Growth and Development of Radish (Raphanus sativus, L.) Under Selected Light Environments

Plants of radish (Raphanus sativus L.) were grown under selectedlight conditions in controlled environmental chambers in orderto monitor the role of photoperiod, irradiance level and inputlight energy in plant development. Results indicated that thedaily input of light energy was the most important light factoraffecting leaf development while photoperiod and irradiancelevel had the major influences on storage organ development.Distribution of assimilates to leaves and storage organs variedunder different light regimes with long photoperiods and highirradiances producing the largest storage organs. Once initiated,the rate of storage organ growth was similar under all testedlight environments. Raphanus sativus L., radish, growth, development, light, photoperiod, assimilate distribution, storage organ     

The Effect of Atmospheric Carbon Dioxide Elevation on Plant Growth in Freshwater Ecosystems

We developed a dynamic model to investigate the effect of atmospheric carbon dioxide (CO₂) increase on plant growth in freshwater ecosystems. Steady-state simulations were performed to analyze the response of phytoplankton and submerged macrophytes to atmospheric CO₂ elevation from 350 to 700 ppm. We studied various conditions that may affect this response, such as alkalinity, the air–water exchange rate of CO₂, the community respiration rate, and the phosphorus (P) supply rate. The increase in atmospheric CO₂ could affect submerged plant growth only under relatively eutrophic conditions and at a low community respiration rate. Alkalinity had little effect on the response of the different species. When the air–water exchange was low, the proportional effect of the CO₂ increase on plant growth was higher. Under eutrophic conditions, algae and macrophytes using CO₂ and HCO₃^– may double their growth rate due to atmospheric CO₂ elevation, while the growth of macrophytes restricted to CO₂ assimilation may be threefold. The differences in response of the species under various conditions indicate that the elevation of atmospheric CO₂ may induce drastic changes in the productivity and species dominance in freshwater systems.     

萝卜总RNA提取与mRNA差异显示技术

以萝卜幼小花药与叶片为材料,初步建立了mRNA差异显示技术体系.4种提取总RNA方法中,改进的SDS/酸酚法比CTAB/酸酚法和SDS/碱酚法更合适;改进的热硼酸法(HB)提取的RNA质量也较高,但所需时间较长,成本较高.以改进的SDS/酸酚法获得的RNA进行纯化后,其OD260/OD280在2.0～2.2之间,表明RNA样品杂质较少;总RNA进行反转录与差异显示分析表明,高分辨力的cDNA片段在100～380 bp之间.     

萝卜品种指纹图谱SRAP与AFLP分析

应用SRAP与AFLP两种分子标记技术进行了萝卜品种鉴定分析。对萝卜基因组DNA的SRAP-PCR反应体系中引物、Mg2 、dNTPs浓度进行优化,确定最优体系为引物0.3μmol.L-1,dNTP 0.2 mmo.lL-1,Mg2 3.0 mmo.lL-1。对SRAP-PCR中的退火温度(50℃)设置了12个梯度处理,以em2-me2为引物时带型无明显差异。7个供试萝卜材料的SRAP和AFLP指纹图谱分析表明,供试材料均可被SRAP和14个AFLP引物准确鉴定,每对引物组合都产生独特的指纹图谱。11个SRAP引物组合共产生155条带,多态性条带84条。聚类分析与相对遗传距离(GD)表明,供试材料聚为4类,CB-03-2与SHCB-02-1亲缘关系最近(GD=0.054 9);齐虹大连和Heiseng的亲缘关系最远(GD=0.203 4)。基于16个AFLP标记引物组合分析结果表明,供试材料聚为3类,CB-03-2和SHCB-02-1的亲缘关系最近。SRAP与AFLP综合分析结果表明,供试材料可聚为3类,其中CB-03-2与SHCB-02-1亲缘关系最近(GD=0.047 6)。     

