Carlos A. Barassi

Root colonization vs. seedling growth, in two Azospirillum -inoculated wheat species

Data evaluating the growth promoting effects of Azospirillum on wheat seedlings according to the inoculum level/root colonization effectiveness (number of bacterial cells), is scarce. Uniform 1-cm size, 72-h old wheat seedlings grown in the dark at 22 °C were inoculated with: i) 10 3 , 10 5 , 10 7 and 10 8 A. brasilense cells per T. aestivum cv. ProINTA Federal seedling; ii) 10 2 , 10 5 and 10 8 A. brasilense cells per T. durum cv. Buck Topacio seedling; iii) 10 6 heat killed bacteria (HKB) cells per cultivar seedling; iv) phosphate buffer pH 6.8 (NI) as control seedlings for both cultivars. Afterwards, seedling growth proceeded in water in the dark at 22 °C for another 48 h. Alive or dead Azospirillum cells were suspended in phosphate buffer pH 6.8. Root and shoot growth were determined measuring the length and projected area of their digitalized images. When treated with inocula concentrations ranging from 10 2 to 10 5 cells per seedling, both Triticum species reached a maximum level of colonization har...

Incorporation of 32P during early amphibian embryogenesis

Abstract 1. 1. The incorporation of 32 P during early embryogenesis was surveyed and a comparative study was made with neural phosphoproteins. 2. 2. In oocytes and in blastulas 90 per cent of the 32 P was incorporated into the acid-soluble fraction and 4 per cent into phosphoproteins. 3. 3. An increase of incorporation into phospholipids was found from oocyte (1·5 per cent) to blastula (4·5 per cent). Since this level did not change a 64 per cent rise in specific radioactivity was observed. 4. 4. The high content of phosphoprotein in the egg and blastula contrasted with a low level in the retina and brain. However, the specific radioactivity in the retina and brain was seven and sixteen times higher respectively than that in the unfertilized oocyte.

Azospirillum spp. and Related PGPRs Inocula Use in Intensive Agriculture

From the beginning of plant domestication, extensive farming has been the main strategy adopted by agriculture to produce large amounts of food. However, plant production in a continuously deteriorating environment and an exponentially growing human population are important factors that challenge agriculture nowadays. Moreover, agricultural lands are currently expanded to marginal, arid, or semiarid regions where crops are exposed to abiotic stresses as drought and salinity, this last negative factor aggravated by different anthropogenic actions. In addition, contemporary society requires from agriculture to provide food products with high market and nutritional qualities as fruits and vegetables, which should also be free of agrochemicals. In consequence, it is imperative to develop friendly, non-contaminant, sustainable, and energy-saving plant production strategies. In this regard, vegetable production by intensive farming in controlled environments is continuously expanding. On the other hand, recent reports show that plant inoculation with plant-growth promoting rhizobacteria (PGPR) could improve vegetable quality and yield under abiotic stresses, and to reduce the pressure that current agriculture exerts on the environment. Within this context, our main purpose was to describe a number of techniques aimed to study the plausible beneficial effects of Azospirillum and related PGPR inoculation on vegetable growth and nutritional quality, with emphasis on the promotion of antioxidant activity.