Leaf anatomy and photosynthetic carbon metabolic characteristics in Phragmites communis in different soil water availability

Abstract

To investigate the variations of anatomical and photosynthetic carbon metabolic characteristics within one species in response to increasing soil water stress, leaf anatomical characteristics, gas exchange and the activity of key enzymes in photosynthesis and photorespiration were compared in different ecotypes of Phragmites communis growing in an oasis-desert transitional zone (ODTZ) from swamp habitat (plot 1-3) via heavy salt meadow (plot 4-7) and light salt meadow habitat (plot 8-9) to dune habitat (plot 10-13) in Northwest China. The results showed that interveinal distance (ID) decreased with increasing water stress except that in plots of dune reed (DR). Vein mean diameter (VMD) in plot 10, 11 and 12 of the DR was significantly larger than that in other ecotypes. Leaf specific porosity (LSP) enhanced from plot 4 to plot 13 from heave salt meadow reed (HSMR) to light salt meadow reed (LSMR) and to DR. Chlorophyll fluorescence in bundle sheath cells were microscopically found in four ecotypes, especially significantly in the DR. Net CO 2 assimilation rate (A n ) dropped rapidly from the swamp reed (SR) to the HSMR and then increased progressively from the LSMR to the DR. Stomatal conductance (g s ) decreased and the water use efficiency (WUE) rose from the wet to the dry ecotypes. Sensitivity of g s to intercellular CO 2 concentration (C i ) increased, but glycolate oxidase (GO) activity gradually reduced with increasing soil water deficiency. The RuBPCase activity did not reduce in four ecotypes even in DR, but, the PEPCase and NAD-ME activities as well as the ratio of PEPCase/RuBPCase were gradually enhanced with increasing soil water stress. We concluded that anatomical and photosynthetic carbon assimilating characteristics in P. communis were developing to the direction of C 4 metabolism in response to the increasing drought stress in desert areas. The DR enduring severe water stress had more C 4 like photosynthetic features than the HSMR and LSMR as well as SR, according to significantly increased VMD and LSP and higher g s sensitivity to C i as well as higher PEPCase activity and lower GO activity in the DR.

Morphophysiology, morphoanatomy, and grain yield under field conditions for two maize hybrids with contrasting response to drought stress

“…This characteristic provides higher ability in translocating photoassimilates and higher distribution of water in leaves (Sage 2004). Similar data were also found in Phragmites communis subjected to drought (Gong et al 2011).…”

Global regulation of reactive oxygen species scavenging genes in alfalfa root and shoot under gradual drought stress and recovery

“…1). Previous studies on GLO regulation under drought stress found no consensus, with some finding reduction in GLO activity 11,21 consistent with our results, and others finding an increase in GLO gene expression 22 and protein activity [23][24][25] under drought.…”

Presence of chloroplasts in mestome sheath cells of the C3 Pooid grass Elymus tsukushiensis

“…The PS cells had smaller and fewer chloroplasts than mesophyll cells had ( Figures 1-3). Although some ecotypes of Phragmites communis have recently been reported to have C 3 -C 4 intermediate or C 4 -like traits (Gong et al, 2011;Zhu et al, 2012), the PS cells of our plants had only a few small chloroplasts, as is typical of C 3 grasses (Figures 1(b) and 3 (a)). Under the light microscope, it was not easy to determine the presence or absence of small chloroplasts in MS cells: they were barely visible in E. tsukushiensis (Figure 1(a)) and not visible in P. communis (Figure 1(b)) and L. japonica (Figure 1(c)).…”