Morphological Responses Of Picea Koraiensis, Pinus Tabuliformis And Pinus Bungeana Seedlings To Different NH₄⁺/NO₃^-Ratios

Picea koraiensis, Pinus tabuliformis and Pinus bungeana are mainly used coniferous evergreen species in northern China forest afforestation. In this paper, the seedlings of these three kinds of species were used as material, and were fertilized by different NH4+/NO3-nitrogen fertilizer (1/4,1/1,4/1and CK) under exponential regime with randomized block experimental design in the greenhouse. The seedlings harvested after90d were measured in morphological, physiological and biochemical indexes to study the morphology responses of these three species seedlings to the different NH4+//NO3-, and to provide a theoretical basis for fertilization regime of different coniferous afforestation species seedling growing in greenhouse.Test results showed that:(1) The fertilization has little effect on the three kinds of seedlings height, but increased Picea koraiensis and Pinus tabuliformis seedlings ground diameter as well as Picea koraiensis and Pinus bungeana total dry biomass effectively. From the perspective of seedling growth,4/1was better for Picea koraiensis and Pinus bungeana, and1/4was conductive to Pinus tabuliformis. The accumulation of three kinds of seedlings biomass was focused mainly in aboveground part, and the underground part accumulated slowly.4/1was conducive to the increasing of the proportion of three species aboveground biomass, and1/4was the better for their underground biomass.(2) The result sorted by the respond level of three kinds of seedlings root morphology to the fertilization was Picea koraiensis> Pinus tabuliformis> Pinus bungeana.4/1was better for the increasing of Pinus bungeana root length, root area and root volume, but1/4was better for Pinus tabuliformis. Picea koraiensis had little reaction to the different NH4+/NO3.4/1was conducive to the increasing of three kinds of seedlings specific root length and specific root area, which mean that4/1was better for the increasing of the root absorption efficiency. The result sorted by the respond level of three kinds of seedlings root numbers and branch intensity to the fertilization was Pinus tabuliformis> Pinus bungeana> Picea koraiensis.4/1made Picea tabuliformis root number and branch intensity highest,1/4made Pinus bungeana highest, but Picea koraiensis was unresponsive to them.(3)4/1could effectively improve the establishment of the nutrient pool of three kinds of seedling aboveground and underground parts and the main storage form of the pool was the nitrate.4/1was conductive to the accumulation of Picea koraiensis chlorophyll,1/4was conductive to Pinus tabuliformis and1:1was conductive to Pinus bungeana.