Winter photosynthetic activity of twenty temperate semi-desert sand grassland species

Zoltán Tuba, Zsolt Csintalan, Kálmán Szente, Zoltán Nagy, Gábor Fekete, Walter Larcher, Hartmut K. Lichtenthaler

Research output: Contribution to journalArticle

8 Citations (Scopus)

Abstract

The winter photosynthetic activity (quantified by net CO2 assimilation rates and chlorophyll (Chl) a fluorescence parameters) of 20 plant species (including two lichens and two mosses) of a Hungarian temperate semi-desert sand grassland was determined on one occasion per year in 1984, 1989 and 1994. Throughout winter, the overwintering green shoots, leaves or thalli were regularly exposed to below zero temperatures at night and daytime temperatures of 0-5 °C. In situ tissue temperature varied between -2.1 and +6.9 °C and the photosynthetic photon flux density (PPFD) between 137 and 351 μmol m-2 s-1. Under these conditions 18 of the grassland species exhibited photosynthetic CO2 uptake (range: vascular plants ca. 0.2-3.8 μmol m-2 s-1, cryptogams 0.3-2.79 μmol kg-1 s-1) and values of 0.9-5.1 of the Chl fluorescence decrease ratio RFd. In 1984, Festuca vaginata and Sedum sexangulare had net CO2 assimilation at leaf temperatures of -0.85 to -1.2 °C. In 1989, all species except Cladonia furcata showed net CO2 assimilation at tissue temperatures of 0 to +3.3 °C, with the highest rates observed in Poa bulbosa and F. vaginata. The latter showed a net CO2 assimilation saturation at a PPFD of 600 μmol m-2 s-1 and a temperature optimum between +5 and +18 °C. At the 1994 measurements, the photosynthetic rates were higher at higher tissue water contents. The two mosses and lichens had a net photosynthesis (range: 1.1-2.79 μmol CO2 kg-1 s-1) at 2 °C tissue temperature and at 4-5 °C air temperature. Ca. 80% of the vascular grassland plant species maintained a positive C-balance during the coldest periods of winter, with photosynthetic rates of 1.5-3.8 μmol CO2 m-2 s-1. In an extremely warm beginning March of the relatively warm winter of 2006/2007, the dicotyledonous plants had much higher CO2 assimilation rates on a Chl (range 6-14.9 μmol g-1 Chl s-1) and on a dry weight basis (9-48 μmol kg-1 dw s-1) than in the cold winter of 1994. However, the assimilation rates of the three investigated cryptogams (Tortula and two Cladonia) and the two grasses Festuca and Poa were not affected by this increase. The results indicate that the photosynthetic activity of temperate semi-desert sand grassland species can help somewhat in slowing the general CO2 rise in winter and function as a potential carbon sink of the investigated semi-desert Hungarian grassland species.

Original languageEnglish
Pages (from-to)1438-1454
Number of pages17
JournalJournal of Plant Physiology
Volume165
Issue number14
DOIs
Publication statusPublished - Sep 29 2008

Keywords

  • CO assimilation
  • Chlorophyll fluorescence decrease ratio
  • Light response curve
  • Overwintering
  • Temperature response curve

ASJC Scopus subject areas

  • Physiology
  • Agronomy and Crop Science
  • Plant Science

Fingerprint Dive into the research topics of 'Winter photosynthetic activity of twenty temperate semi-desert sand grassland species'. Together they form a unique fingerprint.

  • Cite this