Abstract

SANTANA M, Giovanna F  and  ASCENCIO, Jocelyne. Capacity de growth of Crotararia juncea L.  in condittions phosphorus deficiency. Agronomía Trop. [online]. 2011, vol.61, n.3-4, pp.221-230. ISSN 0002-192X.

Crotararia juncea L. is an important cover crop under marginal soils conditions particularly in tropical countries, the species has been reported as a plant with ability of growing with deficient P soils. With the objective of investigating some growth responses under P deficiency, plants were cultivated in pots 900 ml filled with nutrient solution Hoagland 2, with aereation artificial. The experiment was conducted in desing completely randomized, with two phosphorus treatments (+P = 0,86 mMP and -P = 0,004 mMP) with 48 repeats. Plants were harvested at 15, 20, 25 and 30 days of age for determine dry biomass, relation shoot/root, total leaf area, root length (total and specific), soluble P inorganic (leaf), total P, also were determined the absorption of P (PAE), distribution index of P and use efficiency P (PUE). According to the results, were observed a reductions 61,3% leaf area, 61,74% in dry shoot biomass, and 50,19% in dry root biomass following reductions in leaf soluble Pi and total P under -P. On the other hand, at 20 days of age the root length increased in -P, and were larger (2,44 times) as compared to the +P plants .Under deficient phosphorus conditions, the plants showed high P absorption and use efficient P. These results suggest that this species combines morphological and physiological strategies that contribute to the tolerance to phosphorus deficiency.

Keywords : Crotararia juncea L; nutrient solution; P-efficiency; tolerance.

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