The Studies On The Dwarfing Habit And Mechenism Of Early Bearing Walnut

Walnut is the major dry fruit species. Recently, the study on breeding tand culture of walnut have made a mighty advance .It is the right settlement oft problem in the intense fiction of farming, that we should choose the suitable dwarfstock and extend the clonal variety.Dwarf culture is tendency for fruit growing. Because the stock affects the vigor of the plant very much, using the dwarf stock is an effect way of dwarfing plant. To attain the abundant production and early bearing, the stock must have the dwarfish. The experiment studied the dwarfing habit and mechanism of early bearing walnut through its growing character, the anatomy structure of shoots and leaves, IOD enzyme and POD enzyme activity, endogenous hormonal context, resistor and conduct resistance of shoot. The main results are as follows.1. In five and six years, the early bearing walnut have entered growing and fruiting period .It has completed the nutrition growing, and growing rate chopped steady little by little. But late bearing walnut is growing period, the main is nutrition growing, and growing speed is rising little by little .In this period, growing characteristics and speed haven't unclear difference, but the length of internode of the early-bearing walnut is shorter than that of the late bearing walnut.2. The shoot's resistor of early bearing walnut is smaller than that of late bearing. The reason is phloem of early bearing walnut has more nutrition and living cellule,which results in fruit bud .The conduct resistance of early bearing walnut is higher *than that of late bearing walnut, and hadromestom resistant inhibits aerial growth,{ decent moisture potential of shoots and leaves.3. The ABA content of early bearing walnut is higher, that inhibits the growth of plant. The endogenous hormonal content of early bearing walnut is higher than that of late-bearing walnut. The endogenous hormonal content of early bearing walnut is attribute to reproductive growth, but the effect of the endogenous hormonal of late37bearing walnut resulted in nutrition growth,4. The activity of IOD enzyme and POD enzyme has unclear distinguish between early walnut and late walnut, and the variability of varieties isn't resemblance. This phenomenon may relate to special age period of material and sibship of variety.5. Some items including the length of internode.the shoot's conduct and resistor ,content of ABA and (IAA+GA) / (Z+ABA) can be regarded as standard for selecting dwarf form walnut.