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We have examined in vitro rooting of apple ‘Jork 9‘ shoots exposed for three weeks to each of the three auxins commonly used for ex vitro rooting: indole-3-acetic acid (IAA), indole-3-butyric acid (IBA) and α-naphthaleneacetic acid (NAA). During the initial five days of the rooting treatment, the cultures were incubated in darkness. In this period, the root initials are formed. Then, the cultures were moved to the light. NAA resulted in a low (ca. 8 roots), and IAA or IBA in a high (ca. 15 roots) maximal root number. The maximal root number was reached at a wide range of IAA concentrations (10-100 μM) but at only one concentration of IBA (10 μM) or NAA (3 μM). With NAA and IBA, growth of roots and shoots was much more inhibited than with IAA. For these reasons, IAA is the preferable auxin for in vitro rooting of apple ‘Jork 9’ shoots.

Isolated embryos are more suitable for in vivo study of protein synthesis than non-isolated embryos because, after isolation, the uptake of labeled amino acids is about 1000 times higher. However, isolation also stimulates protein synthesis: Up to 4 h after isolation, the capacity to incorporate labeled amino acids increased 7 times. Therefore, data on incorporation obtained with isolated embryos cannot be extended to non-isolated embryos. The increase of protein synthesis was not due to synthesis of specific proteins, but was a general increase. Furthermore, ripening, dormant, and afterripened embryos showed the same degree of increase. Isolation therefore stimulates protein synthesis nonspecifically. When embryos were kept under anaerobic conditions after isolation, protein synthesis did not increase. Therefore, higher oxygen consumption after removal of the seedcoat is probably the cause of the higher incorporation capacity. Furthermore, the activation of protein synthesis lagged several hours behind the increase of oxygen consumption.

This is an attempt to interpret the history of mechanism vs. vitalism in relation to the changing framework of culture and to show the interrelation between both these views and experimental science. After the scientific revolution of the seventeenth century, causal mechanism of classical physics provided the framework for the study of nature. The teleological and holistic properties of life, however, which are incompatible with this theory yielded — as a result both of internal developments within biology and of a general reaction against dogmatic rationalism — to a vitalistic interpretation of life which ascribed a mysterious force to living organisms. It will be shown that both mechanism and vitalism are related to the experimental climate of the time in which they were popular. The controversy has now lost its raison d'être as a result of the development of the theory of systems and of a better understanding of the chemistry and evolution of life.