694 



THE IRRIGATION AGE. 



stalk, and growing branches, drawing up from the soil for 

 that purpose the various ingredients they require from 

 among the inorganic elements, which unite with the vege- 

 table acids in the sap and form compounds which are 

 essential to the perfection of the grain or seed. In the 

 first stage of its growth the starch of the seed is trans- 

 formed into gum, and then sugar; in its second stage, 

 when the leaves are expanded, the starch is transformed 

 into woody fiber. 



From the Flower to the Ripening of the Fruit. 



The sap has now become sweet and milky, indicating 

 sugar and starch. These during the third period are grad- 

 ually transformed in the sap into starch, a process exactly 

 the reverse, or contrary of that in the first and second 

 periods. The opening of the flower from the swollen bud 

 is the first step taken by the plant to produce the seed by 

 which its species is to be perpetuated. At this period a 

 new series of chemical changes commences in the plant. 



1. The flower leaves absorb oxygen and emit car- 

 bonic acid all the time, both by day and by night. 



2. They also emit pure nitrogen gas. 



3. The juices of the plant cease to be sweet, even in 

 the maple, sugar cane, and beet; the sugar becomes less 

 abundant when the plant has begun to blossom. A change 

 not difficult to understand when it is considered that nature 

 is at work preparing to perfect the seed or fruit, and is 

 not working for commercial interests. The structure of 

 the plant is now of no consequence, and ceases to be of 

 any importance. The imbibing of oxygen, which is the 

 parent of all acids, is intended to convert the sugar into 

 material for the seed, or fruit, the wheat or the peach, 

 the strawberry or the squash. 



The husk of grain bearing grasses, corn, wheat, oats, 

 etc., is filled at first with a milky fluid which becomes 

 gradually sweeter and more dense, or thicker, and finally 

 consolidates into a mixture of starch and gluten, such as 

 may be extracted from the grain as has already been said. 



The fleshy envelopes of many plants, at first, taste- 

 less, become sour and finally sweet, except in the lime, 

 lemon and tamarind, in which the acid remains sensible 

 to the taste when the seed has become perfectly ripe. 



Fruits, when green, act upon the air like green leaves 

 and twigs, that is, they imbibe oxygen and give off car- 

 bonic acid, but as they approach maturity they also absorb 

 or retain oxygen gas. The same absorption of oxygen 

 takes place when unripe fruits are plucked and left to 

 ripen in the air, as is common in the case of tomatoes, 

 oranges, lemons, and bananas. After a time, however, 

 they begin throwing off carbonic acid and then they fer- 

 ment, spoil or rot. 



In the case of pulpy fruits, such as the grape, lemon, 

 orange, apple, peach, plum, etc., when unripe and taste- 

 less, they consist of the same substances as the leaf, a 

 woody fiber filled with tasteless sap, and tinged with the 

 green coloring matter of the plant. For a time, the young 

 I'ruit performs the functions of the leaf, that is, it absorbs 

 carbonic acid and gives off oxygen, thus extracting from 

 the atmosphere a portion of the food by which its growth 

 :s promoted and its size is gradually increased. Remember 

 what has been heretofore said about carbon constituting 

 the bulk of the plant. 



By and by, however, the fruit becomes sour to the 

 taste, and this sourness rapidly increases, while at the 

 same time it gives less oxygen than before, the retaining 

 of the oxygen being, as has been said, the cause of the 

 sourness, the oxygen converting the sugar into tartaric 

 acid and water. The grape is an illustration, though the 

 same thing happens in fruits abounding in the other 

 vegetable acids. 



This formation of acid proceeds for a certain time, 

 the fruit becoming sourer and sourer. Then the sharp 

 sourness begins to diminish, sugar is formed, and the 

 fruit ripens. The acid, however, rarely disappears entirely, 

 even in the sweetest fruits, until they begin to decay. 



During the ripening of the fruit, the. woody or cellu- 

 lar fiber gradually diminishes and is converted into sugar. 

