The regulatory role of the RUS family in plant growth and development / 生物工程学报

The chloroplast genome encodes many key proteins involved in photosynthesis and other metabolic processes, and metabolites synthesized in chloroplasts are essential for normal plant growth and development. Root-UVB (ultraviolet radiation B)-sensitive (RUS) family proteins composed of highly conserved DUF647 domain belong to chloroplast proteins. They play an important role in the regulation of various life activities such as plant morphogenesis, material transport and energy metabolism. This article summarizes the recent advances of the RUS family proteins in the growth and development of plants such as embryonic development, photomorphological construction, VB6 homeostasis, auxin transport and anther development, with the aim to facilitate further study of its molecular regulation mechanism in plant growth and development.

Analysis of differential genes and metabolic pathway related to functional male sterility in eggplant / 生物工程学报

Based on observing the cytological characteristics of the flower buds of the functional male sterile line (S13) and the fertile line (F142) in eggplant, it was found that the disintegration period of the annular cell clusters in S13 anther was 2 days later than that of F142, and the cells of stomiun tissue and tapetum in F142 disintegrated on the blooming day, while it did not happen in S13. The comparative transcriptomic analysis showed that there were 1 436 differential expression genes (DEGs) (651 up-regulated and 785 down-regulated) in anthers of F142 and S13 at 8, 5 days before flowering and flowering day. The significance analysis of GO enrichment indicated that there were more unigene clusters involved in single cell biological process, metabolism process and cell process, and more catalytic activity and binding function were involved in molecular functions. Through KEGG annotation we found that the common DEGs were mainly enriched in the biosynthesis of secondary metabolites, metabolic pathway, protein processing in endoplasmic reticulum, biosynthesis of amino acids, carbon metabolism and plant hormone signal transduction. The fifteen genes co-expression modules were identified from 16 465 selected genes by weighted gene co-expression network analysis (WGCNA), three of which (Plum2, Royalblue and Bisque4 modules) were highly related to S13 during flower development. KEGG enrichment showed that the specific modules could be enriched in phenylpropanoid biosynthesis, photosynthesis, porphyrin and chlorophyll metabolism, α-linolenic acid metabolism, polysaccharide biosynthesis and metabolism, fatty acid degradation and the mutual transformation of pentose and glucuronic acid. These genes might play important roles during flower development of S13. It provided a reference for further study on the mechanism of anther dehiscence in eggplant.

The Effect of Temperature and Growth Regulators on Callus Induction in Watermelon Anthers

HIGHLIGHTS Callogenesis was induced from watermelon anthers The auxin 2,4-D at 2.0 and 5.0 μM concentrations induced callus formation. Anthers' responses to the pre-treatment at 4 °C varied according to the watermelon genotype.

Abstract Callus induction is one of the pathways required for haploid plant regeneration through anther culture. Pollen viability, as well as the effect of growth regulators and cold pretreatment on anthers of two watermelon lines (Smile and Sugar Baby) to induce callus formation were herein evaluated. Pollen viability was estimated through the staining technique using 2% acetic carmine. Male flower buds were collected and disinfested to allow removal anthers. These anthers were placed on Murashige and Skoog medium, which was supplemented with 2,4-dichlorophenoxyacetic (2,4-D) at 0.0, 0.5, 1.0, 2.0 or 5.0 μM or with 6-benzylaminopurine at 0.0, 0.5, 1.0, 1.5, or 2.0 μM, in combination with 2.0 μM of 2,4-dichlorophenoxyacetic. Anthers were pretreated at 4 °C, for two days and then placed in vitro. Both watermelon lines provided high pollen viability rates (from 93 to 98%). The 2.0 and 5.0 μM concentrations of 2,4-D stimulated higher friable callus formation. The optimal concentration of 2,4-D was estimated at 3.78 μM and 4.17 μM, which had callus induction rates of 64% and 52%, respectively. The combination of 2.0 μM of 2,4-D and 6-benzylaminopurine did not lead to increased anther response to callus induction. The pre-treatment applied to flower buds at 4 °C enabled callus induction and the anther response to callus induction was genotype-dependent.

