148 Mr Gregory, The Abortive Development 



The Abortive Development of the Pollen in certain Sweet- 

 Peas (Lathyrus odoratus). By R. P. Gregory, M.A., St John's 

 College. 



[Read 14 May 1905.] 



Among the plants produced from the self-fertilization of a 

 certain race-hybrid of Lathyrus odoratus Mr Bateson obtained, 

 during 1903, a certain number of individuals whose anthers were 

 contabescent*. 



In the plants with coloured flowers the sterility was, with a 

 very few exceptions, correlated with a somatic character, the sterile 

 plants possessing a green leaf axil, while the fertile plants, with 

 the rare exceptions noticed, had red axils. 



The same phenomenon was repeated in 1904, with every 

 indication that the sterility occurs in a definite proportion of the 

 plants, both in those with coloured and in those with white 

 flowers. That is to say, the sterility is a character which under- 

 goes segregation in accordance with Mendelian principles f. 



Mr Bateson kindly allowed me to take material from his plants 

 for the purpose of making an examination into the cytological 

 phenomena which accompany the sterility of the male organs. 

 The fixing fluids used were (1) a mixture of glacial acetic acid, 

 1 part ; absolute alcohol, 2 parts ; and (2) a 1 °/ Q solution of 

 chromic acid in water. It was found that anthers preserved in 

 the early morning yielded a rather larger proportion of favourable 

 preparations than did those taken later in the day. 



From an examination of fresh material by various methods 

 it became clear that the abnormal forms taken by the cells 

 of the sterile plants were somewhat variable. In most cases 

 the anthers contained a semi-fluid mass, in which a few cells 

 of irregular outline could sometimes be distinguished ; others 

 contained a few pollen grains, which however appeared to be bad. 

 This observation was confirmed by the detailed study, which 

 revealed a considerable range of divergence between the behaviour 

 of the nuclei of the pollen-mother-cells, not only of different plants 

 but sometimes of different anthers of the same plant. The 

 appearance presented by the pollen-mother-cells of any one loculus 

 is generally the same, except for slight differences corresponding 

 with the slightly more or less advanced stages of development 

 reached by some of the cells. But it seems probable that the 

 degree of abnormality exhibited by pollen-mother- cells produced 

 in different loculi of one anther is not necessarily the same. 



* Bateson, Saunders, and Punnett, Roy. Soc. Evol. Com., Rep. ii. p. 91. 

 t Ibid. pp. 91, 92. 



