Effects of salt accumulation on the leaf water potential and transpiration rate of pot-grown wheat with a controlled saline groundwater table(Plant Nutrition)

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概要

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• We investigated the effects of continuous salt accumulation in the root zone of wheat. Leaf water potential and transpiration rate were measured in plants grown in an experimental pot system. Plants were grown in a controlled-environment glasshouse in sand-filled pots, in which the groundwater table was maintained at a desired depth. Saline water was recharged from the base, providing constant water content in the unsaturated root zone. At 52 days after sowing, the water table was set at a depth of 47cm from the soil surface. Groundwater and initial soil water were replaced with saline water with electrical conductivities (EC) of 0.2dS m^<-1> (Control [C]), 8dS m^<-1> (EC8) and 16dS m^<-1> (EC16). The daily transpiration rate, leaf water potential (Ψ_L) and EC of the soil water at a depth of 45cm were measured during the experiment. Stomatal behavior was expressed using the transpiration ratio E_t/E_<tc> (the ratio of the transpiration rates of EC8 and EC16 to that in the control). Our results indicated that Ψ_L and E_t/E_<tc> gradually decreased with increasing soil water EC as a result of transpiration and water uptake by the roots. The final Ψ_L values of EC8 and EC16 were -4.0MPa and -7.0MPa, respectively, and the final E_t/E_<tc> values of EC8 and EC16 were 0.3 and 0.2, respectively. E_t/E_<tc>, decreased with decreasing Ψ_L, and induced stomatal closure. The E_t/E_<tc> of the wheat was 0.5 when Ψ_L was -2.5MPa and 0.3 when Ψ_L was -3.0MPa. Although a reduction in Ψ_L from -1.5MPa to -3.0MPa caused a steep decline in E_t/E_<tc>, a subsequent reduction of Ψ_L to -7.0MPa caused only a minor reduction. This relationship between stomatal behavior and salt accumulation is similar to that reported in previous studies for plants grown in drought conditions. Changes in the transpiration ratio were expressed in an empirical equation as a function of Ψ_L.

著者

• Nishida Kazuhiro

  Graduate School Of Agricultural And Life Sciences The University Of Tokyo

• Khan Nasir

  Graduate School Of Agricultural And Life Sciences The University Of Tokyo

• Shiozawa Sho

  Graduate School Of Agricultural And Life Sciences The University Of Tokyo

関連論文

• Effects of salt accumulation on the leaf water potential and transpiration rate of pot-grown wheat with a controlled saline groundwater table(Plant Nutrition)

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