My journey from horticulture to plant biology

Photoperiod Control of Plant Growth: Flowering Time Genes Beyond Flowering

Fluctuations in environmental conditions greatly influence life on earth. Plants, as sessile organisms, have developed molecular mechanisms to adapt their development to changes in daylength, or photoperiod. One of the first plant features that comes to mind as affected by the duration of the day is flowering time; we all bring up a clear image of spring blossom. However, for many plants flowering happens at other times of the year, and many other developmental aspects are also affected by changes in daylength, which range from hypocotyl elongation in Arabidopsis thaliana to tuberization in potato or autumn growth cessation in trees. Strikingly, many of the processes affected by photoperiod employ similar gene networks to respond to changes in the length of light/dark cycles. In this review, we have focused on developmental processes affected by photoperiod that share similar genes and gene regulatory networks.

A Central Role for Genetics in Plant Biology

This article describes my involvement in the development of genetics as an essential tool in the integrated study of plant biology. My research comes from a strong background in plant genetics based on my education as a plant breeder at Wageningen University and collaborations with plant physiologists and molecular geneticists in Wageningen and the wider scientific community. It initially involved the isolation and physiological characterization of mutants defective in biosynthesis or mode of action of plant hormones, photoreceptors and traits such as flowering time in both Arabidopsis and tomato. I also generated a genetic map of Arabidopsis. Subsequently, the exploitation of natural variation became a main area of interest, including the molecular identification of underlying genetic differences. The integration of various disciplines and the adoption of Arabidopsis as a main model species contributed strongly to the impressive progress in our knowledge of plant biology over the past 40 years.

The phytotronist and the phenotype: plant physiology, Big Science, and a Cold War biology of the whole plant

This paper describes how, from the early twentieth century, and especially in the early Cold War era, the plant physiologists considered their discipline ideally suited among all the plant sciences to study and explain biological functions and processes, and ranked their discipline among the dominant forms of the biological sciences. At their apex in the late-1960s, the plant physiologists laid claim to having discovered nothing less than the "basic laws of physiology." This paper unwraps that claim, showing that it emerged from the construction of monumental big science laboratories known as phytotrons that gave control over the growing environment. Control meant that plant physiologists claimed to be able to produce a standard phenotype valid for experimental biology. Invoking the standards of the physical sciences, the plant physiologists heralded basic biological science from the phytotronic produced phenotype. In the context of the Cold War era, the ability to pursue basic science represented the highest pinnacle of standing within the scientific community. More broadly, I suggest that by recovering the history of an underappreciated discipline, plant physiology, and by establishing the centrality of the story of the plant sciences in the history of biology can historians understand the massive changes wrought to biology by the conceptual emergence of the molecular understanding of life, the dominance of the discipline of molecular biology, and the rise of biotechnology in the 1980s.

"The awe in which biologists hold physicists": Frits Went's first phytotron at Caltech, and an experimental definition of the biological environment

After Darwin, experimental biology sought to unravel organisms. By the early twentieth century, organisms were broadly conceived as the product of their heredity and their environment. Much historical work has explored the scientific attack on the genotype, particularly through the new science of genetics. This article explores the tandem efforts to assert experimental control over the environment in which plants grew and developed. The case described here concerns the creation of the first phytotron at Caltech by botanist and plant physiologist Frits Went. Opening in 1949, the phytotron was a plant laboratory that, across a series of rooms and chambers, kept genes constant while regulating and maintaining defined ranges of known environments. This article details the context in which the phytotron emerged, how the phytotron gained its sobriquet, and how it served to cement the "environment" as a category of biological knowledge. Describing the institutional context of Caltech, its interdisciplinary culture, and its encouragement of adopting technology into biological science, I argue that the phytotron and the commensurate category of the "environment", were the product of the familiar movement to integrate the physical and biological sciences. In addition, however, the creation of the phytotron was also a broader story of plant physiologists establishing a definition of the "environment" in both physical and technological terms.