Aechmea Blanchetiana Research Articles

Anatomical and physiological responses of Aechmea blanchetiana (Bromeliaceae) induced by silicon and sodium chloride stress during in vitro culture.

Salt stress is one of the most severe abiotic stresses affecting plant growth and development. The application of silicon (Si) is an alternative that can increase the tolerance of plants to various types of biotic and abiotic stresses. The objective was to evaluate salt stress's effect in vitro and Si's mitigation potential on Aechmea blanchetiana plants. For this purpose, plants already established in vitro were transferred to a culture medium with 0 or 14 µM of Si (CaSiO3). After growth for 30 days, a stationary liquid medium containing different concentrations of NaCl (0, 100, 200, or 300 µM) was added to the flasks. Anatomical and physiological analyses were performed after growth for 45 days. The plants cultivated with excess NaCl presented reduced root diameter and effective photochemical quantum yield of photosystem II (PSII) (ΦPSII) and increased non-photochemical dissipation of fluorescence (qN). Plants that grew with the presence of Si also had greater content of photosynthetic pigments and activity of the enzymes of the antioxidant system, as well as higher values of maximum quantum yield of PSII (FV/FM), photochemical dissipation coefficient of fluorescence (qP) and fresh weight bioaccumulation of roots and shoots. The anatomical, physiological and biochemical responses, and growth induced by Si mitigated the effect of salt stress on the A. blanchetiana plants cultivated in vitro, which can be partly explained by the tolerance of this species to grow in sandbank (Restinga) areas.

Selenium biofortified Aechmea blanchetiana (Bromeliaceae) can resist lead-induced toxicity during in vitro culture

Selenium biofortified Aechmea blanchetiana (Bromeliaceae) can resist lead-induced toxicity during in vitro culture

Anatomical, physiological, and biochemical modulations of silicon in Aechmea blanchetiana (Bromeliaceae) cultivated in vitro in response to cadmium

Anatomical, physiological, and biochemical modulations of silicon in Aechmea blanchetiana (Bromeliaceae) cultivated in vitro in response to cadmium

Morphophysiological responses of Aechmea blanchetiana (Bromeliaceae) to excess copper during in vitro culture

The use of plants as bioindicators can be effective for environmental monitoring, mainly related to heavy metals such as copper (Cu). In vitro conditions are more easily controlled, to enable isolating the stress factors that can interfere in plants’ responses. The aim was to investigate the morphophysiological responses of Aechmea blanchetiana submitted to excess Cu, and to verify the degree of tolerance and potential as a bioindicator of this species. Previously cultured shoots of A. blanchetiana were transferred to agar-solidified MS medium. After 60 days, the tank system was recreated, with the addition of stationary liquid MS medium with different concentrations of Cu (0, 25, 50 and 100 μM). After 90 days with excess Cu, anatomical analysis along with quantification of the contents of nutrients, photosynthetic pigments and chlorophyll a fluorescence were carried out. Alterations in the stomatal density and chlorenchyma thickness were observed in the plants grown with excess Cu. There was an increase in the Cu content in the plants in function of the Cu levels. However, the adjustments in the content of the other nutrients were essential for tolerance to excess Cu. Aechmea blanchetiana tolerates high Cu concentrations and has potential for use as a bioindicator.

Impacts of photoautotrophic, photomixotrophic, and heterotrophic conditions on the anatomy and photosystem II of in vitro-propagated Aechmea blanchetiana (Baker) L.B. Sm. (Bromeliaceae)

