Tracing the Evolution of Form and Function

August 11, 2017

Viewing wood anatomy

Tracing the Evolution of Form and Function

As a pioneering botanical institution with nearly 150 years of observed data on plants and their development, the Arnold Arboretum of Harvard University has long championed the study of the formal attributes that distinguish plant species from one another. With an advanced center for plant research now within sight of the collections at Weld Hill, the Arboretum also offers state-of-the-art tools to explore the mysteries of the plant world at the molecular level. These disciplines intersect as life science students from around the world gather at the Arboretum this month to better understand the the structures we observe in the plant kingdom through an intensive short course in plant anatomy in the teaching labs at Weld Hill.

microMORPH class

2017 microMORPH summer short course students and instructors gather on the balcony at Weld Hill.

For the fifth consecutive year, the Arboretum has hosted student scientists for two-weeks of lectures and lab practicums that illuminate the fundamental concepts of organismic plant biology. Taught by a distinguished and international faculty, the experience provides a unique and comprehensive analysis of plant form and development—subjects that have lost ground at many colleges as genomic studies have gained prominence. Understanding the basic biology of plants, however, remains fundamental to making further progress even as technology pushes research in new directions. This course provides an extraordinary opportunity for students to study how plants have diversified across the globe by linking genes through development to form, and ultimately to adaptation and fitness.

Open to postdoctoral researchers, graduate students, and undergraduates in their final year of study, the Arboretum accepts up to a dozen applicants each year. This summer the student body reflects the international character of contemporary botanical science with participants from the U.S., Argentina, Australia, China, Denmark, Great Britain, and Madagascar. Some of the world’s foremost authorities in plant developmental and evolutionary science teach the course: Pieter Baas from Naturalis Biodiversity Center in the Netherlands; Pamela Diggle of the University of Connecticut; William Friedman of Harvard University and the Arboretum; Peter Gasson of the Royal Botanic Gardens, Kew; Cynthia Jones from the University of Connecticut; and Elisabeth Wheeler from North Carolina State University. The students’ first week of study focused on anatomy of the primary plant body throughout development and evolutionary trends in plant anatomy. Week two (finishing today) focuses on the anatomy of secondary growth in plants and the diversity of wood anatomy—topics of historical interest at the Arnold Arboretum.

Wood anatomy sampling

Students Lucy Delaney (left) and Amy Ny Aina Aritsara collect softwood samples to view vascular tissues under the microscope in Weld Hill’s teaching lab.

“We just started delving into wood anatomy, and it is so incredible having access to the Arboretum and its incredible plants,” said Lucy Delaney, a plant evolutionary biology major at the University of Illinois at Chicago. “We wondered how the structures we were studying in flowering plants might be different in conifers, and almost in real time we had a sample cut from the collection to examine under the microscope.” The lab work also made a huge impression on Amy Ny Aina Aritsara, a PhD student from Madagascar currently studing at China’s Guangxi University. “I particularly enjoyed sectioning and studying live plant material like geranium stems,” he offers. “I’ve worked mostly with wood in the past, so stems, roots and meristems are new to me and such interesting topics of study.”

Viewing wood anatomy

Student Neeke Hammers views softwood tissues under the microscope.

If access to diverse plant collections provides an inspiring environment and raw materials for study, students also benefit from close interaction with each other and some of the world’s most distinguished authorities in plant evolution, function, and development. The group develops a strong camaraderie through collaboration, open discussion, and even communal activities like sharing meals together. “What makes this experience extraordinary is learning from some of the leading figures in plant science,” said Lucy. “Every day they take us to the boundaries of where the world’s knowledge exists—you can see the line between what we know and what we still need to learn.”

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