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Background and Aims: Bromeliads are able to occupy some of the most nutrient-poor environments especially because they possess absorptive leaf trichomes, leaves organized in rosettes, distinct photosynthetic pathways [C 3 , Crassulacean acid metabolism (CAM) or facultative C 3 -CAM], and may present an epiphytic habit. The more derived features related to these traits are described for the Tillandsioideae subfamily. In this context, the aims of this study were to evaluate how terrestrial predators contribute to the nutrition and performance of bromeliad species, subfamilies and ecophysiological types, whether these species differ in their ecophysiological traits and whether the physiological outcomes are consistent among subfamilies and types (e.g. presence/absence of tank, soil/tank/atmosphere source of nutrients, trichomes/roots access to nutrients)., Methods: Isotopic ( 15 N-enriched predator faeces) and physiological methods (analyses of plant protein, amino acids, growth, leaf mass per area and total N incorporated) in greenhouse experiments were used to investigate the ecophysiological contrasts between Tillandsioideae and Bromelioideae, and among ecophysiological types when a predatory anuran contributes to their nutrition., Key Results: It was observed that Bromelioideae had higher concentrations of soluble protein and only one species grew more (Ananas bracteatus), while Tillandsioideae showed higher concentrations of total amino acids, asparagine and did not grow. The ecophysiological types that showed similar protein contents also had similar growth. Additionally, an ordination analysis showed that the subfamilies and ecophysiological types were discrepant considering the results of the total nitrogen incorporated from predators, soluble protein and asparagine concentrations, relative growth rate and leaf mass per area., Conclusions: Bromeliad subfamilies showed a trade-off between two strategies: Tillandsioideae stored nitrogen into amino acids possibly for transamination reactions during nutritional stress and did not grow, whereas Bromelioideae used nitrogen for soluble protein production for immediate utilization, possibly for fast growth. These results highlight that Bromeliaceae evolution may be directly associated with the ability to stock nutrients., (© The Author 2016. Published by Oxford University Press on behalf of the Annals of Botany Company. All rights reserved. For Permissions, please email: journals.permissions@oup.com.)

Background and Aims: Several members of Bromeliaceae show adaptations for hummingbird pollination in the Neotropics; however, the relationships between floral structure, nectar production, pollination and pollinators are poorly understood. The main goal of this study was to analyse the functional aspects of nectar secretion related to interaction with pollinators by evaluating floral biology, cellular and sub-cellular anatomy of the septal nectary and nectar composition of Ananas ananassoides, including an experimental approach to nectar dynamics., Methods: Observations on floral anthesis and visitors were conducted in a population of A. ananassoides in the Brazilian savanna. Nectary samples were processed using standard methods for light and transmission electron microscopy. The main metabolites in nectary tissue were detected via histochemistry. Sugar composition was analysed by high-performance liquid chromatography (HPLC). The accumulated nectar was determined from bagged flowers ('unvisited'), and floral response to repeated nectar removal was evaluated in an experimental design simulating multiple visits by pollinators to the same flowers ('visited') over the course of anthesis., Key Results: The hummingbirds Hylocharis chrysura and Thalurania glaucopis were the most frequent pollinators. The interlocular septal nectary, composed of three lenticular canals, extends from the ovary base to the style base. It consists of a secretory epithelium and nectary parenchyma rich in starch grains, which are hydrolysed during nectar secretion. The median volume of nectar in recently opened 'unvisited' flowers was 27·0 µL, with a mean (sucrose-dominated) sugar concentration of 30·5 %. Anthesis lasts approx. 11 h, and nectar secretion begins before sunrise. In 'visited' flowers (experimentally emptied every hour) the nectar total production per flower was significantly higher than in the 'unvisited' flowers (control) in terms of volume (t = 4·94, P = 0·0001) and mass of sugar (t = 2·95, P = 0·007), and the concentration was significantly lower (t = 8·04, P = 0·0001)., Conclusions: The data suggest that the total production of floral nectar in A. ananassoides is linked to the pollinators' activity and that the rapid renewal of nectar is related to the nectary morphological features.

Background and Aims: Plants with crassulacean acid metabolism (CAM) can be divided into two groups according to the major carbohydrates used for malic acid synthesis, either polysaccharide (starch) or monosaccharide (hexose). This is related to the mechanism and affects energy metabolism in the two groups. In Kalanchoë pinnata and K. daigremontiana, which utilize starch, ATP-dependent phosphofructokinase (tonoplast inorganic pyrophosphatase) activity is greater than inorganic pyrophosphate-dependent phosphofructokinase (tonoplast adenosine triphosphatase) activity, but the reverse is the case in pineapple (Ananas comosus) utilizing hexose. To test the hypothesis that the energy metabolism of the two groups differs, day-night changes in the contents of ATP, ADP, AMP, inorganic phosphate (Pi), phosphoenolpyruvate (PEP) and inorganic pyrophosphate (PPi) in K. pinnata and K. daigremontiana leaves and in pineapple chlorenchyma were analysed., Methods: The contents of energy-rich compounds were measured spectrophotometrically in extracts of tissue sampled in the light and dark, using potted plants, kept for 15 d before the experiments in a growth chamber., Key Results: In the three species, ATP content and adenylate energy charge (AEC) increased in the dark and decreased in the light, in contrast to ADP and AMP. Changes in ATP and AEC were greater in Kalanchoë leaves than in pineapple chlorenchyma. PPi content in the three species increased in the dark, but on illumination it decreased rapidly and substantially, remaining little changed through the rest of the light period. Pi content of Kalanchoë leaves did not change between dark and light, whereas Pi in pineapple chlorenchyma increased in the dark and decreased in the light, and the changes were far greater than in Kalanchoë leaves. Light-dark changes in PEP content in the three species were similar., Conclusions: These results corroborate our hypothesis that day-night changes in the contents of energy-rich compounds differ between CAM species and are related to the carbohydrate used for malic acid synthesis.