Palinologia e a interação planta-abelha: Revisão de literatura / Palynology and plant-bee interaction: Literature review / Palinología y la interacción planta y abeja: Revisión de literatura

A Palinologia é responsável pelo estudo do pólen de angiospermas, esporos de pteridófitas e de fungos, cistos de algas, dinoflagelados, foraminíferos acritarcas e partículas de carvão. Três hipóteses embasam as análises palinológicas: (1) a chuva polínica vigente reflete a vegetação presente na área em estudo; (2) o acúmulo e a conservação dos palinomorfos não prejudicam a personificação da chuva polínica; e (3) a amostragem, o processamento químico, a contagem e a identificação dos palinomorfos reconstituem fielmente a chuva polínica da área. A aplicação da Palinologia nos diversos ramos da ciência torna-se viável graças à imensa variabilidade morfológica presente no pólen (ou nos palinomorfos), o que possibilita definir famílias, gêneros e espécies botânicas. As relações entre abelhas e plantas podem ser feitas por meio da análise do pólen transportado pelas fêmeas ou daquele armazenado em células de cria ou em potes de alimento. A interação entre abelhas e plantas está relacionada ao processo de polinização, responsável pela renovação da flora de vários ecossistemas.(AU)

Palynology is responsible for the study of angiosperms pollen, pteridophyte and fungal spores, algae cysts, dinoflagellates, actinic foraminifera and charcoal particles. Three hypotheses support palynological analyzes: (1) the pollen rain reflects the vegetation present in the study area; (2) the accumulation and conservation of palynomorphs do not impair the personification of pollen rain; and (3) the sampling, chemical processing, counting, and identification of palynomorphs faithfully reconstitute the pollen rain area. The application of palynology in the various branches of science becomes feasible due to the immense morphological variability present in pollen (or palynomorphs), which makes it possible to define families, genera and botanical species. The relationships between bees and plants can be made through the analysis of pollen carried by the female animals or stored in the breeding cells or food pots. The interaction between bees and plants is related to the pollination process, responsible for the renewal of the flora of several ecosystems.(AU)

La Palinología es responsable por el estudio del polen de angiospermas, esporos de pteridofitas y de hongos, quistes de algas, dinoflagelados, foraminíferos, acritarcas y partículas de carbón. Tres hipótesis embazan los análisis palinológicos: (1) la lluvia polínica vigente refleja la vegetación presente en el área en estudio; (2) el acúmulo y la conservación de los palinomorfos no perjudican la personificación de la lluvia polínica; y (3) el muestreo, el procesamiento químico, el conteo y la identificación de los palinomorfos reconstituyen fielmente la lluvia polínica del área. La aplicación de la Palinología en los diversos seguimientos de la ciencia se hace viable gracias a la inmensa variabilidad morfológica presente en el polen (o en los palinomorfos), lo que posibilita definir familias, géneros y especies botánicas. Las relaciones ente abejas y plantas pueden ser hechas a través del análisis del polen transportado por las hembras o de aquel almacenado en células de cría o en potes de alimentos. La interacción entre abejas y plantas está relacionada al proceso de polinización, responsable por la renovación de la flora de varios ecosistemas.(AU)

The effect of three plant bioregulators on pollen germination, pollen tube growth and fruit set in almond [Prunus dulcis (Mill.) D.A. Webb] cvs. Non Pareil and Carmel

Background In commercial almond [Prunus dulcis (Mill.) D.A. Webb] orchards in Chile, the percentage of fruit set is low and commonly reaches 5–30%. As almond trees bloom during a cool period and also suffer from self-incompatibility, any factor that can improve pollination, pollen germination and pollen tube growth or extend the effective pollination period, such as the application of plant bioregulators (PBRs), should be beneficial for fruit production. Results Three plant bioregulators (PBRs): brassinolide (BL), gibberellic acid (GA3) and kinetin (KN) were evaluated for pollen germination and pollen tube growth in vitro, as well as for fruit set in almond cultivars Non Pareil and Carmel, in central Chile, during the 2013 and 2014 seasons. For pollen germination in vitro, the BL concentration of 10 mg L- 1 had the highest value in Non Pareil (97.7%), after 4 h germination in 2014 growing season (the control was 90.9%). KN at a concentration of 50 µL L- 1 induced the longest pollen tube growth of 1243.4 µm in Carmel after 8 h germination in 2013 (the control was 917.7 µm). In Non Pareil, the highest percentage of fruit set (31.0%) was achieved in 2014 by spraying during bloom at pink bud stage with KN at 50 µL L- 1 (the control was 16.7%). Conclusions A significant favorable effect of the tested PBRs was observed in pollen germination and pollen tube growth in vitro, as well as on fruit set in Non Pareil and Carmel almonds.

