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Botany of cultivated fruit plants


Botany of cultivated fruit plantsBuds of fruit plants are generally formed at the nodes and in the axils of leaves, but may also develop under certain conditions anywhere on the stem or root. Plums, cherries, raspberries, and blackberries thus develop buds when cut back or injured. The fruit buds of apples, pears, and European plums are usually produced on short spurs at least two years old.

The peach fruit buds are borne only on the new growth formed the preceding season. Fruit buds are usually larger than leaf buds. With orchard fruits they are formed during late summer and early fall, and with a little practice can be readily distinguished in winter. In most cases the embryo flower within the bud can be seen with the naked eye. The proper development of the fruit bud is influenced by factors which are brought to bear upon the tree prior to and during the period at which fruit-bud formation takes place. In the practice of such orchard operations as are designed to influence or control fruitĀ­bud formation, it appears that such operations should be more effective in the spring and early summer than at other stages of development.

Leaves of Fruit Plants - An abundance of healthy leaves is essential to the rapid growth of the tree and the regular development of fruit. The leaves combine and elaborate the crude sap from the soil and the carbon dioxid of the air into new compounds suitable for wood growth and fruit. Spraying, even in years of unfruitfulness, is often of advantage because it permits the maturing of a full crop of healthy leaves.

Fruit - A true fruit, strictly speaking, is the ripened seed vessel and its contents. This agrees with the horticulturist's definition of such fruits as apples, pears, peaches, apricots, plums, gooseberries, and currants, but in the case of strawberries, blackberries, and mulberries it would permit only the single grams on the sides of the berries to be called fruits, whereas the fleshy center is the part referred to by the fruit grower when he speaks of them as fruits.

Flower - The time of flowering in the spring of a given variety of fruit, is dependent upon a number of causes or conditions, chief among them being, first, the number of positive temperature units received in the spring preparatory to flowering; second, the stage of development of the flower-buds as dependent upon the climatic conditions of the summer and fall preceding the flowering; third, the fruiting of the trees, whether light or heavy the year previous to flowering; fourth, soil conditions and the amount of plant food present in the soil; and fifth, the individual characteristics and state of health of the tree or plant.

From the data presented it would appear that there is but little relationship between the time of flowering and the temperature in the spring, up to the time of flowering, while there appears to be considerable evidence that the temperature and other climatic conditions during summer and fall preceding flowering has much to do with the time of flowering.

As a general statement, it is true that a given variety of fruit trees will flower when it has received a reasonable number of temperature units, but it is also true that this number is not constant, but rather variable, and on this account cannot be used in formulating a physiological constant.

On the other hand, there are greater reasons for constructing a physiological constant from the sum of positive temperature units received during the summer, fall, and spring preceding the life event, though, as has been stated, other factors enter into the calculation. But, eliminating these factors, it seems reasonable from the evidence presented, a physiological constant can be formulated from the climatic conditions during the ten months preceding the time of flowering.