The Effects Of Branch Bending On Fruiting, Leaf Nutrition And Photosynthetic Characteristics In Chinese Jujube

Branch bending is one of the common method in fruit tree training and prunning. As a result of simplification in fruit cultivation, branch bending attract more and more attention recently. Ziziphus jujuba Mill.'Xianwangzao'and Z. jujuba Mill.'Pozao'were used to study the effects of different degree of branch bending (30°, 60°, 90°) on fruiting, leaf nutrition and photosynthetic characteristics. The main results were as following:1.The effects of branch bending on shoot growthIn case of all the branches of a tree were bended into same angle in'Xianwangzao', shoot growth became lower with the branch angle increasing, The situation in'Pozao'is simmilar to that in'Xianwangzao'.2.The effects of branch bending on fruit setting and fruit qualityIn case of all the branches of a tree were bended into same angle in'Xianwangzao', the contents of soluble sugar and reducing sugar, fruit weight, average fruit number per bearing shoot as well as fruit shape index became bigger with the branch angle increasing, and the highest Vc content was found in the fruits from brances of 60°angle; In case of different angle branch at same plant, the contents of soluble sugar, reducing sugar and VC, average fruit number per bearing shoot and fruit shape index increased as the angle of branch became bigger, fruit weight was highest when branch angle at 60°. The situation in'Pozao'is simmilar to that in'Xianwangzao'.3. The effects of branch bending on leaf mineral element contentWhen all branches of a tree were bended into same angle in'Xianwangzao', the contents of phosphorus, potassium, calcium and copper in leaves increased with branch angle increasing; the contents of nitrogen, magnesium, iron, manganese and zinc were highest when the branch angle was 60°; In case of different angle branch at same plant, the contents of phosphorus, potassium, iron, manganese, zinc and copper increased with the increasing of branch angle, and the contents of nitrogen, calcium and magnesium were highest at 60°.In'Pozao', when all branches of a tree were bended into same angle, the contents of nitrogen, phosphorus, potassium, calcium, magnesium, iron, copper and zinc were highest at 60°, and manganese content was highest at 90°. In case of different angle branch at same plant, nitrogen, phosphorus, potassium, calcium, magnesium, iron, manganese and zinc were highest at 90°, and copper content was highest at 60°.4.The effects of branch bending on leaf photosynthetic characteristicsIn both'Xianwangzao'and'Pozao'branches after processing through different angle, the net photosynthetic rate, transpiration rate, intercellular CO2 concentration and stomatal conductance increased with the increasing of branch angle. The diurnal variation of net photosynthetic rate was mainly bimodal with obvious"midday depression"; the diurnal variation of transpiration rate was mainly a single peak around 12:00; the intercellular CO2 concentration was highest in the morning, followed by evening and lowest near noon; stomatal conductance was highest at 8:00 and then decreased gradually. In general, the net photosynthetic rate, transpiration rate, and intercellular CO2 concentration in'Pozao'were higher than those in'Xianwangzao'.