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(Objective) Turgor pressure in crops varies with root water uptake as a response to occurrence of water stress. This paper investigates how turgor pressure in the leaf of celery responds to drip irrigation and the factors which affect the pressure variation. (Method) The experiment was conducted in a greenhouse. It consists of sufficient irrigation (FI) and deficit irrigation (NI) treatment. Change in leave turgor pressure, characterized by expansion parameters Pp and Pp*, in each treatment was measured using a probe. We also measured the environmental factors and physiological traits of the plant, and analyzed their relationship with Pp/Pp* using multiple regression, path analysis and time warping methods. (Result) 1 The parameter Pp* maximized at daytime and minimized at night on typical sunny days, regardless of the irrigation treatments and growing stage. However, Pp* started to increase earlier in NI than in FI treatment, with the peak of Pp* in the former being 39.3%~66.7% higher than that in the latter. 2 The diurnal change in Pp* was similar to that in the stomatal conductance (Gs) and transpiration rate (Tr). Pp* was positively correlated to Gs and Tr, but negatively to leaf water potential (Ψ). 3 The change in leaf turgor pressure varied with irrigation. The maximum and minimum Pp increased gradually priori to irrigation and decreased rapidly after irrigation, especially in the NI treatment where the change was more profound. 4 Pp* was positively correlated to atmospheric temperature (TA) and vapour pressure deficit (VPD), but negatively to relative humidity (RH) and wind speed (WS). Path analysis showed that the highest correlation between Pp* and TA, and VPD was an indirect factor affecting Pp*. Stepwise regression indicated that WS impacted Pp* significantly only in NI. We also found that the impact of TA on Pp* was not instant but existed a delay, especially in NI where the delay was more than 10~30 min than that in FI.(Conclusion) Variation in leaf turgor pressure in greenhouse celery was closely related to irrigation amount and meteorological factors. Insufficient irrigation increased the maximum turgor-pressure variation parameter but delayed the effect of atmospheric temperature on the turgor pressure. [ABSTRACT FROM AUTHOR]

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Copyright of Chinese Journal of Oil Crop Sciences is the property of Oil Crops Research Institute of Chinese Academy of Agricultural Sciences and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)