Resumen

RESTREPO, HERMANN et al. Biochemical response of maize (Zea mays L.) seedlings to different conditions of nighttime temperatures. rev.colomb.cienc.hortic. [online]. 2013, vol.7, n.2, pp.252-262. ISSN 2011-2173.

Maize is grown from 0 to 3,000 m a.s.l. in Colombia, meaning that plants are exposed to a wide range of temperatures. In warm and cold regions of Colombia (≤1,000 and ≥2,000 m a.s.l., respectively), physiological disorders can be observed in maize crops due to the high or low night temperatures in certain periods of the year. 'Porva' maize plants were exposed to 5 and 25°C (the low and high nighttime temperatures, respectively); meanwhile, the control plants were maintained under growing conditions during the experiment (15°C). The temperature treatments were carried out in the maize plants during the V3 stage. Physiological variables such as lipid peroxidation (MDA content), proline, chlorophyll fluorescence and membrane permeability damage resulting from electrolyte leakage were estimated. The results showed that the proline content in the maize leaves was higher in the plants submitted to high nighttime temperatures when compared to plants exposed to 5°C for 36 hours. In addition, the nighttime treatments (5 and 25°C) increased the electrolyte leakage in the maize leaves. Changes due to temperature treatments were not observed for MDA content and Fv/ Fm ratio. These results seem to indicate that the cell walls are the first component to be affected in maize leaves by low temperatures in the cold regions of Colombia. Furthermore, this study is a guide for finding agronomic techniques in maize crops that ameliorate the negative effects of cell wall damage caused by the membrane permeability damage resulting from cold stress.

Palabras clave : fluorescence; heat; cold; proline; malondialdehyde; electrolyte leakage.

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