Publications (3)2.82 Total impact
- [Show abstract] [Hide abstract] ABSTRACT: The amount and conformation of light-harvesting chlorophyll a/b-protein complex (LHC II) of photosystem II and the expression of a gene encoding for LHC II were investigated when maize (Zea mays L.) seedlings were exposed to water stress and rewatering. The relative water content (RWC) and water potential in maize leaves decreased markedly after 72 h of water stress; the content of chlorophyll and apoproteins of LHC II and the mRNA level of a gene encoding for LHC II were reduced pronouncedly, but not recovered after 24 h of rewatering. However, the conformation of LHC II in thylakoids was also altered by water stress but could be recovered by 24 h of rewatering. The authors proposed that two ways of dissipating relative excess excitation energy may be encountered in the photosynthetic membrane. A fast way is by changing the conformation of LHC II and another relatively slow way is the reduction of components of LHC II , through which the reduction of apoproteins of LHC II can be regulated partly at the transcript level.
- [Show abstract] [Hide abstract] ABSTRACT: Three ecotypes of reed (Phragmites communis Trinius), swamp reed (SR), dune reed (DR), and heavy salt meadow reed (HSMR), growing in desert regions of northwest China were simultaneously investigated in their natural state for gas exchange patterns and the expression of three photosynthesis-related genes, cab (the gene for the light-harvesting chlorophyll a/b binding protein, LHC), psbA (the gene for the reaction centre D1 protein of photosystem 2, PS2), and 16S rDNA (the gene for plastid 16S rRNA). Stomatal conductance (gs) and intercellular CO2 concentration (ci) were markedly lower in the two terrestrial ecotypes (DR and HSMR) as compared to SR, paralleling a similar observed depression in net photosynthetic rate (PN). However, DR with the lowest measured gs and ci still exhibited a higher PN compared to HSMR. These results suggest that both stomatal and non-stomatal factors account for the comparatively low carbon assimilation in the terrestrial ecotypes. An increase in the expression of photosynthesis-related genes was observed in DR compared to SR, whereas the reverse situation was true in HSMR. The expression of photosynthesis-related genes may contribute to reed plants' photosynthetic capacity per leaf area under natural water deficits, but the levels of photosynthesis-related gene expression are not directly correlated with reed plants' general ability for survival and adaptation under water deficient conditions.
- [Show abstract] [Hide abstract] ABSTRACT: There is a distinct leaf shape polymorphism within a single plant of P. euphratica Olivier. The anatomical structure, carbon isotope discrimination (Δ13C), and stomatal and photosynthetic behaviour were investigated in broad-ovate (BOL) and lanceolate (LL) leaves, located at the top and bottom in crown, respectively, of a mature Euphrates poplar growing in its native habitat. Both types of leaves had a non-Kranz anatomy and low Δ13C values. However, Δ13C of a LL was in average 3.2‰ larger than that of a BOL. In comparison with the LL, the BOL had a smaller stomatal conductance, causing subsequent decreases in transpiration rate and ratio of CO2 concentrations in intercellular spaces to air. Carbon assimilation rate and water use efficiency were higher in the BOLs than in the LLs. The BOL exhibited C4-like enzymological features, the activity of glycollate oxidase, and the ratio of activities of ribulose-1,5-bisphosphate carboxylase (RuBPC) to phosphoenolpyruvate carboxylase (PEPC) was lower in BOL than in LL throughout the whole growing season. The lowered ratio of RuBPC/PEPC in BOL was mainly associated with a marked decline in the activity of RuBPC, and only a slight increase in the activity of PEPC. These differences might contribute to microclimate adaptation in both types of leaves. broad-ovate leaf–Δ13C–glycollate oxidase–lanceolate leaf–leaf morphology and anatomy–phosphoenolpyruvate carboxylase–polymorphism–poplar–ribulose-1,5-bisphosphate carboxylase/oxygenase
Lanzhou UniversityKao-lan-hsien, Gansu Sheng, China