(54 SUMMARY OF CURRENT RESEARCHES RELATING TO 



Physiology. 

 Nutrition and Growth. 



Transpiration in Plants.* — G. F. Freeman has experienced some 

 difficulty in physiological and ecological work connected with plant- 

 breeding in rinding an accurate and practical method of measuring 

 transpiration. The potometer does not record the normal rate of plant- 

 transpiration, neither can it be made to show the comparative transpira- 

 tion of different plants. By modification and adaptation of the methods 

 of Lamarliere and E. and J. Verschaffelt, the author has been aide to 

 measure accurately the transpiration of plants under known and con- 

 stant conditions. Moreover, individual differences in the transpiration 

 rates of different plants can be measured, and the apparatus may be 

 used with advantage in plant selection and breeding. The most 

 important differences between the new and the old form of apparatus 

 are the use of a different absorbent, the modification permitting of the 

 measurement of transpiration of plants still attached to their own roots 

 and the supply of normal air. 



Irritability. 



Gravitation-sensitiveness of Root.f — F. C. Newcombe has experi- 

 mented upon Zea Mays, Lupinus alius, Pisum sativum, Pl/aseolas 

 jiut.lt iff oras, Virtu Faba, Ricinus communis, and Cucurbita pepo, and is of 

 the opinion that there is no proof that gravitation-sensitiveness is 

 limited to the apical 2 mm. of the root. Centrifugal experiments show 

 that sensitiveness extends backwards as far as 2*5 mm., and in some 

 species more than 4 mm. The geotropic curve described by an ortho- 

 tropic root displaced from its normal position is dependent upon the 

 relation between its geotropism and autotropism. Frecpiently the 

 autotropism of such displaced roots prevents the seedling from sending 

 roots vertically downwards. The length of the elongating zone does 

 not appear to be related to the extent of the sensitive zone. 



Influence of Aluminium Salts on Protoplasm. £ — M. Fluid has 

 experimented upon Spirogyra, Elodea, Lemna, etc., in order to test the 

 influence exerted by salts of aluminium upon protoplasm. The experi- 

 ments show that the process of assimilation is retarded, but not 

 inhibited, by the presence of sulphate, nitrate, chlorate, and bichromate 

 of aluminium. Also, the cells become permeable to substances which 

 do not usually pass through the cell-walls, lint the amount of tin' 

 substances which thus enters the protoplasm is too small to be detected 

 by usual chemical tests. Streaming of the protoplasm continues, but is 

 less rapid than under normal conditions. The effects produced by the 

 aluminium salts are neutralised by glucose, glycerin, and isodulcit, but 

 are unaffected by salt or nitre. 



Martel, E. — Contribuzione all' anatomia de fiore dell' Hedera Helix, dell' Aralia 

 Sieboldii e del Cornus sanguinea. 



[An anatomical study of the flowers of these three species, with special 

 reference to vascular tissue relations.] 



Alcm. Beale Accad. Sci. Torino, lviii. (1908) pp. 561-76 (1 pi.) 



* Bot. Gaz., xlvi. (1908) pp. 118-29 (1 fig.). 



t Beih. Bot. Centralb, xxiv. (1908) pp. 96-110 (1 pi. and 3 figs ). 



X Flora, xcix. (1908) pp. 81-126. 



