Plant water relations as affected by osmotic potential of the nutrient solution and potential transpiration in tomato (<i>Lycopersicon esculentum</i>Mill.)

Li, Ya Ling; Marcelis, L.F.M.; Stanghellini, C.

doi:10.1080/14620316.2004.11511750

Cited by 15 publications

(6 citation statements)

References 33 publications

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“…The difference in overall F H2O in both experiments reported was mainly caused by the difference in VPD (Fig. 2a, b), which is in accordance to Li et al (2004) who used misting (i.e. decreasing VPD) to lower the potential transpiration rate.…”

Section: Environmental Conditions and General Plant Behavioursupporting

confidence: 86%

Linking stem diameter variations to sap flow, turgor and water potential in tomato

Swaef

Steppe

2010

Functional Plant Biol.

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Water status plays an important role for fruit quality and quantity in tomato (Solanum lycopersicum L.). However, determination of the plant water status via measurements of sap flow (FH2O) or stem diameter (D) cannot be done unambiguously since these variables are influenced by other effectors than the water status. We performed a semi-seasonal and a diurnal analysis of the simultaneous response of FH2O and D to environmental conditions, which allowed us to distinguish different influences on ΔD such as plant age, fruit load and water status and to reveal close diurnal relationships between FH2O and ΔD. In addition, an analysis of the diurnal mechanistic link between both variables was done by applying a slightly modified version of a water flow and storage model for trees. Tomato stems, in contrast with trees, seemed to maintain growth while transpiring because a large difference between turgor pressure (Ψp) and the yield threshold (Γ) was maintained. Finally, the simultaneous response of D and FH2O on irrigation events showed a possibility to detect water shortages.

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Section: Environmental Conditions and General Plant Behavioursupporting

confidence: 86%

Linking stem diameter variations to sap flow, turgor and water potential in tomato

Swaef

Steppe

2010

Functional Plant Biol.

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“…This was proven and has been reported extensively Li et al, , 2002Li et al, , 2004 and has been implicitly confirmed by Romero Aranda et al (2002). Central to the experiment was a "transpiration control", an algorithm that constantly maintained crop transpiration to 65% of the rate in an identical compartment, using the opening of the roof ventilators and fogging as sole actuators.…”

Section: Introductionsupporting

confidence: 61%

Steering of Fogging: Control of Humidity, Temperature or Transpiration?

Stanghellini¹,

Kempkes²

2008

Acta Hortic.

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Fogging systems are increasingly used to cool greenhouses and prevent water stress. More recently, fogging systems are applied also in relatively low radiation environments (such as The Netherlands), for a better control of product quality than whitewashing and to reduce need for natural ventilation -thus allowing for higher CO 2 concentrations to be maintained in the greenhouse. Most commonly the steering of such systems is done by setting an upper limit to the deficit of specific humidity that, whenever exceeded, triggers the fogging system. In both cases, however, one may wonder whether static and pre-fixed set points are the most effective choice.In the experiment presented in this paper, fogging and venting were controlled with the purpose of steering crop transpiration. The desired transpiration rate was the input of an algorithm that calculated on-line the required humidity and air temperature set points in view of the current weather factors. The set points were then the input of a standard P-controller that calculated vent opening and time of operation of the fogging system. In this paper, the resulting climate and actuator control operations are discussed and compared with a similar greenhouse controlled in a traditional fashion. The study concluded that a desired crop transpiration rate (an all-round indicator of crop well-being) could be used to select dynamic set points for the climate control in a greenhouse equipped with a fogging system. INTRODUCTIONThe management of humidity has two purposes: maintaining crop transpiration within boundaries and preventing condensation on the crop. With respect to transpiration: too low and too high rates may result in local Ca deficiencies; in addition, a high ratenot matched by water uptake -results in turgor loss, partial stomatal closure and loss of assimilation. Condensation is known to increase incidence of pathologies such as mildew and botrytis (Köhl et al., 2007). In a traditional greenhouse both aims are combined in setpoints for humidity (a maximum relative humidity or a minimum humidity deficit) whose crossing triggers procedures combining ventilation and heating, estimated to result in some 20% of the energy consumption of Dutch greenhouse (Bakker, 1991). There is little that can be done in a traditional greenhouse about too high transpiration, except shading or whitewashing, which obviously lower assimilation.Fogging systems are a very effective tool to prevent water stress. Most commonly the steering of such systems is done by setting an upper limit to a measure of the deficit of humidity that, whenever exceeded, triggers the fogging system. The underlying assumption is that the deficit of humidity is a good indicator of potential evaporation, and limiting the deficit is equivalent to limit crop transpiration. It is known, however, that the same deficit of humidity can results in quite different potential evaporations, depending on other climate factors, particularly solar radiation, so that one may wonder whether static, pre-fixed set poin...

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“…By showing that manipulating the pressure in the root zone can compensate the effect of increased salinity on leaf elongation, Passioura & Munns (2000) have demonstrated that this response is solely due to cell water relations. Similarly, although on a different time scale, Li et al (2003) have shown that it was possible to modify the yield response to salinity in tomato by manipulating water outflow from the leaves, i.e. increased vapour pressure in the greenhouse air.…”

Section: Introductionmentioning

confidence: 99%

Salinity Effects on Fruit Yield in Vegetable Crops: A Simulation Study

Heuvelink¹,

Bakker²,

Stanghellini³

2003

Acta Hortic.

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Salinity can reduce crop growth and yield through its impact on plant water relations by: (1) increased fruit dry matter content, (2) reduced leaf expansion and (3) stomatal closure. In this simulation study the tomato model TOMSIM was used to predict salinity impact on fruit fresh yield, based on single or combined effects through plant water relations. The following influences were tested: Increase in fruit dry matter content (5% at EC=2 dS m -1 ) by 0.2% per dS m -1 ; decrease in specific leaf area (SLA) by 8% per dS m -1 starting from a threshold of 3 or 6 dS m -1 ; increase in stomatal resistance (r s ) by a factor 2 or 4 over the range 1 to 10 dS m -1 . Simulations showed threshold salinity levels of 2.9-4.4 dS m -1 , except when only r s or only SLA was affected (higher threshold). Impact of r s was small as total resistance for CO 2 import is determined by a series of resistances in which r s is rather small, under non-stressed conditions. Yield decline in % per dS m -1 varied between 1.9 and 17.8. When only an effect of salinity on r s was simulated this decline was lowest, whereas a salinity effect on SLA from EC=3 dS m -1 onwards, gave the strongest decline per unit rise in EC. Simulations showed that delayed leaf picking or increased plant density mitigate the negative effect of salinity via leaf expansion, as average leaf area index increases. For example, at EC=7 dS m -1 one week delay in leaf picking resulted in 10% yield increase (24.2 instead of 22.0 kg m -2 ), whereas at EC=9 dS m -1 this was 25% (14.7 instead of 11.8 kg m -2 ). Applicability of these results, if confirmed by targeted experiments, would not be limited to tomato as the processes described in the model are general.

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Plant water relations as affected by osmotic potential of the nutrient solution and potential transpiration in tomato (Lycopersicon esculentumMill.)

Cited by 15 publications

References 33 publications

Linking stem diameter variations to sap flow, turgor and water potential in tomato

Linking stem diameter variations to sap flow, turgor and water potential in tomato

Steering of Fogging: Control of Humidity, Temperature or Transpiration?

Salinity Effects on Fruit Yield in Vegetable Crops: A Simulation Study

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