萝卜品种指纹图谱SRAP与AFLP分析

应用SRAP与AFLP两种分子标记技术进行了萝卜品种鉴定分析。对萝卜基因组DNA的SRAP-PCR反应体系中引物、Mg²⁺、dNTPs浓度进行优化,确定最优体系为引物0.3 μmol·L^-1,dNTP 0.2 mmol·L^-1,Mg²⁺ 3.0 mmol·L^-1。对SRAP-PCR中的退火温度（50℃）设置了12个梯度处理,以em2-me2为引物时带型无明显差异。7个供试萝卜材料的SRAP和AFLP指纹图谱分析表明,供试材料均可被SRAP和14个AFLP引物准确鉴定,每对引物组合都产生独特的指纹图谱。11个SRAP引物组合共产生155条带,多态性条带84条。聚类分析与相对遗传距离（GD）表明,供试材料聚为4类,CB-03-2与SHCB-02-1亲缘关系最近(GD=0.054 9);齐虹大连和Heiseng的亲缘关系最远(GD=0.203 4)。基于16个AFLP标记引物组合分析结果表明,供试材料聚为3类, CB-03-2和SHCB-02-1的亲缘关系最近。SRAP与AFLP综合分析结果表明,供试材料可聚为3类,其中CB-03-2与SHCB-02-1亲缘关系最近(GD=0.047 6)。     

Arabinogalactan-Proteins from Primary and Mature Roots of Radish (Raphanus sativus L.)

Organ-specific variations in blood group H-like activity were observed in developing radish plants. A temporary increase in serological activity was found to occur in the roots at the earlier stages of development. Arabinogalactan-proteins (AGPs) were isolated from primary and mature roots, and investigated for changes in their physicochemical properties, structure, and serological activities. These root AGPs were composed mainly of l-arabinose and d-galactose but were distinguishable from each other in their contents of l-fucose as well as of protein and hydroxyproline. The structures of the carbohydrate moieties of the root AGPs were essentially similar to those of AGPs isolated from seeds and mature leaves in that they consisted of consecutive (1→3)-linked β-d-galactosyl backbone chains having side chains of (1→6)-linked β-d-galactosyl residues, to which α-l-arabinofuranosyl residues were attached in the outer regions. One prominent feature of the primary root AGPs was that they contained appreciable amounts of l-fucose, which was presumably responsible for expression of the serological activity. In their immunological reactions with rabbit anti-radish leaf AGP antibody, the root AGPs were shown to share common antigenic determinant(s) with those of seed and leaf AGPs.     

Anaerobic Accumulation of gamma-Aminobutyric Acid and Alanine in Radish Leaves (Raphanus sativus, L.)

In leaves, the anaerobic accumulation of alanine was accompanied by a loss of aspartate, and these changes preceded γ-aminobutyrate accumulation and glutamate loss. Changes in keto acid content did not appear to be the cause of amino acid changes. Accumulation of γ-aminobutyrate was due to acceleration of glutamate decarboxylation and arrest of γ-aminobutyrate transamination. Changes in enzyme content did not explain the changes in reaction rates in vivo. Most of the aspartate may be converted anaerobically to alanine via oxalacetate and pyruvate.     

Storage Organ Development in Radish (Raphanus sativus L.). 2. Effects of Growth Promoters on Cambial Activity in Cultured Roots, Decapitated Seedlings and Intact Plants

The radish varieties Cherry Belle and Long White Icicle wereused to investigate the role of the shoot and the effects ofsynthetic growth promoters in controlling cambial activity inthe seedling axis. Development was compared in excised roots, roots with hypocotylsattached and intact seedlings cultured aseptically on a nutrientmedium. No cambial divisions were seen in isolated radicleswhich had been cultured for ten days following excision butretention of hypocotyl tissue or the entire shoot resulted incambial activity and the production of secondary vascular tissues.Enriching the culture medium by raising the sucrose conantrationto 8% and including 10^–5 M indol-3yl acetic acid (IAA)5 x 10^–6 M 6-benzylaminopurine (BA) and 5 x 10^–4Minositol enhanced root thickening, increasing stele and xylemdiameters in roots cultured both with and without attached shoottissues. The effects of shoot tissues and enrichment of themedium were additive. The effects of auxin, cytokinin and gibberellin (gibberellicacid, GA²) were also studied on daxpitated seedlings. BA wasmuch more effective in inducing cell divisions in the hypocotylthan either IAA or GA supplied separately but a mixture of IAA+GAalso produced clearly defined arcs of cambial tissue. Littlesecondary tissue had been produced after seven days' treatment,and stelar enlargement was due to the development of a cambialzone and cell expansion in the primary tissues. Only minor differencesin response were observed between the two varieties. No stimulation of storage organ development occurred when auxin,cytokinin or inositol was inwrporated into the inorganic culturesolution in which plants of Cherry Belle were grown. Rnphanus sarivus, radish, storage organ, cambial activity, growth promoters, indol-3-ylacetic acid, 6-benzylaminopurine, gibberellic acid     

