赤霉素对盆栽白桦无性系早期生长及结实的影响

【目的】种子园种子产量低以及丰歉年周期性结实问题一直是白桦等林木良种生产的瓶颈。开展赤霉素处理对白桦生长及结实影响的研究,筛选最佳激素处理方案进而提高其生长量及结实量,对于白桦良种生产及推广具有重要意义。【方法】以1个白桦无性系为研究对象,分别用质量浓度0、0.2、0.4、0.6 g/L的GA₃和GA₄₊₇处理,连续试验3 a,第2年调查其高生长节律,第4年调查各处理下的树高、胸径及结实量。【结果】树高、胸径及结实量等性状的方差分析显示,不同浓度的GA₃和GA₄₊₇ 处理下,树高及结实量性状的差异均达到极显著水平(P<0.01)。GA₃和GA₄₊₇均能促进白桦生长及结实量,其中GA₄₊₇的效果更好,综合生长及结实性状确定处理的最佳质量浓度为0.4 g/L,该处理下高生长较对照提高了13.69%,单株果序数、单株果序鲜质量、单株种子干质量较对照分别提高了203.6%、186.8%、187.2%。白桦无性系在各浓度赤霉素处理下树高生长符合“S”形曲线模型, 各处理下拟合的Logistic方程系数均高于0.99。根据白桦树高生长模型参数可知,赤霉素促进白桦生长量的增加主要是延长了速生期的生长时间所致。【结论】GA₄₊₇和GA₃均促进白桦生长及结实,GA₄₊₇较GA₃效果好;确定0.4 g/L的GA₄₊₇是促进白桦结实的最适激素处理。

Effects of gibberellin on early growth and fruiting of potted Betula platyphylla clones

【Objective】 This study aimed to identify the best gibberellin treatment to increase the growth and fruiting ofBetula platyphylla. 【Method】 In this experiment, a birch clone was used as the research object and the ramets were treated with GA₃ and GA₄₊₇ at concentrations of 0.0, 0.2, 0.4 and 0.6 g/L. The test lasted for 3 years. In the second year, the rhythmicity of growth height was investigated. In the third year, the growth height, breast diameter, number of infructescences, fresh weight of infructescences and dry weight of seeds under each treatment were investigated. 【Result】 Analysis of variances of growth height, diameter at breast height, and fruit-bearing amount showed that the differences in growth height and fruit-bearing amount were significantly higher at different concentrations of GA₃ and GA₄₊₇(P < 0.01). Both GA ₃ and GA₄₊₇ can promote the growth and fruiting of B. platyphylla; however, the effect of GA₄₊₇ is better. The optimal concentration was determined to be 0.4 g/L by comprehensive evaluation of growth height and fruit-bearing amount. Under this treatment, the growth height 13.69% was higher than that under the control, and the number of infructescences, fresh weight of infructescences, and dry weight of seeds increased by 203.6%, 186.8% and 187.2%, respectively. The growth height curve of B. platyphylla under each treatment accords with the “S” curve model. The fitting coefficients of the logistic equation under each treatment were all higher than 0.99. According to the parameters of the tree height growth model, the reason that gibberellin promotes the growth of B. platyphylla is mainly due to the prolongation of the fast growth period. 【Conclusion】 Both GA₄₊₇ and GA₃ promoted the growth and fruiting of B. platyphylla. GA₄₊₇ was more efficacious than GA₃. GA₄₊₇ at 0.4 g/L is the best concentration and hormone to promote the growth of B. platyphylla.