Fosfatasa acida, nitrato reductasa, glutamina sintetasa y eficiencia de uso de fosforo y nitrogeno en cereales
2005
Cruz-Flores, G. | Flores, R.D. | Alcantar-Gonzalez, G. | Trinidad-Santos, A.
In order to find the relationship of the activity of root enzymes present in cereals with the efficiency of the use of N and P, at 30 and 45 days after germination, acid phosphatase (AP), nitrate reductase (NR), and glutamine synthetase (GS) activities were determined in wheat (Triticum aestivum L), triticale (X Triticosecale Wittmack), and corn (Zea mays L.) in plants cultivated in hydroponics with four treatments of N and P supply under greenhouse conditions. Two genotypes of each species were used, one more efficient (+E) and the other less efficient in N and P uptake. NR diminished after 45 days in reference to the observed at 30 days. Nitrogen supply induced an increment of about 50% in NR in wheat and corn, whereas the addition of P slightly reduced the NR at 30 days but at 45 days the addition of P increased it. Greater NR activity was observed in the genotypes with high nutrimental efficiency in the three species: it was greater in +E than in -E genotypes. GS activity of the -E genotypes was less than that showed by those of high nutrimental efficiency (+E). Although GS takes part in ammonium assimilation, it was found that for wheat and triticale, P supply, and not that of N, showed greater influence on the increase of GS activity, unlike corn in which N supply did induce greater GS activity. With the addition of P, reductions superior to 100% in AP activity were induced in +E genotypes while in -E, it was not modified significantly, since in them AP variations did not appear under nitrogen deficiency independently of phosphorus supply. The determination of the activity of these enzymes may be a good indicator of nutrimental efficiency to select genotypes.
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