Recorded Books Inc. - Seed to Seed

SEED TO SEED

SEED TO SEED

The Secret Life of Plants

Nicholas Harberd

BLOOMSBURY

Copyright 2006 by Nicholas Harberd

Illustrations copyright by Polly Napper

All rights reserved. No part of this book may be used or reproduced in any manner whatsoever without written permission from the publisher except in the case of brief quotations embodied in critical articles or reviews. For information address Bloomsbury
Publishing, 175 Fifth Avenue, New York, NY 10010.

Published by Bloomsbury Publishing, New York and London
Distributed to the trade by Holtzbrinck Publishers

All papers used by Bloomsbury Publishing are natural, recyclable products made from wood grown in well-managed forests. The manufacturing processes conform to the environmental regulations of the country of origin.

Library of Congress Cataloging-in-Publication Data has been applied for.

eISBN: 978-1-59691-797-2

First U.S. Edition 2006

1 3 5 7 9 10 8 6 4 2

Typeset by Hewer Text UK Ltd, Edinburgh
Printed in the United States of America by Quebecor World Fairfield

For Jess

... what greater delight is there than to behold the earth apparelled with plants, as with a robe of embroidered worke, set with Orient pearls and garnished with great diversitie of rare and costly jewels? If this varietie and perfection of colours may affect the eie, it is such in herbs and floures, that no Apelles, no Zeuxis ever could by any art expresse the like: if odours or if taste may worke satisfaction, they are both so sover-aigne in plants, and so comfortable that no confection of the Apothecaries can equall their excellent vertue. But these delights are in the outward senses: the principal delight is in the mind, singularly enriched with the knowledge of these visible things, setting forth to us the invisible wisdome and admirable workmanship of Almighty God...

John Gerard, The Herball

or General Historie of Plants, 1597

CONTENTS

PREFACE

THIS is a book that attempts to show how science can enhance our vision of the world. It is a book written principally for non-scientists. On one level it describes the wonders of the area of science with which I am particularly engaged: the developing understanding of how and why plants grow. On another level it depicts these recent advances within the context of a wider representation of mind. That mind is my own, occupied as it is with some of what I think to be the most exciting current questions in plant biology. The book is, therefore, in part, a mental self-portrait. Like all portraits, it abstracts: it exaggerates some features, omits others. It is drawn in the hope of revealing things that were previously not visible.

I am a scientist who is fortunate to be working at one of the world's foremost scientific research institutions. I direct a research team at the John Innes Centre in Colney, on the outskirts of Norwich. Our experiments are revealing the hidden fundamentals of how the growth of plants is controlled. Finding the genes and proteins that build plants into the visible shapes and forms they have. Exploring the intrinsic beauties of these invisible things.

The book is really a notebook, a diary of the year 2004. At its core is the progression of a chosen plant through the stages of its life-cycle, set within the context of the seasons. This description is combined with an outline of the unseen molecular forces that drive plants from stage to stage. Other progressions are also recorded: the deepening of scientific understanding of the growth of plants (a history of the recent work of my research group); the realisation of a new research direction; a personal journey from frustration to enlightenment.

What more needs to be said by way of introduction? Perhaps that much of what follows consists of notes and sketches rapidly executed in snatched moments. Often neither finished nor complete. Sometimes half-thoughts. My intention was to try to capture a sense of the scientific process within a more general picture of a mind that is engaged with it. Feelings are recorded and feelings are things which we scientists are often overly constrained in expressing. Most of all, I hope that I have occasionally managed to evoke a sense of life. The passing of a moment in a few dashed jottings.

N.H.

January 2006

Thursday 8th January

EIGHTEEN years ago today, I first flew out from London to California. A new beginning. And, for someone who had lived most of his life in England, a huge change. So many things were different. The quality of the light, for instance. It penetrated,had a revealing clarity I'd not previously seen. I have splintered memories: a glimpse of the Golden Gate bridge, a great ochre harp shimmering in ochre beyond the flecked blue ocean; sudden alarm at a brief, ground-shuddering earth-tremor; violent rain in a storm from the Pacific.

Whilst I was in California I absorbed new styles of thinking, new ways of doing science. Things that seemed to have grown from the place, from the landscape and from its people.

I am a plant geneticist, and had gone to California to begin work in a new area. As well as swapping continents, I was swapping plants: from wheat to maize. And I was quickly captivated by the bold magnificence of the maize plant, the vigour of its growth. With a summer crop in California and a winter crop in Hawaii we had two generations a year: six months in between to plan new crosses and consider the outcomes of the previous ones.

It was an exhilarating time in plant genetics. I worked long hours with enthusiasm, returning from the heat of the field drenched in pollen and sweat. Around the world, other groups were using a variety of different plants for genetic research: wheat, barley, rice, tobacco, even snapdragons. New concepts were coming from all directions, new areas of research were continually opening up in front of us.

And then, on top of all this, there began at that time a shift in thinking that was eventually to propel plant genetics on to an entirely new plane. This shift was based on a unifying idea. An idea rooted in the concept that all plants are essentially as one, that the different species of plant have more in common than they do that divides them. That cacti, tree-ferns, redwoods, oats and sunflowers are more similar than different. The idea was that concentration of effort on the study of a single species would advance understanding of all.

As acceptance of this idea grew, so the next question arose: which single species? In the end, the species that many plant biologists settled on was the thale-cress: Arabidopsis thaliana. Thale-cress? What is thale-cress? You've probably never heard of it. A squat rosette of leaves that bolts to a height of a foot or less, flowers, then dies shortly thereafter. Scattered about in the neglected parts of gardens, in wasteland or on walls. Inconspicuous and ignored; common, but unfamiliar.

So why was thale-cress preferred? Because it has attributes that are perfect for the plant geneticist, making it our own Drosophila (fruit-fly). First, it's easy to grow in glasshouse and laboratory, its small size allowing many thousands of plants to be grown in limited space. Second, it has a relatively short generation time: seed to seed in six weeks in the lab. That's eight generations a year, rather than the two with maize. Four times as many new crosses every year, each one bringing new insights, deeper understanding. Third, thale-cress has a relatively small genome, a property of great potential to a geneticist. Determination of the DNA sequence of the entire genome, the totality of the DNA that contains the genes, was therefore a more realistic proposition than for other species. It would be the first sequenced plant genome. An exciting prospect since the DNA is the key to understanding how a plant grows. If we knew the sequence of all of the genes of the thale-cress we could really get to grips with solving some of the most important questions in plant biology.