Improvement of anther cultures conditions using the Taguchi method in three cereal crops

Background: Plant tissue cultures have the potential to reprogram the development of microspores from normal gametophytic to sporophytic pathway resulting in the formation of androgenic embryos. The efficiency of this process depends on the genotype, media composition and external conditions. However, this process frequently results in the regeneration of albino instead of green plants. Successful regeneration of green plants is affected by the concentration of copper sulfate (CuSO4) and silver nitrate (AgNO3) and the length of induction step. In this study, we aimed at concurrent optimization of these three factors in barley (Hordeum vulgare L.), wheat (Triticum aestivum L.), and triticale (x Triticosecale spp. Wittmack ex A. Camus 1927) using the Taguchi method. We evaluated uniform donor plants under varying experimental conditions of in vitro anther culture using the Taguchi approach, and verified the optimized conditions. Results: Optimization of the regeneration conditions resulted in an increase in the number of green regenerants compared with the control. Statistic Taguchi method for optimization of the in vitro tissue culture plant regeneration via anther cultures allowed reduction of the number of experimental designs from 27 needed if full factorial analysis is used to 9. With the increase in the number of green regenerants, the number of spontaneous doubled haploids decreased. Moreover, in barley and triticale, the number of albino regenerants was reduced. Conclusion: The statistic Taguchi approach could be successfully used for various factors (here components of induction media, time of incubation on induction media) at a one time, that may impact on cereals anther cultures to improve the regeneration efficiency

Regulation of plant MYB transcription factors in anther development / 生物工程学报

MYB transcription factor is one of the largest transcription families and involved in plant growth and development, stress response, product metabolism and other processes. It regulates the development of plant flowers, especially anther development, a key role in the reproduction of plant progeny. Here, we discuss the regulatory effects of MYB transcription factors on the development of anther, including tapetum development, anther dehiscence, pollen development, carbohydrates and hormone pathways. We provide a reference for the further study of the regulation mechanism and network of plant anther development.

Exploring factors affecting anther culture in rice (Oryza sativa L.)

Anther culture is an important in vitro culture technique for the production of double haploids. It is largely speciesand genotype specific. Asian-cultivated rice (Oryza sativa, ssp. indica) is recalcitrant to anther culture which limits itspractical application in rice breeding. Several researchers tried to optimize the medium recipes and culture techniquesfor callus induction and plantlet regeneration. Negligible response to callus induction and recovery of a higherfrequency of albino plants are the major hindrance for the use of the technique in crop improvement. Shortening theculture period and sexual hybridization of rice subgroups (japonica/indica) may be adopted to improve green plantregeneration from anther-derived callus in indica rice. However, genetic transformation technology using individualgenes related to different aspects of anther culture could be a more direct approach. Besides, the role of genotypes,physiological status of donor plant, developmental stage of pollen, pre-treatment, culture media, phytohormones, andculture conditions for successful anther culture have been discussed.

High species richness of native pollinators in Brazilian tomato crops / Alta riqueza de espécies de polinizadores nativos em plantações Brasileiras de tomateiro

Abstract Pollinators provide an essential service to natural ecosystems and agriculture. In tomatoes flowers, anthers are poricidal, pollen may drop from their pore when flowers are shaken by the wind. However, bees that vibrate these anthers increase pollen load on the stigma and in fruit production. The present study aimed to identify the pollinator richness of tomato flowers and investigate their morphological and functional traits related to the plant-pollinator interaction in plantations of Central Brazil. The time of anthesis, flower duration, and the number and viability of pollen grains and ovules were recorded. Floral visitors were observed and collected. Flower buds opened around 6h30 and closed around 18h00. They reopened on the following day at the same time in the morning, lasting on average 48 hours. The highest pollen availability occurred during the first hours of anthesis. Afterwards, the number of pollen grains declined, especially between 10h00 to 12h00, which is consistent with the pollinator visitation pattern. Forty bee species were found in the tomato fields, 30 of which were considered pollinators. We found that during the flowering period, plants offered an enormous amount of pollen to their visitors. These may explain the high richness and amount of bees that visit the tomato flowers in the study areas. The period of pollen availability and depletion throughout the day overlapped with the bees foraging period, suggesting that bees are highly effective in removing pollen grains from anthers. Many of these grains probably land on the stigma of the same flower, leading to self-pollination and subsequent fruit development. Native bees (Exomalopsis spp.) are effective pollinators of tomato flowers and are likely to contribute to increasing crop productivity. On the other hand, here tomato flowers offer large amounts of pollen resource to a high richness and amount of bees, showing a strong plant-pollinator interaction in the study agroecosystem.

