MicroCT technology facilitating archaeobotany and the study of origin and evolution of agriculture

The emergence of agriculture stands as a pivotal juncture in human history, garnering widespread interest within the field of archaeology. The identification of both macro and micro plant remains has marked considerable progress in studies pertaining to the origin and evolution of agriculture. Nevertheless, challenges persist, including suboptimal flotation results, limited or inadequately preserved macro plant remains, and the imperative for further exploration in identifying micro plant remains at the species level. Consequently, numerous questions in archaeobotanical research deserve further clarification. Indeed, equal emphasis should be placed on the examination of plant impressions, frequently unearthed within soil-related artifacts such as pottery shards, fired clay, and clay sculptures. These impressions faithfully replicate the morphology of plant remains in their "fresh" state, providing valuable insights into various aspects, including subsistence strategies, the diverse utilization of plant resources, the origin of agriculture, crop domestication, and the reconstruction of natural environments. In China, numerous deposits of unearthed artifacts containing significant information on plant impressions await exploration. In recent years, there has been a notable shift in focus towards studies that leverage microCT (micro computed tomography) technology, emerging as a central component in the investigation of plant impressions. Previous research endeavors have applied scanning analyses to scrutinize plant impressions extracted from archaeological sites situated in Southeast Asia, East Asia, and Africa. These initial forays into impression studies utilizing the microCT approach have made significant contributions to the exploration of various issues in archaeobotany. As pioneering efforts, these studies underscored a substantial potential within the broader archaeological context. The current study provides a comprehensive survey of the historical trajectory of plant impression studies and recent advancements in research utilizing microCT scanning technology. In particular, we outline potential breakthroughs expected to address specific scientific inquiries in the future, summarizing key areas of exploration across three aspects. Firstly, in regions characterized by challenging preservation conditions for macro plant remains and limited stratigraphic information within geomorphic units, such as deserts, plateaus, and wastelands, microCT scanning of plant impressions within the field of view becomes invaluable in supplying crucial information on plant residues. This aids in understanding local subsistence strategies and fills gaps in cross-regional transmission paths of crops, promising substantial breakthroughs in research areas like early East-West cultural exchanges and interactions. Moreover, advancements in the methodology for identifying stem and leaf genera will significantly enhance our understanding of ancient human plant utilization practices through systematic examinations of stem and leaf imprints. It is noteworthy that certain plant parts, such as awns and rachises, which may be absent from flotation but well-preserved in impressions, offer a fresh perspective for investigating crop domestication. Additionally, microCT technology holds significant potential for quantitative research on prehistoric organic-tempered pottery. This opens up new avenues to explore ancient pottery technologies, providing insights into the quantitative aspects of prehistoric practices related to plant residues and additives. This paper concludes by clarifying the current challenges and upcoming opportunities in microCT applications for the analysis of ancient plant remains. It emphasizes the substantial potential of artificial intelligence to make significant contribution to this field.