Bulletin of Botanical Research ›› 2026, Vol. 46 ›› Issue (4): 751-763.doi: 10.7525/j.issn.1673-5102.2026.04.015

• Original Paper • Previous Articles     Next Articles

Effects of Different Nitrogen Forms on Growth, Water Status and Osmoprotectants in Pinus koraiensis Seedlings under Drought Stress

Jiawei HAN, He HUANG, Huiliang LIU, Haibo WU, Hailong SHEN, Peng ZHANG()   

  1. College of Forestry,Northeast Forestry University,Harbin 150040
  • Received:2026-03-07 Online:2026-07-20 Published:2026-07-22
  • Contact: Peng ZHANG E-mail:zhangpeng@nefu.edu.cn

Abstract:

To investigate the response patterns to nitrogen forms and determine the optimal nitrogen supply form for enhancing drought tolerance, seedling morphology, biomass, needle water status, and osmoprotectant mass fraction were examined in two-year-old P.koraiensis seedlings under drought levels(moderate and severe drought, with full irrigation as the control) and nitrogen forms(nitrate nitrogen, ammonium nitrogen, and glycinate nitrogen, with no nitrogen application as the control). The results indicated that the interaction between drought levels and nitrogen forms significantly affected the root morphology, root and needle biomass, seedling quality, needle water status, and osmoprotectants in P.koraiensis seedlings(P<0.05). Under full irrigation, seedlings fertilized with ammonium nitrogen exhibited significantly superior performances in seedling height, total root length, total root area, root biomass, Dickson’s quality index, and osmoprotectant mass fraction compared to those fertilized with glycinate nitrogen(P<0.05). Under moderate drought, seedlings fertilized with glycinate nitrogen showed no significant differences in seedling height, root collar diameter, total root volume, root tip number, biomass in various organs and the whole plant, Dickson’s quality index, needle water status, and proline mass fraction compared to those fertilized with ammonium nitrogen. Under severe drought, seedlings fertilized with glycinate nitrogen demonstrated significantly better performances in root collar diameter growth, total root length, total root area, root biomass, needle biomass, total biomass, Dickson’s quality index, needle water status, and needle osmoprotectant mass fraction compared to those fertilized with inorganic nitrogen(P<0.05). The response of P. koraiensis seedlings to nitrogen forms was significantly affected by drought levels. Under full irrigation, inorganic nitrogen(especially ammonium nitrogen) favored seedling growth and osmoprotectant accumulations. However, under severe drought, glycinate nitrogen improved seedling water status by promoting osmoprotectant accumulations, being more beneficial for seedling growth than inorganic nitrogen. This study elucidates the growth response of P. koraiensis seedlings to different nitrogen forms under drought stress, providing theoretical basis and technical reference for cultivating drought tolerant seedlings through nitrogen application in nurseries.

Key words: Pinus koraiensis, drought stress, nitrogen form, growth, water status, osmoprotectants

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