MRI: Empowering Plant Science Research at Rancho Santa Ana Botanic Garden with High Resolution and Variable Pressure Scanning Electron Microscopy Instrumentation

Rancho Santa Ana Botanic Garden, Claremont CA

Investigators

Abstract

An award is made to Rancho Santa Ana Botanic Garden (RSABG) to acquire modern instrumentation and analytical capacity for the Scanning Electron Microscopy (SEM) laboratory. SEM is one of the principal methods for examination of detailed surface structure (micromorphology) of biological materials. This instrument is of fundamental importance to research and training at RSABG, the largest botanic garden dedicated to California native plants and an important research center for plant comparative biology. Specifically, RSABG will acquire a Hitachi SU3500S Variable Pressure SEM, together with specimen preparation equipment and SEM-image analysis software. Vastly improved SEM capabilities will support research by RSABG faculty, staff scientists and students to further our understanding of the evolution of plant diversity through integrating comparative morphological and anatomical research on plants with cutting-edge molecular methods and phylogenetic analysis. The enhanced view of meristems, surfaces of leaves and stems, floral structures, seeds and pollen grains enabled by SEM imaging expands our knowledge of plant form and function. Notably, for many plant groups, SEM photomicrographs of pollen grains are essential components of species descriptions. In addition, quality SEM micrographs are an important means of effective and exciting visual communication, both in scientific presentations and in formal and informal education. SEM imagery from the Hitachi SEM will enhance our work in plant conservation through enhancing our ability to observe reproduction in rare plants. It will also contribute to public and formal education by providing images that are both beautiful and information-packed to support programming for K-6 and college students, as well as other visitors to RSABG through use of such images in exhibits. The facility will also augment microscopy capabilities available to researchers at the Claremont Colleges. The SU3500S Variable Pressure Scanning Electron Microscope, the Cressington 108 Auto Sputter Coater with an MTM-20 high resolution thickness controller and MountainsMap Universal software represent significant improvements to and expansion of research infrastructure at RSABG. This integrated system will dramatically improve our conventional (i.e., high vacuum) SEM capabilities and also significantly expand our research tool chest by adding (1) higher resolution and magnification than currently achievable, (2) low vacuum capacity and a Peltier cooling stage for observing hydrated, living tissue and (3) sophisticated image analysis software. The low vacuum capabilities of the instrument will expand considerably the research questions that we can address while also ensuring that observations made are accurate. The image analysis software that is a vital part of the package will transform our analytical power to gather data from SEM images: to characterize, quantify and analyze 2D and 3D structure, and to integrate these morphometric data with comparative phylogenetic analyses to advance our knowledge of the patterns of plant evolution.