Abstract: Flooding stress has many important morphological and biochemical effects on plants. Because of the importance of determination the effects of flooding on plants and understanding of the tolerance mechanisms, in this research 4 day old zea mays L. (cv. single cross 704) seedlings were exposed to 4, 7 and 10 days flooding stress. At the end of each treatment the roots and shoots of seedlings were harvested separately. To show the histological effects of flooding on plants, cross section of roots and shoots were studied with light microscope. There was no clear change in the tissues structures of leaves and stems of different treatments in comparison with controls, but in the roots of plants the aeranchyma had been developed under stress condition especially in the mesocotyl region. The roots of flooded plants grow towards the soil surface despite positive geotropism of control roots. The chlorophyll a and b content and the ratio of chlorophylls a/b have been decreased but the amounts of soluble sugars have been increased in both the roots and shoots of seedlings. We conclude that flooding influences plants growth and life and development of aeranchyma and vegetative roots help plants to adapt itself to stress condition. So it is very important to know which plants are sensitive or tolerant and what are tolerance mechanisms in different plants to succeed in agricultural efforts.
L. Pourabdal , R. Heidary and T. Farboodnia , 2008. Effects of Different Flooding Periods on Some Histochemicals of Zea mays L. Seedlings. Plant Sciences Research, 1: 8-12.