Photosynthetic parameters of sexually different parts of Porphyra katadai var. hemiphylla (Bangiales, Rhodophyta) during dehydration and re-hydration

Abstract

Physiological data from extreme habitat organisms during stresses are vital information for comprehending their survival. The intertidal seaweeds are exposed to a combination of environmental stresses, the most influential one being regular dehydration and re-hydration. Porphyra katadai var. hemiphylla is a unique intertidal macroalga species with two longitudinally separated, color distinct, sexually different parts. In this study, the photosynthetic performance of both PSI and PSII of the two sexually different parts of P. katadai thalli during dehydration and re-hydration was investigated. Under low-grade dehydration the variation of photosystems of male and female parts of P. katadai were similar. However, after the absolute water content reached 42%, the PSI of the female parts was nearly shut down while that of the male parts still coordinated well and worked properly with PSII. Furthermore, after re-hydration with a better conditioned PSI, the dehydrated male parts were able to restore photosynthesis within 1 h, while the female parts did not. It is concluded that in P. katadai the susceptibility of photosynthesis to dehydration depends on the accommodative ability of PSI. The relatively lower content of phycobiliprotein in male parts may be the cause for a stronger PSI after severe dehydration.

Activities of principal photosynthetic enzymes in green macroalga Ulva linza: functional implication of C4 pathway in CO2 assimilation

“…The following formulae were used to calculate the optimum quantum yield (F v /F m ) and the effective PS II quantum yield (Y(II)), which reflect the potential and the actual rate of photosynthesis, respectively [31]:…”

Morphological and photosynthetic variations in the process of spermatia formation from vegetative cells in Porphyra yezoensis Ueda (Bangiales, Rhodophyta) and their responses to desiccation

“…The samples were then placed on a culture dish and allowed to dry naturally at room temperature (*20°C) (Burritt et al 2002;Shafer et al 2007;Lin et al 2009b). The relative water content (RWC) of a thallus was calculated according to the for-…”

Chlorophyll Fluorescence Characteristics Responses of Two Strains of Porphyra haitanensis to Emersion and Submersion

“…One of the most important factors that restrict the development of photosynthetic organisms is water deficiency (Bukhov et al, 2004;Lin et al, 2009;Ma et al, 2016). When exposed to high light and temperature stress, many species of Porphyra lose 85-95% of their cellular water during daytime low tides (Blouin et al, 2011).…”

“…Chlorophyll fluorescence has recently been used as an independent method for assessing algal physiology in aquatic environments (Lin et al, 2009;Prasil et al, 2008). Compared with the apparent gas exchange index, pulse amplitude modulated (PAM) fluorescence instruments can be used to study chlorophyll fluorescence parameters that reflect their intrinsic physiological characteristics.…”

“…The chlorophyll fluorescence kinetics technique is a fast, noninvasive assay for measuring leaf photosynthetic function, especially in photosystem II (PS(II)) functional studies (Schreiber et al, 1994;Zhao et al, 2010). In particular, PAM fluorometry has been widely used in investigating photosynthetic properties of algae (Lin et al, 2009;Li et al, 2013;Liu et al, 2017;Wang et al, 2016), making it possible to study the chlorophyll fluorescence characteristics of P. haitanensis in both emersed and submersed conditions.…”