截干措施对刺槐种子园采种树表型性状和营养元素的影响

随着树龄增加,刺槐种子园的采种树出现结果部位上移、采种困难、产种率下降以及树体衰弱等问题,针对出现的问题,对树体进行截干矮化处理,探究截干措施的效果和营养元素的变化规律。以2个试验基地的刺槐种子园的采种树为研究对象,3个截干高度处理(0.8、1.0、1.2 m),在2016年和2017年分别进行截干,在2018年进行表型调查和营养元素含量分析。凌海基地3个截干高度的采种树的当年生枝条长度、花序量显著优于未截干采种树,对比试验中发现截干高度为1.0 m时采种树在分枝长度和花序数量表现最优;测定10种营养元素发现不同的截干高度对P、Mg的吸收均有显著促进作用。吉县基地刺槐种子园研究结果表明2017年和2016年截干均优于未截干采种树,截干措施能够显著提高采种树的当年生枝条长度和基径、复叶量和复叶重;2017年截干的采种树有利于Mg元素吸收。研究结果可为今后刺槐种子园矮化栽培和树体营养元素平衡提供依据。

Effects of Truncation Measures on the Phenotypic Characters and Nutrient Elements of Seed Harvesting Trees in Seed Orchard of Robinia pseudoacacia

With the increasing of tree age, there are problems in the seed trees of Robinia pseudoacaia seed orchard, such as high fruit position, difficult seed collection, low seed production rate and weak tree body. In view of these problems, the trunk of seed trees were truncated and dwarfed to explore the effect of trunk truncating measures and the changing law of nutrient elements. Taking the seed trees in two experimental bases of R. pseudoacacia seed orchard as the research object, three truncating height treatments (0.8, 1.0 and 1.2 m) were conducted respectively in 2016 and 2017, and phenotypic investigation and nutrient content analysis were conducted in 2018. The results showed that the branch length and inflorescence amount of the seed trees with three cutting height in Linghai base were significantly better than those of the non-truncating trees. In the comparative experiment, it was found that the branch length and inflorescence number of the seed trees were the best when the truncating height was 1.0 m; the determination of 10 nutrient elements showed that different truncating height had significant promoting effect on the absorption of both P and Mg element. The results of the research on R. pseudoacacia seed orchard in Jixian base showed that truncating trunk seed trees in 2017 and 2016 were superior to that of non-truncating seed trees, and the cutting measures could significantly improve the length and base diameter of the current-year-branches, and the amount and weight of compound leaves; the trunk truncating trees were conducive to Mg element absorption in 2017. These results could provide a basis for dwarf cultivation and nutrient balance of tree body in the seed orchard of R. pseudoacacia in the future.