Lily Pollen Tubes Pulse According to a Simple Spatial Oscillator.

Polar growth is a fundamental mode of cell morphogenesis observed in nearly all major groups of organisms. Among polarly growing cells, the angiosperm pollen tubes have emerged as powerful experimental systems in large part because of their oscillatory growth, which provides a window into the network of interactions regulating morphogenesis. Empirical studies of oscillatory pollen tubes have sought to uncover the temporal sequence of cellular and molecular events that constitutes an oscillatory cycle. Here we show that in lily pollen tubes the distance or wavelength (λ = 6.3 ± 1.7 µm) over which an oscillatory cycle unfolds is more robust than the period of oscillation (τ = 39.1 ± 17.6 s) (n = 159 cells). Moreover, the oscillatory cycle is divided into slow and fast phases, with each phase unfolding over precisely one half of the wavelength. Using these observations, we show that a simple spatial bi-oscillator predicts the most common modes of oscillation observed in pollen tubes. These results call into question the traditional view of pollen tube morphogenesis as a temporal succession of cellular events. Space, not time, may be the most natural metric to inteprete the morphogenetic dynamics of these cells.

Influence of vernalization and bulb size on the production of lily cut flowers and lily bulbs / Vernalização e tamanho do bulbo na produção de flores e de bulbos de lírio de corte

Exposure of bulbs to cold, a physiological phenomenon called vernalization, and bulb size are important factors in the production of lily bulbs and flowers. This study aimed to verify the influence of vernalization of bulbs on flowering cut lily plants, as well as the impact of size and shape of harvest on the production and quality of flowers and bulbs. In turn, the way the stems of the plants used for cut-flower production are cropped is of higher importance for the production of new flower bulbs. In this sense, the experiment was conducted in Viçosa, MG, in a greenhouse in a randomized block design, in split splot scheme with three replications, in which the vernalization periods (25, 35 and 45 days at 4 ± 1 C) constituted the plots; bulb sizes (diameters of 3.2-3.8 cm; 2.5-3.2 cm 1.9- and 2.5 cm), subplots and ways to harvest (full harvest of the stem at the required length for the commercial harvest of the flower, commercial stem harvest at the commercial length, maintaining 10cm of stem in the soil; removal of the floral buds as soon as their appearance is observed and harvest at the end of the season), the sub subplots. The bulbs were planted in beds, with 15 x 20 cm spacing. It was evaluated the number of plants that flowered and the number of flowers, the length and the diameter of the floral buds, fresh and dry weights, diameter and plant height as well as number, perimeter and amount of fresh and dry bulbs.There was a decrease in the plant height with the increase of the vernalization period and a reduction ofthe diameter of the planted bulbs, as well as of the number and the fresh and dry weights of the producedbuds. The production of flowers and buds in number, size and weight was directly proportional to thesize of the planted bulbs, while the form of harvest with removal of flower buds increased the number,the perimeter and the fresh and dry weights of the buds...(AU)

A exposição dos bulbos ao frio, fenômeno fisiológico denominado vernalização, e o tamanho do bulbo são importantes na produção de flores de lírio. Por sua vez, a forma de colheita das hastes das plantas utilizadas para corte de flor é preponderante na produção de bulbos filhos. Este estudo teve como objetivo verificar a influência da vernalização dos bulbos em plantas de lírio em flor, bem como o impacto do tamanho e forma da colheita na produção e qualidade de flores e bulbos. O experimento foi conduzido em Viçosa, MG casa de vegetação, em blocos casualizados, com parcelas sub-subdivididas, com três repetições, em que os períodos de vernalização (25, 35 e 45 dias, a 4± 1? C) constituíram as parcelas; os tamanhos de bulbo (diâmetros de 3,2- 3,8 cm; 2,5-3,2 cm e 1,9- 2,5 cm), as subparcelas e as formas de colheita (colheita total da haste no ponto de colheita comercial da flor; colheita da haste no ponto comercial, mantendo 10 cm da haste no solo; retirada do botão floral assim que seu surgimento foi observado e colheita no fim do ciclo vegetativo), as sub subparcelas. Os bulbos foram plantados em canteiros, em espaçamento de 15 x 20 cm. Foram avaliados o número de plantas que floresceram e número de flores, comprimento e diâmetro do botão floral, massas fresca e seca, diâmetro e altura da planta e número, perímetro e massa fresca e seca de bulbos. Houve decréscimo na altura da planta como aumento do período de vernalização e redução do diâmetro do bulbo plantado, assim como do númeroe da massa seca e fresca dos bulbos produzidos. Já, a produção de flores e bulbos, em número, tamanhoe peso, foi diretamente proporcional ao tamanho do bulbo plantado, enquanto a forma de colheita, comretirada do botão floral aumentou o número, o perímetro e as massas frescas e secas dos bulbos. Bulboscom diâmetro entre 3,2 - 3,8 cm, armazenados por 25 dias em câmara fria possibilitam maior produçãode flores e a maior altura da haste, fatores que favorecem o aumento do...(AU)

