三倍体毛白杨分枝格局对不同土壤供水水平的响应

Response of Branching Pattern of Triploid Populus tomentosa to Variation Soil Water Regime

【目的】研究不同土壤供水水平对三倍体毛白杨分枝格局及适应性的影响,为毛白杨人工林冠层管理提供理论依据。【方法】以2年生三倍体毛白杨人工林为研究对象,采用完全随机区组设计,分析充分灌溉(FI)、控水灌溉(CI)和不灌溉(CK)3种处理下9株样树的分枝格局。【结果】1)不同土壤供水水平对一级枝条平均枝长和分枝角度有显著影响(P<0.05),FI处理下一级枝条平均枝长最长(3.31 m)、分枝角度最大(59.81°);2)不同处理对RD2∶1有显著影响(P<0.05),随着土壤供水量增加枝径比呈增大趋势,CK、CI和FI的RD2∶1分别为0.39、0.39和0.51;3)不同处理间毛白杨的总体分枝率和逐步分枝率均差异不显著(P>0.05),FI处理下当年生新生枝条较多,CK处理下较少。【结论】在不同土壤供水水平下,毛白杨平均枝长、分枝角度、枝径比具有较强的可塑性和变异性,土壤水分充足时,毛白杨分枝数增多,一级枝条生长较快,分枝角度加大,总体分枝率较低。

【Objective】In this study,the effects of different irrigation quantity on the branching pattern and adaptability of biennial triploid Populus tomentosa plantation were investigated,in orderto provide theoretical basis for canopy management of triploid P.tomentosa plantation.【Method】The branching patterns of 9 trees in a two-year-old triploid P.tomentosa plantation were measured under the sufficient drip irrigation,deficit drip irrigation and no irrigation treatment(CK).【Result】The results showed that:1)the average branch length and branching angle of the first-order branches of P.tomentosa were significantly affected by different irrigation quantity(P<0.05).Under drip irrigation,the average branch length of the first-order branches was the longest(3.31 m)and the branching angle was the largest(59.81°).2)The different treatments significantly affected branch diameter ratio(2:1)(P<0.05).The branch diameter ratio(2:1)of control,full drip irrigation and deficit drip irrigation were 0.39,0.51 and 0.39,respectively.3)There were no significant differences inthe total branching rate and gradual branching rates of P.tomentosa among different treatments(P>0.05).Under the conditions of sufficient drip irrigation,there were more new branches in the current year,and less new branches in CK treatment.【Conclusion】In summary,the twig length,branching angle and branch diameter ratio of two-year-old P.tomentosa have strong plasticity and variability under different irrigation condition.When the soil moisture is sufficient,the number of branches of P.tomentosa increased,the first-order branches grow faster,the branching angle increased,and the overall branching rate was lower.The results of this study will be helpful to understand the branching pattern and the adaptive strategies of the poplar,and provide a theoretical basis for making the reasonable pruning measures.