The History of Germination Research and the Lesson It Contains for Today
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ISRAEL JOURNAL OF BOTANY, Vol. 29, 1980/81, pp. 4-21 THE HISTORY OF GERMINATION RESEARCH AND THE LESSON IT CONTAINS FOR TODAY MICHAEL EvENARI Department of Botany, The Hebrew University ofJerusalem, Jerusalem, Israel When the ancient Egyptians entombed their mummies they added a special vessel containing seeds prepared for germination as a symbol of the mystery of death, resur rection and life after death. This belief in resurrection was not restricted to the ancient Egyptians but is common to many peoples and religions. Seed germination recurs frequently in the scriptures of the various religions as a symbol of this nearly universal faith. I cite only one example which is interesting because of its intentional ambiguity: "But some man will say, How are the dead raised up? and with what body do they come? Thou fool, that which thou sowest is not quickened, except it die. And that which thou sowest, thou sowest not that body that shall be, but bare grain, it may chance of wheat, or of some other grain. But God giveth it a body as it hath pleased him, and to every seed its own body" (I Corinthians, 15:35-38). It is no wonder that germination became the symbol of these mysteries as it is itself something of a mys tery: a thing apparently dead, which even today by simply looking at it we cannot say whether it is dead or alive, when submitted to the right conditions comes alive, sprouts a whole new plant and creates a whole new generation. For the ancients germination was not only a mysterious symbol. It became a prob lem from the moment man invented agriculture. Sometimes the seeds of his agricultural crops did not germinate properly, resulting in catastrophic consequences. And so we read in the Old Testament: "They have sown wheat and have reaped thorn" (Jeremiah 12:19), or "You have sown much and brought in little" (Hagai 1:6), or "You shall sow, but shall not reap" (Micah 6: 15). We can state with certainty that since man first started agriculture he has always been faced with germination problems in one way or another. The close relationship between seed germination and agriculture was stressed by Theophrastus of Eresos (c. 372-287 B.C.) and later Roman authors, and since then germination research has never lost touch with agriculture. Theophrastus is the ftrst all-round botanist known to us, though he had predeces sors such as Hesiod (8th century B.C.?) who in his book "Work and Days" was "put ting forth rules for agriculture" (Pliny (Plinius), N.H. Book XN, 1:3), Empedocles, Democritus (5th century B.C.) and his teacher Aristotle (384-322 B.C.). He also has a number of Roman successors - Cato the Elder (234-140 B.C), Varro (116-27 B.C.), Received April 22, 1980 Vol. 29, 1980/81 HISTORY OF GERMINATION RESEARCH 5 Virgil (70-19 B.C.) and Pliny the Elder (23-79 A.D.), who all wrote agricultural treatises. But while they are agriculturists, Theophrastus is a true biologist and scientist, relating to observations in a critical way and questioning their accuracy (the "scientific method"). The typical sentence "This is yet to be investigated" is often repeated in his books (e.g. D.H.P. Book IV, IX:3). Many of his observations show that he is a plant physiologist. When attempting to show that not all underground organs are roots he says: "for we must base our definition (of roots) on natural function and not on position" (D.H.P. Book I, VI:9). Another of his statements is most remarkable consi dering that it was only proved experimentally over 2000 years later by lngenhousz (1779) and Senebier (1788): "When the crop changes with the country the mutation evidently follows the air and the soil since all plants get their food through these and from these" (D.C.P. Book II, XIII:l). He is also the first to report allelopathy, which Molisch investigated only some 2000 years later (1922). Theophrastus reports: " ... some things though they do not cause death enfeeble the tree as to the production of flavours and scents; thus cabbage and sweet bay have this effect on vine. For they say that the vine scents the cabbage and is affected1 by it wherefore the vine shoot, whenever it comes near this plant, turns back and looks away as though the smell was hostile to it" (D.H.P. Book IV, XVI:S). He is a plant ecologist and plant geographer since he recognises clearly that soil in general, and its salt and water content, the depth of ground water, dew fall, topography (mountain and plain flora) and geographic latitude "give a special character to vegetation" (D.H.P. Book III, 11:6), and determine growth and reproduction of plants (e.g. D.H.P. Book III, 11:6; Book III, III:S; Book N, III:S & 7). Long before Raunkiaer (1900), he is the first botanist to recognise the importance of life forms: "The first and most important classes which comprise all plants are tree, shrub, dwarf shrub,2 herb" (D.H.P. Book I, 11:6). In the context of this paper, however, the most important point is that Theo phrastus is also the first seed physiologist and seed ecologist. He knew that during seed maturation plants deposit food reserves in seeds, reserves which are needed for seedling growth: " ... all plant seed has in itself a certain amount of nourishment which is produced with it at the beginning just as is the case in eggs. Wherefore the remark of Empedocles is not badly put when he says: 'And the tall trees oviposit'; for the devel opment of seeds is very much like that -of eggs except that we must extend Empe docles's dictum to include the seeds not only of trees, but of all plants, for every kind of seed has nourishment in itself' (D.C.P. Book I, VII:l). Fruit coats and seed coats have different functions and differ in their resistance to environmental conditions. "When the fruit case, which is for man's use, is different from the seed,3 it must ripen within a limited period, since after this has passed, the tree will suffer from the onslaught of winter and rainy weather. There need, however, be no limit for a seed case since this falls down with the seed or first shoots them out, as in the pitch pine or the conifers generally. In these, while the cones are still fast to 1 The English translation reads "infected". It should read "affected". 2 The English translation reads "under-shrub". 3 This implies that Theophrastus knew that this "difference" does not always exist. .