Kinetics and mechanisms of cowpea root adaptation to changes in solution calcium

Blamey, F. Pax C., Wehr, J. Bernhard, Wang, Peng, Menzies, Neal W. and Kopittke, Peter M. (2014) Kinetics and mechanisms of cowpea root adaptation to changes in solution calcium. Plant and Soil, 379 1-2: 301-314. doi:10.1007/s11104-014-2065-1


Author Blamey, F. Pax C.
Wehr, J. Bernhard
Wang, Peng
Menzies, Neal W.
Kopittke, Peter M.
Title Kinetics and mechanisms of cowpea root adaptation to changes in solution calcium
Journal name Plant and Soil   Check publisher's open access policy
ISSN 0032-079X
1573-5036
Publication date 2014-06-01
Year available 2014
Sub-type Article (original research)
DOI 10.1007/s11104-014-2065-1
Volume 379
Issue 1-2
Start page 301
End page 314
Total pages 14
Place of publication Dordrecht Netherlands
Publisher Springer Netherlands
Collection year 2015
Language eng
Formatted abstract
Background and aims

Close regulation of cellular Ca in roots is required in the face of marked changes in soil solution Ca over time and space. This study’s aims were to quantify and gain insights into the ways in which roots respond to changes in solution Ca.

Methods

Root elongation rate (RER) of cowpea (Vigna unguiculata (L.) Walp.) seedlings was determined at 0.05 to 15 mM Ca for up to 24 h both without and with added K, Mg, or Na. Root tip concentrations of Ca, K, Mg, and Na were determined and binding of cations by root tips estimated by subsequent Cu sorption.

Results

Transfer from higher to lower Ca solutions (and with added K at high Ca) resulted in RER ≥ 2 mm h−1 within minutes. This was attributed to greater cell wall relaxation through lower Ca binding aided by a decrease to pH ≤ 5.1 in solution. Transfer to higher Ca solutions, which remained at ~pH 5.6, led to an equally rapid decrease in RER to ~0.5 mm h−1, an effect ascribed to greater cell wall binding of Ca. Thereafter, a gradual increase in RER to ~1.8 mm h−1 occurred over 24 h, an effect likely due to reduced cell wall Ca binding as shown by decreasing Cu sorption at a rate of 0.027 mmol Cu kg−1 FM h−1 over 24 h.

Conclusion

The kinetics of changes in RER and cations in root tips suggest that roots respond to changes in solution Ca through effects on cell wall relaxation of the rhizodermis and outer cortex in the elongation zone.
Keyword Calcium
Cowpea
Magnesium
Potassium
Sodium
Root growth
Q-Index Code C1
Q-Index Status Confirmed Code
Institutional Status UQ

Document type: Journal Article
Sub-type: Article (original research)
Collections: School of Agriculture and Food Sciences
Official 2015 Collection
 
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