COCONUT PLANTER'S MANUAL. 125 



All shade lias, of course, the same effect. It makes no difference 



whether it comes from a cloud or a mountain or some shade tree 

 or from another palm which is planted too close. Every leaf or part 

 of a leaf which is in the shade has its transpiration cut down to about 

 a. quarter of what it might he, and therefore it gets only a quarter of 

 the food it might get from the soil. 



The palm itself does its best to obtain for each of its leaves the 

 maximum amount of direct sunlight. Although to a casual observer 

 the leaves may appear to be without any regular arrangement upon the 

 palm, careful inspection shews that they are distributed on the stern 

 in a very definite order. They radiate outwards from the stem like the 

 spokes of a wheel at perfectly regular intervals, the obvious design 

 being that each leaf should shade those below it to the least possible 

 extent. 



This is the experience of the low yield* of nuts obtained from those 

 estates on which the palms are planted too closely. The soil may be 

 fertile, the cultivation good and the water supply abundant, and in 

 spite of all these favourable conditions the yield in nuts will be small 

 and will remain small so long as the palms continue to shade each other. 



2. When the atmosphere is saturated with moisture as on a close 

 damp day, transpiration is almost entirely stopped. The air being 

 already thoroughly soaked it refuses to take up additional moisture 

 from the vegetation. 



On the other hand a dry atmosphere leads to a very considerable 

 transpiration, which frequently becomes excessive, particularly in the 

 case of young and delicate plants which have not had time to develop 

 largo root systems. Such plants as these require to be protected by 

 shade so as to check transpiration, otherwise they very soon wilt and die. 



3. A decrease in the amount of water in the soil reduces transpira- 

 tion. Up to a certain point transpiration increases with an increase in 

 the amount of water, but as soon as the soil becomes in any way water- 

 logged the process is very severely checked. 



Transpiration is also checked when the soil-water contains exces- 

 sively large amounts of substances dissolved in it. It has also been 

 found that plants which have taken up large quantities of common salt 

 transpire less than those which have no access to this substance; and 

 that while potash, soda and ammonia increase transpiration, acids tends 

 to decrease it. 



• Respiration or breathing is carried tin by all ordinary plants and. is 

 as necessary for their existence as it is for the existence of animals. 



