Publisher Summary This chapter illustrates the developments in the field of aeration since 1960, which have culminated in the modeling of the oxygen movements within the plant. The chapter collates the mathematical approaches to the aeration process and explains the concepts of modeling in a simplified manner. It is noted that the environment exerts a considerable influence on the directional flow of the respiratory gases within the plant and the directional exchange with the atmosphere. Oxygen can enter the plant body in a variety of ways. In non-aquatic species, the stomata and lenticels provide paths of low resistance for the entry and exit of both oxygen and carbon dioxide. In submerged astomatal aquatics, surface permeabilities are sufficiently high to allow the necessary gas transference. Plants rooted in unsaturated soils are exposed to an oxygen-rich environment over the greater part of their shoot and root surfaces. Oxygen enters the plant in the combined state as water. As water, it is transported from root to shoot in the xylem where a proportion is finally released into the liquid phase within the chloroplasts during the photolysis stage of photosynthesis.

Aeration in Higher Plants

Plant adaptations to anaerobic stress

Thèse de 3ème cycle

CHAPTER 3 – Effects of Flooding on Growth and Metabolism of Herbaceous Plants

Exposure to oxygen deficits is more widespread in biological systems than is commonly believed. Until recently, the general perception of anaerobic metabolism was often limited to the induction of alcoholic or lactic acid fermentation as the sole biochemical response to hypoxia/anoxia. Developments in the physiology, biochemistry, and molecular biology of anaerobic responses in invertebrates, lower plants, and higher plants have demonstrated that, depending upon the species, anaerobic metabolism may encompass much more than simple glycolytic metabolism. Here, recent progress in elucidating the mechanism(s) determining tolerance versus intolerance to anaerobic environments in higher plants is discussed, drawing most heavily on experimental systems using seeds or seedlings.

Anaerobic Metabolism in Plants

Summary
The distribution and activity patterns of several enzymes of glycolytic and respiratory metabolism are considered in nineteen species of higher plants previously classified as tolerant or intolerant of experimental flooding. These results are combined with previous work on glycolysis, the inductive properties of alcohol dehydrogenase, and on tissue malic acid levels, to formulate a metabolic system of flooding tolerance. This system is based mainly on: (1) the control of glycolysis through the inductive and kinetic properties of alcohol dehydrogenase; and (2) a diversion from ethanol to malate accumulation, dependent upon the presence or absence of ‘malic’ enzyme.

https://nph.onlinelibrary.wiley.com/doi/pdf/10.1111/j.1469-8137.1971.tb02529.x

M. Mcmanmon

Papers

A metabolic theory of flooding tolerance: the significance of enzyme distribution and behaviour