Principles and Methods pp. 89-91 (1929/1952)
Pear on Lemon
Ivan Michurin

Fig. 5. A six-month-old lemon graft on pear (the larger leaves are the lemon)

And, lastly, a profoundly interesting and highly valuable experiment has been carried out in our nursery by my immediate assistant, P. N. Yakovlev. In this experiment, lemons have been grafted as mentors onto a pear, one on June 5 and the other on October 25, 1926. Here we have an opportunity to observe the influence exercised on each other by two plants belonging not only to totally different species and genera, but even to two different tribes — in the one case, one-year-old seedlings of the lemon, an evergreen subtropical plant (Citrus Limonium Risso) from Central Asia, in the other, a one-year-old hybrid seedling of the Michurin Beurré Zimnaya pear. It was probably only because they were so young and were taken out of their accustomed environmental conditions that the two could lend themselves to such symbiosis. The lemon, being an evergreen plant, naturally did not shed its leaves with the coming of winter; nay more, at quite an early stage it correlatively, through its influence upon the root system of the stock, prevented the pear too from halting in its growth and losing its leaves, although next to it, in the same room, similar hybrid pear seedlings potted out at the same time discarded their foliage at the usual season.

I need hardly say that we have no intention of growing lemons grafted on pears; we only want by this experiment to see and study the vegetative influence exercised on each other's constitution by two plants essentially so far apart.