1,721,040 research outputs found
Differenze genetiche nell' efficienza di assorbimento dei nutrienti rivelate dalle cinetiche di influsso ed efflusso del solfato in plantule di mais
No full textGenetic regulation of nitrate reductase and nitrate uptake activities in maize (Zea mais L.)
No full textFour lines and six hybrids from crosses amongst them were studied. The line 33-16
had the lowest rate of nitrate uptake in the roots and the highest nitrate reductase activity in
the leaves; the reverse was true of B14. All the hybrids showed heterosis for nitrate transport;
heterosis was greatest in 33-16 X L1058. Heterosis for nitrate reductase activity was
appreciable only in 33-16 X WF9
Risposte del trasporto ed assimilazione del solfato alla deprivazione di zolfo in plantule di mais
No full textEvaluation of some enzymatic activities involved in the nitrogen metabolism of Asparagus cells cultures during 6 days growth
No full text
Influenza delle concimazioni fozfoazotate sulla produttività di ibridi di mais con diversa efficienza del sistema di trasporto radicale.
No full textSulfate influx and efflux in seedlings of maize genotypes of different productivity [in Italy]
No full textPattern of sulfate uptake during root elongation in maize: its correlation with productivity
No full textThe efficiency of sulfate uptake was evaluated in excised roots of 22 maize genotypes, 12 inbreds and 10 hybrids, in order to study the relationship between the kinetic characteristics of the uptake and the grain productivity. During root elongation, the uptake capacity showed a pulse which appeared when the root reached 1/3 to 1/2 of its final length. The size of the accumulated pool of sulfate was significantly correlated with the productivity. The kinetic parameters of the uptake, Vmax and Km, followed the same trend, showing pulses, whoxe maximum had the same position for Vmax and Km in each genotype. The variability with the genotype of the size and duration of the Vmax pulse was not strictly connected with that of Km. The main correlation between Vmax and Km patterns was the following; inbreds were generally characterized by low Vmax and low Km; hybrids by high Vmax and high Km. As a consequence, in most cases, the benefit of the heterotic stimulation of Vmax was contrasted by the loss of affinity of the transport system or the nutrients
Variability and inheritance of sulfate uptake efficiency and ATP-sulfurylase activity in maize
No full textSulfate uptake efficiency of roots and ATP-sulfurylase activity in leaves and in roots were evaluated in maize (Zea mays L.) inbreds W75, 65B, 103B, and in the diallel set of F1 hybrids, in order to assay the variability and the inheritance of the two characters. The correlation at the level of genetic regulation between the uptake and the first step of sulfate metabolism was also determined. Wide genetic differences were seen in the uptake efficiency and in enzyme activity. These traits demonstrated a close correlation and a high level of heterosis. The kinetics of sulfate uptake was also affected by crossing; Vmax followed the same pattern as uptake efficiency, while Km, with the exception of the 103B ✕ 65B cross, showed a low level of heterosis
Assessment of a selection pressure for improved nitrate and sulfate recovery by maize.
No full textThe increase in grain yield of current maize cultivars has been conditioned by the abundant supply of fertilizers, potentially involving energy waste and environment pollution. The shift from frugality to luxury consumption has been attributed to the scarce or zero selection pressure for improved nutrient recovery, due to the high fertility of soils usually adopted in breeding programs. Seven cycles of recurrent selection, starting from the same maize population and carried out on the same soil in conditions of either large (HF) or limited supply (LF) of macronutrients, have demonstrated the effectiveness of the selection pressure by reduced fertilizer application. Physiological parameters determined in seedlings growing in nutrient solution evidenced, in the LF population, a connection with both grain yield and efficiency of nitrate and sulfate recovery. Influx and efflux at steady supply or after deprivation, translocation to shoot, internal pool of both anions, and ATPase‐dependent H+ transport in plasmalemma vesicles were particularly significant
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