61 8 FIBRO- VASCULAR SYSTEM OiF THE APPLE, 



• 



It is necessary to understand how the growing apple is 

 nourished, before the wide distribution of the vascular system 

 can be properly appreciated. It is not simply the develop- 

 ing seeds, with the case containing them, which require to be 

 nourished as in ordinary fruits, but also the much larger 

 mass of tissiie outside of that, constituting the flesh. So much 

 growth has to be made in a comparatively short time, that 

 the apple-tree has to store up the necessary material during 

 the previous season, for the early spring growth. The short 

 branches known as fruit-spurs bear the fruit-buds, which are 

 plump and well-nourished in order to give rise to the flowers. 

 The material stored up in the branches is passed on to the 

 flower when it is fertilised. It is easy to tell, within a few 

 days, when fertilisation has occurred, for the flower-stalk 

 stiffens and begins to swell. This stiffening and thickening 

 are due to the rush of food-materials, and after the fall of 

 the petals the stored-up food is practically exhausted. Then 

 the young apple is partly nourished by the parent-plant, with 

 its fresh green leaves, and partly by its own exertions. The 

 water containing mineral matter in solution enters from the 

 soil, passes along the roots, and up the stem, until it reaches 

 the fruit-spurs. Here it enters through the stalk of the 

 fruit, and is distributed along the various channels, until it 

 bathes the tissues wherever the fine net-work reaches. The 

 vessels are shown in one of the strands in Fig. 17. 



The amount of water contained in a ripe and sound apple 

 is 84 per cent, on an average, so that a proper water-supply 

 is all-important for the formation of the fruit. The fruit 

 increases in size, not so much from the multiplication as from 

 the enlargement of the cells ; and it can readily be under- 

 stood hoAv nicely the balance must be adjusted, in order to 

 regulate the supply. The water-stream will be directed 

 along the main channels towards the apex of the fruit, and 

 if the cells are overgorged, then rupture of the tissue may result ; 

 and if there is a dearth of water, a concenti-ation of the contents 

 of the cells may follow. 



