Julius Sachs (1868): The father of plant physiology

Are tropical forests approaching critical temperature thresholds?

There is growing concern about the fate of tropical forests in the face of rising global temperatures. Doughty et al. (2023) suggest that an increase in air temperature beyond ∼4 °C will result in massive death of tropical forest leaves and potentially tree death. However, this prediction relies on assumptions that likely underestimate the heat tolerance of tropical leaves.

Light signaling in plants-a selective history

In addition to providing the radiant energy that drives photosynthesis, sunlight carries signals that enable plants to grow, develop and adapt optimally to the prevailing environment. Here we trace the path of research that has led to our current understanding of the cellular and molecular mechanisms underlying the plant's capacity to perceive and transduce these signals into appropriate growth and developmental responses. Because a fully comprehensive review was not possible, we have restricted our coverage to the phytochrome and cryptochrome classes of photosensory receptors, while recognizing that the phototropin and UV classes also contribute importantly to the full scope of light-signal monitoring by the plant.

How plants sense and respond to osmotic stress

Drought is one of the most serious abiotic stresses to land plants. Plants sense and respond to drought stress to survive under water deficiency. Scientists have studied how plants sense drought stress, or osmotic stress caused by drought, ever since Charles Darwin, and gradually obtained clues about osmotic stress sensing and signaling in plants. Osmotic stress is a physical stimulus that triggers many physiological changes at the cellular level, including changes in turgor, cell wall stiffness and integrity, membrane tension, and cell fluid volume, and plants may sense some of these stimuli and trigger downstream responses. In this review, we emphasized water potential and movements in organisms, compared putative signal inputs in cell wall-containing and cell wall-free organisms, prospected how plants sense changes in turgor, membrane tension, and cell fluid volume under osmotic stress according to advances in plants, animals, yeasts, and bacteria, summarized multilevel biochemical and physiological signal outputs, such as plasma membrane nanodomain formation, membrane water permeability, root hydrotropism, root halotropism, Casparian strip and suberin lamellae, and finally proposed a hypothesis that osmotic stress responses are likely to be a cocktail of signaling mediated by multiple osmosensors. We also discussed the core scientific questions, provided perspective about the future directions in this field, and highlighted the importance of robust and smart root systems and efficient source-sink allocations for generating future high-yield stress-resistant crops and plants.

Our sisters the plants? notes from phylogenetics and botany on plant kinship blindness

Before the upheaval brought about by phylogenetic classification, classical taxonomy separated living beings into two distinct kingdoms, animals and plants. Rooted in 'naturalist' cosmology, Western science has built its theoretical apparatus on this dichotomy mostly based on ancient Aristotelian ideas. Nowadays, despite the adoption of the Darwinian paradigm that unifies living organisms as a kinship, the concept of the "scale of beings" continues to structure our analysis and understanding of living species. Our aim is to combine developments in phylogeny, recent advances in biology, and renewed interest in plant agency to craft an interdisciplinary stance on the living realm. The lines at the origin of plant or animal have a common evolutionary history dating back to about 3.9 Ga, separating only 1.6 Ga ago. From a phylogenetic perspective of living species history, plants and animals belong to sister groups. With recent data related to the field of Plant Neurobiology, our aim is to discuss some socio-cultural obstacles, mainly in Western naturalist epistemology, that have prevented the integration of living organisms as relatives, while suggesting a few avenues inspired by practices principally from other ontologies that could help overcome these obstacles and build bridges between different ways of connecting to life.

Light and plant development: the discovery of phototropins by Winslow R. Briggs (1928-2019)

The American biologist Winslow Russel Briggs (1928-2019) was a global leader in plant physiology, genetics and photobiology. In this contribution, we try to share our knowledge of the remarkable career of this outstanding scientist. After earning his PhD at Harvard (Cambridge, Massachusetts), he started his independent research program at Stanford University (California). Among many major contributions was his elegant experiment that conclusively demonstrated the role of auxin transport in the phototropic bending response of grass coleoptiles. During subsequent years as Professor of biology at Harvard University, Briggs focused on phytochrome and photomorphogenesis. In 1973, he re-located to Stanford to become Director of the Department of Plant Biology, Carnegie Institution for Science, and faculty member in the Biology Department at Stanford University. After his retirement (1993), he continued his research on "light and plant development" as an emeritus at Carnegie until the day of his death on February 11, 2019. Through his long research career, Briggs stayed at the cutting edge by re-inventing himself from a plant physiologist, to biochemist, geneticist, and molecular biologist. He made numerous discoveries, including the LOV-domain photoreceptor phototropin. Winslow Briggs, who was also a naturalist and gifted pianist, inspired and promoted the work of generations of young scientists - as mentor, colleague and friend.

Julius von Sachs' forgotten 1897-article: sexuality and gender in plants vs. humans

One hundred and fifty years ago, Julius von Sachs' (1832-1897) monumental Lehrbuch der Botanik (Textbook of Botany) was published, which signified the origin of physiological botany and its integration with evolutionary biology. Sachs regarded the physiology of photoautotrophic organisms as a sub-discipline of botany, and introduced a Darwinian perspective into the emerging plant sciences. Here, we summarize Sachs' achievements and his description of sexuality with respect to the cellular basis of plant and animal biparental reproduction. We reproduce and analyze a forgotten paper (Gutachten) of Sachs dealing with Die Akademische Frau (The Academic Woman), published during the year of his death on the question concerning gender equality in humans. Finally, we summarize his endorsement of woman's rights to pursue academic studies in the natural sciences at the University level, and conclude that Sachs was a humanist as well as a great scientist.