 This will be noticed in several kinds of fruits, particularly 

 winter pears, which are uneatable when actually ripened 

 on the tree, but become ripe, long after plucking, by con- 

 tinuing to absorb oxygen, which converts the woody fiber, 

 or cellular tissue, into sugar, which is not difficult to un- 



derstand, as woody fiber is very similar to sugar in its 

 chemical constitution. 



It should be noted that the entire forces of the plant 

 are concentrated upon the seed, the element, or agent of 

 reproduction, the pulp of the most delicious fruit, the ker- 

 nel of the sweetest nut being nothing but protective en- 

 velopes and food supplies for the germ when the time and 

 opportunity shall arive for germination. So that the 

 object of the plant in making so many transformations is 

 not fruit, but seed. 



From the Fall of the Leaf to the Following Spring. 



When the seed is fully ripe the functions of annual 

 plants are ended. There is no longer any necessity for 

 absorbing and decomposing carbonic acid; the leaves, 

 therefore, begin to take in only oxygen, with the result 

 that they are burned up, so to speak, and they become 

 yellow, or parti-colored; the roots decline to take in any 

 more food from the soil, and the whole plant prepares 

 for its death and its burial in the soil by becoming re- 

 solved into the organic and inorganic elements from which 

 it sprang, and of which it was originally compounded. 



But of trees and perennial plants, a further labor is 

 required. The ripened seed having been disposed of, 

 there are incipient young buds to be provided for, buds 

 which are to shoot out from the stem and branches on 

 the ensuing spring. These buds are so many young plants 

 for which a store of food must be laid away in the inner 

 bark of the tree, or in the wood of the shrub itself. 



The sap continues to flow rapidly until the leaves 

 wither and fall, and then the food of the plant is con- 

 verted partly into wood fiber and partly into starch. It 

 has been shown how these substances are converted into 

 food by chemical changes, or transformations, and these 

 changes do not cease so long as the sap continues to- 

 move. Even in the depth of winter the sap slowly and 

 secretly stores up starchy matter, in readiness, like the 

 starch in the seed, to furnish food to the young buds when 

 they shall awaken in the spring from their winter sleep. 

 It is the same process as in the "case of a seed planted in 

 the ground. 



Rapidity of Growth. 



It has been shown that from carbonic acid and water 

 the plant can extract all the elements of which its most 

 bulky parts consist, and can build them up in numerous 

 ways. But the rapidity with which the plant can perform 

 this building up is almost incredible. 



Wheat will shoot up several inches in three days, bar- 

 ley six inches in that time, and a vine twig will grow about 

 two feet in three days. Cucumbers have been known to 

 attain a length of twenty-four inches in six days, and a 

 bamboo has increased its height nine feet in less than 

 thirty days. 



The rapid growth of vegetation in semi-tropical arid 

 and semi-arid regions is phenomenal. A young eucalyp- 

 tus tree has been known to grow thirty feet in a single 

 season, and wheat or barley three inches high three days 

 after planting is not uncommon. Potatoes (solanum tube- 

 rosum) have run up to fifteen pounds in weight before the 

 plant had time to blossom, in fact, it never did blossom. 



Three-pound onions, eighty-pound watermelons and 

 five-hundred-pound squash are not rarities, and I have 

 been told of a field of corn, of the white Mexican variety, 

 that grew fourteen feet with four perfect ears of corn to 

 the stalk with only twelve inches of rain. As for sweet 

 potatoes, or yams, thirty pounds weight do not occasion 

 surprise, and beets after two years' growth are often as 

 large as nail kegs, all woody fiber, of course, and unfit 

 for food. 



It is true that such examples are mere experiments, 

 indeed they may be called specimens of "freak" vegeta- 

 tion, and rarely mean perfection of quality, but they indi- 

 cate the ability of the plant to rapidly assimilate from the 

 soil and air large, even excessive, quantities of the ele- 

 ments it needs, or fancies, provided they exist in abund- 

 ance, and they demonstrate that the farmer has it within 

 his power to covert this enormous productive energy into 

 "quality" of product by regulating it through adequacy 

 of moisture and cultivation without excess. 



In the foregoing articles nothing but the mere out- 

 (Continued on page 725.) 