Resumo Polinizadores fornecer um serviço essencial para os ecossistemas naturais e para agricultura. Em tomateiros, as anteras são poricidas e o pólen pode sair a partir dos poros quando as flores são agitadas pelo vento. No entanto, as abelhas que vibram as anteras aumentam a carga de pólen no estigma e na produção de frutos. O presente estudo teve como objetivo identificar a riqueza dos polinizadores das flores de tomate e investigar suas características morfológicas e funcionais relacionadas com a interação planta-polinizador em plantações do Brasil central. Foram registrados o tempo de antese, duração flor, bem como o número e viabilidade de grãos de pólen e óvulos. Os visitantes florais foram observados e coletados. Os botões florais abriram-se em torno 06h30 e fechou em torno de 18h00. As flores reabrem no dia seguinte ao mesmo tempo na parte da manhã, com longevidade média de 48 horas. A maior disponibilidade de pólen ocorreu durante as primeiras horas da antese. Depois disso, o número de grãos de pólen diminuiu, especialmente entre as 10h00 às 12h00, o que é consistente com os padrões de visitação de polinizadores. Quarenta espécies de abelhas foram encontradas nos campos de tomate, 30 das quais foram consideradas polinizadores. Durante o período de floração, as plantas oferecem enorme quantidade de pólen para os seus visitantes. Isto pode explicar a alta riqueza e quantidade de abelhas que visitam as flores de tomate nas áreas de estudo. O período de disponibilidade e redução de pólen durante todo o período do dia é sobreposto com o período de alimentação das abelhas, o que sugere que elas são altamente eficazes na remoção de grãos de pólen das anteras. Muitos desses grãos provavelmente são depositados no estigma da mesma flor, levando à auto-polinização e o desenvolvimento de frutos. Abelhas nativas (Exomalopsis spp.) são polinizadores efetivos de flores de tomate, podendo contribuir para o aumento da produtividade das culturas. Por outro lado, as flores de tomate oferecem grandes quantidades de pólen de recursos para uma alta riqueza e quantidade de abelhas, que mostram um estudo forte interação planta-polinizador nos agroecossistemas.

Study on effect elements of anthers opening-closing movement and its cell morphology regulatory mechanism of Paris polyphylla var. yunnanensis / 中国中药杂志

In order to study the effect elements of anthers opening-closing movement of Paris polyphylla var. yunnanensis, and its cell morphology regulatory mechanism. Anthers daily opening in the morning and closing in the evening and its corresponding ecological elements changes were recorded. Different light, temperature, humidity experiment and artificial rainfall experiment were designed to observe the effect on anthers opening-closing movement, paraffin sections were made to observe the cell morphology change when the anthers daily opening and closing. The result showed that the movement of anthers daily opening and closing was regulated by ecological elements. The overall trend was high temperature and strong light, low humidity was favorable for anther opening, and low temperature, weak light, high humidity was favorable for anther closing. In this experiment, the effect of these ecological elements on the movement of anthers opening from strong to weak was humidity, temperature, light. The effect of these ecological elements on the movement of anthers closing from strong to weak was light, humidity, temperature. The direct contact of the raindrops causes the rapid closing of the anthers in the rain. Observing the cell morphology change when anthers opening and closing, it was a pollen sac dehydration and water-absorption process, different light, temperature and humidity conditions induce different physiological activities in the cell, which caused the cell osmotic pressure change, eventually resulting in anther opening and closing movement. But anthers closing caused by the rain was a simple physical adjustment process, the raindrops fell on the anthers directly, which caused anthers soaked water and change of the cell osmotic pressure, then resulting in anther closing.

