Articles
CARBON ISOTOPE COMPOSITION INDICATES IMPROVED PHOTOSYNTHETIC WATER USE EFFICIENCY OF STRAWBERRY PLANTS UNDER DEFICIT IRRIGATION
Article number
889_49
Pages
397 – 402
Language
English
Abstract
During photosynthesis, the extent of discrimination against the heavier isotope of carbon, 13C, in relation to the lighter isotope, 12C, is related to the ratio of internal to external partial pressure of CO2. This is influenced by both stomatal conductance and photosynthetic rate, and therefore is indirectly related to water use efficiency, with greater 13C enrichment i.e. a higher carbon isotope composition (δ13C) being associated with greater water use efficiency.
The shallow root system, large leaf area, and high water content of fruits of the commercial strawberry, Fragaria × ananassa Duch., means that strawberry production uses large quantities of water.
To save water via deficit irrigation requires greater understanding of the response of strawberry plants to limited water availability.
We explored the impact of deficit irrigation on δ13C of the cultivar Elsanta in a series of experiments in which plants in pots were given either full or deficit irrigation (80% ETp or lower). In three separate experiments when 60-day Elsanta was grown under plastic tunnels, δ13C was significantly increased under deficit compared with full irrigation.
Similarly when 60-day Elsanta was grown in a controlled environment unit, δ13C was significantly increased under deficit irrigation.
The only case where there was no significant effect of irrigation on δ13C of 60-day plants was when they were grown in freely-draining perlite rather than in a peat-based growing substrate.
When Elsanta was grown as a main season crop, δ13C was not significantly affected by irrigation, but was higher than in the other experiments.
The lowest δ13C (poorest water use efficiency) was found in leaves of fully-irrigated plants grown in the controlled environment unit.
The largest differences in δ13C between fully- and deficit-irrigated plants also occurred in this environment.
This suggests that where water use efficiency is poorest, the potential to improve it using deficit irrigation may be greatest.
The shallow root system, large leaf area, and high water content of fruits of the commercial strawberry, Fragaria × ananassa Duch., means that strawberry production uses large quantities of water.
To save water via deficit irrigation requires greater understanding of the response of strawberry plants to limited water availability.
We explored the impact of deficit irrigation on δ13C of the cultivar Elsanta in a series of experiments in which plants in pots were given either full or deficit irrigation (80% ETp or lower). In three separate experiments when 60-day Elsanta was grown under plastic tunnels, δ13C was significantly increased under deficit compared with full irrigation.
Similarly when 60-day Elsanta was grown in a controlled environment unit, δ13C was significantly increased under deficit irrigation.
The only case where there was no significant effect of irrigation on δ13C of 60-day plants was when they were grown in freely-draining perlite rather than in a peat-based growing substrate.
When Elsanta was grown as a main season crop, δ13C was not significantly affected by irrigation, but was higher than in the other experiments.
The lowest δ13C (poorest water use efficiency) was found in leaves of fully-irrigated plants grown in the controlled environment unit.
The largest differences in δ13C between fully- and deficit-irrigated plants also occurred in this environment.
This suggests that where water use efficiency is poorest, the potential to improve it using deficit irrigation may be greatest.
Authors
O.M. Grant, C.M. James, P.A.A. Dodds, N. Šurbanovski
Keywords
assimilation, drought tolerance, ‘Elsanta’, fruit, stomatal conductance, transpiration
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