Differential sprouting ability during micropropagation of Nidularium minutum Mez (Bromeliaceae)

Nidularium minutum is an ornamental bromeliad from the Brazilian Rainforest. The micropropagation of this species is essential for obtaining plants available for conservation programs or commercial use. Our study aimed to establish an efficient plant production method by in vitro sprouting. This bromeliad takes a long time to sprout in vitro, and 10% of the plants produce shoots in a culture medium without plant growth regulators (PGRs). When subcultured in a PGR-free medium, these individualized shoots can sprout like the mother plant. The Murashige and Skoog basal medium (MS) containing 1.0 mg L-1 of 6-benzylaminopurine (BAP) promoted the induction of adventitious shoots in greater than 90% of the plants after 240 days of culture with an average of more than eight shoots per plant. Approximately 100% of the in vitro-produced shoots survived after acclimatization, reaching the flowering stage. Therefore, our results showed that in vitro regeneration of N. minutum depends on the cultivation period and that plants with a higher sprouting capacity can be selected and used as micropropagation matrices, contributing to the production of this endangered bromeliad.(AU)

Tillandsia usneoides: A successful alternative for biomonitoring changes in air quality due to a new highway in São Paulo, Brazil.

Tillandsia usneoides is an aerial epiphytic bromeliad that absorbs water and nutrients directly from the atmosphere by scales covering its surface. We expanded the use of this species as a broader biomonitor based on chemical and structural markers to detect changes in air quality. The usefulness of such comprehensive approach was tested during the construction and opening of a highway (SP-21) in São Paulo State, Brazil. The biomonitoring study was performed from 2009 to 2012, thus comprising the period during construction and after the highway inauguration. Metal accumulation and structural alterations were assessed, in addition to microscopy analyses to understand the metal chelation in plant tissues and to assess the causes of alterations in the number and shape of scale cells. Altogether, our analyses support the use of this species as a wide biomonitor of air quality in urbanized areas.

Tillandsia usneoides: a successful alternative for biomonitoring changes in air quality due to a new highway in São Paulo, Brazil.

Tillandsia usneoides is an aerial epiphytic bromeliad that absorbs water and nutrients directly from the atmosphere by scales covering its surface. We expanded the use of this species as a broader biomonitor based on chemical and structural markers to detect changes in air quality. The usefulness of such comprehensive approach was tested during the construction and opening of a highway (SP-21) in São Paulo State, Brazil. The biomonitoring study was performed from 2009 to 2012, thus comprising the period during construction and after the highway inauguration. Metal accumulation and structural alterations were assessed, in addition to microscopy analyses to understand the metal chelation in plant tissues and to assess the causes of alterations in the number and shape of scale cells. Altogether, our analyses support the use of this species as a wide biomonitor of air quality in urbanized areas.

Soluções nutritivas alternativas para o cultivo de bromélias ornamentais / Alternative nutritional solutions for the culture of ornamental bromélias / Soluciones alimenticias alternativas para la cultura de bromelias ornamentales

O cultivo de bromélias ornamentais tem sido considerado uma importante estratégia de preservação dessas plantas, pois possibilita ofornecimento de maior quantidade de plantas ao mercado, reduzindo a procura por exemplares provenientes do ambiente natural. Geralmente, osprodutores utilizam fertilizantes baseados em diferentes composições de nitrogênio, fósforo e potássio. Contudo, estudos nutricionais utilizandoa técnica de cultivo in vitro têm mostrado um desenvolvimento satisfatório de bromélias na presença de outros nutrientes existentes nos meios de cultura utilizados, tais como os presentes em Murashige & Skoog (MS) e em Knudson (K). O objetivo deste trabalho foi verificar o crescimento de plantas de três espécies de bromélias ornamentais: Acanthostachys strobilaceae (Schult. f.) Klotzsch, Aechmea bromeliifolia (Rudge) Baker e Alcantarea imperialis (Carrière) Harms, obtidas a partir da germinação de sementes e adubadas com soluções nutritivas baseadas em MS e K. Plantas com dois meses foram transferidas para bandejas de isopor, contendo como substrato casca de Pinus, sendo adubadas por seis mesescom MS e K originais e uma diluição do meio MS à metade (MS/2). Foram analisados números de folhas, comprimentos dos eixos caulinares eradiculares, teores de massas seca e fresca das partes aérea e radicular, além de pigmentos fotossintéticos. Observou-se que as soluções maisdiluídas (K e MS/2) foram mais adequadas ao crescimento das três espécies de bromélias. As maiores concentrações de cálcio e magnésio presentes em K provavelmente favoreceram o desenvolvimento das plantas, indicando serem importantes como suplementação nutricional no cultivo de bromélias.

