Resumo

MANFREDA, V.T.  e  COGLIATTI, D.H.. An alternative scale to evaluate intensity of P deficiency in wheat. Agriscientia [online]. 2006, vol.23, n.2, pp.67-75. ISSN 1668-298X.

The response of sixteen growth variables to internal P concentration were examined in wheat plants with the aim to establish the basis for an objetive qualification of P-deficiency intensity. Two experiments were carried out with wheat plants grown in pots under outdoor and greenhouse conditions. In a first experiment, two wheat genotypes were used and the variables were determined at two harvest times (27 and 32 days after germination, DDG). In a second, only one genotype was used and 18 harvests were performed between 14 and 30 DDG. Crítical P levels (NC) were estimated by mathematical fitting of each variable to the whole plant P-concentration. Variables were ordered by 1) standarized NC, calculated as the variable NC divided by NC for whole plant biomass (NCrel), and 2) dry biomass obtained at each NC as the percentage of the dry biomass achieved at non limiting P doses (BSp%). Both criteria arrived at similar variable ranks in terms of sensibility to P-stress, supporting a proposed P-stress intensity scale.

Palavras-chave : P-deficiency; Nutritional status; Wheat.

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