根际酸化作用对杨树无性系磷营养效率的影响  

Effects of rhizosphere acidification on phosphorus efficiency in clones of poplar.

作　　者：张焕朝[1] 王改萍[1] 徐锡增[1] 徐成凯[2] 胡正义[2] 

机构地区：[1]南京林业大学森林资源与环境学院,南京210037 [2]中国科学院南京土壤研究所,南京210008

出　　处：《应用生态学报》2003年第10期1607-1611,共5页Chinese Journal of Applied Ecology

基　　金：国家自然科学基金资助项目(39770610)

摘　　要：应用土培盆栽技术,研究了杨树P营养效率的元性系差异与根际酸化作用的关系.P处理设4个水平,分别为0、40、80和120 mg·kg-1(P2O5),每个处理重复3次,各用土40 kg,随机排列.结果表明,在缺P胁迫下,P营养高效型无性系S17、S19和105的根际pH值明显降低,最大为1.32个单位,降幅均在10％以上;而P营养低效型无性系106、797、I-69、1388和3244的根际pH值的降低则很小,最大的仅为0.21个单位,降幅均在2.5％以下.高效型无性系的根际pH值,随缺P胁迫的增加而逐渐降低,一旦缺P胁迫缓和,根际pH值随之增高.低效型无性系则不具有这种反应机理.S17、S19和105在缺P胁迫环境下,根际有效磷分别为2.64、3.27和3.28 mg·kg-1,根际有效磷的积累率均在60％以上;而无性系106、797、I-69、1388和3244的根际有效磷均不足2.00 mg·kg-1,根际有效磷的积累率不足10％.高效型无性系在缺P胁迫环境下对P的吸收量显著高于低效型无性系.统计分析也证明,缺P胁迫条件下,无性系根际有效磷的积累与根际pH值降低呈显著相关,说明根际酸化作用是根际有效磷增加的原因.Effects of rhizosphere acidification on P efficiency in different poplar clones were conducted by the method of soil culture in greenhouse. Potassium dihydrogen phosphate was applied to furnish 0, 40, 80, and 120 mg P2O5 kg-1. The experiment consisted of three replicatesof each treatment, with a pot of 40 kg soil in a randomized block. The results showed that high P efficiency clones, such as S17, S19, and 105, could decrease their pH values in rhizosphere under P deficiency stress much stronger than clones 106, 797, 1-69, 1388, and 3 244, which were low P efficiency clones. The most decrement of pH for the former even accounted to 1.32 pH units and the ratios of the decrements were over 10% in comparison with the pH values in bulk soil. Whereas for the latter less than 0. 21 pH units and 2.5% of the decreasing ratio respectively. In contrast to low P efficiency clones, high P efficiency clones could acidify their rhizosphere through a kind of specific mechanism because the pH values in rhizosphere of high P efficiency clones were gradually decreased corresponding with the intensity of P deficiency stress and vice versa. The amounts of available P in rhizosphere of clone S17, S19, and 105 reached 2.64, 3.27, and 3.28 mg·kg-1, respectively, obviously higher than those of the other five low P efficiency clones, which all were below 2.00 mg·kg-1 under P deficiency stress, and the summation percentages of available P in rhizosphere were over 60% for all high P efficiency clones, but less than 10% for low P efficiency clones. The amounts of P taken up by high P efficiency clones wore statistically greater than by low P efficiency clones. Regression analysis also indicated that the increment of available P in rhizosphere was closely correlated with the decrement of pH values in rhizosphere under P deficiency stress. This demonstrated the impact of rhizosphere acidification on availability of rhizosphere P, and identified that high P efficiency clones could enhance their contents of available P in rhizosphere, absorb

关 键 词：杨树 无性系 P营养效率 根际酸化作用 根际有效磷 

分 类 号：S718.43[农业科学—林学]