In vitro pollen germination and anther culture of Senna obtusifolia / 中草药

Objective: To observe the morphology, measure the activity of pollen of Senna obtusifolia, determine the optimum conditions for pollen germination, induce the formation of callus from its anthers as well as identify its ploidy levels, and thus to lay a basis for its haploid breeding. Methods: Microscopic observation of the anther squashed method was used to reveal the morphology of pollen; The pollen activity was investigated using I2-KI staining and the size of the flower buds with the highest pollen activity was determined; Liquid culture and microscopic observation were performed to determine the optimum culture medium, pH value, and temperature for pollen germination; Microscopic observation of the acetocarmine-stained pollen was performed to determine microspore development stages; The optimum conditions for callus formation were studied by in vitro anther culture; The phenol fuchsin staining was improved for the identification of callus ploidy levels. Results: Pollen of S. obtusifolia is ellipsoid with three germinal furrows, and mostly two germination holes showed germination; The highest pollen activity was found in buds with vertical diameters about 1.0-1.1 cm; The optimum culture medium for pollen germination was determined to be 10% sucrose + 1% boric acid, with maximum germination cultured for 1-3 h at 25 ℃; The uni-nucleate microspore stage was in buds with vertical diameters about 0.9-1.1 cm; Calluses were successfully obtained by culturing the uni-nucleate stage anthers in an inducing medium MS + 1.0 mg/L 6-BA + 2.0 mg/L NAA + 3% sucrose + 0.6% agar and callus enrichment culture was done in MS + 1.0 mg/L 6-BA + 1.0 mg/L IAA + 1.0 mg/L 2,4-D + 1.0 mg/LGA3 + 3% sucrose; There was ploidy separation in callus, with the haploid and diploid cells coexisted. Conclusion: The optimum culture medium for pollen germination is 10% sucrose + 1% boric acid; The optimum anthers for in vitro culture is within flower buds with a vertical diameter of 0.9-1.1 cm; The chimeric calluses obtained from anthers of S. obtusifolia lay a solid foundation for the further induction of haploid plants from its pollen for breeding.

Global proteomic and phosphoproteomic analysis of the premature maize anther / 生物工程学报

Reversible phosphorylation plays a crucial role in regulating protein activities and functions. Sexual reproduction directly affects yield of most agricultural crops. As the male reproductive organ, anther generates microspores (pollen), delivering gametes (sperms) to complete double fertilization in higher plants. Here, we took the advantage of Nano UHPLC-MS/MS to analyze maize (Zea mays, B73) early anthers at proteomic and phosphoproteomic levels, to explore the protein and phosphorylation modification regulatory networks controlling maize anther development. Our proteomic analysis identified 3 016 unique peptides, belonging to 1 032 maize proteins. MapMan analysis revealed variously potential proteins associated with maize anther development, such as receptor-like kinases (GRMZM2G082823_P01 and GRMZM5G805485_P01). Using phospho-peptides enriched by TiO2 affinity chromatography, our phosphoproteomic analysis detected 257 phospho-peptides from 210 phosphoproteins, discovering 223 phosphosites. Compared to the 86 maize phosphoproteins collected in the Plant Protein Phosphorylation Data Base (P3DB), we found that 203 phosphoproteins and 218 phosphosites were not revealed before. Further bioinformatics analysis revealed that phosphorylation of 14-3-3 proteins, kinases, phosphatases, transcription factors, cell cycle and chromatin structure related proteins might play important roles in regulating normal anther development in maize. Our findings not only enlarged the maize phosphoproteome data, but also provided information for analyzing the molecular mechanism controlling maize anther development at genetic and biochemical levels.

Androgenesis in chickpea: Anther culture and expressed sequence tags derived annotation.

Double haploid technique is not routinely used in legume breeding programs, though recent publications report haploid plants via anther culture in chickpea (Cicer arietinum L.). The focus of this study was to develop an efficient and reproducible protocol for the production of double haploids with the application of multiple stress pre-treatments such as centrifugation and osmotic shock for genotypes of interest in chickpea for their direct use in breeding programs. Four genotypes, ICC 4958, WR315, ICCV 95423 and Arearti were tested for anther culture experiments. The yield was shown to be consistent with 3-5 nucleate microspores and 2-7 celled structures with no further growth. To gain a further insight into the molecular mechanism underlying the switch from microsporogenesis to androgenesis, bioinformatics tools were employed. The challenges on the roles of such genes were reviewed while an attempt was made to find putative candidates for androgenesis using Expressed Sequenced Tags (EST) and interolog based protein interaction analyses.