Influence of vernalization and bulb size on the production of lily cut flowers and lily bulbs / Vernalização e tamanho do bulbo na produção de flores e de bulbos de lírio de corte

Exposure of bulbs to cold, a physiological phenomenon called vernalization, and bulb size are important factors in the production of lily bulbs and flowers. This study aimed to verify the influence of vernalization of bulbs on flowering cut lily plants, as well as the impact of size and shape of harvest on the production and quality of flowers and bulbs. In turn, the way the stems of the plants used for cut-flower production are cropped is of higher importance for the production of new flower bulbs. In this sense, the experiment was conducted in Viçosa, MG, in a greenhouse in a randomized block design, in split splot scheme with three replications, in which the vernalization periods (25, 35 and 45 days at 4 ± 1 C) constituted the plots; bulb sizes (diameters of 3.2-3.8 cm; 2.5-3.2 cm 1.9- and 2.5 cm), subplots and ways to harvest (full harvest of the stem at the required length for the commercial harvest of the flower, commercial stem harvest at the commercial length, maintaining 10cm of stem in the soil; removal of the floral buds as soon as their appearance is observed and harvest at the end of the season), the sub subplots. The bulbs were planted in beds, with 15 x 20 cm spacing. It was evaluated the number of plants that flowered and the number of flowers, the length and the diameter of the floral buds, fresh and dry weights, diameter and plant height as well as number, perimeter and amount of fresh and dry bulbs.There was a decrease in the plant height with the increase of the vernalization period and a reduction ofthe diameter of the planted bulbs, as well as of the number and the fresh and dry weights of the producedbuds. The production of flowers and buds in number, size and weight was directly proportional to thesize of the planted bulbs, while the form of harvest with removal of flower buds increased the number,the perimeter and the fresh and dry weights of the buds...

A exposição dos bulbos ao frio, fenômeno fisiológico denominado vernalização, e o tamanho do bulbo são importantes na produção de flores de lírio. Por sua vez, a forma de colheita das hastes das plantas utilizadas para corte de flor é preponderante na produção de bulbos filhos. Este estudo teve como objetivo verificar a influência da vernalização dos bulbos em plantas de lírio em flor, bem como o impacto do tamanho e forma da colheita na produção e qualidade de flores e bulbos. O experimento foi conduzido em Viçosa, MG casa de vegetação, em blocos casualizados, com parcelas sub-subdivididas, com três repetições, em que os períodos de vernalização (25, 35 e 45 dias, a 4± 1? C) constituíram as parcelas; os tamanhos de bulbo (diâmetros de 3,2- 3,8 cm; 2,5-3,2 cm e 1,9- 2,5 cm), as subparcelas e as formas de colheita (colheita total da haste no ponto de colheita comercial da flor; colheita da haste no ponto comercial, mantendo 10 cm da haste no solo; retirada do botão floral assim que seu surgimento foi observado e colheita no fim do ciclo vegetativo), as sub subparcelas. Os bulbos foram plantados em canteiros, em espaçamento de 15 x 20 cm. Foram avaliados o número de plantas que floresceram e número de flores, comprimento e diâmetro do botão floral, massas fresca e seca, diâmetro e altura da planta e número, perímetro e massa fresca e seca de bulbos. Houve decréscimo na altura da planta como aumento do período de vernalização e redução do diâmetro do bulbo plantado, assim como do númeroe da massa seca e fresca dos bulbos produzidos. Já, a produção de flores e bulbos, em número, tamanhoe peso, foi diretamente proporcional ao tamanho do bulbo plantado, enquanto a forma de colheita, comretirada do botão floral aumentou o número, o perímetro e as massas frescas e secas dos bulbos. Bulboscom diâmetro entre 3,2 - 3,8 cm, armazenados por 25 dias em câmara fria possibilitam maior produçãode flores e a maior altura da haste, fatores que favorecem o aumento do...

