Resumen

CASTANEDA-CASTRO, Odón; GOMEZ-MERINO, Fernando C.; TREJO-TELLEZ, Libia I.  y  PASTELIN-SOLANO, Miriam C.. Osmotic stress induced by polyethylene-glycol alters macronutrient concentrations in sugarcane (Saccharum spp.) plants in vitro. Agrociencia [online]. 2015, vol.49, n.8, pp.859-873. ISSN 2521-9766.

The potential capacity of plant roots to absorb water and nutrients generally declines in osmotic-stressed plants, presumably because of a reduction in the nutrient element demand, and such decrease varies among plant genotypes. In order to investigate the effect of the osmotic stress caused by polyethylene-glycol 6000 (PEG) on the macronutrient concentration in sugarcane (Saccharum spp.) in vitro, we established a factorial experiment with a completely randomized distribution. Study factors were variety (Mex 69-290 and CP 72-2086) and PEG in the nutrient medium (0, 3, 6 and 9 %, to generate osmotic potential corresponding to -0.18, -0.45, -0.65 and -0.80 MPa, respectively), which resulted in eight treatments, with five replicates each. The experimental unit consisted of a 500 mL flask, with 50 mL liquid MS medium, and three sugarcane plantlets each. Results were analyzed using an analysis of variance and means were compared using the Tukey test (p≤0.05). Plants were harvested 20 and 30 d after treatment (dat). In both varieties at 20 dat no effect on K, Ca, Mg and S concentrations was observed; however, N was lower in CP plants and P diminished in Mex plants. A different response was observed 30 dat with N, K, Ca, Mg and S concentrations higher in Mex plants, whereas P showed no differences between varieties due to the osmotic stress imposed by PEG. As for the osmotic stress, since PEG concentrations decreased in the nutrient medium, N and Ca concentrations diminished 20 dat, whereas N and K concentrations were lower 30 dat. Interaction between variety and osmotic stress showed highly significant effects on most minerals, with N and Ca being the most affected. In general, Mex 69-290 plants showed higher nutrient concentrations than CP 72-2086 plants under our experimental conditions.

Palabras llave : Plant nutrition; Poaceae; PEG; nitrogen; phosphorus; potassium.

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