Impact of soil compaction stress combined with drought or waterlogging on physiological and biochemical markers in two maize hybrids

In field conditions plants undergo combinations of stresses like soil compaction combined with soil drought or flooding. In maize there exists an intraspecific variation in responses to environmental stresses, e.g. drought, flooding and soil compaction. In this study seedlings of two maize hybrids (sensitive and resistant to soil compaction) were grown under low, moderate and high soil compaction levels and drought or flooding. Water potential, electrolyte leakage, chlorophyll a content, gas exchange, ABA and antioxidant activity were measured. In seedlings exposed to different soil compaction levels differences between soil, leaf and root water potentials were observed at noon and later in the day. Significant differences between hybrids grown in low and severe soil compactions and exposed to drought or flooding were noticed in membrane injury, leaf water potential, chlorophyll a content and gas exchange parameters. Statistically significant differences between hybrids were observed in ABA content in the stem under severe and in the root under low soil compaction and exposed to drought and flooding, and in antioxidant activity in leaf under severe soil compaction and under low soil compaction with drought or flooding stresses. Further studies on physiological responses of genotypes contrasting in tolerance to different stresses would help us explore stress tolerance mechanisms.