Regulation of Aerenchyma Formation in Roots and Shoots by Oxygen and Ethylene

摘要: Excess water, especially around roots and the lover parts of shoot, is a frequent cause abnormally slow rates gaseous exchange between plants their environment (Armstrong, 1979) in wide range habitats that embrace tidal estuaries, river lake margins, swamp marshland, poorly drained agricultural land, rice paddies irrigated land arid areas. The challenge this presents to survival compounded by activities soil microflora initially competes with for oxygen later, when rendered anaerobic, chemically reduces iron sulphur, sequence, soluble phytotoxic forms (Ponnamperuma, 1972). Thus, it not surprising most species are severely injured temporary flooding excluded completely from areas experience prolonged waterlogging. However, some dryland such as wheat, maize, tomato sunflower can survive adaptation (Jackson Drew, 1984). Their does usually reflect metabolic tolerance anoxia per se. Instead, new existing shoot bases avoid forming highly porous (aerenchymatous) interiors permit gas along internal pathways small resistance linking root cells air or photosynthetically generated leaves. These constitute linearized form cell separation.