engleski

Germination and growth of wheat cultivars under PEG-induced drought

Soil water potential is an important environmental factor influencing germination and seedling development, and drought stress is one of the most significant abiotic constraints of growth and productivity of crop plants worldwide. The main purpose of this study was to define the influence of reduced water potential on germination indicators and physiological and biochemical parameters of seedlings of two winter wheat cultivars (Felix and El Nino, with moderate and low drought resistance). To imitate the water potential of the actual conditions in the soil, eight different concentrations of polyethylene glycol (PEG 6000) were used, ranging from -0.03 (field capacity) to -1.5 MPa (permanent wilting point). The variables measured were final germination percentage, mean germination time and germination rate index, fresh weight of seedlings, and shoot and root length, as well as lipid peroxidation (as malondialdehyde content), osmotic substances (soluble proteins and free proline) and the activities of scavenging enzymes (guaiacol peroxidase, ascorbate peroxidase and catalase) in both shoots and roots of seedlings. The results indicated that reduced water potential decreased germination indicators and seedling vigor in both cultivars. The cultivar El Nino had a slightly lower germination percentage in the control growth medium (89%), unlike to Felix with 97%, as well as higher mean germination time compared to Felix. Germination index of El Nino significantly decreased only at the water potential of germination substrate at -0.7 MPa, while germination index of Felix significantly decreased already at -0.3 MPa. Root length decreased in both cultivars by 30%, and shoot length by 16% in El Nino and 46% in Felix cultivars. With increasing PEG concentrations, two times more proline accumulated in El Nino seedlings compared to Felix, and in both cultivars roots accumulated twice as more proline than shoots. Lipid peroxidation and concentrations of antioxidative enzymes increased, more in Felix than El Nino, indicating that plants sustained considerable damage and that damage was proportional to water shortage, but the accumulation of osmolytes and increased activity of antioxidative enzymes helps them cope with drought injury.

drought ; PEG 6000 ; wheat seedlings ; germination ; proline content ; antioxidative enzymes

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