EFFECTS OF DIFFERENT CONCENTRATIONS AND FORM RATIOS OF NITROGEN ON CHLOROPHYLL BIOSYNTHESIS, PHOTOSYNTHESIS, AND BIOMASS PARTITIONING IN FRAXINUS MANDSHURICA SEEDLINGS

• 不同氮浓度和形态比例对水曲柳幼苗叶绿素合成、光合作用以及生物量分配的影响