Articles
IRRIGATION EFFECTS ON GRAPEVINE PHOTOSYNTHESIS
Article number
449_62
Pages
449 – 455
Language
English
Abstract
In previous work irrigation effect on grapevine leaf conductance and photosynthetic rate was assayed in two contrasting cultivarsz Tempranillo, a common spanish cultivar, and Manto Negro, a majorcan cultivar with enhanced drought resistance.
The objective of the present study was to compare irrigation effect on leaf photosynthesis capacity estimated by light and CO2 response curves in both cultivars.
Differences between treatments and cultivars in A (photosynthetic rate) vs PPFD (photosynthetic photon flux density) response curves were achieved during the ripening measurements in which midday leaf P of -1,6 and -1,2 MPa for Manto Negro and Tempranillo respectively were recorded in unirrigated plants.
For this treatment, at ambient CO2 and saturating light A was similar for both cutivars (6 and 5 umol CO2 but apparent quantum yield was more reduced in Manto Negro.At saturating light, A (photosynthetic rate) vs Ci (internal CO2 concetration) curves showed similar values for irrigation and drought until ripening.
In that sampling time, Tempranillo showed a coincident reduction in Amax, at saturating Ci in irrigated and water stressed plants.
In Manto Negro, irrigation enables to maintain these parameters unchanged but, under drought, was a clear reduction in Amax at saturating Ci and initial slope were found.
Photosynthetic capacity was independent of moderate irrigation during berry growth and veraison for both cultivars.
During the ripening period, moderate irrigation enables to maintain photosynthetic capacity in Manto Negro but not in Tempranillo, however for some parameters such as quantum yield and initial slope of A vs.
Ci curve, the higher drought effects were recorded for Manto Negro.
The objective of the present study was to compare irrigation effect on leaf photosynthesis capacity estimated by light and CO2 response curves in both cultivars.
Differences between treatments and cultivars in A (photosynthetic rate) vs PPFD (photosynthetic photon flux density) response curves were achieved during the ripening measurements in which midday leaf P of -1,6 and -1,2 MPa for Manto Negro and Tempranillo respectively were recorded in unirrigated plants.
For this treatment, at ambient CO2 and saturating light A was similar for both cutivars (6 and 5 umol CO2 but apparent quantum yield was more reduced in Manto Negro.At saturating light, A (photosynthetic rate) vs Ci (internal CO2 concetration) curves showed similar values for irrigation and drought until ripening.
In that sampling time, Tempranillo showed a coincident reduction in Amax, at saturating Ci in irrigated and water stressed plants.
In Manto Negro, irrigation enables to maintain these parameters unchanged but, under drought, was a clear reduction in Amax at saturating Ci and initial slope were found.
Photosynthetic capacity was independent of moderate irrigation during berry growth and veraison for both cultivars.
During the ripening period, moderate irrigation enables to maintain photosynthetic capacity in Manto Negro but not in Tempranillo, however for some parameters such as quantum yield and initial slope of A vs.
Ci curve, the higher drought effects were recorded for Manto Negro.
Authors
J. Escalona, E. Delgado, H. Medrano
Keywords
vitis vinifera, drought, CO2, assimilation, water potential
Online Articles (101)