. In general, the presence of other metal ions did not influence significantly the targeted metal sorption capacity of the test plant biomasses. Ion exchange was proven the main mechanism involved in bio-sorption and there was a strong ionic balance between adsorbed (H(+) and M(2+)) to the released ions (Na(+) and K(+)) to and from the biomass. No significant difference was observed in the metal exchanged amount, by doubling of metal concentration (15-30 mg/l) in the solution and employing individual-metal and multi-metal solutions.     

外源酚对凤眼莲体内酚含量和与酚代谢有关酶的影响

凤眼莲能够吸收和在体内聚集外源苯酚,体内的酸含量随着环境中酚浓度的上升而上升。从生长于合酚培养液中的凤眼莲体内能够检测到酚糖苷,说明凤眼莲体内有酚精苷转移酶的存在。浓度小于５０ｍｇ／Ｌ的外源酚能提高凤眼莲体内的多酚氧化酶和过氧化物酶的活性。多酚氯化酶与过氧化物酶在线粒体和微粒体中均有不同程度的分布,而酚糖苷转移酶则不存在于这些细胞器中。     

Interchangeable effects of gibberellic acid and temperature on embryo growth, seed germination and epicotyl emergence in Ribes multiflorum ssp. sandalioticum (Grossulariaceae)

Morphophysiological dormancy was investigated in seeds of Ribes multiflorum Kit ex Roem et Schult. ssp. sandalioticum Arrigoni, a rare mountain species endemic to Sardinia (Italy). There were no differences in imbibition rates between intact and scarified seeds, suggesting a lack of physical dormancy, while methylene blue solution (0.5%) highlighted a preferential pathway for solution entrance through the raphe. Embryos were small at seed dispersal, with an initial embryo:seed ratio (E:S) of ca. 0.2 (embryo length, ca. 0.5 mm), whereas the critical E:S ratio for germination was three times longer (ca. 0.6). Gibberellic acid (GA(3), 250 mg · l(-1)) and warm stratification (25 °C for 3 months) followed by low temperature (<15 °C) enhanced embryo growth rate (maximum of ca. 0.04 mm · day(-1) at 10 °C) and subsequent seed germination (radicle emergence; ca. 80% at 10 °C). Low germination occurred at warmer temperatures, and cold stratification (5 °C for 3 months) induced secondary dormancy. After radicle emergence, epicotyl emergence was delayed for ca. 2 months for seeds from three different populations. Mean time of epicotyl emergence was affected by GA(3) . Seeds of this species showed non-deep simple (root) - non-deep simple (epicotyl) morphophysiological dormancy, highlighting a high synchronisation with Mediterranean seasonality in all the investigated populations.     

橙黄玉凤花种子萌发培养及小苗组培快繁研究

对橙黄玉凤花Habenaria rhodocheila种子进行无菌萌发培养以获得大量原球茎,并对原球茎组培,建立其快繁体系。结果表明,橙黄玉凤花种子以0.1%升汞消毒15 min为最佳处理。种子萌发培养基中,添加0.2%活性碳(AC)有利于种子萌发。种子萌发的最佳培养基为1/2MS＋NAA 0.5 mg·L-1＋AC 0.2%,原球茎增殖分化最佳培养基为1/2MS＋NAA 0.2 mg·L-1＋ZT 3.0 mg·L-1＋AC 0.2%;生根最佳培养基为1/2MS＋NAA 0.1 mg·L-1＋6-BA 2.0 mg·L-1＋AC 0.2%。     

PEG引发对芹菜种子活力影响的研究

以芹菜种子为试验材料,研究了不同浓度的聚乙二醇（PEG）及其不同浸种时间对芹菜种子活力指标以及电导率的影响。结果表明,选择50mg／L的PEG处理芹菜种子能够显著提高其发芽率、发芽势、发芽指数、活力指数、芽长、根长、鲜重和干重。不同浓度PEG处理的芹菜种子的浸泡电导率和绝对电导率均显著低于对照组,且以50mg／L的PEG处理的两种电导率值最低。因此,通过选择50mg／LPEG浸泡芹菜种子4h,能够使其活力得到显著的提高。     

