﻿BOTANICAL GAZETTE 



movement. Kuster believes that the usual movement of chromatophores is 

 passive, these organs being carried in the direction of protoplasmic streaming, 

 whatever the direction taken by the pseudopodia. From these studies it is 

 concluded that the chromatophores in question are fluid. It is suggested that 

 other chromatophores, as those in Listera and Iris, may have the character- 

 istics of the Orchis chromatophore. — H. C. Cowles. 



Parthenogenesis in Nicotiana. — Goodspeed 1 ? has made some very inter- 

 esting experiments in connection with parthenogenesis in Nicotania, suggested 

 by a strain of N. Tabacum in which Mrs. R. H. Thomas reports parthenogenesis. 

 Over 500 attempts to produce parthenogenetic seed from a number of species 

 and varieties of Nicotiana yielded negative results. These experiments 

 included crossing and propagation through several generations. In the case 

 of the parthenogenetic strain referred to, however, approximately 800 experi- 

 ments resulted in over 100 normally matured fruits. In the majority of these 

 parthenogenetic fruits empty seeds were produced in great numbers, and for 

 this type of seed production, either with or without pollination, Goodspeed 

 suggests the term "phenospermy," referring to the seed condition usually 

 described as "abortive" or "empty." Approximately 50 seeds occurred in 

 nine of the parthenogenetic fruits, some of which showed mature endosperm 

 and embryos. A small proportion of the seed from the parthenocarpic fruits 

 was neither parthenogenetic nor phenospermic, but contained traces of endo- 

 sperm only. — J. M. C. 



Bactericidal substances. — That the juices of plants may contain bacteri- 

 cidal substances which figure in protecting the plants against the attacks of 

 certain organisms has been shown by Wagner. 18 Varying numbers of bac- 

 teria of the non-parasitic species Bacillus vulgatus, B, asterosporus, and Bac- 

 terium putridum were injected into the tissues of potato tubers, beet roots, 

 and the leaves and roots of Sempervivum Hausmanii. The injected organisms 

 proved parasitic only when present in enormous numbers (3000-8000), and in 

 that case were able to bring about the decay of the injected tissues. When 

 injected in smaller numbers, the bacteria are destroyed. In case of the potato 

 and of Sempervivum, the freshly expressed juice was found to possess bactereo- 

 lytic and agglutinating properties, but from the sugar beet no bactericidal juice 

 could be obtained. The active substances were found to be contained in the 

 protein fraction of the juice. When the fresh filtered juice containing enzymes, 

 carbohydrates, and salts is allowed to stand for two days, its bactericidal power 

 is destroyed, probably by the action of oxidases and other enzymes. — H. 



, Thomas H., Parthenogenesis, pari 



