xii VEGETABLE PHYSIOLOGY 



PAGE 



stratification, middle lamella Lignin and its reactions Cutin 

 Impregnation of cell-walls with various matters Mucilage 

 Differences between temporary and permanent portions of the 

 skeleton .... . 41-57 



CHAPTER IV 



THE RELATION OF WATER TO THE PROTOPLASM OF 

 THE CELL 



Dependence of the protoplasts on water ; function of the vacuole 

 Renewal of the water of the vacuole Osmosis Formation of the 

 vacuole as the protoplast develops Regulation of osmosis by the 

 cell- protoplasm ; the plasmatic membranes Movements of water 

 from cell to cell Evaporation into the intercellular spaces 

 Turgescence and its dependence on the protoplasm Storage of 

 water 58-70 



CHAPTER V 



THE TRANSPORT OF WATER IN THE PLANT 



Varied needs of different plants in this respect Transport in a ter- 

 restrial plant The ascending sap Condition of water in the soil ; 

 absorption of water a function of the root-hairs ; mechanics of 

 the root-hair Path of the ascending stream ; forces causing the 

 movement Evaporation of water from the interior Influence of 

 the stream of water upon the development of the plant . 71-82 



CHAPTER VI 



THE TRANSPIRATION CURRENT. ROOT-PRESSURE. 

 TRANSPIRATION 



The ascending sap, sometimes called the transpiration current Its 

 path ; methods of demonstration Rate of the transpiration 

 current Causes of the upward flow ; root pressure ; transpira- 

 tion ; capillarity ; pumping action of living cells ; osmotic action 

 of the parenchyma of the leaves Root pressure ; its nature and 

 mode of action ; bleeding of cut stems ; of entire plants ; measure- 

 ment of root pressure ; conditions of the activity of roots ; diurnal 

 variations of root pressure Transpiration ; methods of demonstra- 

 tion ; amount of water given off ; negative pressure in the wood 

 vessels ; character of the evaporation of transpiration ; regulation 

 by stomata, their mode of action ; variations in numbers of 

 stomata ; conditions affecting transpiration ; light, temperature, 



