The chapter discusses the application of growing knowledge about energy conversion processes in plants to improve agricultural productivity and control. About one-third of the papers focus on this aspect, highlighting the work of fundamental researchers and their insights into energy conversion processes. The main topics covered include biochemical aspects of photosynthesis, carbon metabolism, chloroplast structure and genetics, water and carbon dioxide transport, and photosynthetic limits on crop yield. Notable contributions include an introductory address by Sterling Hendricks on how light is used by plants and a summary paper by Martin Kamen on the future of photosynthesis research. The section on carbon metabolism is particularly noteworthy, with detailed descriptions of the process and the discovery of light-regulated enzyme activity control in the carbon reduction cycle, which opens new avenues for understanding metabolic regulation. This volume, edited by A. A. Moscona and Alberto Monroy, aims to establish developmental biology as a distinct field from embryology. The articles cover a wide range of topics, emphasizing the continuous and regulated nature of differentiation rather than the role of inductor theory. The volume includes papers on connective tissue differentiation, protein synthesis, gene action during cleavage stages, and the regulation of transcription in amphibian development. It also explores ultrastructural changes and macromolecular synthesis in Wolffian lens regeneration and the cellular interactions in teratocarcinoma. The editors' goal of bridging interdisciplinary information gaps is largely achieved, with only one paper on the Ig A antibody system feeling out of place. This symposium, held as part of the International Biological Programme, discusses chemical methods for analyzing water and their effects on biological growth. The first chapter covers general parameters like oxygen, carbon dioxide, pH, and specific ions, while the second chapter focuses on silicon, phosphorus, and nitrogen compounds. Notable contributions include a review of orthophosphate determination and the use of tetraethyl silicate for diatoms. The symposium also addresses the dangers of freezing samples for dissolved silica preservation and the measurement of molecular nitrogen fixation using nitrogen-15.The chapter discusses the application of growing knowledge about energy conversion processes in plants to improve agricultural productivity and control. About one-third of the papers focus on this aspect, highlighting the work of fundamental researchers and their insights into energy conversion processes. The main topics covered include biochemical aspects of photosynthesis, carbon metabolism, chloroplast structure and genetics, water and carbon dioxide transport, and photosynthetic limits on crop yield. Notable contributions include an introductory address by Sterling Hendricks on how light is used by plants and a summary paper by Martin Kamen on the future of photosynthesis research. The section on carbon metabolism is particularly noteworthy, with detailed descriptions of the process and the discovery of light-regulated enzyme activity control in the carbon reduction cycle, which opens new avenues for understanding metabolic regulation. This volume, edited by A. A. Moscona and Alberto Monroy, aims to establish developmental biology as a distinct field from embryology. The articles cover a wide range of topics, emphasizing the continuous and regulated nature of differentiation rather than the role of inductor theory. The volume includes papers on connective tissue differentiation, protein synthesis, gene action during cleavage stages, and the regulation of transcription in amphibian development. It also explores ultrastructural changes and macromolecular synthesis in Wolffian lens regeneration and the cellular interactions in teratocarcinoma. The editors' goal of bridging interdisciplinary information gaps is largely achieved, with only one paper on the Ig A antibody system feeling out of place. This symposium, held as part of the International Biological Programme, discusses chemical methods for analyzing water and their effects on biological growth. The first chapter covers general parameters like oxygen, carbon dioxide, pH, and specific ions, while the second chapter focuses on silicon, phosphorus, and nitrogen compounds. Notable contributions include a review of orthophosphate determination and the use of tetraethyl silicate for diatoms. The symposium also addresses the dangers of freezing samples for dissolved silica preservation and the measurement of molecular nitrogen fixation using nitrogen-15.