Metabolite gradients and carbohydrate translocation in rosette leaves of CAM and C3 bromeliads

Abstract

Summary• The Bromeliaceae encompass predominantly rosette, terrestrial or epiphytic species, including C3 and crassulacean acid metabolism (CAM) photosynthetic types within its three subfamilies. Here, leaf diurnal changes and longitudinal gradients of soluble sugars, organic acids and starch, were quantified to estimate the rates of carbohydrate translocation from mature leaves of C3 and CAM species.• Leaves of Ananas comosus , Aechmea fendleri , Bromelia humilis , Guzmania mucronata , Tillandsia fendleri , Tillandsia flexuosa and Tillandsia utriculata , were sampled at the base, middle, and upper sections during the day. We measured osmolality in sap from frozen subsamples, sugars and organic acids in hot-water extracts from microwave-dried subsamples, and starch hydrolysed with α -amylase or 1.1% HCl.• CAM activity was expressed by malate accumulation, citrate was present, but fluctuations were not significant. Nocturnal reductions in sucrose in bromelioid CAM species accounted for most of the acidification requirements. Tillandsioid CAM species used starch for acid synthesis. Both CAM and C3 bromeliads exported significant amounts of hexose during the night, particularly from the leaf base.• Leaf bases of CAM species showed lowest acid accumulation but similar or more positive δ 13 C-values to the active CAM sections. Exported carbohydrates probably derive from carbon fixed during the night period.

Effect of low irradiance on the photosynthetic performance and spiking of Phalaenopsis

“…The contents of organic acids (malate and citrate) were calculated from the integrated peak area of the corresponding standards, total organic acid [μg g [g]. The amount of malic acid accumulated nocturnally can be estimated by its content at 06:00 minus that at 18:00 (Popp et al 2003).…”

“…Sediment was digested with a mixture of pullulanase and amyloglucosidase and the released glucose was estimated by a glucose oxidase and peroxidase method to determine the starch content (Chen et al 2008). The amount of starch deposited at day time can be estimated by its content at 18:00 h minus that at 06:00 h (Popp et al 2003).…”

Environment or Development? Lifetime Net CO2 Exchange and Control of the Expression of Crassulacean Acid Metabolism inMesembryanthemum crystallinum

“…Since then, there have been frequent reports of some CAM activity in well-watered, non-salt-treated mature to old plants (e.g. Cushman et al, 1990) and M. crystallinum is now commonly described in the literature as ''a halophyte with a developmentally programmed switch from C 3 photosynthesis to CAM which is accelerated by salinity and drought'' (p. 171; Adams et al, 1998; see also Herppich et al, 1992;Cushman, 2001;Yen et al, 2001;Cushman and Bohnert, 2002;Cushman and Borland, 2002;Grams and Thiel, 2002;Black and Osmond, 2003;Dodd et al, 2003;Popp et al, 2003;Trofimova et al, 2003;Berg et al, 2004;Bozhko et al, 2004;Hurst et al, 2004;Libik et al, 2004;Lü ttge, 2004;Niewiadomska et al, 2004).…”

Stomatal Biology of CAM Plants

“…One promising route for future research will be to make use of known C 3 -CAM intermediates and facultative CAM species as tools for exploring the molecular changes associated with the commencement of CAM stomatal rhythms (Winter and Holtum, 2014;Brilhaus et al, 2016). The identification of gradients in the relative contributions of C 3 and CAM along the linear leaves of C 3 -CAM intermediate monocot species is another naturally occurring system ripe for further investigation (Popp et al, 2003;Freschi et al, 2010). Increasingly sensitive technologies will improve the ease of in situ and ex situ physiological characterization (e.g.…”