A high quality international journal   Physiologia Plantarum is SPPS's international journal published by Wiley-Blackwell. It is dedicated to original research that advances our understanding of the primary physiological and molecular mechanisms governing plant development, growth and productivity.   Physiologia Plantarum presented its new cover January 2005. Graphic by Gorm Palmgren. In addition to regular articles, Physiologia Plantarum also publishes Minireviews and Technical Focus papers. Moreover, Special Issues that contain several reviews focusing on recent advances in a selected field are published several times every year. Physiologia Plantarum ranks as an impressive #8 among the 136 most cited international plant science journals. The impact factor is presently 2.017 and rising. Editor-in-Chief Vaughan Hurry, Associate Professor at Umeå Plant Science Centre in Sweden, and the journal representatives have recently taken several initiatives in order to make the journal even better for both readers and authors. Read about these efforts in two recent aricles in SPPS Newsletter by clicking here and here. You can find more information about Physiologia Plantarum on the journals official website.   Read featured articles for free   An article of general interest from Physiologia Plantarum is highlighted and commented in each issue of SPPS Newsletter. Below you can see our recent pickings and the original article is freely available from the publisher, Blackwell, by simply clicking the reference!   Transcriptome reveals phosphate responses Microarrays are increasingly being used for global expression studies and over the last few years this has been used to build up substantial information about the plant transcriptome. Using internet-based data ressources from previous analysis on Arabidopsis thaliana, Danish researchers have dissected the complex regulatory network involved in responses to phosphate deprivation. Tom Hamborg Nielsen and co-workers from University of Copenhagen and Aalborg University evaluated the functional relationship between several transcription factors, microRNAs (miRNAs) and feedback loops that contribute to keep P-homeostasis. The authors propose a model for the complex coordinated responses to phosphate starvation, which affect all parts of the plant and include Pi-signalling miRNAs that are transported via the phloem. However, the model still lacks any sensor of P-status, since the precise role of several recent candidates for this crucial function still needs to be verified. Read full article free: Nilsson et al (June 2010) Physiologia Plantarum 139: 129-143   Shedding light in the canopy Since plants get most of their light from above, photosynthetic activity is highest in the upper part of the canopy. Applying light directly into the canopy might, accordingly, contribute to a more uniform photosynthetic profile and could potentially increase overall photosynthesis leading to higher yield of crops. This hypothesis has now been tested by Dutch researchers from Wageningen University in the Netherlands. They supplied cucumber plants grown in the greenhouse with 38% of their light from LEDs within the canopy and compared them with controls that got all the light from above. Light from within the canopy significantly increased photosynthesis in the lower leaf layers, however, this was not followed by a concomitant increase in overall biomass and fruit yield. This was apparently caused by a more stunted growth when less light came from above and because the LEDs seemingly caused the leaves to curl and thus reduced light interception. Read full article free: Trouwborst et al (March 2010) Physiologia Plantarum 138: 289Ð300   Changes in atmospheric CO2 affect respiration efficiency The increasing atmospheric have resulted in a general increase in photosynthesis and biomass, but less is known about how plants adapt to this environmental change in terms of respiration. Now, scientists at University of Illinois at Chicago have taken up this issue by growing Arabidopsis thaliana plants adapted to Pleistocene sub-CO2 levels of 200 µl/l at current 360 µl/l CO2. The results show that these plants exhibited reduced respiration as compared to plants adapted to ambient CO2. The lower respiration rate was, however, not associated with a corresponding reduction in nitrogen content of the tissues. The results suggest, that plants adapt to changes in atmospheric CO2 by adjusting mitochondrial energy coupling and activity of the so called alternative pathway, where photosynthate is consumed in a less energy efficient way leading to lower ATP production. Read full article free: Gonzalez-Meler et al (December 2009) Physiologia Plantarum 137: 473-484   Climate change causes greenhouse gas emission by plants Global warming seems to be self-sustaining by making plants emit the potent greenhouse gas, methane (CH4), while simultaneously reducing their assimilation of CO2. This conclusion was obtained by Mirwais M. Qaderi and David M. Reid from University of Calgary, Canada, who tested methane emission and several growth parameters from six crop species grown under various environmental conditions. An increase in temperature from 24/20 °C (day/night) to 30/26 °C led to a 15% increase in methane emission, while the effect of water stress, which will accompany global warming in many regions, increased emission of the greenhouse gas by 22%. The figures are average measurements from faba bean, sunflower, pea, canola, barley and wheat. Under ambient conditions the six crops emitted between 85 (barley) and 170 (pea) ng methane per g dry weight per hour. At the same time, the higher temperature caused CO2 assimilation to decrease 27%, while water stress reduced CO2 assimilation by 31%. The researchers will now investigate how elevated CO2 levels affect methane emission in order to get a better picture of how global warming can turn plants into greenhouse gas contributors. Read full article free: Qaderi & Reid (October 2009) Physiologia Plantarum 137: 139-147   Vine disease causes senescence Pierce's disease has become a major problem for wine growers in California and Central America. It is caused by the bacterial pathogen Xylella fastidiosa that uses leafhoppers for transmission. In diseased plants, a gel like substance forms in the xylem tissue and leaves turn yellow and brown. It is generally believed that symptoms arise from occlusion of xylem conduits but this may not be so according to new research conducted by Brendan Choat and colleagues at University of California, Davis. They measured leaf hydraulic conductance (i.e. how easy water is transported) in infected and uninfected Vitis vinifera cv. Chardonnay under different irrigation regimes and found that susceptibility to Pierce's disease was apparently favored by water stress. In addition, hydraulic conductance of infected leaves from field-grown vines was similar to naturally senescing leaves. From these results the researchers concluded that infection of X. fastidiosa leads to a systemic response that accelerates senescence. Read full article free: Choat et al. (March 2009) Physiologia Plantarum 136: 384-394   Virus affects electron transport Infection of cucumber or tomato with cucumber mosaic virus (CMV) not only slows down photosynthesis and respiration but also leads to increased oxidative stress. These effects are accomplished by the same mechanism, namely changes to the electron transport system. Jing-Quan Yu and co-workers from Zhejiang University in China studied the long-term effect of CMV infection in the two plant species and noted, that the 'normal' electron flux decreased while the alternative flux increased significantly. This change was accompanied by increased superoxide dismutase activity and accumulation of H2O2. Read full article free: Song et al. (March 2009) Physiologia Plantarum 135: 246-257   Comforting proteins A dehydrin protein from Rhododendron plays a key role in freezing tolerance due to protection from cellular dehydration caused by extracellular freezing. Rajeev Arora and co-workers from Iowa State University have shown that purified RcDhn5-encoded acidic SK2 type dehydrin can protect enzyme activity against dehydration in in viro assays. When the gene was constitutively expressed in Arabidopsis, the transgenic plants exhibited increased freezing tolerance withour prior cold acclimation. With cold acclimation, however, the effect was less pronounced. This is apparently due to dilution of the Rhododendron dehydrin by less effective native dehydrins. Read full article free: Peng et al. (December 2008) Physiologia Plantarum 134: 583-597   Design and technical solution © 2005 Palmgren kommunikation.