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Comparative effects of deficit irrigation and alternate partial root-zone irrigation on xylem pH, ABA and ionic concentrations in tomatoes.

Wang Y, Liu F, Jensen CR - J. Exp. Bot. (2011)

Bottom Line: Results showed that PRI plants had similar or significantly higher xylem pH, which was increased by 0.2 units relative to DI plants.In most cases, the xylem ABA concentration was similar for PRI and DI plants, and a clear association between increases in xylem pH with increasing xylem ABA concentration was only found when the soil water content was relatively low.It is therefore essential that the soil water content in the wet zone should be maintained relatively high while that in the drying soil zone should not be very low, both conditions are crucial to maintain high soil and plant water status while sustaining ABA signalling of the plants.

View Article: PubMed Central - PubMed

Affiliation: Department of Agriculture and Ecology, University of Copenhagen, Taastrup, Denmark. wang_yao_sheng@yahoo.com.cn

ABSTRACT
Comparative effects of partial root-zone irrigation (PRI) and deficit irrigation (DI) on xylem pH, ABA, and ionic concentrations of tomato (Lycopersicon esculentum L.) plants were investigated in two split-root pot experiments. Results showed that PRI plants had similar or significantly higher xylem pH, which was increased by 0.2 units relative to DI plants. Nitrate and total ionic concentrations (cations+anions), and the proportion of cations influenced xylem pH such that xylem pH increases as nitrate and total ionic concentrations decrease, and the proportion of cations increases. In most cases, the xylem ABA concentration was similar for PRI and DI plants, and a clear association between increases in xylem pH with increasing xylem ABA concentration was only found when the soil water content was relatively low. The concentrations of anions, cations, and the sum of anions and cations in PRI were higher than in the DI treatment when soil water content was relatively high in the wetted soil compartment. However, when water content in both soil compartments of the PRI pots were very low before the next irrigation, the acquisition of nutrients by roots was reduced, resulting in lower concentrations of anions and cations in the PRI than in the DI treatment. It is therefore essential that the soil water content in the wet zone should be maintained relatively high while that in the drying soil zone should not be very low, both conditions are crucial to maintain high soil and plant water status while sustaining ABA signalling of the plants.

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Relationships between biophysical parameters measured in tomato plants under DI and PRI treatments in Exps I and II. MN and ON indicate mineral and organic N fertilizer treatment, respectively. ** Significance of lines at P <0.01. For Fig. 3E, the regression line was made from the data points of Exp. I.
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fig4: Relationships between biophysical parameters measured in tomato plants under DI and PRI treatments in Exps I and II. MN and ON indicate mineral and organic N fertilizer treatment, respectively. ** Significance of lines at P <0.01. For Fig. 3E, the regression line was made from the data points of Exp. I.

Mentions: When analysed on the data across the two experiments, it was found that RWP declined exponentially with decreasing averaged soil water content in the whole pot (Fig. 4A), and was positively correlated with LWP and the sum of anions and cations in the xylem (Fig. 4B, C) while negatively correlated with xylem ABA concentration (Fig. 4D). Significant positive linear relationship between xylem pH and the xylem ABA concentration was only found in Exp. I (Fig. 4E). There was a significant negative linear relationship between nitrate concentration and xylem pH (Fig. 4F). Moreover, a significant negative linear relationship was also observed between the sum of anions and cations and the xylem pH (Fig. 4G); while there was a significant positive linear relationship between the proportion of cations to the total ions in the xylem and the xylem pH (Fig. 4H). In addition, a significant positive linear relationship was found between the concentrations of the total anions and the total cations (Fig. 4I).


Comparative effects of deficit irrigation and alternate partial root-zone irrigation on xylem pH, ABA and ionic concentrations in tomatoes.

Wang Y, Liu F, Jensen CR - J. Exp. Bot. (2011)

Relationships between biophysical parameters measured in tomato plants under DI and PRI treatments in Exps I and II. MN and ON indicate mineral and organic N fertilizer treatment, respectively. ** Significance of lines at P <0.01. For Fig. 3E, the regression line was made from the data points of Exp. I.
© Copyright Policy - creative-commons
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC3295386&req=5

fig4: Relationships between biophysical parameters measured in tomato plants under DI and PRI treatments in Exps I and II. MN and ON indicate mineral and organic N fertilizer treatment, respectively. ** Significance of lines at P <0.01. For Fig. 3E, the regression line was made from the data points of Exp. I.
Mentions: When analysed on the data across the two experiments, it was found that RWP declined exponentially with decreasing averaged soil water content in the whole pot (Fig. 4A), and was positively correlated with LWP and the sum of anions and cations in the xylem (Fig. 4B, C) while negatively correlated with xylem ABA concentration (Fig. 4D). Significant positive linear relationship between xylem pH and the xylem ABA concentration was only found in Exp. I (Fig. 4E). There was a significant negative linear relationship between nitrate concentration and xylem pH (Fig. 4F). Moreover, a significant negative linear relationship was also observed between the sum of anions and cations and the xylem pH (Fig. 4G); while there was a significant positive linear relationship between the proportion of cations to the total ions in the xylem and the xylem pH (Fig. 4H). In addition, a significant positive linear relationship was found between the concentrations of the total anions and the total cations (Fig. 4I).

Bottom Line: Results showed that PRI plants had similar or significantly higher xylem pH, which was increased by 0.2 units relative to DI plants.In most cases, the xylem ABA concentration was similar for PRI and DI plants, and a clear association between increases in xylem pH with increasing xylem ABA concentration was only found when the soil water content was relatively low.It is therefore essential that the soil water content in the wet zone should be maintained relatively high while that in the drying soil zone should not be very low, both conditions are crucial to maintain high soil and plant water status while sustaining ABA signalling of the plants.

View Article: PubMed Central - PubMed

Affiliation: Department of Agriculture and Ecology, University of Copenhagen, Taastrup, Denmark. wang_yao_sheng@yahoo.com.cn

ABSTRACT
Comparative effects of partial root-zone irrigation (PRI) and deficit irrigation (DI) on xylem pH, ABA, and ionic concentrations of tomato (Lycopersicon esculentum L.) plants were investigated in two split-root pot experiments. Results showed that PRI plants had similar or significantly higher xylem pH, which was increased by 0.2 units relative to DI plants. Nitrate and total ionic concentrations (cations+anions), and the proportion of cations influenced xylem pH such that xylem pH increases as nitrate and total ionic concentrations decrease, and the proportion of cations increases. In most cases, the xylem ABA concentration was similar for PRI and DI plants, and a clear association between increases in xylem pH with increasing xylem ABA concentration was only found when the soil water content was relatively low. The concentrations of anions, cations, and the sum of anions and cations in PRI were higher than in the DI treatment when soil water content was relatively high in the wetted soil compartment. However, when water content in both soil compartments of the PRI pots were very low before the next irrigation, the acquisition of nutrients by roots was reduced, resulting in lower concentrations of anions and cations in the PRI than in the DI treatment. It is therefore essential that the soil water content in the wet zone should be maintained relatively high while that in the drying soil zone should not be very low, both conditions are crucial to maintain high soil and plant water status while sustaining ABA signalling of the plants.

Show MeSH
Related in: MedlinePlus