402 SUMMARY OF CURRENT RESEARCHES RELATING TO 



BOTANY. 



GENERAL, 



Including tlie Anatomy and Physiology of Seed Plants. 



Csrtology, 

 Including' Cell-Contents. 



Chondriomes of the Tulip.* — A. Guilliermond contributes a note 

 upon the chondriomes of TuVvpa suaveolens. The writer finds the flower 

 of this species particularly suitable for observation since the epidermal 

 cells are unusually large and transparent. The chondriome is composed 

 of a large number of long, thin, undulate chondriocontes, frequently 

 branched and entangled ; granular, rod-like mitochondrias are also 

 present in smaller numbers. In the base of the petals, where a 

 santhophyll pigment is present, it can easily be seen that the latter is 

 localized in the elements of the chondriome, and the different stages in 

 the elaboration can readily be followed. In the earliest stages the 

 chondriomes are composed of granular mitochondrias and rod-like 

 chondriocontes ; the former appear to be primitive forms of the latter, 

 and gradually disappear. During the growth of the chondrioconte, it 

 is not unusual for transitory grains of starch to be formed, while the 

 chondrioconte becomes charged with a pale pigment and a few fatty 

 globules. These observations are entirely in accordance with those made 

 upon Iris germanica, and go to prove that the xanthophyll pigment is 

 elaborated by the chondriocontes. 



The same authorf contributes a further note upon the subject. He 

 has studied the alterations in the chondriome during the degeneration 

 of the cell and under certain physico-chemical influences. The first 

 change visible is the appearance in the neighbourhood of the chondrio- 

 contes of a series of vesicular swellings, each consisting of a globule 

 of colourless liquid surrounded by a thin, pigmented covering. 

 Subsequently these swellings separate into spherical vesicles which 

 increase greatly in size, come into contact with one another, break up 

 and mingle with the cytoplasm, in which the fragments of the pigmented 

 walls are distinctly visible. These alterations, together with those 

 observed under the influence of NaCl, saccharose, osmic acid, etc., show 

 that the mitochondrias are the most fragile elements of the cell, and are 

 the first to show signs of degeneration or osmotic disturbances. It 

 is the transformation of the mitochondrias which imparts the alveolar 

 structure to cytoplasm. 



* Comptes Rendus, clxiv. (1917) pp. 407-9. 

 t Comptes Rendus, clxiv. (1917) pp. 609-12. 



