Crane • Lysenko's Experiments 253 



leaves and red fruits. Seeds were sown gans of the potato-leaved lower part, 



from the red fruits of the latter part then plants with pinnate leaves and yel- 



and we are told that most of the result- low fruits would arise, 



ing plants "did not differ from the ini- Admittedly natural cross-pollina- 



tial strain." "Six plants, however, had tion in tomatoes is rare between sepa- 



pinnate leaves, and some had yellow rate undisturbed plants, but it is not 



fruits." Lysenko concludes that this unknown and where, as in this grafted 



result is due to both the leaves and the plant, two forms are growing together 



fruits having changed under the influ- and are probably being interfered with 



ence of the yellow-fruited, pinnate- by the experimenter, the chance for 



leaved shoot grafted upon it. cross-pollination is greater than be- 



In this experiment and indeed in all tween separate plants, 



the experiments referred to in the book, There is another possibility which 



Lysenko and his associates seem to we may consider. As shown by Jorgen- 



have had no scientific method. At least sen and Crane (1927), plants grafted 



we are left in the dark on many im- together, and especially solanaceous 



portant points. It would have been of plants, frequently develop tissues in 



value if we were told if all the six which the two components are inti- 



pinnate-leaved plants had yellow fruits, mately combined. The most common 



and, if not, how many were yellow, development is the so-called periclinal 



and what was the color of the re- chimera where even only a small area 



mainder. Also, if control plants were of one component may be over the 



grown and whether the two plants used other. If such an area is two layers 



to make the composite grafted plant thick, resulting seeds and offspring will 



were homozygous or not. be like the component of which these 



The inheritance of leaf-shape and layers are composed. On the other 

 fruit color in tomatoes has long been hand, if the outer component is only 

 known. The pinnate cut-leaf character one layer thick— then the offspring 

 C is dominant to the non-pinnate po- would be like the inner component. In 

 tato-leaf c. Two major genes R and Y this way seeds from a single fruit could 

 are concerned with fruit color; RY is give both pinnate and yellow and non- 

 bright red as in the common tomato of pinnate and red-fruited plants. With 

 commerce, Ry is dull red, rY deep yel- two varieties of tomatoes, especially if 

 low, and ry pale yellow. Since no men- only a small area of a flower was in- 

 tion is made of control plants, the first volved, such a development could be 

 question which arises is, were the passed unnoticed. Periclinal tissue has 

 plants, and especially the red-fruited occurred from time to time in other 

 plant, used in the grafting homozygous plants such as apples, medlars, and 

 or heterozygous. That is to say, was it roses following the common horticul- 

 of the constitution RRYY, RrYY or tural practice of grafting, but without 

 RrYy, for although the fruits of all any other interference, 

 three would be red and indistinguish- Later, Lysenko refers to a tomato 

 able, seeds from the latter two would plant which had one yellow and one 

 give a proportion of plants with yel- red fruit. When we consider the nu- 

 low fruits, but we should expect them merous recorded and well authenti- 

 to have the recessive potato-leaf char- cated examples of spontaneous somatic 

 acter. If, however, a few grains of variations in plants, see for example 

 pollen from the pinnate-leaved upper Darwin (1899) and Crane and Law- 

 part of the composite grafted plant rence (1947), involving all kinds of 

 came in contact with the female or- characters including the color of flowers 