Emerging role of ER quality control in plant cell signal perception

The endoplasmic reticulum quality control (ER-QC) is a conserved mechanism in surveillance of secreted signaling factors during cell-to-cell communication in eukaryotes. Recent data show that the ER-QC plays important roles in diverse cell-to-cell signaling processes during immune response, vegetative and reproductive development in plants. Pollen tube guidance is a precisely guided cell-cell communication process between the male and female gametophytes during plant reproduction. Recently, the female signal has been identified as small secreted peptides, but how the pollen tube responds to this signal is still unclear. In this review, we intend to summarize the role of ER-QC in plants and discuss the recent advances regarding our understanding of the mechanism of pollen tube response to the female signals.

Pollen germination in vitro and pollen tube growth of Scutellaria baicalensis / 中国中药杂志

<p><b>OBJECTIVE</b>To study the pollen germination in vitro and pollen tube growth of Scutellaria baicalensis.</p><p><b>METHOD</b>Two years-old S. baicalensis that in the experiment field of Shangluo university were used as the materials. The effects of culture medium, sucrose, PEG, pH value, culture time and temperature on the pollen germination and tube growth of S. baicalensis were investigated using the method of liquid culture.</p><p><b>RESULT AND CONCLUSION</b>The results showed that 100 g x L(-1) sucrose was helpful for the germination and growth of pollens. However, higher concentration of sucrose would inhibit strongly pollen germination and the growth of pollen tubes. PEG could accelerate pollen germination and tube growth, and the optimal concentration was 150 g x L(-1). The optimum culture medium was BK and BK + 10% sucrose + 150 g x L(-1) PEG (pH 5.8) , and the latter was more benefit for pollen germination and tube growth. The pollen of germination was better at 25-35 degrees C, and it was the best at 30 degrees C for 2-3 hours, while pollen tube growth was slower at 25 degrees C.</p>

Ultrastructural features of Mimulus aurantiacus (Scrophulariaceae) pollen tubes in vivo

The aim of this study is to give information on ultrastructure of in vivo pollen tubes of Mimulus aurantiacus which were collected from the Botanical Garden of the University of California at Berkeley. Materials were prepared according to electron microscopy methods and examined under Zeiss electron microscope. Four zones were examined in the pollen tubes of Mimulus aurantiacus. APICAL ZONE: Mitochondria, smooth endoplasmic reticulum, rough endoplasmic reticulum, dictyosomes and secretory vesicles were observed. SUBAPICAL ZONE: This area contained abundant rough endoplasmic reticulum and occasionally some smooth endoplasmic reticulum. The polysomes, mitochondria, proplastids that contain starch, small vacuoles and a few lipid bodies were detected. NUCLEAR ZONE: Both generative and vegetative cell nuclei lie in this zone. The vegetative cell nucleus was large and long. Rough endoplasmic reticulum, mitochondria, ribosomes, dictyosomes, and amyloplasts that are rich of starch were observed. VACUOLATION AND PLUG FORMATION ZONE: Cytoplasm of the tubes was full of large vacuoles. Few organelles such as mitochondria, dictyosome and rough endoplasmic reticulum were detected along their periphery.

O objetivo deste estudo é informar sobre a ultraestrutura de tubos de pólen de Mimulus aurantiacus in vivo coletados no "Botanical Garden" da Universidade da Califórnia em Berkeley. O material foi preparado de acordo com os métodos de microscopia eletrônica e examinado em microscópio eletrônico Zeiss. Quatro zonas dos tubos de pólen de Mimulus aurantiacus foram examinadas. ZONA APICAL: foram observados mitocôndrias, retículo endoplasmático liso; retículo endoplasmático rugoso, dictiossomos e vesículas secretoras. ZONA SUBAPICAL: esta área continha retículo endoplasmático rugoso em abundância e, ocasionalmente, algum retículo endoplasmático liso. Foram detectados polissomos, mitocôndrias, proplastídeos que contêm amido, pequenos vacúolos e alguns corpos lipídicos. ZONA NUCLEAR: nesta área, existem tanto núcleos de células geradoras como vegetativas. O núcleo de célula vegetativa é grande e longo. Foram observados retículo endoplasmático rugoso, mitocôndria, ribossomos, dictiossomos e amiloplastos ricos em amido. ZONA DE VACUOLIZAÇÃO E DE FORMAÇÃO DE "PLUG": o citoplasma dos tubos estava cheio de grandes vacúolos. Algumas organelas como mitocôndria, dictiossomo e retículo endoplasmático rugoso foram detectadas em toda a periferia desta área.

