Salt-induced respiration in Bruguiera cylindrica — role in salt transport and protection against oxidative damage

Abstract

Leaves of Bruguiera cylindrica plants grown in the greenhouse and irrigated with fresh water (FW plants) and those from salt-adapted plants from the seacoast (SW plants) showed about 5-fold and 3-fold increase in respiration, respectively, when immersed in 4M NaCl solution. The increase in respiration was not due to dehydration effect of high salt concentration, since PEG-imposed dehydration stress to the leaves led to an inhibition of respiration rates in both FW and SW plants. The saltinduced increase in respiration rate was specific to monovalent cations, especially Na + and K + , but not divalent or trivalent cations, and to Cl -, but not other anions. Pretreatment of leaves of FW plants with 1mM amiloride, an inhibitor of the Na + / H + antiporter, reduced the NaCl-induced respiration surge. At least some part of the observed respiratory increase could therefore be for providing energy for ion transport, since the Na + / H + antiport activity is driven by activities of the tonoplast and plasma membrane H + -ATPases and H + -PPases. Respiration of the leaves from both FW and SW plants was accounted for by the COX pathway and was inhibited by KCN. But 4M NaCl-induced increase in FW, but not SW plants, was inhibited by the AOX inhibitor, SHAM. Also, generation of ROS was reduced by treatment with KCN, but increased with SHAM. This pointed to a protective role of AOX in reducing ROS generation during salt-induced respiration. Our results indicated that NaCl-induced increase in leaf respiration of B. cylindrica plants irrigated with fresh water was required for (a) salt transport and (b) reducing the harmful effects of ROS that are known to accompany increased respiratory activity.

Distinct responses of growth and respiration to growth temperatures in two mangrove species

“…high O 2 respiration rate) for their maintenance and growth. Previous studies reported that leaf and root respiration rates of mangrove species in the genera Avicennia , Bruguiera and Rhizophora lie within the range of 1–6 nmol O 2 or CO 2 g −1 s −1 ( Burchett et al , 1984 ; Hovenden et al , 1995 ; Lovelock et al , 2006 ; Atreya and Bhargava, 2008 ). This range is lower than that of terrestrial plants, i.e.…”

NaCl-stimulated ATP synthesis in mitochondria of a halophyte Mesembryanthemum crystallinum L.

“…ATP is needed in the processes of growth, and thus, ATP synthesis would also be increased for the growth enhancement stimulated by NaCl. Several previous studies have observed variances in mitochondrial respiration rate in some halophyte species under salt stress conditions (Atreya & Bhargava, 2008;Jacoby, Taylor & Millar, 2011). For example, recent proteomics-based studies have proposed an increase of mitochondrial ATP synthesis in several halophytes under salinity, such as Thellungiella halophila (Wang et al, 2013), Kandelia candel (Wang et al, 2014), and Puccinellia tenuiflora (Yu et al, 2011), through the observation of increased abundances of proteins involved in tricarboxylic acid (TCA) cycle, electron transport chain (ETC) complexes, and ATP synthases.…”