The effect of irradiance and temperature on the photosynthesis of two agarophytes Gelidium elegans and Pterocladiella tenuis (Gelidiales) from Kagoshima, Japan

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SUMMARY Knowledge concerning the effects of several abiotic factors on the physiology of carrageenophytes is essential both in ecological and economic standpoints, to ensure their sufficient supply for the sustainability of seaweed‐based industries. This paper presents the photosynthetic characteristics of farmed carrageenophytes, E ucheuma denticulatum and K appaphycus alvarezii [brown (BRN) and green (GRN) color morphotypes] from Sulawesi Utara (Sulawesi Island), Indonesia, as determined by examining their photosynthetic response across different temperatures and irradiances using dissolved oxygen measurements and pulse‐amplitude modulated fluorometer. Net photosynthesis–irradiance ( P – E ) curves at 26°C revealed that net photosynthetic rates of the three seaweeds gradually increased until the estimated saturation irradiances ( E k ) of 58 μmol photons m− 2 s−1 (49–68 μmol photons m− 2 s−1, 95% Bayesian prediction intervals; BPI) for E . denticulatum, and 158 and 143 μmol photons m− 2 s−1 (134–185 and 99–203 μmol photons m− 2 s−1, 95% BPI) for BRN and GRN K . alvarezii, respectively; and that no photoinhibition was observed at the highest irradiance of 1000 μmol photons m− 2 s−1. All seaweed samples exhibited photosynthetic tolerance to high PAR as shown by their recovery in maximum quantum yields (Fv / Fm ) following chronic exposures; as well as tolerance over a broad range of temperature, which is from 19 to 33°C for E . denticulatum, 20–29°C for BRN K . alvarezii, and 17–32°C for GRN K . alvarezii. Temperature responses of these carrageenophytes indicated that they were well‐adapted to the annual seawater temperatures in the cultivation site; however, they are also likely close to threshold levels for thermal inhibition, given the decline in Fv / Fm above 30°C.

Section: Discussionmentioning

confidence: 86%

R_{d} = R_{24} italicexp ((),, - \frac{E_{a}}{R} ((),, \frac{1}{K - 297.15}))

…”

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Light and temperature effects on photosynthetic activity of Eucheuma denticulatum and Kappaphycus alvarezii (brown and green color morphotypes) from Sulawesi Utara, Indonesia

Borlongan

Gerung

Nishihara

et al. 2016

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“…Our recent studies have revealed the clear response of photosynthesis along a gradient of temperature and PAR for a number of commercially important algae using the pulse amplitude modulated (PAM) fluorometer (Watanabe et al , ,, ). We have previously noted that, assessing maximum and effective quantum yields ( F v / F m and Φ PSII ) of photosystem II under a variety of environmental conditions are a quick and valuable indicator of photosynthetic response (Fujimoto et al , ; Kokubu et al ; Terada et al ). Indeed, our recent study of Pyropia tenera (Kjellman) Kikuchi, Miyata, Hwang et Choi demonstrated that the optimum temperature ranges for F v / F m of the macroscopic gametophyte and microscopic sporophyte differed, and were most likely related to the temperatures occurring in their habitat (Watanabe et al , ).…”

Section: Introductionmentioning

confidence: 99%

Chronological change and the potential of recovery on the photosynthetic efficiency of Pyropia yezoensis f. narawaensis (Bangiales) during the sporelings frozen storage treatment in the Japanese Nori cultivation

Watanabe

Morikawa²,

Mine³

et al. 2017

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The chronological change of photosynthetic efficiency in a frozen storage treatment of the Japanese Nori cultivation industry was examined in the cultivated red alga, Pyropia yezoensis f. narawaensis (Saga-#5 Strain, Bangiales) by using pulseamplitude fluorometry. During the desiccation process that was conducted after the nursery cultivation season in November, the maximum quantum yield (F v /F m ) of the gametophytic sporelings growing on the Nori-net decreased monotonically with decreasing absolute water content (AWC), and was around 0.1 at 20% AWC. During frozen storage of the Norinet, the F v /F m of the frozen gametophyte was low but stable, and ranged between 0.10 AE 0.02 SD and 0.14 AE 0.05 SD. The magnitude of F v /F m for the gametophyte of the freezing treatment, after 10 min and 3 h of immersion in seawater, recovered quickly. After 10 min and 3 h of immersion, these values were 0.29 AE 0.12 SD and 0.47 AE 0.05 SD during the 14 days of freezing treatment, and 0.15 AE 0.02 SD and 0.29 AE 0.04 SD after 71 days of freezing treatment, and suggest that the ability to recover gradually decreased as the storage duration increased. The response of F v /F m from general cultivation (i.e., directly cultivated from the nursery cultivation season) and those after 47 days of freezing were almost identical, suggesting that the current Nori-net frozen storage period (6 or 7 weeks) was not detrimental to the gametophyte.

“…fitting the data to a non-linear P-I model and estimating P-I parameters and their differences at a time (e.g. Fujimoto et al 2014;Borlongan et al 2017). The data in our study were not paired and therefore we applied the latter approach by using the following P-I curve (Webb et al 1974;Jassby & Platt 1976;Platt et al 1980;Henley 1993) as the basal equation to fit P n :…”

Section: Photosynthesis and Respiration Ratesmentioning

confidence: 99%

Photosynthesis and growth of Ulva ohnoi and Ulva pertusa (Ulvophyceae) under high light and high temperature conditions, and implications for green tide in Japan

Nakamura

Kumagai

Tamaoki

et al. 2019

SUMMARY The macroalga Ulva ohnoi constitutes a considerable fraction of green tides in coastal areas of Japan, but little is known about the physiological characteristics of this species. To investigate the environmental factors that promote the formation of green tides, we tested the responses of U. ohnoi and another common Japanese species, Ulva pertusa, to various levels of irradiance at different water temperatures. Because the two species are morphologically similar, we identified them using the PCR‐restriction fragment length polymorphism method. Under laboratory conditions, we evaluated the photosynthetic, dark respiration, and relative growth rate at a range of water temperatures (5 to 35°C) and photosynthetically active radiation (0 to 1000 μmol photons m−2 s−1). The maximum gross photosynthetic rate of U. ohnoi was larger than that of U. pertusa. The dark respiration rates revealed no significant differences among the species and temperature conditions. At 500 μmol photons m−2 s−1, the relative growth rate of U. ohnoi was larger than that of U. pertusa in higher temperature and the difference was the largest at 20°C. The estimated compensation irradiance and estimated saturation irradiance of U. ohnoi and U. pertusa ranged from 0.709 to 5.510 and 40.530 to 58.674 μmol photons m−2 s−1, which were lower than those in other intertidal green macroalgae, from 6 to 11 and 50 to 82 μmol photons m−2 s−1, respectively. Thus, U. ohnoi which exists as free‐floating near the water surface and accumulating inside the green tide can survive extensively in the water column of the intertidal zone, furthermore, the species can maintain rapid growth in this situation. Therefore, as a result of this study, it is suggested that the ecological success of U. ohnoi in shallow waters such as the tidal flats, estuarine, and coasts of the inner bay in comparison with U. pertusa.