Molecular cloning and mRNA expression profile of Sucrose Transporter Gene BnSUT1C from Brassica napus L.

The genomic and cDNA sequences of BnSUT1C were isolated from B. napus. Combination of cDNA and genomic DNA sequences revealed that the BnSUT1C gene contained three exons and two introns. The cDNA encodes a protein of 513 amino acids with a calculated molecular mass of 54.7 kDa and an isoelectric point of 9.12. It exhibits typical features of sucrose transporter with 12 trans-membranes spanning domains. BnSUT1C showed highly homologous with AtSUC1 and AtSUC5. A histidine residue, which is conserved across all functional sucrose transporter proteins in higher plants, is located at position 66 of the BnSUT1C. Two putative pollen-specific cis-elements, AGAAA and GTGA motifs, are located in 5′-upstream of BnSUT1C. The spatial and temporal expression patterns carried out by semi-quantitative RT-PCR and Real-Time PCR, which indicated that BnSUT1C predominantly expressed in later developmental stages of anther, as tapetal cells began to shrink and collapse. BnSUT1C could mediate the uptake of sucrose in the pollen and retrieval of tapetal degenerated products during pollen maturation.

Rates and pattern of ovule abortion vis-à-vis in situ pollen germination in some populations of Trifolium fragiferum L.

The present study is based on four populations of Trifolium fragiferum L. of the family Fabaceae growing at four different sites in Jammu region, India. The species, which grows as a common weed in the area of study, follows an annual life cycle of about 3½month in the subtropical climates of Jammu region. While all of these populations were recorded in full bloom during February and March, they displayed a temporal scatter. Detailed studies revealed these population types to be morphologically similar but distinct in the many aspects studied. An interesting phenomenon noted for the plants of this species was in situ pollen germination, which was recorded in about 28.8% of the flowers studied. The species under investigation also showed an appreciable amount of ovule abortion. The ovule abortion in pistils was found to be non-random, with the peduncular ovule aborting at a higher rate than the stylar one. The rates and patterns of ovule abortion were studied vis-à-vis in situ pollen germination and were compared between different populations. Interesting results were obtained, indicative of the fact that precocious pollen germination does affect the ovule abortion in one way or other.

Nuevos genotipos de arroz resistentes a la Piriculariosis obtenidos por cultivo de anteras / New blast resistant rice genotypes obtained by and anthers culture

En la Estación Experimental del Arroz Los Palacios, perteneciente al Instituto Nacional de Ciencias Agrícolas de Cuba (INCA), se efectuaron cruzamientos entre cuatro cultivares resistentes a la Piriculariosis y seis de buen comportamiento agronómico y las anteras de las plantas F2 fueron cultivadas in vitro para evaluar la formación de callos en tres medios líquidos: N6-1, N6-m y NL, así como la regeneración de plantas verdes y albinas, en el medio MS. Las dos primeras generaciones de las nuevas líneas obtenidas fueron evaluadas para caracteres agronómicos y la segunda generación, además, para resistencia frente a la Piriculariosis. Las líneas que combinaron resistencia a la Piriculariosis y buenos caracteres agronómicos fueron evaluadas en condiciones de infección natural, con alta presión del patógeno. La utilización de la técnica del cultivo de anteras mostró alta dependencia del genotipo y el medio de cultivo. Con el medio NL se lograron los valores más altos para la formación de callos. Se obtuvieron nuevos genotipos resistentes a la Piriculariosis y de alto rendimiento agrícola.

Crosses were made between four blast resistant and six rice varieties of good agronomic performance, at the Los Palacios Rice Research Station of the National Agricultural Sciences Institute of Cuba (INCA) and the anthers from F2 plants were in vitro culture using three liquid media: N6-1, N6m, and NL, for callus formation and after plants regenerations using MS medium. The first two generations of breeding lines were evaluated for agronomic characters and the second generations, also, for Blast resistant. The lines that combined resistance to Blast and good agronomic performance were evaluated under high pressure of natural Blast infection conditions. The success rate of anther culture was highly dependent on the genotype and culture media used. NL medium led to the highest callus formation values. In the process, new blast resistant and high yielding genotypes were obtained.

