Ecophysiology of seedlings of three Mediterranean pine species in contrasting light regimes

Tala Awada, Kalliopi Radoglou, Mariangela N. Fotelli, Helen I.A. Constantinidou

Research output: Contribution to journalArticlepeer-review

90 Scopus citations

Abstract

Seasonal dynamics of net photosynthesis (Anet) in 2-year-old seedlings of Pinus brutia Ten., Pinus pinea L. and Pinus pinaster Ait. were investigated. Seedlings were grown in the field in two light regimes: sun (ambient light) and shade (25% of photosynthetically active radiation (PAR)). Repeated measures analyses over a 12-month period showed that Anet varied significantly among species and from season to season. Maximum Anet in sun-acclimated seedlings was low in winter (yet remained positive) and peaked during summer. Maximum Anet was observed in June in P. pinea (12 μmol m-2 s-1), July in P. pinaster (23 μmol m-2 s-1) and August in P. brutia (20 μmol m-2 s-1). Photosynthetic light response curves saturated at a PAR of 200-300 μmol m-2 s-1 in winter and in shade-acclimated seedlings in summer. Net photosynthesis in sun-acclimated seedlings did not saturate at PAR up to 1900 μmol m-2 s-1 in P. brutia and P. pinaster. Minimum air temperature of the preceding night was apparently one of the main factors controlling Anet during the day. In shade-acclimated seedlings, photosynthetic rates were reduced by 50% in P. brutia and P. pinaster and by 20% in P. pinea compared with those in sun-acclimated seedlings. Stomatal conductance was generally lower in shaded seedlings than in seedlings grown in the sun, except on days with a high vapor pressure deficit. Total chlorophyll concentration per unit leaf area, specific leaf area (SLA) and height significantly increased in P. pinea in response to shade, but not in P. pinaster or P. brutia. In response to shade, P. brutia showed a significant increase in total chlorophyll concentration but not SLA. Photosynthetic and growth data indicate that P. pinaster and P. brutia are more light-demanding than P. pinea.

Original languageEnglish (US)
Pages (from-to)33-41
Number of pages9
JournalTree Physiology
Volume23
Issue number1
DOIs
StatePublished - Jan 2003

Keywords

  • Diurnal
  • Gas exchange
  • Mediterranean region
  • Pinus brutia
  • Pinus pinaster
  • Pinus pinea
  • Seasonal

ASJC Scopus subject areas

  • Physiology
  • Plant Science

Fingerprint

Dive into the research topics of 'Ecophysiology of seedlings of three Mediterranean pine species in contrasting light regimes'. Together they form a unique fingerprint.

Cite this