In vitro culture conditions have a major impact on the physiology and anatomy of micropropagated plants. Sucrose plays a very important role in micropropagation protocols, and is frequently employed during in vitro culture. However, it may induce disorders that negatively interfere with plant growth and development, such as a low photosynthetic rates. The aim of this study was to analyze the impacts of in vitro conditions on the anatomy and photosynthetic performance of Aechmea blanchetiana (Baker) L.B. Sm. Plants previously grown in vitro were transferred to culture media containing 0, 15, 30, or 45 g L−1 sucrose. Two different culture container sealing systems were tested: lids with a filter (permitted gas exchange), and with a PVC-covered filter (blocking fluent gas exchange). Plants grown with exogenous sucrose displayed anatomical traits that could decrease mineral and carbohydrate uptake from the medium. Plants cultured under photoautotrophic conditions had a thinner exodermis and the highest number of metaxylem vessels in the roots. This positively impacted the plant growth and physiological status. Sucrose induced plants with photosystem II (PS II) disorders, such as a lower number of active reaction centers. Under photoautotrophic conditions, there was an increase in absorbed energy flux per cross section (ABS/CSm), and energy transport flux (ETo/CSm), followed by a decrease in the energy dissipation flux (DIo/CSm). This indicated a high PS II efficiency, according to the performance index (PI(ABS)). The use of sucrose can induce physiological disorders in A. blanchetiana plants during in vitro propagation. Photoautotrophic conditions induce plants without anatomical disorders, and positively influence PS II efficiency.

Sources and concentrations of silicon modulate the physiological and anatomical responses of Aechmea blanchetiana (Bromeliaceae) during in vitro culture

The use of silicon (Si) has been shown to be a good alternative to improve the growth and content of photosynthetic pigments of plants propagated in vitro. So far, it is not well understood how the sources and concentrations of Si can affect the root and leaf anatomy as well as the functioning of the photosynthetic apparatus of these plants. The aim was to assess the physiological and anatomical responses of Aechmea blanchetiana plants in function of sources and concentrations of Si during in vitro culture. Side shoots of plants previously established in vitro were excised and transferred to a culture medium containing CaSiO3 or Na2SiO3 in four concentrations (0, 7, 14 or 21 µM). After culture for 90 days, the chlorophyll a fluorescence transient, root and leaf anatomy, contents of photosynthetic pigments and mineral nutrients as well as growth were analyzed. Plants grown in medium supplemented with Na2SiO3 presented characteristics of salt stress, such as smaller stomata, higher potassium content and lower number of active reaction centers (RC/CSM). On the other hand, plants cultured with 7 and 14 µM CaSiO3 had an increase in photosynthetic pigment content and performance of photosynthetic apparatus, verified by the performance indexes (PI(ABS) and PI(TOTAL)). The employment of concentrations equal to or higher than 21 µM Si, independent of Si source, caused toxicity symptoms in the plants. The use of CaSiO3 had a positive effect on the concentration interval between 7 and 14 µM by improving physiological and anatomical quality of A. blanchetiana plants. Silicon source and concentration can affect the physiological responses of Aechmea blanchetiana during in vitro culture. This study highlights that CaSiO3 increases the photosynthetic pigment content and photosynthetic apparatus performance.

Effects of 6-benzylaminopurine on photosystem II functionality and leaf anatomy of in vitro cultivated Aechmea blanchetiana

Cytokinins (CKs) are often used during the in vitro cultivation of plant species. However, it is not clear how CKs, such as 6-benzylaminopurine (BAP), affect photosystem PS) II functionality and leaf anatomy over a long period of in vitro plant propagation. The aim of this study was to analyze the residual effects of BAP on the photosynthetic performance and leaf anatomy of Aechmea blanchetiana after 120 d without exposure to CKs. Aechmea blanchetiana plants previously grown in vitro were transferred to Murashige and Skoog (MS) culture media containing 0, 5, 10, 15, or 20 μM BAP. After 60 d on the MS medium with BAP, explants were subcultivated twice on the MS medium without growth regulators, first in a stationary liquid medium for 60 d and then in a solidified medium with 6 g dm-3 agar for 60 d. Leaf anatomy, pigment content, and chlorophyll a fluorescence were assessed for plants from each treatment after 120 d on the CK-free medium. Stomatal density presented a negative linear correlation with BAP concentration. Pigment content decreased in plants subjected to previous BAP exposure. An increase in absorbed energy flux per reaction center (ABS/RC) and a sharp decrease in energy transport flux (ETo/RC) followed by an increase in energy dissipation flux (DIo/RC) also occurred. Furthermore, maximum quantum yield (FV/FM) decreased as a function of BAP concentration. Thus, the use of BAP during in vitro propagation of A. blanchetiana induced long-term physiological defects.

