88 SUMMARY OF CURRENT RESEARCHES RELATING TO 



BOTANY. 



GENERAL, 



Including the Anatomy and Physiology of Seed Plants. 



Cytology, 

 including- Cell-Contfmts. 



Spirogyra-cells under Action of Centrifugal Force.* — E. W. 

 Schmidt describes the behaviour of Spiroffyra-ce\h after subjection to 

 high centrifugal force. He subjected fibiuients of the alga to various 

 degrees of centrifugal force up to <s,320 revolutions a minute. The 

 nucleolus was never seen to fly out of the nucleus, though other 

 interesting phenomena occurred. The power of regeneration of the 

 contents was most marked, especially the return of the chloroplasts 

 which had been hurled against the cell-wall. Fine filaments of cyto- 

 plasm, which are formed soon after the recovery of the cells, take part 

 in this return. Whether they actively draw the' chloroplasts or wliether 

 the chloroplasts are pushed by protoplasmic streams is undetermined. 



• 



Pigments of Fruits of Capsicum.f — W. R. G. Atkins and G. 

 Sherrard have studied the pigments of the fruit in lelation to some 

 genetic experiments on Capsicum cmiiuum. The unripe fruits are green 

 as a rule, but pale yellow in one form ; in the four varieties employed 

 the ripe fruit is red, chocolate, orange, and yellow respectively : red is 

 found to be dominant to yellow, and appears to be a simple dominant 

 to chocolate and orange. The different shades of green in unripe fruits 

 are due to variations in the numbers of chromatopiieres contained in each 

 cell. The colours of the ripe fruits are due to red, chocolate, orange, and 

 yellow plastid-pigments ; it has not been possible to show that the red 

 or the chocolate is due to a mixture of pigments. Some red fniits 

 contain small quantities of yellow pigment soluble in water. The red 

 and chocolate pigments when pure are oily liquids which have not been 

 obtained in a crystalline state ; tliis chai'acter, and their ready solubility 

 in cold alcohol and in petroleum ether, distinguishes them from lycopin, 

 carotin and xanthophyll. The above solutions become colourless when 

 allowed to evaporate in sunlight. The amount of peroxidase present in 

 all Capsicum fruits appears to diminish as they ripen, and bears no 

 simple relation to the variety of fruit. The enzyme is frequently 

 present only in the epidermis, while the deeper tissues may contain an 

 inhibitor with a strong reducing action. 



* Ber. Deutsch. Bot. Gesell., sxxii. (1914) pp. 35-47. See also Bot. Centralbl., 

 cxxix. (1915) p. 440. 



t Sci. Proc. R. Dublin Soc, xiv. n.s. (1915) pp. 328-35. 