Desenvolvimento de populações duplo-haplóides de cevada cervejeira associadas à atividade das enzimas (1-3, 1-4)-β-glucanases / Development of doubled-haploids populations in malting barley associated to activity of enzymes (1-3, 1-4)-β-glucanases

Populações duplo-haplóides apresentam especial vantagem para análises genéticas, uma vez que a informação que elas oferecem pode ser maximizada, devido ao fato que todos os locos encontram-se em homozigose. O objetivo deste trabalho foi o desenvolvimento de duas populações duplo-haplóides (DHs) de cevada (Hordeum vulgare ssp. vulgare L.) segregantes para a atividade das enzimas (1-3, 1-4)-β-glucanases, através da técnica de cultura de anteras. Foram realizados dois cruzamentos com cultivares contrastantes para esta característica. As cultivares parentais selecionadas foram 'MN 698' e 'CEV 97047', para o desenvolvimento da população "malte verde" (MV), e 'Embrapa 127' e 'CEV 96025' para o desenvolvimento da população "malte seco" (MS). Foram cultivadas 10.734 anteras da população MS e 4.139 anteras da população MV. A população MV produziu 50 por cento mais plântulas verdes quando comparada à população MS, refletindo a importância do genótipo na resposta à cultura de anteras e na regeneração. A maioria das plantas adultas duplo-haplóides foi obtida através da duplicação espontânea in vitro do genoma haplóide, ocorrendo em 66 por cento das plantas da população MS e 76 por cento das plantas da população MV. Também foram observadas, em menor frequência, plantas haplóides, triplóides e tetraplóides. Através da técnica de cultura de anteras, foram desenvolvidas 204 linhagens duplo-haplóides, das quais 72 linhagens são da população "malte seco" e 132 linhagens são da população "malte verde". Este material constitui um importante germoplasma para o melhoramento genético da cevada.

Doubled haploid populations offer special advantages in genetic analyses, since the information they provide may be maximized due to the fact that all loci are homozygous. The aim of this study was to develop two barley (Hordeum vulgare ssp.vulgare L.) doubled-haploid (DHs) populations segregating to (1-3, 1-4)-β-glucanases activity, utilizing the anther culture protocol. Two crosses were performed with contrasting cultivars to (1-3, 1-4)-β-glucanases activity. Parental cultivars used were 'MN 698' and 'CEV 97047' for the development of 'green malt' population (MV) and Embrapa 127 and 'CEV 96025' for the development of "dry malt" population (MS). For the MS and MV populations, 10,734 and 4,139 anthers were cultured, respectively. MV population produced 50 percent more green seedlings as compared to MS population, which reflects the importance of genotype to the culturing of anthers and to regeneration. Most doubled-haploid adult plants were obtained by in vitro spontaneous duplication of the haploid genome, which occurred in 66 percent of plants from the MS population and 76 percent of plants from the MV population. Haploid, triploid and tetraploid individuals were also observed, though at low frequencies. The anther culture protocol afforded to develop 204 double-haploid lineages, of which 72 were generated by the 'dry malt' population and 132 from the "green malt" population. This material should be considered as important germplasm for barley genetic improvement.

Factors Affecting Embryogenic Callus Production and Plant Regeneration in Anther Culture of Bupleurum chinense / 中草药·英文版

Objective To evaluate the influences of the genotypes,anther developmental stages,and cultural conditions on the efficiency of embryogenic callus induction and plant regeneration in the anthers culture of Bupleurum chinense.Methods The different effects such as four genotypes,plant growth regulators,and temperature condition were compared in the experiments.The histological study was performed with the process of the anther culture.Results The highest inducing rate of embryogenic calli were achieved for the genotypes Zhongcaiyihao(ZCYH),Z4,and Z5 at the early-to middle-uninucleate stages,except for genotype ZPM1 at the tetrad stage.Cold pretreatment increased the production of the embryogenic callus,in which 4-day cold pretreatment improved the production of embryogenic callus from 0% to 2.2% and 5.0% for genotypes ZPM1 and ZCYH,respectively.No embryogenic callus was induced in the medium containing less than 0.75 mg/L 2,4-dichlorophenoxyacetic acid(2,4-D).The highest regeneration rate (34.6%)was obtained in 1/2 MS salts regeneration medium supplemented with 0.1 mg/L 6-benzylmaminopurine (BA).The low concentration of BA was able to promote the embryogenic callus formation and subsequent plantlet regeneration via somatic embryogenesis.Chromosome counting of regenerated plantlets showed mostly diploid plant (2n = 12)with only one haploid plant(n = 6).Because of the low rate of microspore embryo formation,we only tracked the process of embryogenesis from the connective tissue,instead of microspore by histological observations.Conclusion This study establishes an efficient system for embryogenic callus induction and plant regeneration system.This is the first report on the haploid plantlet through the anther culture orB.chinense.

