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Comparison of Growth Responses of Barnyard Grass (Echinochloa oryzoides) and Rice (Oryza sativa) to Submergence, Ethylene, Carbon Dioxide and Oxygen Shortage

1991; Oxford University Press; Volume: 68; Issue: 3 Linguagem: Inglês

10.1093/oxfordjournals.aob.a088245

1095-8290

D. M. E. Pearce, Michael B. Jackson,

Coastal wetland ecosystem dynamics

Unlike germination of wheat (Triticum aestivum), millet (Eleucine coracana), and sorghum (Sorghum caudatum), that of Echinochloa oryzoides (barnyard grass) and Oryza satwa (rice) was not inhibited by poorly aerated solutions with 11 k Pa oxygen (equilibrium partial pressure) or less In the dark, seedling shoots of rice included a coleoptile, and in Echinochloa, a mesocotyl also Growth in fresh and dry weight of shoots was strongly depressed by poorly aerated solutions in both rice and Echinochloa but the effects on extension differed in the two species in rice, coleoptile extension was promoted by solutions partly depleted of oxygen, and also by the absence of oxygen The stimulation in partly de-oxygenated solutions resulted from the combined promoting effects of small oxygen partial pressures, carbon dioxide, ethylene and buoyant tension in contrast, these treatments neither promoted nor inhibited elongation by the Echinochloa coleoptile while severely inhibiting extension of the mesocotyl Overall, poorly aerated solutions lengthened the shoot of rice and shortened it in Echinochloa when compared with those submerged in well-aerated solutions These opposite effects were brought about by the same gaseous changes, i e oxygen shortage, elevated ethylene and carbon dioxide The effect on Echinochloa was almost entirely restricted to the mesocotyl, coleoptile extension being remarkably insensitive to large increases in ethylene and carbon dioxide, or to extreme oxygen shortage Seedlings of the two species thus have contrasting strategies for survival