Mucilage secretion in the inflorescences of Aechmea blanchetiana: Evidence of new functions of scales in Bromeliaceae

The peltate trichomes of Bromeliaceae comprise an important feature of this plant group. Although recognized for their capacity for water and nutrient absorption, little is known concerning their secretory functions. This study aimed to identify and describe the structures observed to secrete mucilage in the inflorescences of Aechmea blanchetiana, a species of Bromeliaceae endemic to Brazil. Samples of different portions and developmental stages of inflorescences were collected and processed for study under light and electron microscopy. Mucilage is secreted by peltate trichomes covering the inflorescence axis, which have a structure typical of bromeliad scales, although often having an irregular shield commonly exhibiting a stellate outline. Secretion is performed by cells comprising the so-called wing portion of the trichome and begins even in initial stages of inflorescence expansion. In expanded portions, secretory activity ceases and the remaining secretion appears as a thin dehydrated film covering the inflorescence surface. Ultrastructural data show the presence of well-developed Golgi apparatus and endoplasmic reticulum, confirming a secretory function related to non-cellulosic polysaccharide production. We believe that the mucilage is related to protection against desiccation, especially at early stages of expansion. Such a functional role, in association with the nature and dynamics of the secretion, suggests that these structures act as colleters. As far as we know, this is the first record for exogenous secretory activity by the typical peltate trichomes of Bromeliaceae, and the first time when colleter-like functions have been considered and discussed in this family.

Anatomy and photosystem II activity of in vitro grown Aechmea blanchetiana as affected by 1-naphthaleneacetic acid

Auxins are one of the main regulators of in vitro plant growth and development. However, the mechanisms, by which auxins, such as 1-naphthaleneacetic acid (NAA), affect in vitro root and leaf anatomy and photosystem function, remain unclear. Accordingly, the aim of the present study was to analyze the effect of different NAA concentrations on the anatomy and photosynthetic performance of in vitro-propagated Aechmea blanchetiana and to determine whether such a treatment affects micropropagated plants after acclimatization. In vitro-established A. blanchetiana plants were transferred to culture media that contained 0, 2, 4, or 6 μM NAA, and after 50 d, they were transplanted into plastic seedling trays with a commercial substrate and cultivated for 60 d in a greenhouse. The plants were evaluated after a 50-d in vitro NAA exposure (growth traits, chlorophyll α fluorescence, and root and leaf anatomy) and after 60 d of acclimatization in the greenhouse (root and leaf growth). Changes induced by NAA in root anatomy might improve uptake of minerals and sugars from the medium, thereby increasing the in vitro growth. In the leaves, the lowest chlorenchyma thickness and sclerenchyma area were observed in plants grown without NAA, and NAA exposure also improved photosystem II activity. The highest ex vitro growth rate was observed for plants that were propagated with 4 μM NAA. Therefore, the use of NAA during in vitro propagation can improve the anatomical and physiological quality of A. blanchetiana plants, as well as to improve ex vitro transfer.