Morphological markers for microspore developmental stage in maize

The use of maize in anther culture has been limited because only few genotypes presented a high androgenetic potential. Obtaining the proper stage of microspore development at culture initiation is one of the most crucial factors for success in the androgenesis. For Brazilian maize genotypes there are no studies reporting a correlation between cytological features and morphological parameters. In this study, morphological parameters were recorded and associated with cytological specific stages of the the microsporogenesis in two Brazilian maize genotypes that were sowed in different places (field and growing chamber). For both genotypes, the plants of the growing chamber presented a delay in development. Spikelets length and anther length/spikelet length ratio are not good parameters since they can be greatly influenced by the environment. The anther length was the more reliable parameter to correlate with a specific developmental stage. Nevertheless, variations between genotypes and environment were detected.

A utilização do milho (Zea mays) na cultura de anteras é limitada devido ao baixo número de genótipos com alto potencial androgenético. A obtenção de micrósporos no estádio de desenvolvimento apropriado no início da cultura é um dos fatores cruciais para o sucesso do processo androgenético. Em genótipos brasileiros de milho não existem estudos relatando a correlação entre características citológicas e parâmetros morfológicos. Neste estudo, parâmetros morfológicos foram avaliados e associados com estádios específicos da microsporogênese em dois genótipos brasileiros de milho os quais foram semeados em diferentes locais (campo e câmara de crescimento). Para ambos os genótipos, as plantas crescidas na câmara de crescimento apresentaram atraso no desenvolvimento. O comprimento da espigueta e a razão comprimento da antera/comprimento da espigueta não são bons parâmetros uma vez que podem ser muito influenciados pelo ambiente. O comprimento da antera foi o melhor parâmetro para indicar o estádio de desenvolvimento do micrósporo. Todavia, variações entre genótipos e ambiente foram detectadas.

Reproductive studies in ipecac (Psychotria ipecacuanha (Brot. ) stockes; Rubiaceae): pollen development and morphology

The aim of this work was to carry out the reproductive studies on Brazilian accessions of ipecac, Psychotria ipecacuanha. It presented heterostyly, with brevistylous and longistylous flowers. The pollen development was observed from the sections of the anthers embedded in resin. Anther development was normal as usually observed in dicotyledones, displaying four layers: outer epidermis, endothecium, middle layer and inner tapetum. The pollen was bicellular and filled with starch at the microspore stage. Pollen morphology was studied using SEM, which showed pollen polymorphism within and between the two floral morphs. Five types of pollen with reticulate or perforate exine were identified. The characteristics showed that the sexual process was as important as the vegetative propagation for the reproduction of this species.

Foram realizados estudos reprodutivos em acessos brasileiros de poaia, Psychotria ipecacuanha. Poaia apresenta heterostilia, com flores brevistilas e longistilas. O desenvolvimento do pólen foi estudado em cortes de anteras embebidas em resina. O desenvolvimento da antera seguiu o padrão normal para as dicotiledôneas, a qual apresentou quatro camadas: epiderme, endotécio, camada média, e tapete, a mais interna. O pólen apresentou-se bicelular e preenchido com amido no estágio de micrósporo. A morfologia do pólen foi estudada utilizando-se MEV. Foi observado polimorfismo polínico dentro e entre as duas formas florais. Foram identificados cinco tipos de grãos de pólen, com exina reticulada ou perfurada. Em seu hábitat natural, sabe-se que essa espécie apresenta propagação por multiplicação vegetativa, mas as características estudadas demonstraram que o mecanismo sexuado é tão importante para a reprodução dessa espécie quanto à propagação vegetativa.

