广州地区澳洲坚果抽梢与坐果的关系

Investigation on Fruit Set of Macadamia in Relation to Flushing in Guangzhou

广州地区澳洲坚果一年主要抽生三次梢,以多年生枝和春梢为主要结果母枝,分别占43.1%和39.1%.结果能力以更梢母枝最强,平均每枝坐果3.0个,其次为多年生枝(2.0个).平均花坐果率0.22%.坐果数与结果母枝长度、粗度、粗/长比和叶片数无显著相关,与花序数和初始坐果数密切相关(R^2=0.7653).树冠郁闭条件极显著地减少初始坐果数.花后5周内落掉总花量的99%以上.幼果的另一个脱落高峰在花后第5至8周,主要是旺盛营养生长与迅速生长的果实的营养竞争所致.

Experiment was conducted on Macadamia integrifolia in 1989-1990 in Guangzhou. Trees grew 3 flushes a year, i. e. , in mid-February to later-March; late-May to mid-June and mid-July through early-October. Fruit set mainly on the shoots more than one year old and spring flushes, the fruit-setting was 43. 1% and 39.1%, respectively. While the summer flushes show the highest fruit-setting, bearing 3 nuts per shoot, followed by the shoots more than one year old and the spring flushes, bearing 2. 4 and 0. 4 nuts per shoot, respectively. No correlation between number of fruit-setting per raceme and shoot length, shoot diameter, shoot length/diameter ratio were detected. But the fruit number per florets were highly correlated with the raceme number and the number of initial set of the nut (R2 = 0. 7653). Dense canopy significantly reduced initial furit set. Over 99% of florets and fruitlets abscissed in first 5 weeks after bloom. Another abscission peak occurred in the weeks of 5 to 8 after bloom. It was caused probably by the nutrient competation induced by the vigorous growth of the summer flushes.