It is difficult to establish agronomic practices for wheat (Triticum aestivum L.) production in Mediterranean regions because of high annual variability in rainfall. Plant density is a factor of particular importance in wheat production systems because it can be controlled. This study was conducted to determine the optimum seeding rates of Mediterranean types of wheat in irrigated Mediterranean systems. Field experiments were conducted under irrigation at two locations of the Ebro Valley, Spain, during two growing seasons, 1999–2000 and 2000–2001. Six seeding rates were compared: 150, 175, 250, 300, 400, and 500 seeds m−2 with four adapted wheat varieties including a hybrid wheat. Seeding rate affected grain yield and yield components in three of the four environments, but its effect varied with the environment. The plant densities giving the highest yields were at least 400 to 500 plants m−2 for most of the varieties studied. The results suggest that the rate of seeding under irrigation for Mediterranean areas might be higher than those used in other wheat‐growing areas.
With the commercialization and increasing availability of Unmanned Aerial Vehicles (UAVs) multiple rotor copters have expanded rapidly in plant phenotyping studies with their ability to provide clear, high resolution images. As such, the traditional bottleneck of plant phenotyping has shifted from data collection to data processing. Fortunately, the necessarily controlled and repetitive design of plant phenotyping allows for the development of semi-automatic computer processing tools that may sufficiently reduce the time spent in data extraction. Here we present a comparison of UAV and field based high throughput plant phenotyping (HTPP) using the free, open-source image analysis software FIJI (Fiji is just ImageJ) using RGB (conventional digital cameras), multispectral and thermal aerial imagery in combination with a matching suite of ground sensors in a study of two hybrids and one conventional barely variety with ten different nitrogen treatments, combining different fertilization levels and application schedules. A detailed correlation network for physiological traits and exploration of the data comparing between treatments and varieties provided insights into crop performance under different management scenarios. Multivariate regression models explained 77.8, 71.6, and 82.7% of the variance in yield from aerial, ground, and combined data sets, respectively.
dAcetogenic bacteria can grow by the oxidation of various substrates coupled to the reduction of CO 2 in the Wood-Ljungdahl pathway. Here, we show that growth of the acetogen Acetobacterium woodii on 1,2-propanediol (1,2-PD) as the sole carbon and energy source is independent of acetogenesis. Enzymatic measurements and metabolite analysis revealed that 1,2-PD is dehydrated to propionaldehyde, which is further oxidized to propionyl coenzyme A (propionyl-CoA) with concomitant reduction of NAD. NADH is reoxidized by reducing propionaldehyde to propanol. The potential gene cluster coding for the responsible enzymes includes genes coding for shell proteins of bacterial microcompartments. Electron microscopy revealed the presence of microcompartments as well as storage granules in cells grown on 1,2-PD. Gene clusters coding for the 1,2-PD pathway can be found in other acetogens as well, but the distribution shows no relation to the phylogeny of the organisms.A cetogenic bacteria are a diverse group of anaerobic bacteria able to reduce two molecules of CO 2 to acetate by the WoodLjungdahl pathway (WLP) (1-4). Electrons may derive from molecular hydrogen (autotrophic growth) or from organic donors (heterotrophic growth), such as hexoses, pentoses, formate, lactate, alcohols, and methyl group donors (1). This not only provides the cell with organic material for biomass formation, but the pathway is also coupled to energy conservation for ATP supply (2, 5). The energy-conserving reactions remained an enigma for a long time, but recent discoveries in the model acetogen Acetobacterium woodii provided insights into the energy metabolism of this group of anaerobic bacteria (6, 7). In A. woodii, the reactions for the oxidation of the substrate can in general be regarded as isolated modules separate from the reactions of the WLP for the reoxidation of the electron carriers by the reduction of CO 2 . One has to emphasize that all enzymes of the WLP are soluble and located in the cytoplasm (6). With molecular hydrogen as the electron donor, only one enzyme is necessary for its oxidation, providing the reducing equivalents as reduced ferredoxin (Fd) and NADH in a 1:1 stoichiometry (8). Oxidation of organic substrates, such as hexoses, also yields reduced ferredoxin and NADH that are reoxidized in the WLP. The WLP in A. woodii does not use both electron carriers in equal amounts; therefore, a membranebound Fd:NAD oxidoreductase (presumably the Rnf complex) provides NADH from reduced ferredoxin, thereby translocating sodium ions across the cytoplasmic membrane that are used for subsequent ATP synthesis by a membrane-bound, sodium iondependent ATP synthase (7, 9, 10). The reaction is reversible, and the enzyme can drive Fd reduction at the expense of the electrochemical sodium ion potential.Besides CO 2 , acetogenic bacteria can use different alternative electron acceptors, e.g., nitrate (Moorella thermoacetica [11]) or phenylacrylates (A. woodii [12]). These acceptors have a more positive redox potential than the CO 2 -acetate pair,...
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