Effects of Cadmium on the Metabolic Activity of Avena sativa Plants Grown in Soil or Hydroponic Culture

Oat (Avena sativa L.) plants cultured in soil and hydroponic culture were treated with cadmium [0.154 mg g -1 (dry soil) and 100 µM CdSO4, respectively] for 21 d and growth rate and various biochemical processes were studied. Applied cadmium reduced plant growth and chlorophyll content. Changes in activity of enzymes involved in C, N and S metabolism and in guaiacol peroxidase activity were observed. In particular, O-acetylserine sulphydrylase (OASS; EC 4.2.99.8) activity was increased by Cd exposure in both growth conditions, probably as a resistance mechanism to cadmium based on the production of phytochelatins. Results show that both field and hydroponic conditions represent suitable systems for investigating Cd effects on plant growth and metabolism. Additional keywords: carbon metabolism, nitrogen metabolism, sulphur metabolism, guaiacol peroxidase activity

Nitrate induction triggers different transcriptional changes in a high and a low nitrogen use efficiency maize inbred line

In higher plants, NO3 - can induce its own uptake and the magnitude of this induction is positively related to the external anion concentration. This phenomenon has been characterized both in herbaceous and woody plants. Here, different adaptation strategies of roots from two maize inbred lines differing in NUE and exhibiting different timing of induction were discussed by investigating NO3 - -induced changes in their transcriptome. Lo5 line (high NUE) showing the maximum rate of NO3 - uptake 4\u2009h after the provision of 200\u2009\u3bcM NO3 - treatment modulated a higher number of transcripts relative to T250 (low NUE) that peaked after 12\u2009h. The two inbred lines share only 368 transcripts that are modulated by the treatment with NO3 - and behaved differently when transcripts involved in anion uptake and assimilation were analyzed. T250 line responded to the NO3 - induction modulating this group of genes as reported for several plant species. On the contrary the Lo5 line did not exhibit during the induction changes in this set of genes. Obtained data suggest the importance of exploring the physiological and molecular variations among different maize genotypes in the response to environmental clues like NO3 - provision of in order to understand mechanisms underlying NUE