Photosynthetic apparatus performance in function of the cytokinins used during the in vitro multiplication of Aechmea blanchetiana (Bromeliaceae)

During the in vitro multiplication phase, the employment of cytokinins may be necessary to induce side shoots of many plant species. However, the mechanism by which cytokinins influence the physiology of plants in vitro is not well understood. Therefore, the objective of this study was to assess the influence of two cytokinins in function of concentration on the o photosynthetic apparatus performance and the stomatal functionality of Aechmea blanchetiana during in vitro multiplication. Plants previously established in vitro were transferred to MS culture media supplemented with 6-benzylaminopurine (BAP) or 6-furfurylaminopurine (kinetin—KIN) at concentration of 0, 5, 10, 15 or 20 µM. After 60 days of exposure to the plant growth regulators, the multiplication rate, photosynthetic apparatus performance and stomatal functionality were assessed. The use of KIN did not induce the formation of microshoots. On the other hand, the shoot number increased with rising BAP concentration. There was a reduction of the maximum fluorescence (Fm) and maximum quantum yield (φP0) as a function of concentration of cytokinins. The most pronounced decrease was observed in the microshoots grown with KIN. The increase in concentration of cytokinins induced greater absorption flux (ABS/RC), trapping flux (TR0/RC) and dissipation flux (DI0/RC) of energy per reaction center. The stomatal functionality declined with rising cytokinin concentration. The use of KIN is not recommended for in vitro multiplication of this species. The use of BAP at low concentrations assures a multiplication rate with lower degree of disorders in the photosynthetic apparatus of the formed microshoots.

Effect of nitrogen, phosphorus and calcium on in vitro growth and development of Aechmea blanchetiana

Effect of nitrogen, phosphorus and calcium on in vitro growth and development of <i>Aechmea blanchetiana</i>

DETERMINATION OF METALS IN WATER AND LEAF OFAechmea blanchetiana(Baker) L.B

The aim of this research was to determine the concentrations of calcium, iron, manganese, zinc, potassium and sodium in the water and leaves of Aechmea blanchetiana (Baker) L.B species collected between the cities of Ilheus and Itacare, Bahia, Brazil and verify if the metals found in the water can be absorbed by the leaves. Flame atomic absorption spectrometry (F AAS) and flame photometry were used for the determination of metals. pH measurements, dissolved oxygen and water temperature were also made. The results obtained were used in an exploratory analysis. Principal component analysis (PCA) showed clearly the distinct formation of two clusters and the correlation analysis indicated that the leaves of A. blanchetiana seem to absorb iron, calcium, manganese and zinc from the water tank.

Análise da epiderme foliar durante a aclimatização de bromélia micropropagada

O objetivo do trabalho foi estudar as alterações anatômicas na epiderme de folhas de bromélia ornamental (Aechmea blanchetiana) micropropagadas, durante o período de aclimatização, no qual ocorre grande perda de plantas, e o início da produção comercial em estufa. Realizou-se a análise, em microscopia fotônica, das características estruturais da epiderme abaxial de folhas da espécie, provenientes de mudas cultivadas in vitro, nas plantas aos 0, 7, 28, 49, 70 e 91 dias de aclimatização. Foram utilizadas as técnicas usuais no preparo do material para obtenção das lâminas semipermanentes de secções paradérmicas. A densidade estomática foi determinada na região mediana da folha. Os parâmetros estudados evidenciaram alterações anatômicas significativas nas primeiras semanas, sendo que a espessura das paredes celulares epidérmicas, a densidade dos estômatos, e a área e densidade das escamas apresentaram diminuição considerável nas primeiras semanas de aclimatização. A partir dos 49 dias, as folhas apresentaram características da planta adulta, possivelmente indicando o término do período de aclimatização.

EFFECT OF POTASSIUM ON THE CONTENTS OF MICRONUTRIENTS ON IN VITRO CULTURE OF AECHMEA BLANCHETIANA (BROMELIACEAE)

This study investigated the contents of micronutrients in leaves of an in vitro ornamental bromeliad, Aechmea blanchetiana, cultured on media with different concentrations of potassium. In vitro seedlings were cultured in modified MS liquid medium with 2.5, 5, 10, 20 or 40 mM potassium. Concentrations of MS nutrients were adjusted by ionic balance. The copper, iron, manganese and zinc in the leaves of A. blanchetiana were found to decrease when the potassium concentration increased, whilst the boron content in leaves did not change.

