Effects of Salinity on the Photosynthesis of Two Poaceous Halophytes

Abstract

To explore the difference of C4 and C3 photosynthetic pathways in responding to high salinity and its potential role in determining vegetation zonation in coastal saltmarshes, two Poaceous halophytes, C4 Spartina alterniflora and C3 Phragmites australis, were studied with different salinities. The results showed that proper salinities were required for both species to maintain optimal photosynthesis. The maximal net assimilation rates of S. alterniflora and P. australis appeared with 400 and 100 mmol L−1 NaCl, respectively. Both species exhibited similar responses of stomatal conductance towards the set salinities, and chlorophyll contents in P. australis were even promoted by 100–400 mmol L−1 NaCl. Although no significant changes in the maximal quantum yield of photosystem II were found in either species treated by NaCl, instant quantum yield of photosystem II of P. australis was significantly decreased, whereas that of S. alterniflora increased. We suggest that the zonation between S. alterniflora and P. australis is not exclusively caused by the CO2‐concentrating mechanism of the C4 pathway and stomatal conductance is not a restricting factor for either species. It might be that the electron transfer from photosystem II and the energy use efficiency being limited in the C3 P. australis grown under high salinity.

Progress in the Study and Use of Seawater Vegetables

“…The absorption, transfer, and conversion of light energy are completed by pigment complexes in the chloroplast. 93,94 Chlorophyll (Chl) is an important photosynthetic pigment in plant chloroplasts. Chlorophyll can collect light energy in the antenna system and drive electron transfer in the reaction center.…”

“…The absorption, transfer, and conversion of light energy are completed by pigment complexes in the chloroplast. , Chlorophyll (Chl) is an important photosynthetic pigment in plant chloroplasts. Chlorophyll can collect light energy in the antenna system and drive electron transfer in the reaction center. − Studies have shown that salt stress can reduce chlorophyll content. However, salt-tolerant halophytes are reduced less than salt-sensitive plants.…”

Structural modifications in Bermuda grass [Cynodon dactylon (L.) Pers.] ecotypes for adaptation to environmental heterogeneity

“…Storage parenchyma in leaf midrib has only been recorded in the PA-HS ecotype, and this characteristic confirms its better performance in extreme salinity ( Paramonova et al., 2004 ). Moreover, aerenchyma also aids in bulk salt movement in excretory halophytes ( Zhou et al., 2015 ). Therefore, presence of root aerenchyma can be related to ecological success of C. dactylon in a variety of environments.…”

Water conservation strategies through anatomical traits in the endangered arid zone species Salvadora oleoides Decne.

“…Vascular bundles presented a rare formation, xylem in two patches surrounded on each side by phloem. Lignin deposition is a strong response of environmental stresses like aridity (Zhou et al, 2015), salinity (Alam et al, 2015), and high temperature (Rashid and Ahmed, 2011;Ola et al, 2012) where water is a limited commodity. Increased lignification in and outside vascular tissue will ensure survival in hot and dry mountainous region.…”