Carbohydrate metabolism in floral structures of Lilium pumilum in different development stages / Alterações no teor de carboidratos em estruturas florais de Lilium pumilum em diferentes estádios de desenvolvimento

Lilium pumilum is a species that stands out in floriculture for presenting orange inflorescences that attract the consumer. This study thus aimed at characterizing the carbohydrate metabolism of floral structures of L. pumilum in different development stages. For this purpose, carbohydrate levels (total soluble sugars, reducing sugars, non-reducing sugars, and starch), at different floral stages (E0 - bud with no color; E1 - bud at early coloring; E2 - orange bud; E3 - open flower; E4 - senescent flower) were quantified after extraction with ethanol. Lilium pumilum flowers showed high energy potential during floral opening and senescence; total soluble sugars were the main carbohydrates present in the species, reducing with the floral development, and the same occurred with the non-reducing sugar and starch contents. The reducing-sugar content increased with the floral stages. Therefore, this species presents great mobilization of compounds, which are utilized in the production of energy that is employed in floral opening.(AU)

Lilium pumilum é uma espécie que se destaca na floricultura, por apresentar inflorescências alaranjadas que atraem o consumidor. Assim, este trabalho teve como objetivo caracterizar o metabolismo de carboidrato de estruturas florais de L. pumilum em diferentes estádios de desenvolvimento. Para isso, os níveis de carboidratos (açúcares solúveis totais, açúcares redutores, açúcares não redutores e amido), em diferentes estádios florais (E0 - botão sem coloração; E1 - botão em início de coloração; E2 - botão alaranjado; E3 - flor aberta; E4 - flor senescente), foram quantificados a partir da extração com etanol. As flores de L. pumilum apresentaram um alto potencial energético durante a abertura floral e senescência, sendo os açúcares solúveis totais os principais carboidratos presentes na espécie, mas com redução de acordo com o desenvolvimento floral, o mesmo ocorrendo com os teores de açúcar não redutor e amido. O conteúdo de açúcar redutor foi crescente entre os estádios florais. Portanto, a espécie apresenta grande mobilização de compostos, os quais são utilizados na produção de energia, que é empregada na abertura floral.(AU)

Somatic Embryogenesis of Lilium from Microbulb Transverse Thin Cell Layers.

A reliable somatic embryogenesis protocol is a prerequisite for application of other plant biotechniques. Several protocols were reported for genus Lilium, with variable success. Between them, transverse Thin Cell Layers (tTCL) were used efficiently to induce indirect somatic embryogenesis of Lilium. Somatic embryogenesis potential is dependent on the genotype, explant, and culture medium composition, especially as for plant growth regulators and environmental conditions. Usually, the process comprises three phases: embryogenic callus induction, embryogenic callus proliferation and somatic embryo germination. Somatic embryo germination can be achieved in light or dark. In the first case, complete plantlets are formed, with green leaves and pseudobulb in the base. In darkness, microbulbs are formed from single somatic embryos or clusters. A last phase of microbulb enlargement allows plantlets or microbulbs to increase their biomass. These enlarged microbulbs do not need special acclimatization conditions when transferred to soil and quickly produce sturdy plants. This chapter describes a protocol for somatic embryogenesis of Lilium using tTCL from microbulbs.

Cloning and characterization of a benzoic acid/salicylic acid carboxyl methyltransferase gene involved in floral scent production from lily (Lilium 'Yelloween').

In lily flowers, the volatile ester methyl benzoate is one of the major and abundant floral scent compounds; however, knowledge regarding the biosynthesis of methyl benzoate remains unknown for Lilium. In this study, we isolated a benzoic acid/salicylic acid carboxyl methyltransferase (BSMT) gene, LiBSMT, from petals of Lilium 'Yelloween'. The gene has an open reading frame of 1083 base pairs (bp) and encodes a protein of 41.05 kDa. Sequence alignment and phylogenetic analyses of LiBSMT revealed 40-50% similarity with other known benzenoid carboxyl methyltransferases in other plant species, and revealed homology to BSMT of Oryza sativa. Heterologous expression of this gene in Escherichia coli yielded an enzyme responsible for catalyzing benzoic acid and salicylic acid to methyl benzoate and methyl salicylate, respectively. Quantitative real-time polymerase chain reaction analysis showed that LiBSMT was preferentially expressed in petals. Moreover, the expression of LiBSMT in petals was developmentally regulated. These expression patterns correlate well with the emission of methyl benzoate. Our results indicate that LiBSMT plays an important role in floral scent methyl benzoate production and emission in lily flowers.