Excess boron reduces polyphenol oxidase activities in embryo and endosperm of maize seed during germination

The effects of increasing concentrations of boron (0, 0.1, 1, 10 and 20 mM) as boric acid on the rate of germination and polyphenol oxidase activities in embryo and endosperm tissues of maize seeds (Zea mays L. cv. Arifiye) were studied. The germination percentage of maize seeds was not affected by boron concentrations up to 10 mM, and decreased by 20 mM. Distilled water and lower boron concentrations (0.1 and 1 mM) increased polyphenol oxidase activities at the beginning of germination up to 12 h whereas its excess levels (10 and 20 mM) decreased polyphenol oxidase activities in embryos and endosperm during germination. Polyphenol oxidase activities with o-diphenolic substrates (caffeic acid, catechol and dopa) were found to be higher than with a monophenolic substrat (tyrosine) in both embryos and endosperms. Further, caffeic acid oxidizing polyphenol oxidase was found to show more activity in embryos of the seeds germinating in distilled water when compared to other substrates.     

赤霉素、钙和甜菜碱对小桐子种子萌发及幼苗抗低温和干旱的影响

小桐子(Jatropha curcas L.)属大戟科( Euphorbiaceae)麻疯树属(Jatropha L.)的能源植物。分别以小桐子种子和幼苗为实验材料,研究了不同浓度的赤霉素和CaCl₂单独处理,以及不同浓度的赤霉素、CaCl₂和甜菜碱组合处理对小桐子种子萌发及幼苗抗低温和干旱的影响。结果表明:分别用10 mg/L赤霉素和10 mmol/L CaCl₂处理小桐子种子,不仅可以提高其在正常萌发条件(26℃)、低温(18℃)和干旱胁迫(5% PEG6000)下的发芽率,还可缓解小桐子幼苗在低温(2℃)或干旱胁迫(25% PEG6000)下电解质渗漏率的增加和丙二醛(MDA)的积累。用10 mg/L赤霉素、5 mmol/L CaCl₂和15 mmol/L甜菜碱组合处理小桐子种子,也可进一步增强其在正常萌发(26℃)、低温(18℃)和干旱胁迫(5% PEG6000)条件下种子的发芽率,以及缓解小桐子幼苗在低温(2℃)或干旱胁迫(25% PEG6000)下电解质渗漏率的增加和MDA的积累,表明10 mg/L赤霉素和10 mmol/L CaCl₂分别处理或10 mg/L赤霉素、5 mmol/L CaCl₂和10 mmol/L甜菜碱组合处理可提高小桐子种子在低温和干旱胁迫下的发芽率,以及提高小桐子幼苗对低温和干旱胁迫的抵抗能力。     

Density of intraspecific competitors determines the occurrence and benefits of accelerated germination

Germination is a key process in plant recruitment and population dynamics, and seeds are expected to be under strong selection pressure to germinate under conditions that maximize subsequent plant survival. Increased rates of germination (i.e., accelerated germination) may occur in competitive environments. We examined the effects of conspecific density on the timing of germination of seeds of a bird-dispersed plant, Phytolacca americana (Phytolaccaceae, L.), in three different competitive environments. By comparing germination of seeds sown at the same time at different densities, we quantify the benefits of accelerated germination under conditions in which differences in performance among seedlings are attributable to germination timing only, and not to being sown at different times. We find that although the probability of germination is unchanged, the time to initiation of germination is significantly shorter when competition is greater. We also show that plants that germinate earlier are larger and have higher growth rates because they have more time to grow without competitors. Our work demonstrates that shifts in germination timing in response to competition can yield significant dividends for seeds that germinate earliest, but we caution that the magnitude and consequences of accelerated germination will likely depend on the competitive neighborhood.     

