Constitutive expression of foreign glutamate dehydrogenase in Rhizobium etli inhibits bean plant nodulation (A. Mendoza, A. Leija, E. Martínez-Romero, G. Hernández, and J. Mora. Mol. Plant-Microbe Interact. 8:584-592, 1995). Here we report that this inhibition is overcome when controlling gdhA expression by NifA, thus delaying the GDH activity onset after nodule establishment. Expression of gdh...

Nitrogen assimilation plays a vital role in plant metabolism. Assimilation of nitrate, the primary source of nitrogen in soil, is linked to the generation of the redox signal nitric oxide (NO). An important mechanism by which NO regulates plant development and stress responses is through S-nitrosylation, that is, covalent attachment of NO to cysteine residues to form S-nitrosothiols (SNO). Desp...

To understand the physiological mechanism by which soybean (cultivar: Glycine max L. Merr. cv.JH13) regulates its growth in response to drought under elevated CO 2 concentration, a pot experiment with two levels of CO 2 (350 vs. 700 μmol·mol) and two levels of water (well irrigated vs. drought) was conducted. Plant relative growth rate (RGR), water potential (WP), photosynthetic pigment (chloro...

Shrublands are one of the major types of ecosystems in the desert regions of northern China, which is expected to be substantially more sensitive to global environmental changes, such as widespread nitrogen enrichment and precipitation changes, than other ecosystem types. However, the interactive effects of nitrogen and precipitation on them remain poorly understood. We conducted a fully factor...

Cotton (Gossypium hirsutum L. var. ;Stoneville 213'), velvetleaf (Abutilon theophrasti Medic.), redroot pigweed (Amaranthus retroflexus L.), and hemp sesbania (Sesbania exaltata [Raf.] Cory) were grown in a controlled environment room at 31/25 C day/night temperature and three irradiances: 90, 320, and 750 mueinsteins meter(-2) second(-1). From total dry weights and leaf areas determined at int...

Close coordination between leaf gas exchange and maximal hydraulic supply has been reported across diverse plant life forms. However, it has also been suggested that this relationship may become weak or break down completely within the angiosperms. We examined coordination between hydraulic, leaf vein, and gas-exchange traits across a diverse group of 35 evergreen Australian angiosperms, spanni...

Net CO2 assimilation (A) was analysed in situ in 12 pairs of altitudinally separated, herbaceous plant species in the Austrian Alps at 600 and 2600m. Both groups of species show a similar average response to light, saturating at quantum flux densities (400-700mm) (QFD) of more than 1200 VLmol m-2 sol. Temperature optimum of QFD-saturated A differs little (3K) and corresponds to the median of ai...

We studied carbon and nitrogen allocation in mycorrhizal and non-mycorrhizal Scots pine (Pinus sylvestris L.) seedlings grown in a semi-hydroponic system with nitrogen as the growth limiting factor. Three ectomycorrhizal fungi were compared: one pioneer species (Thelephora terrestris Ehrh.: Fr.) and two late-stage fungi (Suillus bovinus (L.: Fr.) O. Kuntze, and Scleroderma citrinum Pers.). By g...

Historically, terrestrial food web theory has been compartmentalized into interactions among aboveground or belowground communities. In this study we took a more synthetic approach to understanding food web interactions by simultaneously examining four trophic levels and investigating how nutrient (nitrogen and carbon) and detrital subsidies impact the ability of the belowground microbial commu...

Cultivar variation in seed characteristics can affect seedling vigor, and nitrogen (N) availability influences early-season growth some instances. However, interactions between cultivar N application rate for have received limited attention. Thus, the objectives of this research were to quantify effects cultivar, N-application rate, their interaction on growth, predict vigor from plant morpholo...