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Transpiration efficiency and carbon‐isotope discrimination of grapevines grown under well‐watered conditions in either glasshouse or vineyard
Author(s) -
GIBBERD MARK R.,
WALKER ROB R.,
BLACKMORE DEIDRE H.,
CONDON ANTHONY G.
Publication year - 2001
Publication title -
australian journal of grape and wine research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.65
H-Index - 77
eISSN - 1755-0238
pISSN - 1322-7130
DOI - 10.1111/j.1755-0238.2001.tb00197.x
Subject(s) - rootstock , transpiration , vineyard , stomatal conductance , horticulture , water use efficiency , photosynthesis , dry matter , carbon dioxide , botany , cultivar , chemistry , biology , ecology
This paper describes variation in transpiration efficiency ‘W’ (where W = dry matter produced/water transpired) among grapevine genotypes grown under well‐watered conditions in either a glasshouse or a vineyard. Nineteen genotypes were grown in a glasshouse where growth and transpiration were measured. W ranged from 2.5 to 3.4 g dm/kg H 2 O transpired. Carbon‐isotope discrimination (Δ) of laminae dry matter ranged from 20.8 to 22.7%o and there was a negative relationship (R 2 = 0.58) between W and Δ. A large proportion of variation in W could be attributed to variation in stomatal conductance. Genotypic variation in photosynthetic capacity was also an important component of variation in W. In a second experiment, lamina Δ was measured for mature field‐grown Shiraz and Chardonnay, grown either on their own roots or grafted to five different rootstocks, and maintained at three sites under well‐watered conditions. At all sites and regardless of rootstock, the laminae of Chardonnay had Δ values 1 to 2%o lower than Shiraz. There was also a 1 to 2%o variation among the sites. Rootstock variety affected Δ values inconsistently and by a maximum of 0.5%o. Leaf gas exchange measurements were performed at a single site on sun‐exposed leaves of Chardonnay and Shiraz on either their own roots or 1103 Paulsen, a moderate to high vigour rootstock. There was no significant effect of rootstock on leaf gas exchange and photosynthetic rates did not differ between scion varieties. However, Chardonnay had a 20% lower stomatal conductance and a 1.4‐fold higher ratio of CO 2 assimilation/H 2 O transpiration (A/T) indicating a potentially higher W, at a leaf level, for Chardonnay compared with Shiraz. We conclude that photosynthetic capacity was also higher for Chardonnay. Δ values, predicted from the C i /C a ratio calculated from leaf gas exchange measurements, did not differ significantly from measured values for laminae Δ. This similarity for Δ, in conjunction with the fact that the lower Δ of Chardonnay was reflected in a higher A/T ratio, suggests that Δ may be a reliable predictor of comparative W under vineyard conditions.