Seed Viability Determinations in Cabbage Utilizing Sinapine Leakage and Electrical Conductivity Measurements

A need exists for the development of rapid seed quality teststhat determine viability (defined as the ability to germinate)without the necessity for completion of germination. In cabbage(Brassica oleracea var. capitata L.) the compound sinapine,a choline ester of sinapic acid, has been shown to leak fromheat-killed (HK.) but not from viable seeds. Sinapine leakagewas studied as a more accurate method for identifying viableseeds than the conductivity test. After an 8 h soak, a 26-folddifference in sinapine leakage was detected between HK and viableseeds (as measured by the absorbance at 388 nm at pH 12) comparedto a 4-fold difference measured by electrolyte leakage. Theremainder of the studies were conducted on two seedlots of thesame cultivar. Viability was predicted on the same seed by assessingleakage from individual seeds into the soak water using threemethods; soak water colour, absorbance at 388 nm, and electricalconductivity. This information was compared with the actualgermination of each seed for the two seedlots. For both seedlots,the presence of sinapine in seed soak water (detected eitherby a yellow solution colour at high pH or by high absorbance),identified more seeds that were non-viable than the partitioncoefficient calculated from conductivity measurements (76%,72% and 28% of non-viable seeds were identified, respectively).It is proposed that leakage of sinapine is a better predictorof cabbage seed viability than electrical conductivity. Key words: Seed deterioration, seed leakage, germination prediction     

In vitro response of encapsulated somatic embryos of Lagerstroemia indica L

A method to produce encapsulatable units for synthetic seeds was developed in L. indica. Somatic embryos were harvested from leaf derived embryogenic callus on Murashige and Skoog's basal medium supplemented with 2, 4-dichlorophenoxy acetic acid (2, 4-D, 0.5 mg/l), 6-benzyl amino purine (BAP, 1 mg/l) and ascorbic acid (AA, 50 mg/l). The embryos were encapsulated in alginate beads and dehydrated. Germination ability of the artificial seeds were investigated. The frequency of regeneration from the encapsulated embryos was significantly affected by (i) the concentration of alginate (ii) the duration of storage, and (iii) the effect of different types of media. A 2% sodium alginate concentration on MS salts resulted in significantly higher germination frequencies than at other concentrations. L. indica showed maximum germination on MS medium (93.84%) after 6 weeks of culture. The germinated synthetic seeds with well developed roots and shoots were transferred successfully to green house. This is the first report on artificial seeds in Lagerstroemnia indica.     

经夏越冬播种水曲柳种子的萌发效应

贮藏的成熟水曲柳种子经夏越冬播种的结果表明,贮藏的成熟种子经夏越冬播种可以萌发,东北地区的播种时间宜在9月之前。用适宜的植物生长调节物质处理可以获得较好的发芽效果,其中以100mg·L^-1激动素浸种1d的效果较好。     

蛋白酶抑制剂对含水生菜种子耐冻性的影响

选取生菜(Lactuca sativa)种子作为试材,外源添加蛋白酶抑制剂2-硝基苯甲酸[5,5'-Dithiobis-(2-nitrobenzoic acid),DTNB]对种子吸胀处理,通过程序降温,分析2-硝基苯甲酸对低温下种子发芽率及生理活性的影响。结果表明,低温下含水生菜种子的致死温度为–20 ℃;外源添加2-硝基苯甲酸2 mmol·L–1时种子发芽率最高,即对种子活性的保护效果显著;在此浓度下种子内SOD活性比对照提高1.38倍,羟基自由基清除能力提高1.17倍;与对照组相比产生两种新的蛋白11 S种子贮藏球蛋白Jug r4和11 S种子贮藏球蛋白2,均属于球蛋白家族,可提高含水种子的耐冻性;低温下种子内积累更小分子量的球蛋白多肽,对种子具有低温保护效果。综上,低温条件下生菜种子产生一定的抗冷反应,外源添加2 mmol·L–1 2-硝基苯甲酸可提高含水种子发芽率及生理活性,产生抗冻蛋白,积累更小分子量的球蛋白多肽进而提高种子抗冻性。     