Effects of Light, Carbon Dioxide, and Temperature on Photosynthesis, Oxygen Inhibition of Photosynthesis, and Transpiration in Solanum tuberosum

Individual leaves of potato (Solanum tuberosum L. W729R), a C₃ plant, were subjected to various irradiances (400-700 nm), CO₂ levels, and temperatures in a controlled-environment chamber. As irradiance increased, stomatal and mesophyll resistance exerted a strong and some-what paralleled regulation of photosynthesis as both showed a similar decrease reaching a minimum at about 85 neinsteins·cm⁻²·sec⁻¹ (about ½ of full sunlight). Also, there was a proportional hyperbolic increase in transpiration and photosynthesis with increasing irradiance up to 85 neinsteins·cm⁻²·sec⁻¹. These results contrast with many C₃ plants that have a near full opening of stomata at much less light than is required for saturation of photosynthesis.     

Inheritance and Molecular Marker for Flowering Time in Radish (Raphanus sativus L.)

Plant Molecular Biology Reporter - The mixed inheritance model involving major genes and polygenes was used to analyze the inheritance of radish flowering time trait in the B1, B2, F1, and F2...     

Influence of Carbon Dioxide Concentration on Growth, Carbohydrate Content, Translocation and Photosynthesis of White Clover

White clover ramets were grown at various carbon dioxide concentrations(200, 350 and 1000 µl 1^–1), defoliated and regrownat the same concentrations. Morphological characteristics, dryweights and non-structural carbohydrate contents of plant organs,diurnal variation of sugar and starch content of leaves, translocationof assimilates and photosynthesis were determined. Carbon dioxide concentration influenced the dry weights, butnot the number and size of the plant organs. However, defoliationof plants at low carbon dioxide concentration resulted in decreasedleaf size and stolon length. Carbon dioxide concentration influencedthe content and diurnal variation of starch and sugar in theleaves. Starch was accumulated at medium carbon dioxide concentrationand sugar at a higher concentration when the storage capacityfor starch seemed to be exceeded. Starch was preferentiallyaccumulated in the first and sugar in the second half of thelight period. Translocation was decreased during the periodsof accumulation. Sugar accumulation in the leaves seemed tobe a consequence of the imbalance between sink and source, whereasstarch accumulation seemed to follow an in-built diurnal pattern.Accumulation of both starch and sugar during the photoperiodwas followed by degradation and export during the dark period.Decreased dark export occurred at low carbon dioxide concentrationwhen neither starch nor sugar was accumulated during the photoperiod. Carbon dioxide, white clover, Trifolium repens L., growth, carbohydrates, starch, sugar, translocation, photosynthesis     

春萝卜抽薹过程中内源激素含量变化分析

采用酶联免疫吸附法(ELISA)测定了春萝卜抽薹过程中顶端生长点处嫩叶的赤霉素(GA₄)、生长素(IAA)、细胞分裂素(iPA)和脱落酸(ABA)等含量的变化情况。研究结果表明,在萝卜抽薹过程中,GA₄含量在现蕾点存在明显的峰值,表明GA₄与现蕾抽薹密切相关,起着主导作用;内源ABA含量变化与GA₄变化趋势基本一致;与GA₄和ABA含量相比,抽薹过程中叶片IAA含量相对较低;iPA含量在现蕾期逐步增加,至抽薹中后期出现一高峰值。研究发现iPA/ABA值增大,GA₄/iPA和GA₄/IAA值变小有利于花芽分化后萝卜植株抽薹开花,表明内源激素之间的平衡对萝卜抽薹开花也起着重要作用。     

On Photosynthesis and Organic Carbon, Carbon Dioxide, and Oxygen Flows in the Ocean

The modern concept of photosynthesis as a mechanism for utilizing the energy of solar radiation is used as the basis for assessing the scale of photosynthetic production of initial organic matter in the ocean (primary biological production), its destruction, the carbon and carbon dioxide cycles (flows) involved in this process, and the size of oil- and gas-bearing hydrocarbonaceous formations originating in sedimentary deposits.     

