EFFECTS OF POTASSIUM ADDITION AND WATER SUPPLY ON XYLEM EMBOLISM IN ACER TRUNCATUM AND LIGUSTRUM LUCIDUM
施水和钾素添加对元宝枫和女贞木质部栓塞的影响

Aims Xylem embolism is a physiological response of tree species to adverse environmental factors, such as water deficit. Potassium plays an important role in plant ability to resist drought. Our objective was to clarify how xylem embolism respond to potassium addition. Methods Tree species, Acer truncatum and Ligustrum lucidum were chosen to study the response of xylem embolism, which was measured as the percentage loss of hydraulic conductivity (PLC), to potassium addition under drought-stressed and well-watered treatments (soil water content of 30%-40% and 70%-80% of field moisture capacity, respectively).Important findings For both species, PLC was higher at 12:30 than at 6:30 and 18:30, while leaf water potential (WP) showed the opposite trend. Potassium addition raised PLC significantly for both species, and the plants with the highest potassium supply generally had the highest PLC. Potassium addition greatly decreased WP of the plants subjected to water deficit. Between the two species, A. truncatum had higher PLC and lower WP. This study suggests that increase in PLC by potassium-addition may result from potassium's effect on water potential and from its controls on stomata movement, cell osmosis, etc.