Effects of salinity on photosynthetic characteristics in photomixotrophic cell-suspension cultures from Alternanthera philoxeroides

Abstract

We studied the effect of NaCl salinity on the development of cellular photosynthesis using a green, photomixotrophic, cell-suspension culture of Alternanthera philoxeroides (Mart.) Griseb. For these cells, increasing the concentration of sucrose in the media produces a rapid drop in net photosynthetic rate, which recovers as sucrose is depleted from the media. This predictable recovery provides a simple system to examine cellular photosynthetic development. Cells, unadapted to high salinity, were transferred to nutrient media with 30 mM sucrose (Control) or nutrient media with 30 mM sucrose and 100 mM NaCl (Salt). A dramatic increase in the dark respiration rate of Control and Salt cells during the first 6 d of the experiment produced net oxygen consumption in the light. The high dark respiration rates during this period were accompanied by a decline in total Chl and the amounts of two photosynthetic proteins, the light harvesting Chl a/b binding protein of photosystem II (LHCP) and the small subunit of ribulose-1,5-bisphosphate carboxylase/oxygenase (rubisco SSU). The dark respiration rate of Salt cells was greater than that of Control cells on days 4-8. After day 4, dark respiration rates decreased and net photosynthesis increased to stable values in both treatments at day 11 after media sucrose concentration reached a minimum. As dark respiration rates decreased and net photosynthetic rates increased, total Chl and the amounts of LHCP and rubisco SSU increased in both Control and Salt cells. The slower development of photosynthetic capacity in salt cells was correlated with a fresh weight that was 20% lower than that of control cells at the end of the experiment.

Differences in ecological and allelopathic traits among Alternanthera philoxeroides populations

“…2008). Other ecological factors, such as sunlight, temperature, salt and pH, can influence the survival strategy of alligator weed (Mudalige & Longstreth 2006; Willingham et al . 2008).…”

Physiological responses to salinity in Silver buffaloberry (Shepherdia argentea) introduced to Qinghai high-cold and saline area, China

“…Stomatal factors include the decrease of g s and the reduction of C i caused by stomatal closure (Stępień andKłbus 2006, Youssef andAwad 2008). Nonstomatal factors include the decrease in chlorophyll (Chl) content (Ranjbarfordoei et al 2006, Gratani et al 2008, the changes in chloroplast ultrastructure (Bergmann et al 2008), the depression in photosystem activity and electron transport (Bastías et al 2004, Lu et al 2008, and the decline in the activity and content of Rubisco (Mudalige andLongstreth 2006, Lu et al 2009). However, there are still some debates on the relative contribution of stomatal and non-stomatal factors to the decline of photosynthesis under salinity.…”

Influence of salt stress on propagation, growth and nutrient uptake of typical aquatic plant species

“…Seven aquatic plant species were used in this study (Table 1), because they are common aquatic plants and known to exhibit salt tolerance to some extent (Calhoun and King 1998, Hunter et al 2000, Mudalige and Longstreth 2006, Sanchez et al 2015, Liang et al 2017a, Liu et al 2018, Xue et al 2018. All species were collected as mature plants from wild populations in Suqian, Jiangsu Province of China in July 2016.…”