Changes in growth and photosynthesis linked with intensity and duration of salinity in Phragmites karka

Comparison of the Photosynthetic Capacity of Phragmites australis in Five Habitats in Saline‒Alkaline Wetlands

“…It is used to characterize the maximum potential of fixing CO 2 under conditions of sufficient light and CO 2 . Photorespiration refers to the consumption of superfluous substances by respiration when high amounts of [H] and ATP accumulate in the photoreaction but the photosynthetic dark reaction is inhibited so as to prevent their accumulation, affecting plant metabolism [ 26 , 27 , 28 , 29 ]. Therefore, the rate of photorespiration (Rl) in plants can reflect their photoreaction rate to a certain extent, and this then affects the final net photosynthetic rate.…”

Photosynthetic Adaptations and Oxidative Stress Tolerance in Halophytes from Warm Subtropical Region

“…The F v /F m in dicotyledonous halophytes such as Haloxylon stocksii (Ehsen et al 2019) and Zaleya pentandra (Ehsen et al 2017) as well as in monocotyledonous halophytes like Desmostachya bipinnata (Asrar et al 2017), Paspalidium geminatum, Paspalum paspalodes, and Sporobolus tremulus (Moinuddin et al 2017) was insensitive to salinity treatments. However, in some halophytes such as Panicum turgidum (Koyro et al 2013) and Phragmites karka (Shoukat et al 2019), a decline in F v /F m was observed only in high (400-600 or more mM NaCl) salinity. The ΦPSII of warm subtropical halophytes in response to salinity exposure varied differently among species (Table 1).…”

“…For instance, in the salt marsh succulent Halopeplis perfoliata, photosynthesis was affected by biochemical limitations (unchanged g s , higher Ci) by short-term exposure (after 7 days) and by CO 2 diffusive limitation (low g s ; low Ci) after 45 days under 600 mM NaCl salinity treatment (Rasool et al 2019). In contrast, the moderately tolerant halophyte grass Phragmites karka experienced CO 2 diffusive limitation after 7 days and biochemical limitation after 45 days under 300 mM NaCl (Shoukat et al 2019). Net CO 2 assimilation rates (P N ) are depressed under saline conditions in most halophytes, whereas photochemical light-harvesting machinery is less sensitive that eventually requires alternate sinks for excess energy of photons (Maricle et al 2007;Moinuddin et al 2017).…”

“…Effects of salinity on photosynthesis are highly complex ranging from direct effects in the form of stomatal/mesophyll resistance or alterations in photochemical/biochemical reactions to indirect impacts caused by overproduction of ROS (Chaves et al 2009;Koyro et al 2013). These may vary with duration/magnitude of salt stress, the developmental stage, and type of plant (Chaves et al 2009;Koyro et al 2013;Hussain et al 2019;Shoukat et al 2019Shoukat et al , 2020. For instance, in the salt marsh succulent Halopeplis perfoliata, photosynthesis was affected by biochemical limitations (unchanged g s , higher Ci) by short-term exposure (after 7 days) and by CO 2 diffusive limitation (low g s ; low Ci) after 45 days under 600 mM NaCl salinity treatment (Rasool et al 2019).…”

“…ΦPSII showed a transient increase under moderate (200 mM NaCl) salinity in Aeluropus lagopoides and Sporobolus tremulus (Moinuddin et al 2017). The ΦPSII remained unaltered in low/moderate salinity followed by a decline at high salinity in Desmostachya bipinnata (Adnan et al 2016;Asrar et al 2017), Panicum turgidum (Koyro et al 2013), Phragmites karka (Shoukat et al 2019), and Haloxylon stocksii (Ehsen et al 2019). Electron transport rate (ETR) of PSII in warm subtropical halophytes seems to be unaffected by low to moderate but not high salinity (Table 1).…”