ZOULOtn AND I'.dTANV, MICROSCOPY, ETC. 381 



BOTANY. 



GENERAL, 



Including the Anatomy and Physiology of Seed Plants. 



Structure and Development. 

 Reproductive. 



Absorption in Ovules of Scrophularia.* — F. E. Lloyd has studied 

 the rates of absorption in ovules of Scrophularia as the result of the 

 injection of stimulatory or other reagents into the living tissues. The 

 author employed two methods of experiment, viz. (1) the injection of 

 1 to 1000 solution of methylen-blue, and (2) the natural absorption of 

 a weak solution by sections of ovules still attached bo the living ovary. 

 The results show that when a reagent such as methylen-blue is passed 

 into the cavity of the ovary, it may reach the egg-apparatus through the 

 funicle, nucellus, and embryo-sac. The walls of the nucellar cells have 

 the power of absorbing methylen-blue owing to some peculiarity of their 

 chemical structure. The innermost layer of the inner integument forms 

 a tapetum, which stains deeply, but is less important than the nucellus in 

 the transfer of the stain ; it is not possible, however, to form any con- 

 clusions as to the relative physiological importance of the tapetum. In 

 ovaries that have been injected shortly after pollination, the stain is 

 taken up abundantly by the pollen-tube and passed to the male nuclei 

 and their cytoplasm ; it then penetrates to the egg-apparatus, probably 

 at a much greater rate than the visible accumulation indicates. 



a* 



Alterations Induced by Treatment of Ovary. f — D. T. MacDougal 

 has studied the aberrant plants produced by seeds from ovaries of 

 Scrophularia which had been treated with a dilute solution of potassium 

 iodide. Cultivation of these plants and of a second generation derived 

 from them points to the following conclusions : — 1. Injection of the 

 ovary may affect the embryo-sac and pollen-tube either singly or 

 simultaneously, or it may affect the fertilized egg. 2. Any such change 

 of the male or female element would result in the formation of a hybrid 

 by the union of a normal and an altered element ; two such hybrids 

 were studied, one of which produced a second generation identical. with 

 itself, while the second generation of the other hybrid tended to revert 

 to the parent-type ; in both cases the changes included structure of 

 leaves and stems, colour of flowers, etc. 3. It appears that the changes 

 noted in the hybrid are due to the effect of the reagent either upon the 

 egg-nucleus or on the fertilized- egg. 1. The colloidal constituents of 



* Year-Book, Carnegie lust., Washington, xiii. (1914) pp. 77-9 (1 fig.), 

 t Year-Book, Carnegie Inst., Washington, xiii. (1914) pp. 79-81 (1 fig.). 



