无患子生殖生长物候期液流特征及其对枝叶修剪的响应OA北大核心CSTPCD

[Objective]The present study aimed to investigate the characteristics of sap flow velocity of Sapindus saponaria and its response pattern to pruning and meteorological factors during the key phenological periods,and to provide a theoretical reference for scientific water management during key reproductive phenological periods of Sapindus.[Method]The present study was conducted in the experimental area of the Sapindus National Forest Germplasm Repository in Jianning County,Sanming City,Fujian Province.Using five-year-old S.saponaria'Yuanhua'.Thermal dissipation probes(TDPs)and automatic weather stations were utilized to monitor sap flow and meteorological data from April 20,2021 to November 9,2021.The probes were installed approximately 30 cm above the ground to ensure that all probes were installed under the first branch.Sample trees in the pruning group were pruned once after inflorescence growth at the inflorescence growth period to remove branches and leaves that shaded the inflorescence from sunlight.Trees in the control group were left unpruned for comparison.[Result]The average daily sap flow velocity of S.saponaria showed a decreasing-increasing-decreasing trend over time during the seven key reproductive phenological periods.The strongest transpiration activities were(1.13±0.05)×10-3 cm/s(pruning)and(1.48±0.05)×10-3 cm/s(CK)in the early ovary growing period,while the weakest transpiration activities were(0.15±0.02)×10-3 cm/s(pruning)and(0.26±0.03)×10-3 cm/s(CK)in the fruit maturity period.Pruning significantly reduced the sap flow velocity of S.saponaria in all phenological periods,except for the bud swelling period.This reduction effect was more pronounced on sunny days when the tree was actively growing and was strongest at the end of the fruit development period.In addition,solar radiation,air temperature,wind speed and vapor pressure deficit(VPD)were the main drivers of sap flow velocity,while precipitation and air humidity were the main limiting factors.Meteorological factors,such as persistent rainfall,were the main limitations of the transpiration activity of S.saponaria from the bud swelling period to the early flowering period and middle fruit development period.Leaf aging and gradual dormancy of the tree were the main reasons for low sap flow velocity during the fruit maturity period.[Conclusion]Pruning significantly reduced the transpiration,with the reduction effect becoming more pronounced as the phenological periods progressed.There were large fluctuations in sap flow velocity throughout the reproductive growth of S.saponaria.Thus,these findings suggested that the water demand for tree and fruit growth is closely related to the water consumption behavior of trees.Meteorological factors,such as persistent excessive rainfall,during inflorescence growth and development are not conducive to transpiration.