Micropropagation of the ornamental vulnerable bromeliads Aechmea blanchetiana and Aechmea distichantha

Aechmea blanchetiana and Aechmea distichantha are Brazilian native bromeliads with great ornamental value, although none of the species are produced commercially. Therefore, market demands are met through nature predatory exploitation. This study intended to (1) evaluate the in vitro seed germination of A. blanchetiana and A. distichantha and (2) establish micropropagation protocols for both species, aiming at producing plantlets for the market, as well as to germplasm in vitro conservation. Germination experiments were carried out in completely randomized designs with two treatments (presence and absence of light) and seven and eight replications respectively for A. blanchetiana and A. distichantha. In vitro seedlings, produced under light conditions, were used as explants in the multiplication experiment (MS medium). The experimental design was again completely randomized, with treatments in factorial 2 (NAA concentrations; 0.05 and 0.5 μM) x 2 (cytokines: BAP and KIN) x 2 (cytokine levels: 2.2 and 4.4 μM) + 1 (control with basal MS, without growth regulators), with ten replications per treatment. We evaluated fungal and bacterial contamination, total and cumulative seed germination and number of shoots per treatment in each subculture. We observed only fungal contamination and only in A. blanchetiana (14.0%). Light favored in vitro seed germination in both species (99 and 62% respectively for A. blanchetiana and A. distichantha). MS medium + 0.5 μM NAA + 2.2 μM BAP resulted in the highest multiplication rate for both species, with significant contrasts between this treatment and the control in both species (105.62 more shoots in A. blanchetiana; 223.80 in A. distichantha). BAP promoted the formation of rootless shoots, while kinetin favored the formation of roots rather than shoots. A. blanchetiana and A. distichantha showed 90 and 97% of survival respectively in plantlet acclimatization.

Effects of leaf herbivory on the bromeliad Aechmea blanchetiana: a study of selective feeding by the scraper Acentroptera pulchella

The scraper Acentroptera pulchella (Chrysomelidae, Hispinae) feeds on the leaves of Aechmea blanchetiana (Bromeliaceae), but not indiscriminately. This insect apparently concentrates its attack on the apical region of the intermediate leaves from the bromeliad tank. To characterise the potential influence of leaf defensive strategies on the intraspecific feeding pattern of A. pulchella on the leaves of the bromeliad A. blanchetiana, we quantified the apparent intraspecific preference of this feeding pattern; compared distinct leaves and portions in relation to morpho-physiological, mechanical, nutritional and chemical anti-herbivore strategies; and investigated whether some or all these defensive strategies help explain the observed feeding pattern. A. pulchella preferentially attacked the mid-upper portions of mature and adult leaves of A. blanchetiana, but not the mid-lower portions of the same leaves, which are more resistant to punch, are thicker and present less nitrogen content than the upper portions. However, soft young leaves were not attacked. Attacked portions also presented higher total phenol content than did non-attacked portions, indicating that phenols do not act defensively. Other morpho-physiological and chemical anti-herbivore strategies evaluated did not differ between portions and leaves. This herbivore feeds preferentially on leaf portions that have higher nitrogen levels, avoiding others that present increased punch resistance. The scraper A. pulchella exhibits a clearly selective feeding pattern that is driven by nutritional benefits rather than strictly mechanical or chemical anti-herbivore strategies.

