Newton's Apple Tree

  • J. Murata (Professor, Koishikawa Botanical Gardens)
Figure 1

Fig. 1 Newton's apple tree

Figure 2

Fig. 2 Newton's apples. It is said that they belong to a variety of cooking apple called “Flower of Kent.” They have a rustic taste.

Figure 3

Fig. 3 The symbolic Ginkgo tree from which zoospore was discovered.

The history of Koishikawa Botanical Gardens, which are situated on the remains of the former Hakusan Palace of the early Edo era where the Tokugawa Shogunate established the Goyakuen (herbal gardens), dates back to a kitchen midden from a prehistoric age. The gardens are now managed by the University of Tokyo - thus, you can see relics from various eras up to the present day. They house a number of treasures that cover not only science, but also archeology, literature, art, medicine and pharmacy.

Isaac Newton's apple tree in the Koishikawa Botanical Gardens has become familiar as a symbolic tree of the garden. It was brought to Japan due to the efforts of Dr. Yuji Shibata, a chemist and a younger brother of Dr. Keita Shibata, who initiated plant physiological chemistry in the Department of Botany that is located within the garden. But the tree was not imported to Japan to be planted in the Koishikawa Gardens. Dr. Yuji Shibata, who became president of the Japan Academy in 1962, asked Sir Gordon Sutherland, director of the National Physical Laboratory of the United Kingdom to provide him offsprings from Newton's apple tree. As a result, a grafted apple tree arrived at Haneda International Airport in 1964. However, when the plant quarantine depot inspected it, it was found to be infected with apple chlorotic leafspot virus. Since the import of plants infected with disease or pest is principally prohibited because of the protection of domestic plants, diseased plants are supposed to be incinerated. However, because it was a valuable cultural heritage related to Isaac Newton, an exception was made and it survived incineration with a stipulation that it be grown in an isolated environment at the Koishikawa Gardens. Later an attempt was made to grow a mother stock under a high temperature in which the apple cell divides but propagation of the virus is restrained, and only the newly grown tip of the branch was grafted on to other rootstocks. This way of grafting was successful, resulting in the growth of five virus-free apple trees. Since no virus was found after an examination, these apple trees were at last permitted to be planted in Japan.

It was 1981 when Newton's apple tree (Fig. 1) was planted at the Koishikawa Gardens and unveiled to the public. A little more than 15 years had passed since it had arrived in Japan. Generally speaking, it is hard for an apple to bear fruit by self-fertilization, so we planted apples of different varieties nearby to cause natural crossbreeding by insects. As a result, fruits of certain size are grown, but they are damaged due to the behavior of crows, so fruits that are big enough to look like an apple (Fig. 2) are rare. Newton's apple trees are now grown all over Japan after being grafted in schools and science-related facilities for the promotion and enlightenment of science.

Next to Newton's apple tree is Gregor Mendel's grape vine. In order to plant the vine in the Koishikawa Botanical Gardens, the second curator of the garden, Manabu Miyoshi, asked a monastery in Bruno in the Czech Republic-Mendel used to do research on breeding of grapes at this monastery-to divide its grape vine. Mendel's grape vines are also now planted all over Japan.

In the Koishikawa Gardens there is a Ginkgo tree (Fig. 3) from which Sakugoro Hirase found a sperm in 1894. That was the first time a zoospore was discovered from gymnosperms.

It is apparent that the Koishikawa Gardens, which are full of treasures, are the treasure of the School of Science. We have launched the Life in Green Project for the maintenance purpose in order to adjust the gardens in accordance with the changes in the times without damaging their history.

The Life in Green project is the name decided for this project. We expect people to pronounce it as “Life'nGreen” as it is analogous to “life with green.” The latter means a people-driven life full of green, while the former includes a wish that people help and complement each other with green, a symbol of nature, and live with green in an integrated manner. As Newton's apple trees are widespread around Japan and nurture the dream of science at schools and facilities, we want the Koishikawa Botanical Gardens to be a place where people who love nature can realize their dreams.