Since 1914, chronicling the discovery of plant hormones, documenting the rise of molecular genetics, and shaping modern botany
Imagine a single publication that has chronicled the discovery of plant hormones, documented the rise of molecular genetics, and provided a stage for the very debates that have shaped modern botany.
For over a century, the American Journal of Botany (AJB) has been this and much more—a living archive of plant science evolution. Since its inception in 1914, this monthly peer-reviewed journal has been instrumental in advancing our understanding of plant biology, from the microscopic workings of plant cells to the global patterns of forest ecosystems 1 .
This article explores the remarkable journey of AJB, from its foundational studies on plant growth to its modern investigations into plant memory and microbiomes, revealing how a century of dedicated science has transformed our relationship with the botanical world.
Foundational studies on plant development and hormones
Documenting the rise of genetic approaches in botany
Current investigations into plant memory and microbiomes
The early years of AJB coincided with a revolutionary period in plant biology, as scientists began unraveling the chemical and physiological mysteries of plant growth. The journal served as a critical platform for disseminating findings that would form the bedrock of modern botany.
One of the most significant early contributions published in AJB was the seminal 1939 paper by Kenneth Thimann and Charles Schneider titled "The relative activities of different auxins." This study systematically compared various auxin compounds—plant growth regulators—and their effects on different plant species 7 .
Using classic bioassays like the Avena coleoptile curvature test, Thimann and Schneider made a crucial discovery: different plant species responded to the same auxin compounds in dramatically different ways 7 .
This finding was revolutionary because it contradicted the prevailing assumption that plant growth regulators would affect all plants in proportionally similar ways. Their work laid the groundwork for structure-activity relationship studies that would eventually reveal the defining characteristics of auxin molecules 7 .
What made this research particularly challenging was the limited technology of the era. Scientists struggled with issues of chemical purity and had no way to track how plants metabolized the applied compounds—limitations that would only be overcome with the molecular biology revolution decades later 7 .
| Auxin Compound | Chemical Characteristics | Relative Activity in Different Plants |
|---|---|---|
| Indole-3-acetic acid (IAA) | Natural plant auxin | Standard for comparison |
| Indole-3-butyric acid (IBA) | Synthetic auxin | Varied significantly between species |
| Naphthalene acetic acid (NAA) | Synthetic auxin | Showed species-specific activity patterns |
| Phenyl-acetic acid (PAA) | Synthetic auxin | Differed from IAA in effectiveness |
As botanical science expanded, so did the scope of AJB. The journal evolved from its physiological roots to embrace the full spectrum of plant biology, with special issues highlighting emerging frontiers.
Today, AJB covers everything from algal ultrastructure to global change biology, reflecting the increasing interdisciplinary nature of plant sciences 1 5 . The journal's associate editors represent expertise across more than 50 botanical specialties, including physiological plant ecology, molecular phylogenetics, paleobotany, and ecological genetics 5 .
To appreciate how botanical research has evolved, let's examine a contemporary AJB study that exemplifies modern approaches to plant science.
A 2019 study published in AJB by Henning and colleagues asked a deceptively simple question: How do complex bacterial communities inside plant roots influence plant growth and resource allocation? This question is crucial for understanding plant health without chemical fertilizers.
The findings challenged conventional wisdom. While individual bacteria only weakly altered plant phenotypes, bacterial mixtures created unexpected and non-additive effects . Most remarkably, low-abundance Pseudomonas strains in the communities disproportionately influenced plant resource allocation and tissue nutrient concentrations, while the dominant Burkholderia strain (comprising 98% of the community) had minimal impact .
Replacing just one Pseudomonas strain (GM17 with GM41) in communities containing both Pseudomonas GM30 and Burkholderia BT03 led to:
| Bacterial Strain | Type | Observed Effects on Populus deltoides |
|---|---|---|
| Burkholderia BT03 | Dominant in community | Minimal impact despite high abundance |
| Pseudomonas GM17 | Rare in community | Significant influence on resource allocation |
| Pseudomonas GM30 | Rare in community | Disproportionate effect on plant function |
| Pseudomonas GM41 | Rare in community | Altered leaf and root mass fractions |
These results demonstrated that microbial interactions drive plant phenotype beyond the contribution of individual strains, challenging the assumption that the most abundant species necessarily have the greatest functional impact . The study also highlighted the potential for designing specific microbial communities to enhance crop performance and sustainability.
Modern plant science relies on sophisticated tools and reagents that have evolved dramatically from the simple agar blocks and coleoptiles of early auxin research.
Auxins like IAA and NAA remain fundamental tools for manipulating plant growth in laboratory settings, directly descending from the early work published in AJB 7 .
Precisely controlled environments allow researchers to separate genetic from environmental effects on plant development.
From simple light microscopy to advanced confocal and electron microscopy, these tools enable visualization of plant structures from the tissue level down to subcellular organelles.
The advent of molecular biology introduced powerful new tools that transformed plant science:
Recent innovations include engineered bacteria that function as all-in-one reagent packets for molecular biology procedures 3 . These cellular reagents eliminate the need for expensive protein purification and constant cold chains, making molecular techniques more accessible 3 .
| Research Era | Primary Methods | Key Limitations | Major Advancements Enabled |
|---|---|---|---|
| Early (1930s-1950s) | Bioassays, chemical extraction, microscopy | Could not track metabolism, limited chemical purity | Discovery of plant growth regulators, basic physiological principles |
| Molecular (1980s-2000s) | Recombinant DNA, PCR, early sequencing | Cost, technical expertise requirements | Gene discovery, transformation techniques |
| Modern (2010s-present) | Genomics, CRISPR, synthetic communities | Data integration, complex systems understanding | Systems biology, microbiome engineering, climate change responses |
As AJB moves beyond its centennial, plant science continues to evolve with several exciting frontiers emerging.
Recent research has revealed that plants possess sophisticated capacities for storing and recalling information from experienced stimuli 8 .
Demonstrates short-term memory through its mechanism requiring two touches of trigger hairs within approximately 20 seconds to close 8 .
Can learn to stop curling their leaves when repeatedly exposed to harmless dropping stimuli, retaining this memory for weeks 8 .
Future botanical research will increasingly focus on addressing pressing global challenges:
The journey of the American Journal of Botany mirrors the evolution of plant science itself—from simple observations of plant curvatures to sophisticated manipulations of entire biological systems.
What began with measuring the bend of a coleoptile has grown into a science that can sequence entire genomes, engineer microbial communities, and explore the molecular basis of plant memory.
Throughout its history, AJB has remained true to its mission while adapting to incorporate new technologies and research paradigms. The journal has chronicled how botany has become increasingly interdisciplinary, integrating methods from physics, chemistry, engineering, and computer science to understand plant life in all its complexity.
As we look to the future, the fundamental importance of plant science only grows more urgent. In a world facing climate change, biodiversity loss, and the need for sustainable agriculture, understanding plants has never been more critical. The next century of discovery in the pages of AJB will undoubtedly reveal plant adaptations and capabilities beyond our current imagination, continuing the "steady and collective advance" that has characterized this field for over a hundred years 7 .