Morphological characteristics of walnut tree

  1. Root system

  Walnut root neck part of the general term for the root system, divided into taproot, lateral roots and fibrous roots. Taproot developed, lateral roots horizontally extended far, fibrous roots more, strong roots. Generally speaking, early bearing walnut root system is more developed than late bearing walnut, especially young trees. According to the measurement, the total number of roots of annual early-bearing walnut is nearly 2 times more than that of late-bearing walnut, and the total root length is 1.8 times more. Therefore, the root system is an important characteristic of early-bearing walnut. The developed root system is beneficial to the absorption of water and inorganic salts, the accumulation of nutrients in the body and the formation of flower buds, and the realization of early bearing and early high yield. The root system of walnut also has mycorrhizal fungi, which concentrate in 10~30 cm soil layer. Mycorrhizal fungi have positive effect on walnut yield.

  II. Bud, branch and leaf

  1. Bud of walnut is divided into mixed bud, male flower bud, leaf bud and latent bud.

  (1)Mixed bud A bud can grow both branches and leaves, but also can grow flowers and fruits, called mixed bud. Bud hypertrophy, suborbicular. After germination, the fruit mother branch is sprouted, and the female bud is born at the top, generally a single bud, but also a double bud; the late fruit walnut is mostly born at the top of the annual branch 1~3, and the axillary bud of the early fruit walnut is mostly mixed bud, and the gentleman grows a branch and then bears fruit.

  (2)Leaf buds are triangular or circular, solitary or superimposed with male flower buds, only sprouting branches and leaves.

  (3)Male flower buds were short conical, scales very small, can not cover the bud, so called naked bud. After germination, only male flowers bloom, forming soft inflorescences, not growing branches and leaves.

  (4)Latent buds, also known as dormant buds, are oblate and thin. Under normal circumstances do not germinate, with the branches thickened growth ambush in the subcutaneous, life up to more than 100 years, easy to germinate by stimulation, walnut renewal rejuvenation are completed by latent buds.

  2, branches

  (1)Vegetative branches (also known as developmental branches, leafy branches) are divided into short branches, medium branches and long branches according to their length. In the middle, long branches can be divided into two kinds, one is the development branch, formed by the development of leaf buds, is the basis for the expansion of crown and the formation of fruit branches; the other is the long branch, formed by the germination of latent buds, if a tree has too many long branches, production should be controlled, senescent trees are mostly updated and rejuvenated with long branches.

  (2)The fruiting branch is formed by the mixed bud on the fruiting mother branch, which is divided into long fruiting branch (more than 20 cm), medium fruiting branch (10~20 cm) and short fruiting branch (less than 10 cm).

  (3)Male flower bud is leaf bud, the following only bear male flower and grow short and thin, male order falls off after the terminal bud following bald, it is born more in old and weak tree or crown bore closed place. Too many male flowers is the performance of weak trees and inferior varieties, so breeding varieties with more male flowers should be avoided.

  3. The leaves are odd-pinnate compound leaves, the terminal leaflet is the largest, and the lower opposite leaflets become smaller in turn. The number of compound leaves varied with species and varieties, such as 5~9 for Juglans regia and 7~17 for Juglans mandshurica.

  Nuisanceless and Efficient Production Technology of Walnut

  III. Flowers and Fruits

  1. The flowering walnut trees are monoecious, dioecious and unisexual flowers. Male inflorescences are 6 - 12 cm long and each inflorescence has 100 - 180 male flowers. Female inflorescences are racemes, solitary, clustered, ordered, and pollen-like, ovary inferior, bicarpels, and ventricles.

  2, fruit walnut fruit developed from the ovary. Fruit shapes are oval, round, oval and so on. Peel green or yellowish green, smooth or velutinous. This kind of fruit ripens after the pericarp loses water dry and exposes the hard seed, is so-called nut. Its size varies with species, varieties and site conditions. The kernel rate is generally 36%~ 65%, and some varieties are as high as 75%.