Plant Growth Regulation

, Volume 49, Issue 2, pp 127–136

High temperature effects on ammonium assimilation in leaves of two Festuca arundinacea cultivars with different heat susceptibility

  • Langjun Cui
  • Rang Cao
  • Jianlong Li
  • Linsheng Zhang
  • Jiazhen Wang
Original Paper

DOI: 10.1007/s10725-006-9002-0

Cite this article as:
Cui, L., Cao, R., Li, J. et al. Plant Growth Regul (2006) 49: 127. doi:10.1007/s10725-006-9002-0

Abstract

The aim of this study was to determine the effects of high temperature stress on ammonium assimilation in leaves of two tall fescue cultivars (Festuca arundinacea), Jaguar 3 brand (J3) (heat-tolerant) and TF 66 (T6) (heat-sensitive). High temperature stress for either 10 d or 20 d, and particularly the 20 d stress, produced dramatic changes in ammonium assimilation. After 20 d of stress treatment, the accumulations of total nitrogen, nitrate, soluble protein and total free amino acid (20 amino acids) decreased in both cultivars. Moreover, the activities of main regulatory enzymes, such as nitrate reductase, glutamine synthetase (GS), NADH-dependent glutamate synthase (GOGAT), as well as Δ1-pyrroline-5-carboxylate reductase (P5CR), also decreased in both cultivars when exposed to 20 d stress. Heat stress had little influence on ammonium accumulation in J3, but this was not the case with T6. The accumulations of nitrate, ammonium, soluble protein, and total free amino acid between the two cultivars were different. This suggests that accumulations of these nitrogen forms were associated with heat tolerance in both tall fescue cultivars. Changes of both NADH-glutamate dehydrogenase (NADH-GDH) activity and Glx (glutamine and glutamic acid) concentration in both cultivars indicated that there is an alternative system for assimilation of nitrogen through glutamate dehydrogenase (GDH) in T6 during longer high temperature stress periods. Our results provide an insight to further selection and breeding of heat-tolerant tall fescue turfgrass cultivars.

Keywords

Ammonium assimilationFestuca arundinaceaFree amino acidHigh temperature stressNitrogen

Abbreviations

DW

Dry weight

FW

Fresh weight

GS

Glutamine synthetase

J3

Jaguar 3 brand

NADH-GDH

NADH-dependent glutamate dehydrogenase

NADH-GOGAT

NADH-dependent glutamate synthase

NiR

Nitrite reductase

NR

Nitrate reductase

P5CR

Δ1-Pyrroline-5-carboxylate reductase

PDH

Proline dehydrogenase

A

Net photosynthetic rate

Pro

Proline

SOD

Superoxide dismutase

T6

TF 66

Copyright information

© Springer Science+Business Media B.V. 2006

Authors and Affiliations

  • Langjun Cui
    • 1
  • Rang Cao
    • 2
  • Jianlong Li
    • 1
    • 3
  • Linsheng Zhang
    • 2
  • Jiazhen Wang
    • 3
  1. 1.School of Life SciencesShaanxi Normal UniversityXi’anP.R. China
  2. 2.School of Life SciencesNorthwest Science and Technology University of Agriculture and ForestryYanglingP.R. China
  3. 3.State Key Laboratory of Pharmaceutical Biotechnology, School of Life SciencesNanjing UniversityNanjingP.R. China