in order to study the effects of co2 enrichment on growth and competitiveness of soybean (glycine max) and millet (panicum miliaceum) against redroot pigweed (amaranthus retroflexus) and lambsquarter (chenopodium albam) an experiment was conducted using two co2 concentrations (350 and 700 ppm). for evaluating effects of co2 variation on inter-and intra-specific competition plants were grown in ...

Global climate change is expected to shift regional rainfall patterns, influencing species distributions where they depend on water availability. Comparative studies have demonstrated that C4 grasses inhabit drier habitats than C3 relatives, but that both C3 and C4 photosynthesis are susceptible to drought. However, C4 plants may show advantages in hydraulic performance in dry environments. We ...

C4 photosynthesis evolved independently numerous times, probably in response to declining atmospheric CO2 concentrations, but also to high temperatures and aridity, which enhance water losses through transpiration. Here, the environmental factors controlling stomatal behaviour of leaf-level carbon and water exchange were examined across the evolutionary continuum from C3 to C4 photosynthesis at...

An hypothesis was formulated that phosphorus (P) partitioning in tissues of C4 leaves would permit C4 plants to resist P deficiency better than C3 plants. To test this hypothesis, 12 C3, C4, and C3-C4 intermediate species were grown at adequate, deficient, and severely deficient P supply in a solid-phase-buffered sand culture system to characterize photosynthetic and growth responses. Species d...

Most physiology comparisons of C3 and C4 plants are made under current or elevated concentrations of atmospheric CO2 which do not reflect the low CO2 environment under which C4 photosynthesis has evolved. Accordingly, photosynthetic nitrogen (PNUE) and water (PWUE) use efficiency, and the activity of the photosynthetic carboxylases [Rubisco and phosphoenolpyruvate carboxylase (PEPC)] and decarb...

background: beta-thalassemia major is one of the major health problems in our country. many studies have confirmed the fact that, these patients have an increased susceptibility to bacterial infections. objective: in this study, we have assessed the humoral immune system in 68 thalassemic patients by measuring their serum concentration of immunoglobulin g (igg), igm, iga, c3 and c4 in order to ...

C4 photosynthesis is a carbon-concentrating mechanism that evolved independently more than 60 times in a wide range of angiosperm lineages. Among other alterations, the evolution of C4 from ancestral C3 photosynthesis requires changes in the expression of a vast number of genes. Differential gene expression analyses between closely related C3 and C4 species have significantly increased our unde...