Severe winters with severe frosts and severe winds, sharp fluctuations in temperature in the second part of it can greatly affect the well-being of the kidney stone fruit crops. Somewhat less often, but also kidney damage occurs in winter and autumn pear varieties, as well as apple trees. The least resistant to winter weather are the flower buds of an apricot tree and, conversely, the most protected, but - for cherries. Peach trees are more resistant to weather, and their buds are less picky than the young branches on which they are located. Perhaps the most frost-resistant stone fruit culture is cherry. Also, frost resistance of the buds of fruit trees can be reduced as a result of damage to the branches by diseases of fungal or viral origin.
The degree of kidney damage often depends on the duration of the frost. If a severe degree of damage is observed, then in the spring the kidneys will not open. Strange as it may seem, the kidneys are most damaged at the end of the winter period, because after the end of the period of deep dormancy, even a brief warming can cause active life in plants. And such trees, emerging from a state of rest, can be damaged even with the slightest change in weather conditions in the negative direction.
The growth buds of a larger number of fruit tree trees are more resistant to low temperature than fruit. But peach, for example, has the opposite situation. A different level of resistance of fruit and growth buds to frost can be explained by the different ability of water retention, as well as the degree of differentiation of flowering buds. The resting period in fruit buds ends somewhat earlier than in growth buds; growth processes in them also begin much earlier. And as soon as this process starts, the frost resistance of organs and tissues decreases sharply.
How to determine if the kidneys were damaged? It is very easy. Such fruit buds acquire a brown color, and, without opening, dry up, and then fall off. If the damage was small, then in the spring they open very slowly, sometimes not completely. And also dry up. In the later stages of their development, frost often damages the pistils, which are the most non-frost-resistant part of the flower. Damage and death of the pestle means a decrease in yield in the gardens. In damaged areas, flowers and buds will have a brown color.
Different frost resistance can be used to characterize different rudiments of flowers in the same bud. Their stability, like all flower buds, is often determined by the time of laying and their differentiation. The earlier flower buds were laid, the stronger they were differentiated, the greater the risk of freezing. At a late stage, flower buds have a large number of cells with small vacuoles, and cells with large ones are not as stable as those filled with protoplasm. Soil moisture affects the depth and duration of the dormant stage. The uneven, limited moisture observed during the growing season can lead to inferior peace in the autumn-winter time, drastically shortening it. The critical temperature mark for the death of flowering buds of different varieties of fruit trees is not constant. And even for one variety it can be different. Sharp fluctuations in temperature in the second half of the winter season or the early onset of frosty days in the autumn period cause damage to flower buds.
In severe winter frosts that occur after a dry summer, in bad weather in January and February, in the upper parts of the crown there is more severe damage and death of flower buds, as well as branches of different ages. More than in the middle and lower parts.
The winter hardiness of flower buds in stone fruits decreases most strongly after warm and rainy autumn. Frost resistance also decreases sharply during the previous winter droughts, or when plants were grown under conditions of excess moisture, increased or, conversely, limited nitrogen nutrition.
Damage to flowering buds is highly dependent on the adaptive properties of the plant. Time, the recovery processes of frost-damaged kidneys are determined by their ability to regenerate.
It is also worth noting that the total damage to the plant depends on the condition of the tree, leafy, its growth rate. Buds located on powerful, strong, well-developed branches are more resistant to frost than on thin, short branches that quickly end their growth and development, which also have foliage damage. The most frost-resistant properties are fruit buds at the base of annual shoots.