Journal of Experimental Botany, Vol. 54, No. 386, pp. 1313 –1316, May 2003
DOI: 10.1093/jxb/erg168
Plant culture: thirteen seasonal pieces
May – two pictures of springtime
Nicholas H. Battey
In May, flowering time, nature animates the northern world. Botticelli’s
Primavera expresses this by reference to Lucretius’ ancient poetic description of
the procession of the spring months, and by connecting earthly love and
procreation to the divine spirit of love. Our modern Primavera II is inspired by
progress in understanding the genetic mechanisms controlling flowering time
in Arabidopsis. It rejoices in the repressions, activations, reinforcements and
redundancies of molecular biology, a language of power and control that
dominates today’s understanding of nature. It illustrates a reductionism that
would have delighted Lucretius.
Titus Lucretius Carus was a citizen of Rome, a materialist who championed
the common sense philosophy of Epicurus, which in turn traces back to the
atomist Democritus. We can recognize in Lucretius the symptoms of an
early scientist; but he was also a poet. And his poetic style did much to
popularize the scientific way of thinking, both on publication of his ideas as
‘De Rerum Natura’ in about 50 BC, and on their translation into English
as ‘On the Nature of Things’ at the birth of the modern age of science.
Lucretius was a fierce enemy of religion, believing that the idea that events
on earth were to be attributed to the (unfathomable) actions of gods was a
tyranny over the minds of men. Be an atomist, be rational, and be free, he
seems to say. But, as part of his poetic style, he still invoked the gods. They
allowed him to express his awe at nature; his wonder, for instance, at the
coming of spring:
Spring comes, and Venus, and Venus’ winged courier
Cupid runs in front. And all along the path that they
will tread dame Flora carpets the trail of Zephyr with
a wealth of blossoms exquisite in hue and fragrance.
As well as expressing wonder and awe, Lucretius was keen to promote the
idea that the regularity and sequence of events in spring (and during the rest
of the year) show a universe bound by physical laws. We should not
suppose, he exhorted, that the sun and moon ‘run their yearly races
between heaven and earth of their own free will with the amiable intention
of promoting the growth of crops and animals, or that they are rolled round
in furtherance of some divine plan’. It is, therefore, even more striking that
it was the poetic aspect to Lucretius’ message that formed the basis for one
Journal of Experimental Botany, Vol. 54, No. 386, © Society for Experimental Biology 2003; all rights reserved
1314 Battey
of the main elements in Botticelli’s famous painting of springtime, the
Primavera (Fig. 1). Out of the mind of Lucretius, the ultra-rational protoscientist, was born, 1500 years later, a most artistic rendering of the events
of spring.
To the foundation provided by Lucretius’ invocation of spring, Botticelli
added some spice from Ovid, in which the rape of the nymph Chloris by
Zephyr changes her into Flora. This represents the fertilizing effects of the
warm west wind, inseminating the earth to bring forth the flowers of April.
To the left, the painting shows the three Graces and Mercury; they owe
their presence to another poetic invocation to Venus, this time by Horace.
The Graces are spirits of the earth, their cycle of three showing the giving,
receiving and returning of gifts, a message that might now be called
‘sustainability’. It derives ultimately from the ancient Greek Hesiod, who
described the seasons of the farmer’s year. Mercury was, before the reform
of the Roman calendar by Julius Caesar, the god most strongly associated
with the month of May, and is seen here stirring the clouds, reflecting his
role as wind-god.
In combining these diverse elements Botticelli created a new image of
springtime that was at the same time ancient in its terms of reference. And it
can be read on several other levels. A strong theme is the possibility of
rarifying earthly lust to love (Zephyr-Chloris-Flora-Venus), and earthly love
to divine love (Venus may be pregnant and readable as the Virgin Mary).
The painting also hints at the pagan May festival, in which the flowering
May branch is harvested. This makes the Venus figure closer to the Queen
Fig. 1. Sandro Botticelli, La
Primavera, Florence, Uffizi
(painted 1478). The painting
reads from right to left;
Zephyr is the west wind
assaulting Chloris (the bare
earth) who, in consequence
is transformed into Flora,
fair-haired bringer of
flowers. Venus is the
goddess of April and
represents the regenerative
power of nature in
springtime. Cupid flies
above Venus’ head, and the
three Graces, spirits of
nature that show the cycle
of giving, receiving and
returning benefits, dance to
her right. At the far left of
the painting is Mercury, son
of Maia and god of the
month of May in the ancient
agrarian calendar of Roman
times. (Photo: Scala,
Florence.)
Plant culture: May 1315
of the May, the animating force of the universe, than the mythological
goddess.
But in every interpretation the idea of renewal is dominant. This is given
organic reality by the 40 species of plants illustrated, each also amenable to
symbolic interpretation. The theme of love, and of the origin of the
painting as a marriage gift to the Florentine Medici family, has been read
from the plants by Mirella Levi d’Ancona. For example, on Mercury’s boot
are depicted tiny cress flowers. The Italian name for cress, crescione, derives
from the verb ‘to grow’, and Levi d’Ancona interprets its presence as an
allusion to the growth of human love to divine love. In a more general
sense, crescione encapsulates one of the main intentions of the painting: by
depicting the beauty of the natural world, to inspire in the observer the
contemplation of the even greater beauty of the heavenly spirit.
Today’s plant scientist, following the intellectual tradition
laid out by Lucretius, might point to a very different
relevance of cress in the context of spring flowering.
Arabidopsis research on flowering time has enabled scientists
rapidly to reach closer to nature: by understanding the
molecular basis for the appearance of flowers we free
ourselves from the grip of false ideas, just as a rational
approach to the passage of the seasons freed Lucretius from
the random actions of the gods. The mechanism of the
circadian clock (Fig. 2) is a 21st century Primavera. The
beauties and varieties of flowering in springtime and the
reactions they engender in humans (love, awe etc.) may all
be reduced to something like this picture.
This new vision of spring has its origin with Bunning, who
in 1936 imagined that photoperiodic responses, such as the
control of flowering, might be based on a circadian system
of time measurement. Subsequent experiments confirmed
this circadian dimension to photoperiodism in many plants,
with the formation of flowers rhythmically responsive to
light flashes during a prolonged dark period lasting for
several ‘days’. Now, molecular analysis of Arabidopsis
mutants has revealed the existence of CONSTANS and
GIGANTEA, genes that control time of flowering and whose expression
fluctuates during the 24 hour cycle. These fluctuations are a result of
regulation by the products of the ‘clock’ genes TOC1, CIRCADIAN
CLOCK ASSOCIATED 1, LATE ELONGATED HYPOCOTYL and other
transcription factors, that generate the circadian rhythm (Fig. 2). The light
sensors phytochrome and cryptochrome entrain the clock to light/dark
transitions via effects on other genes, such as EARLY FLOWERING 3 and
ZEITLUPE. Flowering of Arabidopsis in spring occurs as a consequence of
light from the lengthening days coinciding with the peak of a circadiancontrolled gene, CONSTANS, which activates genes in the shoot meristem
that co-ordinate the construction of the flower.
Fig. 2. Primavera II. Drawing
courtesy of Steven Appleby.
1316 Battey
The history of this modern Primavera is brief—less than one hundred years.
We should look forward to it assuming a prominent place in the history of
the depiction of the world, 1500 years on. The world reduced to molecules,
or atoms, just as Lucretius would have wished.
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The author
Nicholas H. Battey
Plant Science Laboratories, The University of Reading, Whiteknights, Reading
RG6 6AS, UK
Fax: +44 (0)118 3788160. E-mail: [email protected]
Plant culture: thirteen seasonal pieces