Evaluation of gelling agents on anther culture: response of two soybean cultivars

Anthers of two soybean cultivars were cultured in B5 long basal culture media gelled with agarose or PhytagelTM. Cytological examinations of the anthers were carried out during the first 45 days of culture to assay the viability and developmental stage of microspores. Frequency of callus formation was recorded at 45 days of culture. The analysis of variance of the microspore viability assay showed significant Cultivar X Gelling Agent X Day of Culture interactions. The frequencies of viable microspores decreased significantly with time of culture, within each cultivar and gelling agent tested. The interaction Day X Cultivar was significant for the frequencies of binucleate symmetrical grains and multinucleate/multicellular structures. The effect of gelling agents on the frequency of binucleate symmetrical pollens grains and multinucleate/multicellular structures was not significant. About the frequencies of calli and embryogenic calli formed, a significant difference was detected between the cultivars (IAS5= 14.8 percent and BRS 133=6.6 percent). Gelling agents showed no effect over these frequencies.

Anteras de duas cultivares de soja foram cultivadas em meio de cultura basal B5 longo gelificado com agarose ou Phytagel®. Análises citológicas das anteras foram conduzidas durante os primeiros 45 dias de cultura para avaliar a viabilidade e o estágio de desenvolvimento dos micrósporos. A freqüência de formação de calos foi analisada após 45 dias do início da cultura. A análise da variância da viabilidade do micrósporo mostrou interações significativas de Cultivar X Agente Gelificante X Dias de Cultura. As freqüências de grãos de pólen viáveis diminuíram significativamente com o tempo de cultura, dentro de cada cultivar e agente gelificante testado. A interação Dia X Cultivar foi significante para as freqüências de grãos de pólen binucleados simétricos e estruturas multinucleados/multicelulares. O efeito do agente gelificante na freqüência de grãos de pólen binucleados simétricos e estruturas multinucleados/multicelulares não foi significante. Com relação às freqüências de calos e estruturas embriogênicas formadas, houve diferença significativa entre cultivares (IAS5= 14.8 por cento e BRS 133=6.6 por cento). O agente gelificante não mostrou efeito em tais freqüências.

Abelhas (Apoidea) visitantes de flores de Comolia ovalifolia DC Triana (Melastomataceae) em uma área de restinga na Bahia / Bee (Apoidea) visitors of the flowers of Comolia ovalifolia DC Triana (Melastomataceae) in a sandbanks area in Bahia

The flowers of Comolia ovalifolia present poricidal anthers and their pollen serve as protein source to a specific group of bees, able to extract the pollen from the anthers through vibration. From January to December /2001, we observed the flowering of C. ovalifolia and the activity of the most frequent bees throughout the year. The peaks of flowering of C. ovalifolia occurred in March and from September to November/2001. The flowers of C. ovalifolia were visited by 16 species of bees, being the most frequent Centris leprieuri (Spinola), Xylocopa subcyanea Pérez, Centris sp., Euglossa sp. and Florilegus similis Urban. Among these, C. leprieuri was the most frequent visitor in the flowers (89%) and its foraging period overlapped with the blooming of C. ovalifolia. This bee presented adequate size and efficient behavior in pollen collection and transfer to the stigma, being considered an effective pollinator of the flowers.

As flores de Comolia ovalifolia apresentam anteras poricidas e seu pólen serve como fonte protéica a um grupo específico de abelhas, capaz de extrair o pólen das anteras através de vibração. O florescimento de C. ovalifolia e a atividade das abelhas mais freqüentes foram observadas de janeiro a dezembro/2001. Os picos de florescimento de C. ovalifolia ocorreram nos meses de março/2001 e entresetembro e novembro/2001. As flores de C. ovalifolia foram visitadas por 16 espécies de abelhas, sendo as mais freqüentes Centris leprieuri (Spinola), Xylocopa subcyanea Pérez, Centris sp., Euglossa sp. e Florilegus similis Urban. Entre elas, C. leprieuri destacou-se com 89% das visitas e sua atividade forrageira anual coincidiu com a floração de C. ovalifolia. Além disso, essa abelha apresentou tamanho adequado e comportamento eficiente na coleta e transferência de pólen para o estigma, sendo considerada polinizador legítimo dessas flores.