Effect of the type of environmental stress on the emergence of sunflower (Helianthus annus L ), soybean (Glycine max (L ) Merril) and maize (Zea mays L ) seeds with different levels of vigor

Effect of the type of environmental stress on the emergence of sunflower (Helianthus annus L ), soybean (Glycine max (L ) Merril) and maize (Zea mays L ) seeds with different levels of vigor

2003

A:PS

Sowing is a critical time in the cycle of a crop and the seeds are frequently exposed to adverse conditions that may compromise the establishment of seedlings in the field. A study was conducted to determine the effect of the types of environmental stress on the emergence of sunflower, maize and soyabean seeds with different levels of vigour. High vigour seeds were artificially aged to obtain medium and low vigour seeds and then they were sown in plastic boxes and submitted to the following types of environmental stress during the germination process: (1) high temperature (35?), (2) low temperature (15 or 18?), (3) water excess (PSI > -0.0001 MPa), (4) water deficiency (PSI approximately equal to -1.1, -1.2 and -0.6 MPa for sunflower, maize and soyabean, respectively), (5) sowing at a depth of 7 cm, and (6) pathogenic infection of sunflower seeds with Alternaria helianthi, of maize seeds with Fusarium moniliforme [Gibberella fujikuroi] and of soyabean seeds with Colletotrichum dematium var. truncatum [C. truncatum]. The results were compared to those obtained with the controls sown under optimal conditions. It is concluded that: (1) the effect of seed vigour on emergence depends on the type of environmental stress to which the seeds are exposed, (2) the stress to which the seeds demonstrated highest sensitivity varied with species, and (3) high temperature stress was the one that most impaired the emergence of the three species.

v.31(2):465-479, SEED SCIENCE AND TECHNOLOGY

Research > Published Articles