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。     

In vitro shortening of generation time in Arabidopsis thaliana

Shortening of generations is very important for gene validation and a rapid exploitation of genetic novelties. Even if the life cycle of Arabidopsis thaliana is theoretically short, shortening it further would be useful. We developed a strategy where seeds germinated on medium with picloram (0.1 mg/l) and benzylaminopurine (0.5 mg/l) set seed about 40–45 days after sowing. Green seeds from immature siliques (second generation) are sown on half-strength, hormone-free MS medium where they flower and fruit much faster than the first generation (between 20 [C24] and 26 [Col] days/generation). A cold treatment was not needed for germination of immature seeds, and the duration of each cycle could thus be halved compared with the first generation. This strategy, allowing comfortably more than 10 generations per year, may be helpful for genetic studies using this model plant species.     

Effect on the Progeny of Applying Different Day Length and Hormone Treatments to Parent Plants of Lactuca scariola

Seedlings of the self-fertilizing species Lactuca scariola L. grown continuously in 8 h days did not flower even one year from sowing. Seedlings grown in 16 h days uatil flower buds appeared 96 days after germination were either transferred to 8 h days or treated weekly with gibberellic acid (GA₃), abscisic acid (ABA) or chlormequat (CCC) and retained, together with untreated control plants, in 16 h days. Each growth regulator caused characteristic morphological changes in the treated plants. All these plants flowered and produced seeds but the seeds showed distinct differences in weight, in their time to germination and in the seedlings which they produced. Germination and seedling characters depended on the light regime during germination as well as on the chemical applied to the parent plant and the rate of application. The parental treatment also affected the shape and size of the seedlings on a given day after germination, and certain treatments of the parent plant (transfer from long to short days and treatment with CCC in long days) advanced the flowering date of the seedlings. The gibberellin level in the seeds was raised, in increasing order, by treatment of the parent plant with 100 mg/1 GA₃, transfer from long to short days, 10 mg/1 GA₃, and 5000 mg/l CCC. It is suggested that the effect of day length on plant performance is mediated by the level of growth regelating substances within the plant and that the behaviour of seeds can be modified by the parental environment via the accumulation of different levels of certain growth factors in the seeds. A rise of one growth substance in the parent plant can result in the accumulation of a different one in the seeds.     

Influence of Boron and Drought Simulation on Germinability and Hardseededness of Black Medick Seeds (Medicago lupulina L.)

This study deals with the determination of germinability of black medick (Medicago lupulina L.) seeds in conditions of different drought intensity induced by different concentrations of PEG 8000 solutions (0.2; 0.4; 0.6 mol). Four batches of seed were tested (Ekola 2–5). At the same time, the influence of boron, some other elements (N, P, K, Ca, Mg, Zn, Cu, Mn) and compounds (starch, lipids and sugars) contents in black medick seeds on their germinability (percentages of germinated, dead and hard seeds) was evaluated. The effect of drought was manifested by germination which was reduced max. by 8% as compared with the control variant and was only partially significant. Statistically significant (P?<?0.01) negative correlations (R?=?? 0.64) were recorded between germinability and the boron content in the seeds, and positive correlations were found between the percentages of hard seeds and the boron content in the seeds. The results show that the higher content of boron in the seeds of black medick increases the proportion of hard seeds at the expense of the germinated seeds percentages.

     

Germination of seeds ofLemna gibba

Germination ofLemna gibba L. seeds originating from two climatically different regions of Czechoslovakia: (1) South Bohemia, Jordán fishpond: (2) South Moravia, Nesyt fishpond, was examined under both laboratory and field conditions. The influence of water temperature on the rate of germination and the influence of different storage conditions on germination were assessed during 1972–1974. During the first year after ripening, all experimental treatments (i. e. germination at different water temperatures; storage in refrigerator and hibernation in the fishpond prior to germination) except the variant in which the seeds were kept in drought, resulted in roughly 100% germination. The rate of germination increased with increasing water temperature. The seeds lost their germination ability approximately after two years.