| Xanthoceras sorbifolia Bunge is a unique woody-oil tree in China, and was the one of the key development biomass-energy tree species of "forestry-oil integration" in China. It has a great potential of development as biomass-energy material provider, however, at present the poor management of Xanthoceras sorbifolia Bunge caused the low yield, the situation was the bottleneck of the development of biomass-energy in China. Pruning is the key method to have a high and stable yield. Establish a pruning system has important meaning of the long-term development of Xanthoceras sorbifolia Bunge. Branches grading standard and correlation analysis among main branch characters had been researched to provide the theory basis for pruning; Effects of bending branch, notching buds and cutting back on endogenous hormone of buds and shoot growth, the influence of fruitlet, the weight of single fruit, fruit diameter, burliness quantity, seed weight by different sprout amount had been researched to get the appropriate way for Xanthoceras sorbifolia Bunge. The main results were as follows:(1) Grading the annual branches, above 95 mm were the long branches,40-95 mm were the middle branches, under 40 mm were the short branches, the top diameter under 5 mm, base diameter under 6 mm were the weak branches, the top diameter 5-10 mm, base diameter 6-10 mm were the middle branches, top diameter and the base above 10 mm were the strong branches.(2) The correlation ccoefficient of the number of bearing shoots is the largest among all mother branch characters, up to 0.567,so fruit quantity was closely related with number of bearing shoots. The fertile floret, tip diameter and basal diameter of bearing branch had significant correlation with the number of fruitlet, up to 0.823,0.669,0.534,showing that vigorous branch can set more fruit. The relationship between yield and diameter of bearing shoots and mother branches showed that bearing shoots with top diameter over 4mm,basal diameter over 5mm and mother branches with top diameter over 7mm,basal diameter over 9mm could set fruit effectively(3) The contents of soluble sugar, starch and C/N of branches angle of 60° and 90°were significantly higher than those of 30°and 45° (p<0.05),but the contents of nitrogen were the opposite. There was no significant difference between 60° and 90°,30° and 45° (p>0.05). Considering the circumstance of flowering and fruiting and branches damaged,60° is the best angle for Xanthoceras sorbifolia Bunge(4) 1. The contents of GA3、IAA and ZT of top and upper buds were decreased with branch angles added, while the content of middle and basal buds were increased, however, the contents of ABA showed an oppsite trend. The content of GA3、IAA ' ZT in the central part of branch bending angles of 60°were 1283.92,261.02,172.91ng/g,FW and in the base part were 1858.33,312.17,181.84ng/g,FW, both significantly higher than CK, the content of ABA in the central part of branch bending angles of 60°was 124.06ng/g,FW and in the base part was 122.16ng/g,FW, both significantly lower than CK. Budding rates, top diameter, basal diameter, number of fetile florets and fruitlet of branch bending angles of 60°were 78.62%,4.19mm,5.37mm,28.44 and 1.33mm, were significantly lower than CK. 2. The contents of GA3, IAA and ZT of upper, middle and basal buds were increased with notching bud treatment, while ABA decreased. Single notching bud was better than ring notching bud.The content of GA3, IAA,ZT and ABA in the base part of single notching bud were 2139.94,323.82,282.98,183.12ng/g,FW, the trend of upper and central part were the same as the base part. Budding rates, top diameter, basal diameter, number of fetile florets and fruitlet of single notching bud were 73.35%,3.94mm,4,97mm,21.78 and 1.44, all were the best.3. The contents of GA3,IAA and ZT of middle and basal buds were increased with pruning cut length. The content of GA3, IAA and ZT in the central part of branch middle cutting back were 2580.53,1290.27,269.55ng/g, the base part were 2120.46,1060.23,234.92ng/g,FW, all significantly higher than CK. Budding rates, length of new shoots, top diameter and basal diameter of middle cutting back were 64.07%, 29.56cm,4.18mm,5.69mm, were significantly higher than CK(5) The fruitlet of 18 and 20 branches in per unit area were higher than others, were 3.44% and 3.54%, and the single fruit weight were higher than others too, were 565.42g and 617.73g, the number of seeds in single fruit were high, were 291 and 201, the weight of seeds in single fruits were higher than others, were 251.52 and 301.00g. However it had no significant impact on the average diameter of single fruit. |
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