(Matthiola incana), an annual or biennial ornamental plant of the family Cruciferae. The stem is grassy and measures between 20 and 80 cm tall. The leaves are lanceolate or narrowly obovate. The flowers are simple or double, variously colored, fragrant, and gathered into tight or loose racemose inflorescences. Stock grows wild in the Mediterranean region. Its cultivation has been traced back to the 16th century.
According to the duration of the cycle of development, the following varieties are distinguished: ten-week, or intermediate stock (var. annua), winter stock (var. hiberna), and autumn-blooming stock (var. autumnalis). The last is a hybrid of ten-week and winter stock. Each variety is represented by numerous forms, which are united in varietal groups according to the height and shape of the bush, the length and compactness of the inflorescence, and the distinguishing colors of the flowers.
Ten-week stock is an annual plant, used primarily in flower beds, as summer potted plants, and for cut flowers. For early flowering the seeds are planted in the second half of March in benches in green houses. They are transplanted in the ground in May. The seeds can be sown in the open ground in April and May or right before winter.
Winter stock is a biennial plant (in cultivation); in southern regions it is dormant in the open ground during the winter and flowers in spring. It is used in interior decoration as a potted plant. The seeds are sown in April and May in benches in greenhouses or in cold frames, and the seedlings are transplanted in open ground in the first half of July. At the end of September the plants are placed in pots, set up in hotbeds, covered with frames, and shaded. In November or later the plants are transferred to a greenhouse or a room, where they blossom from March through May.
O. V. SELEZNEVA
in fruit growing, a plant or part of a plant upon which a scion of another plant variety is grafted. Stocks may be of seed (seedlings or wildlings) or vegetative origin. The stock and the scion join together to form a single plant, but each performs different functions. The stock supplies the graft with minerals, synthesized organic substances, and water; the scion provides products of assimilation. This feature in the nutrition of the graft leads to a complex relationship between the scion and the stock and to their reciprocal influence. The relationship may be favorable, in which case normally developed plants are formed; an unfavorable relationship results in seedlings and trees that are in some measure deficient. The result depends on the completeness of the joining of stock and scion and the degree of completeness of the metabolism effected between them, that is, on the physiological compatibility of the stock and scion.
The stock influences the growth intensity, early fertility, yield, and longevity of the graft; the beginning and end of growth of grafted trees; and the time of leaf fall and maturation of tissues. It consequently influences the graft’s winterhardiness and its resistance to frost, pests, disease, and unfavorable soil and climatic conditions. However, these characteristics are temporary, not becoming fixed genetically and disappearing with the cessation of the stock’s influence on the grafted tree. The scion may lower or raise the winterhardiness of the stock and may influence the shape and the depth of the root system.
Owing to the importance of the stock in fruit growing, a number of requirements are made of it that guarantee the production of fruit trees with great viability and productivity. Stocks must be well adapted to the soil and climatic conditions of the places where the seedlings are grown and the orchards are planted. They must be winter-hardy, and, in the south, drought resistant. Some must also be salt tolerant. The stocks must be compatible with the varieties to be grafted on them.
In fruit growing, different stocks are used for the same crop. The stock used is determined by production goals. For example, apple is grafted onto seedlings of cultivated varieties and on crab apple trees in the southern and central regions of the USSR, onto the Chinese apple in more northerly regions, and onto the Siberian apple and its strains in the east and north. Stocks are regionalized for different fruit-growing zones and are divided into principal stocks (more important and more frequently used) and supplementary stocks (having secondary or often specialized significance). The specificity of stock use extends the range of commercial fruit crops and the most valuable varieties. In the USSR, nurseries raise about 40 species of stocks, which vary in origin (wild or cultivated), growth intensity (strong or weak), and means of propagation (seed or vegetative).
M. D. KUZNETSOV
the straw of flax, hemp, and certain southern bast crops (for example, jute and kenaf) treated by biological, thermal, or chemical procedures that break down the pectin substances binding the wood and exodermis to the fiber bundles. Fiber for spinning is obtained from stock by mechanical means: breaking, beating, and combing.
(geology), a cylindrical, tear-shaped, or cube-shaped body of rock or useful mineral. Its intersecting contacts with the country rock are irregular in outline and complicated by swells and shoots. Stocks vary in width from a few meters to several kilometers and have a vertical extent of up to several kilometers.
Three types of stocks are distinguished according to conditions of formation: tectonic, magmatic, and metasomatic. Tectonic stocks occur as a result of squeezing out the plastic substance of rocks during tectonic deformations, for example, stocks of rock salt in regions of tectonic salt structures.
Magmatic stocks form when a magmatic melt enters the country rock. In the early géosynclinal stage, stocks of ultrabasic and basic rocks are formed, as well as stocks of chromites and titano-magnetites associated with them. In the middle stage, stocks of granitoids are formed. In the late stage of the géosynclinal cycle and under platform conditions, stocks of syenites, porphyries, porphyrites, diabases, and andésites are formed.
Metasomatic stocks form when the rock is replaced by a mineral substance precipitated from hot hydrothermal solutions circulating in the crust. Examples of such stocks are those of copper, lead, zinc, tin, antimony, and other metal ores.