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10 facts you might not know about Katherine Esau (pronounced EE-saw), the grande dame of botany, plant anatomy and phloem 
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1. She was born in the Russian Empire (1898) in what nowadays is the Ukraine. Her family had immigrated from Prussia at the beginning of the XIX century and belonged to a Mennonite community with an agricultural tradition.
2. Her studies in the Agricultural college in Moscow were interrupted by the Russian revolution only one year after she started. Some months later the family fled to Berlin in fear of the Bolsheviks.
These were not easy times, since WWI ended in 1918, overlapping with a flu pandemic. Despite the tough circumstances, Katherine graduated from the Agricultural college in Berlin and the family moved to California in 1922.
3. While settling, Dr Esau did housework for a family in Fresno and later joined a ranch dedicated to producing sugarbeet seeds until it went bankrupt. She then found a job in a sugar company.
At the time, the company had a sugarbeet strain resistant to the virus causing curly-top disease, transmitted by the beet leafhopper. This resistant strain (P19, parent selected in 1919- much better than our covid19 a century later) was good at staying healthy but
but was not suitable for commercial purposes since it had a low sugar content and a strange root shape. Katherine’s project was to breed an improved P19 when she was appointed for an assistant job at Davies, where she could continue pursuing her objective.
4. She moved to Davies followed by a truck full of beets that she planted on campus but also on colleagues gardens. She was 30 at the time she started her PhD. Don’t know if this was normal at the time, but bringing your own project to PhD sounds outstanding to me.
Of course this is hard if you have just finished your degree/master. The project suffered a severe setback when she was no longer allowed to release infective hoppers over her sugarbeet plots to protect other breeding programs.
Instead of pursuing breeding, she then decided to study the effects of the infection in the plant, focusing on plant anatomy.
5. Although she worked at Davies, she got her PhD from Berkeley in 1932 and then she was appointed instructor in Botany and Junior Botanist at Davies. She was both teaching and doing research and yes, the job market seemed to be a bit better in those days despite the crash of 29!
Apparently it was not necessary to go on postdoc abroad -as good and useful as it is, it was not always this way. However, becoming full professor was equally slow: she got it in 1949 at the age of 51.
6. In 1953 she published ‘Plant Anatomy’, now a classic in the field. 4 years later she became the sixth woman elected to the National Academy of Sciences. In 1960 she published the Anatomy of Seed Plants.
She moved to Santa Barbara in 1963 to what she considered her most productive years.
7. Dr Esau became specially interested in phloem. Phloem transports nutrients and other molecules from green autotrophic organs to non-photosynthetic tissues, like roots. Indeed, some virus are also transported by phloem, spreading tissue degeneration to connected organs.
8. Electron microscopy allowed her to observe the specificities of the sieve element cells, that lose their nucleus upon differentiation to specialize in transport.
She was also interested in plasmodesmata, the nano channels connecting plant cells that were also transporting viral particles bigger than their diameter.
9. She had her own photomicrography equipment and dark room at home. All the micrographs in the first edition of Plant Anatomy are home products.
10. Dr Esau passed away in 1997 at the age of 99. She published her last paper in 1990 and last updated Plant Anatomy in 1992. In 1989 she was awarded the National Medal of Science.
Her obituary in The New York Times ends with ‘There are no survivors’, since she never married or had kids. However her survivors are her students and all those who still benefit from reading her books and articles, some of them among the most influential in the field. THE END
References to know more: https://www.botany.org/bsa/misc/esau.html https://www.nytimes.com/1997/06/18/us/katherine-esau-is-dead-at-99-a-world-authority-on-botany.html https://www.ccber.ucsb.edu/ucsb-natural-history-collections-library-and-historical-information-katherine-esau/life-katherine https://www.britannica.com/biography/Katherine-Esau