The Interactive Effects of Atmospheric Carbon Dioxide and Light on Stem Elongation in Seedlings of Four Species

Four species,Sinapis albaL.,Medicago sativaL.,Gypsophila paniculataL.andPicea abies(L.) Karsten, were grown in three light regimes:darkness, low light (25 µmol m^-2s^-1for 10 min d^-1) andhigh light (120 µmol m^-2s^-1for 12 h  d^-1) and fourlevels of carbon dioxide: 0, 350, 700 and 1400±50 µll^-1. Germination was not affected by any of the treatments.The effects of carbon dioxide on stem elongation were identicalin low and high light: stem length increased at a decreasingrate with level of carbon dioxide in all species. Level of carbondioxide also affected stem elongation in complete darkness,but the pattern was more complex and varied among species. Totalweight did not vary with level of carbon dioxide to any significantextent in either darkness or low light, but increased with levelof carbon dioxide at high light in all four species. Due tothe absence of any effect of carbon dioxide on growth in darknessand low light, we suggest the effects of carbon dioxide on stemelongation are independent of effects on growth and may be dueto a direct interaction with developmental processes. In contrast,level of carbon dioxide had little effect on allocation patternsin the dark and low light experiments, but had marked effectsin high light. Therefore, the effect of carbon dioxide on allocationwas probably due to the effects of carbon dioxide on growthrather than to any direct interaction between carbon dioxideand development. An understanding of the mechanisms by whichcarbon dioxide affects development may help us understand theoften variable effects of carbon dioxide upon plants.Copyright1998 Annals of Botany Company Sinapis albaL.;Medicago sativaL.;Gypsophila paniculataL. andPicea abies(L.) Karsten; elevated carbon dioxide; stem elongation; germination; allocation; phytochrome.     

Effect of Azacytidine on the Expression of Traits Concomitant with in Vitro Tumor Formation in Radish Raphanus sativus

The effect of azacytidine, a demethylating agent, on the expression of traits concomitant with tumor formation was studied in inbred radish (Rhaphanus sativus) lines carrying genomic sequences homologous to thetmr/tml genes of Agrobacteriium tumefaciens. AzaC was found to have no effect on the traits studied, which provided evidence that the capacity for tumor formation in radish lines does not depend on the level of methylation of these sequences.     

Effects of ethylene on tuberization in radish (Raphanus sativus)

The effects of ethylene on the elongation of radish hypocotyls and on dry matter partitioning between tubers and shoots were analysed in order to gain insight into the possible role of ethylene in the regulation of tuberization. Treatment of very young seedlings with ethylene results in heavier tubers (Vreugdenhil et al. 1984). Here we report that addition of ethylene or ethephon two days after germination inhibited the elongation of the hypocotyl; trapping of endogenously produced ethylene had a stimulative effect on elongation. Ethephon, sprayed at a later stage, changed the partitioning of assimilates between tubers and shoots, resulting in lower tuber weights. It is concluded that ethylene had a dual effect on tuberization in radish: at a very early stage of development it inhibited elongation of the hypocotyl, resulting in earlier tuber formation and heavier tubers. At a later stage, it had a negative effect on tuber weight by changing dry matter partitioning.     

Growth of radish (Raphanus sativus) seedlings in magnetic fields

Radish seedlings were grown in asymmetric magnetic fields. The number of seeds germinated and the dry weight of the plants were the two criteria by which possible effects were examined. Two experiments were done; in the first the plants were grown for an average of 7.7 days and in the second for 14.1 days. A statistical analysis of the results failed to reveal any significant difference between control plants grown in dummy magnets and those subjected to the magnetic influence.