Effect of spermidine on ornamental bromeliad cultured in vitro

Plants of the ornamental bromeliad, Aechmea blanchetiana (Baker) L.B. Smith obtained from seeds germinated in vitro , were treated with spermidine (Spd) at various concentrations (0, 10, 50 and 250 μM) or in the presence of 1.07 mM α-naphthaleneacetic acid (NAA) + 22.20 mM 6-benzyladenine (BA) or 0 mM NAA + 0 mM 6-BA for shoot induction and 0, 1.07 and 5.37 mM of NAA for root induction. The number of shoots, fresh and dry weight of shoots on shoot induction and fresh and dry weight of shoots and roots on root induction, and activity of peroxidases were evaluated. Polyamine Spd was not effective on shooting induction, rooting, mass accumulation of fresh and dry weight and had no influence on the activity of the enzyme peroxidase, and had a deleterious effect on dry matter accumulation in the treatment for shooting induction. Spd improved the qualitative and quantitative responses of in vitro rhizogenesis of A. blanchetiana as compared to the free polyamine medium. Peroxidase activity was higher in leaves of plants subjected to shoot induction, with 6-BA+NAA. The exogenous spermidine did not have effect on peroxidase activity. Keywords: Bromeliad, micropropagation, peroxidase activity, polyamine

Acúmulo de minerais em Aechmea blanchetiana (Baker) L.B. Smith (Bromeliaceae), contaminadas com zinco em cultivo in vitro

Com o objetivo de estudar a absorção e translocação de Ca, Co, Fe, K e Zn em Aechmea blanchetiana, plantas foram cultivadas in vitro em meios de cultivo contendo concentrações de Zn (0,0; 0,18; 1,8; 18 e 180 mg Zn L-1). Após 16 semanas de cultivo, os sistemas aéreo e radicular foram separados e determinadas à massa seca para massa de matéria seca e para a análise por ativação com nêutrons (AAN). O procedimento consistiu em irradiar amostras e padrões no reator nuclear de pesquisa IEA-R1 por 16 h para análise por espectrometria de raios gama. O controle dos resultados foi avaliado por meio das análises dos materiais de referência certificados, com desvios padrão relativo de 9,1 % e erros inferiores a 12,9 %. Os resultados das determinações dos elementos mostraram que o Zn alterou absorção e translocação de Ca, Co, Fe, K e Zn. A espécie apresentou alta quantidade de Zn nos sistemas aéreo e radicular indicando, possivelmente, ser bioacumuladora desse elemento.

Analysis of tolerance to copper and zinc in Aechmea blanchetiana grown in vitro

The aim of this study was to evaluate the growth and development of Aechmea blanchetiana Baker L.B. Sm. in vitro on medium with 0.0, 0.145, 1.45 and 14.5 μM Cu and 0.0, 2.75, 27.5 and 275 μM Zn. Significant accumulation of Cu and Zn occurred at 14.5 μM Cu and 27.5 and 275 μM Zn, respectively, and there were no significant changes in contents of the other macro- and micronutrients. Superoxide dismutase (SOD) activity significantly changed in the presence of both metals. Spermine content increased as Zn concentration increased and decreased with increasing concentrations of Cu. There was an accumulation of H2O2 in the leaf tissue of plants grown in 1.45 and 14.5 μM Cu and 27.5 and 275 μM Zn. A. blanchetiana was found tolerant to the Cu and Zn in concentrations used in this study and displays the capacity to accumulate these metals.

Analysis of tolerance to copper and zinc in Aechmea blanchetiana grown in vitro

The aim of this study was to evaluate the growth and development of Aechmea blanchetiana Baker L.B. Sm. in vitro on medium with 0.0, 0.145, 1.45 and 14.5 &mu;M Cu and 0.0, 2.75, 27.5 and 275 &mu;M Zn. Significant accumulation of Cu and Zn occurred at 14.5 &mu;M Cu and 27.5 and 275 &mu;M Zn, respectively, and there were no significant changes in contents of the other macro- and micronutrients. Superoxide dismutase (SOD) activity significantly changed in the presence of both metals. Spermine content increased as Zn concentration increased and decreased with increasing concentrations of Cu. There was an accumulation of H2O2 in the leaf tissue of plants grown in 1.45 and 14.5 &mu;M Cu and 27.5 and 275 &mu;M Zn. A. blanchetiana was found tolerant to the Cu and Zn in concentrations used in this study and displays the capacity to accumulate these metals.