Cultivating ornamental bromeliads has been considered an important strategy for their preservation, because it allows the supply of a greater amount of plants to the market, reducing the use of units proceeding from the natural environment. Generally producers use fertilizers based on different compositions of nitrogen, phosphorus and potassium. However, nutritional studies using in vitro cultivation technique have shown a satisfactory development of bromeliads as compared to other nutrients used in other techniques such as those in Murashige & Skoog (MS) and Knudson (K). The objective of this work was to verify the growth of plants of three species of ornamental bromeliads: Acanthostachys strobilaceae (Schult. f.) Klotzsch, Aechmea bromeliifolia (Rudge) Baker e Alcantarea imperialis (Carrière) Harms, gotten from the germination of seeds and fertilized with nutritional solutions based on MS and K. Plants with two months were transferred to isopor trays with Pinus rind as substratum, and were fertilized during six months with original MS and K and a dilution of half MS and half (MS/2). We examined number ofleafs, stem and root axis lengths, dry and wet masses of aerial and root parts, in addition to photosynthetic pigments. We observed that the morediluted solutions (K and MS/2) were more favorable to the growth of the three bromeliads species. The highest concentrations of calcium andmagnesium in K probably favored the development of the plants, indicating the important of nutritional supplements for bromeliads cultures.

Cultivar bromelias ornamentales es considerado una estrategia importante para su preservación, porque permite la oferta de una mayor cantidad de plantas al mercado, reduciendo el uso de las unidades que procedan del ambiente natural. Los productores utilizan generalmente fertilizantes basados en diversas composiciones del nitrógeno, fósforo y potasio. Sin embargo, estudios alimenticios usan técnicas de cultivación in vitro que han demostrado un desarrollo satisfactorio de bromelias respecto a otros alimentos usados en otras técnicas tales como Murashige y Skoog (MS) y Knudson (k). El objetivo de este trabajo fue verificar el crecimiento de las plantas de tres especies de bromelias ornamentales: Acanthostachys strobilaceae (Schult. f.) Klotzsch, Aechmea bromeliifolia (Rudge) Baker y Alcantarea imperialis (Carrière) Harms, conseguidas porla germinación de semillas y fertilizadas con soluciones alimenticias basadas en MS y K. Plantas con dos meses fueran transferidas a bandejas de espuma de poliestireno con corteza del pinus como substrato, y fertilizadas durante seis meses con MS y K originales y una dilución mitad MS mitad K (MS/2). Examinamos el número de hojas, de vástago y de masas de las longitudes del eje de la raíz, piezas secas y mojadas de las piezas de la antena y de la raíz, además de los pigmentos fotosintéticos. Observamos que las soluciones diluidas (K y MS/2) fueran más favorables al crecimiento de las tres especies de bromelias. Las concentraciones más altas de calcio y de magnesio en K favorecieron probablemente el desarrollo de las plantas, indicando la importancia de los suplementos alimenticios para las culturas de bromelias.

Thermoperiod affects the diurnal cycle of nitrate reductase expression and activity in pineapple plants by modulating the endogenous levels of cytokinins.

Nitrate reductase (NR, EC 1.6.6.1) activity in higher plants is regulated by a variety of environmental factors and oscillates with a characteristic diurnal rhythm. In this study, we have demonstrated that the diurnal cycle of NR expression and activity in pineapple (Ananas comosus, cv. Smooth Cayenne) can be strongly modified by changes in the day/night temperature regime. Plants grown under constant temperature (28 degrees C light/dark) showed a marked increase in the shoot NR activity (NRA) during the first half of the light period, whereas under thermoperiodic conditions (28 degrees C light/15 degrees C dark) significant elevations in the NRA were detected only in the root tissues at night. Under both conditions, increases in NR transcript levels occurred synchronically about 4 h prior to the corresponding elevation of the NRA. Diurnal analysis of endogenous cytokinins indicated that transitory increases in the levels of zeatin, zeatin riboside and isopentenyladenine riboside coincided with the accumulation of NR transcripts and preceded the rise of NRA in the shoot during the day and in the root at night, suggesting these hormones as mediators of the temperature-induced modifications of the NR cycle. Moreover, these cytokinins also induced NRA in pineapple when applied exogenously. Altogether, these results provide evidence that thermoperiodism can modify the diurnal cycle of NR expression and activity in pineapple both temporally and spatially, possibly by modulating the day/night changes in the cytokinin levels. A potential relationship between the day/night NR cycle and the photosynthetic pathway performed by the pineapple plants (C(3) or CAM) is also discussed.