Observation of pollen tube germination of Platycodon grandiflorum by fluorescence microscopy / 中国中药杂志

<p><b>OBJECTIVE</b>To determine the self-compatibility of Platycodon grandiflorum and the location of microspore germination on stigma.</p><p><b>METHOD</b>The microspore germination of self-pollination, self-plant-pollination and cross-pollination and the pollination microspore germination in and outside of stigma were observed with fluorescence microscopy.</p><p><b>RESULT</b>Most pollens of self-pollination, self-plant-pollination and cross-pollination can germinate on the stigma, and after 24 hours, pollen tube entered into the ovary successfully. Pollinated on the outer-surface of stigma, microspores could not germinate, but on the inner-surface of the stigma when it dehisced most microspores can germinate.</p><p><b>CONCLUSION</b>The compatibility of self-plant-pollination of Platycodon grandiflorum is high. The microspore germination loci is on the inner-surface of the dehisced stigma.</p>

Cytomixis impairs meiosis and influences reproductive success in Chlorophytum comosum (Thunb) Jacq. - an additional strategy and possible implications.

Spontaneous intercellular chromatin migration/cytomixis was observed to occur in the pollen mother cells (PMCs) of the Chlorophytum comosum for the first time. The migration through cytomictic channels was more pronounced in meiosis-I and very rare in meiosis-II. The process was associated with erratic meiosis, which was characterized by defects in chromosome organization and segregation. Cytomixis was more intense in the month of April than in July and consequently the frequency of meiotic irregularities was much more pronounced during the month of April. As a consequence of abnormal meiosis, fertility was drastically reduced resulting in meager seed efficiency of 17% only. Recombination system also does not guarantee the release of sufficient variability. We view the phenomenon of cytomixis as genetically controlled mechanism involving meiotic genes and operating through signal transduction pathway triggered by the environmental stimuli. The evolutionary significance and tenable hypothesis in the backdrop of existing literature is also proposed.

Dinámica de crecimiento de tubos polínicos en poblaciones de Pachira quinata (Jacq.) W. Alverson (Bombacaceae) / Dynamics of pollen tube growth in Pachira quinata W. Alverson (Bombacaceae) populations

La dinámica de crecimiento de tubos polínicos fue estudiada en dos poblaciones de Pachira quinata, incluyendo los factores que la afectan como: el tipo de cruce, autopolinización y polinización cruzada intra e interprocedencia. El tiempo de cosecha de las flores afecta el número de óvulos penetrados, pero no afecta la distancia máxima alcanzada por los tubos, ni el número de tubos polínicos a lo largo del estilo. El número de tubos polínicos y la proporción de óvulos penetrados fue significativamente mayor cuando el polen fue almacenado a temperatura ambiente, comparado con los valores de polen refrigerado. El número de tubos polínicos a lo largo del estilo es independiente del tipo de cruce utilizado, asi mismo, la proporción de óvulos penetrados es menor en las polinizaciones interprocedencia que en cruces intraprocedencia y autopolinización. La alta proporción de óvulos penetrados en autopolinización indica que la incompatibilidad en Pachira quinata es una reacción de acción tardía y ocurre a nivel del ovario. El mayor número de óvulos penetrados en cruces intraprocedencia comparado con cruces interprocedencia, sugieren un efecto de depresión en la fecundación entre individuos de distintas áreas geográficas.

The dynamics of pollen tube growth was studied in populations of Pachira quinata, as well as the factors that affect it, such as: the type off crossing, self-pollination and cross-pollination among and inside populations. It was found that the time ofgathering of the flowers determines the number of penetrated ovules, but it does not determine the maximum distance reached by the tubes, neither the number of pollen tubes along the style. The number of pollen tubes and the proportion of ovules penetrated were significantly bigger when the pollen was stored at environment temperature, compared with the values of refrigerated pollen. The number of pollen tubes along the style is independent of the type of crossing used; likewise, the proportion of penetrated ovules is smaller in the pollinations among populations than in crossing among populations and self-pollination. The high proportion of ovules penetrated in self-pollination indicates that the incompatibility in Pachira quinata is an auto-incompatibility of late action that occurs at the ovary zone. The biggest number of ovules penetrated throughout crossing inside populations compared with crossing among populations suggests the existence of an out-breeding depression effect among individuals from different geographical areas.