The growth direction of shoots is regulated by plant hormones (Auxin), which form in growing apical shoots and leaves. They move down the momentum. If the shoots grow intensively, the supply of growth hormones is greater than with weak growth, making, that the shoots take a more horizontal position. The fork angles between the conductor and the lateral shoots are then wider.
The angles at which the branches depart from the conductor are important in the construction of the tree. These angles, called fork angles, can be wide or sharp. If the boughs depart from the guide at a wide angle, they are strongly connected with it, which makes, that the crown loaded with fruit does not break. Under the mass of fruits, boughs sometimes bend to the ground, but the crown does not tear. If, on the other hand, the angle between the branches and the conductor is sharp, the connection is weak. In the forks between the branches and the conductor, layers of dead bark accumulate, which prevent the creation of a strong structure. Strengthening tissues run next to each other almost in parallel and it is easy to tear the loaded branches.
Boughs fork into branches, and these, in turn, in smaller fruit-bearing twigs. Fruit-bearing twigs are different types of annual and perennial shoots. We usually divide them into long shoots, called long shoots and short shoots, called short shoots. Shoots above the length of the length were considered long-shoots 20 Cm, for short shoots -shoots 20-centimeter and shorter. Some short-shoots differ significantly from long-stems in their morphological structure, others differ only in length. Among the short-stems, mycobacteria are usually distinguished, Thorns, Arrow, knots and maces.
Strong shoots, which knock out from the base of the branches and on the guide it is accepted to call them wolves. Wolves are not significantly different from other long-shoots after this, that they grow strongly and reach at the end of summer from 0,5 into 1,5 m length. In orchards, they are usually removed every year. If they are left behind, turn into branches or fruit-bearing twigs.
Flower buds in fruit trees are formed both on long-shoots and on short-stems. In apple and pear trees, flower buds are formed mainly on short-stems. Already in the second year of life of trees from some meshes on long shoots grow short shoots and form flower buds.
In some varieties of apple trees, for example, Mclntosh, Spartan, and short-stem mutants (Starkrimson) almost exclusively flower buds are formed on short shoots. Other varieties, such as Jonathan, Idared, Golden Delicious form about 1/3 flower buds on long shoots, a 2/3 short-shoot.
Plum, apricots and cherries bear fruit both on short shoots and on long-shoots. Cherries form flower buds almost exclusively on short-stems. Only a negligible percentage of flower buds are located at the base of long-shoots. In peaches, the most valuable flower buds are formed on strong long-stems.
Short shoots are formed, as a rule, on older shoots, so in the depths of the crown, Long-shoots, on the other hand, are formed mainly on the periphery of the crown. If the tree bears fruit on short shoots. it is its main fruit-bearing zone that lies inside the crown. If both types of shoots are involved in fruiting, the fruit-bearing zone extends from the base of the branch to its top. Finally, if fruiting takes place mainly on long-stems, the fruit-bearing zone occurs on the periphery of the crown. These characteristic fruiting properties of trees are taken into account when cutting and forming crowns. Fruit trees form three types of buds: leaf, floral and mixed. From leaf buds develop leaves and new shoots. Leaf buds are deposited mainly along long shoots and at their top. They can be seen already in the summer on the shoots, in the axils of the leaves. Colloquially they are also called eyelets. The leaf buds are small, elongated, pointed and adjacent to the shoots.
Proper flower buds, giving rise only to flowers can be found in stone trees: plum, apricot, cherries, cherries and peaches. They are always larger than leaf buds, blunt ended, protruding from the shoots. U plum, apricots and peaches these buds are often set in groups after 2 the 3. On long shoots, they form in the axils of the leaves, usually in pairs, covering one leaf bud between themselves. On older shoots of cherries, flower buds are collected in bouquets after 3, 5 or even 10 together. On annual shoots of cherries we find them primarily at the base. On long-stemmed cherries, they are usually found singly along the shoot.
In apple and pear trees — next to the leaf buds there are mixed buds, from which flowers grow, leaves and shoots. From the bud usually develops an inflorescence composed of 5-7 flowers and 3-5 leaves. Mixed buds of apple and pear trees are commonly called floral. Speaking of flower buds of apple and pear trees, we mean mixed buds, inflorescences.
At the base of the shoots (mainly apple and pear trees), we find many small leaf buds, that remain dormant without developing for many years. These buds are called sleepers. Sleeping buds knock out into shoots usually after strong cutting of trees.
Flower buds of fruit trees begin to form at the beginning of the summer of the previous year, so a few months before flowering. Already in July, buds are formed on short-stems, which end their growth at the earliest. In August and September, the beginnings of flower buds are formed on long-stems. The process of flower development in buds lasts until late autumn. Partially formed flower buds are not able to develop further until they undergo a few weeks of cold. This is the period of absolute rest of the buds. After going through the cold period (usually at the beginning of winter), all buds are capable of further development, but too low temperature does not allow it. Further development of buds occurs in the early spring, when the air temperature rises above 10°C.
The formation of flower buds already 8-10 months before the flowering date of trees is of great practical importance. The condition of the trees and the way they are cared for, including cutting during the summer, determines the intensity of flowering and the size of the crop in the next year.