Micropropagation of Lilium ledebourii (Baker) Boiss as affected by plant growth regulator, sucrose concentration, harvesting season and cold treatments

A protocol for the micropropagation in different harvesting time of Lilium ledebourii (Baker) Boiss, an endangered rare species endemic to Iran has been developed. In vitro scale culture of this species, using bulbs from three harvesting seasons (spring, summer and winter), was attempted. Among the various treatments tested, the Murashige and Skoog (MS) medium supplemented with 0.1 mg l-1 naphthaleneacetic acid (NAA) + 0.1 mg l-1 benzyladenin (BA) and 6% sucrose in all harvesting seasons proved to be superior to others. The best results for fresh weight of bulblets, rooting parameters and the survival rate after transplantation to greenhouse were obtained from early winter-harvested bulbs. Summer-harvested bulbs had the highest number of bulblets per explant. The bulblets at the end of the culture period were given cold treatment at 4ºC for 2-8 weeks at a 2-weeks interval and then transplanted to a potting mixture of sand, leaf mold and peat moss (1:1:1 v/v). The best emergence rate (90%) was achieved at 8 weeks cold treatment for winter harvested bulbs.

NAD(P)H oscillates in pollen tubes and is correlated with tip growth.

The location and changes in NAD(P)H have been monitored during oscillatory growth in pollen tubes of lily (Lilium formosanum) using the endogenous fluorescence of the reduced coenzyme (excitation, 360 nm; emission, >400 nm). The strongest signal resides 20 to 40 microm behind the apex where mitochondria (stained with Mitotracker Green) accumulate. Measurements at 3-s intervals reveal that NAD(P)H-dependent fluorescence oscillates during oscillatory growth. Cross-correlation analysis indicates that the peaks follow growth maxima by 7 to 11 s or 77 degrees to 116 degrees, whereas the troughs anticipate growth maxima by 5 to 10 s or 54 degrees to 107 degrees. We have focused on the troughs because they anticipate growth and are as strongly correlated with growth as the peaks. Analysis of the signal in 10-microm increments along the length of the tube indicates that the troughs are most advanced in the extreme apex. However, this signal moves basipetally as a wave, being in phase with growth rate oscillations at 50 to 60 microm from the apex. We suggest that the changes in fluorescence are due to an oscillation between the reduced (peaks) and oxidized (troughs) states of the coenzyme and that an increase in the oxidized state [NAD(P)(+)] may be coupled to the synthesis of ATP. We also show that diphenyleneiodonium, an inhibitor of NAD(P)H dehydrogenases, causes an increase in fluorescence and a decrease in tube growth. Finally, staining with 5-(and-6)-chloromethyl-2',7'-dichlorohydrofluorescein acetate indicates that reactive oxygen species are most abundant in the region where mitochondria accumulate and where NAD(P)H fluorescence is maximal.

Hydrogen peroxide in micropropagation of Lilium. A comparison with a traditional methodology.

The micropropagation of Lilium longiflorum requires adequate equipment which may not be afforded by small laboratories or producers. In this work we compared traditional methodology with a protocol that included easily available elements to sterilize materials and culture media, together with addition of hydrogen peroxide (H2O2) into the nutrient media as chemical sterilizer. A series of H2O2 concentrations (0.005, 0.010, 0.015 and 0.020% p/v) was used to control contamination during in vitro establishment and subsequent cultivation; the explant organogenic response was also examined and compared to the traditional micropropagation technique. The level of culture contamination was within acceptable limits in all treatments, though it was higher in the H2O2 treatments (40%) compared to the traditional methodology (20%). There were not significant differences in the number of bulblets per explant, and at the end of the multiplication phase, bulblets from 0.02% H2O2 treatment had greater biomass than from other treatments, indicating a beneficial effect. These bulblets also had a higher relative growth ratio with respect to the traditional method when cultivated for an additional period and showed the highest average bulblet fresh weight. It is expected that this higher bulblet mass would result in better performance during ex vitro cultivation.