Interaction of Ethylene and Other Compounds with the Ethylene Receptor: Agonists and Antagonists -- Ethylene and Plant Growth -- Ethylene and Leaf Senescence -- Effect of Ethylene on Adventitious Root Formation -- Ethylene and Plant Responses to Abiotic Stress -- Ethylene in the Rhizobium-Legume Symbiosis -- The Role of Ethylene in the Regulation of Stem Gravitropic Curvature -- Role of Ethylene in Fruit Ripening -- Ethylene Involvement in Photosynthesis and Growth. The plant hormone ethylene plays a prominent role among several intrinsic and extrinsic factors that control growth and physiology of plants. Its biological activity was discovered over a century ago. However, extensive studies on its mode of action came later. To date, it is well documented that ethylene is a versatile signaling molecule that plays an important role in many physiological processes - like growth, senescence, fruit ripening, stress responses, symbioses, and photosynthesis. Molecular-genetic analyses have revealed mechanisms responsible for ethylene production, perception, and signal transduction. The present work brings into focus the recent developments on the biochemical, physiological, and molecular basis for ethylene action in plants.