Abstract: It is still unknown whether the midday depression of photosynthesis under severe water stress, frequently observed in plants growing in a Mediterranean-type climate, is primarily a consequence of diffusional or non-diffusional limitations. We carried out combined measurements of gas exchanges and chlorophyll fluorescence in field-grown Arbutus unedo L. trees during late spring and mid summer, and a quantitative limitation analysis was performed to distinguish between the different limitations to photosynthesis, i.e., diffusional [D (L) = stomatal (S (L)) + mesophyll (MCL)] and non-diffusional (carboxylation capacity and electron transport, B (L)) limitations. Light-saturated assimilation at ambient CO2 (A (max)), stomatal conductance to water vapour (g (sw)) and maximum carboxylation rate (V (cmax) C (i)) showed a marked midday depression during both periods. The total limitations tended to increase during the day and were remarkably similar in June and July (50 and 48%, respectively); on a daily basis, D (L) was similar to B (L) (about 23%) in June; whereas, in July the former was predominant (38 and 4%, respectively). We concluded that the midday depression in photosynthesis was largely caused by diffusional limitations, with non-diffusional limitations playing a smaller role. Although stomatal closure was the main diffusional limitation, the decline in mesophyll conductance was not negligible during the hottest and driest period.

Contribution of diffusional and non-diffusional limitations to midday depression of photosynthesis in Arbutus unedo L / G.Grassi; F.Ripullone; M.Borghetti; S.Raddi; F.Magnani. - In: TREES. - ISSN 0931-1890. - STAMPA. - 23(2009), pp. 1149-1161. [10.1007/s00468-009-0355-7]

Contribution of diffusional and non-diffusional limitations to midday depression of photosynthesis in Arbutus unedo L.

RADDI, SABRINA
Project Administration
;
2009

Abstract

Abstract: It is still unknown whether the midday depression of photosynthesis under severe water stress, frequently observed in plants growing in a Mediterranean-type climate, is primarily a consequence of diffusional or non-diffusional limitations. We carried out combined measurements of gas exchanges and chlorophyll fluorescence in field-grown Arbutus unedo L. trees during late spring and mid summer, and a quantitative limitation analysis was performed to distinguish between the different limitations to photosynthesis, i.e., diffusional [D (L) = stomatal (S (L)) + mesophyll (MCL)] and non-diffusional (carboxylation capacity and electron transport, B (L)) limitations. Light-saturated assimilation at ambient CO2 (A (max)), stomatal conductance to water vapour (g (sw)) and maximum carboxylation rate (V (cmax) C (i)) showed a marked midday depression during both periods. The total limitations tended to increase during the day and were remarkably similar in June and July (50 and 48%, respectively); on a daily basis, D (L) was similar to B (L) (about 23%) in June; whereas, in July the former was predominant (38 and 4%, respectively). We concluded that the midday depression in photosynthesis was largely caused by diffusional limitations, with non-diffusional limitations playing a smaller role. Although stomatal closure was the main diffusional limitation, the decline in mesophyll conductance was not negligible during the hottest and driest period.
23
1149
1161
Goal 13: Climate action
Goal 15: Life on land
G.Grassi; F.Ripullone; M.Borghetti; S.Raddi; F.Magnani
File in questo prodotto:
File Dimensione Formato  
Raddi_Grassi et al 2009.pdf

Accesso chiuso

Tipologia: Pdf editoriale (Version of record)
Licenza: DRM non definito
Dimensione 488.86 kB
Formato Adobe PDF
488.86 kB Adobe PDF   Visualizza/Apri   Richiedi una copia

I documenti in FLORE sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/2158/388142
Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus 26
  • ???jsp.display-item.citation.isi??? 23
social impact