Mycorrhiza

, 15:596

Mycorrhizal impact on drought stress tolerance of rose plants probed by chlorophyll a fluorescence, proline content and visual scoring

Authors

  • Alexandra Pinior
    • Institute of Plant Diseases and Plant ProtectionUniversity of Hannover
    • Institute of Plant Diseases and Plant ProtectionUniversity of Hannover
  • Henning von Alten
    • Institute of Plant Diseases and Plant ProtectionUniversity of Hannover
  • Reto J. Strasser
    • Bioenergetics LaboratoryUniversity of Geneva
Original Paper

DOI: 10.1007/s00572-005-0001-1

Cite this article as:
Pinior, A., Grunewaldt-Stöcker, G., von Alten, H. et al. Mycorrhiza (2005) 15: 596. doi:10.1007/s00572-005-0001-1

Abstract

Micropropagated rose plants (Rosa hybrida L., cv. New Dawn) were inoculated with the arbuscular mycorrhizal (AM) fungus Glomus intraradices (Schenk and Smith) and subjected to different drought regimens. The dual objectives of these experiments were to investigate the mechanism and the extent to which AM can prevent drought damages and whether physiological analyses reveal enhanced drought tolerance of an economically important plant such as the rose. In a long-term drought experiment with four different water regimens, visual scoring of wilt symptoms affirmed that AM in a selected host–symbiont combination increased plant performance. This effect was mostly expressed if moderate drought stress was constantly applied over a long period. In a short-term experiment in which severe drought stress was implemented and plants were allowed to recover after 4 or 9 days, no visual differences between mycorrhizal and non-mycorrhizal roses were observed. Therefore, the early physiological steps conferring drought tolerance were prone to investigation. Proline content in leaves proved to be an unsuitable marker for AM-induced drought tolerance, whereas analysis of chlorophyll a fluorescence using the JIP test (collecting stress-induced changes of the polyphasic O-J-I-P fluorescence kinetics in a non-destructive tissue screening) was more explanatory. Parameters derived from this test could describe the extent of foliar stress response and help to differentiate physiological mechanisms of stress tolerance. AM led to a more intense electron flow and a higher productive photosynthetic activity at several sites of the photosynthetic electron transport chain. A K step, known as a stress indicator of general character, appeared in the fluorescence transient only in drought-stressed non-mycorrhizal plants; conversely, the data elucidate a stabilising effect of AM on the oxygen-evolving complex at the donor site of photosystem (PS) II and at the electron-transport chain between PS II and PS I. If drought stress intensity was reduced by a prolonged and milder drying phase, these significant tolerance features were less pronounced or missing, indicating a possible threshold level for mycorrhizal tolerance induction.

Keywords

Arbuscular mycorrhizaChlorophyll fluorescenceDrought stress toleranceGlomus intraradicesRosa hybrida

Abbreviations

ABS

absorption

AM

arbuscular mycorrhiza

AMF

arbuscular mycorrhizal fungi

Chl a

chlorophyll a

DI

dissipation

ET

energy flux for electron transport

Fo, Fm

initial and maximum Chl a fluorescence

Fv/Fm

maximum quantum efficiency of primary photochemistry of photosystem II

O, K, J, I, P

intermediate steps of Chl a fluorescence rise between Fo and Fm

OEC

oxygen-evolving complex

PI

performance index

PS I and PS II

photosystems I and II

QA

plastoquinone

RC

reaction centre

Sm

normalized area above the Chl a fluorescence transient

TR

energy flux for trapping

Copyright information

© Springer-Verlag 2005