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. 1984 Apr;74(4):882–889. doi: 10.1104/pp.74.4.882

Transpiration- and Growth-Induced Water Potentials in Maize 1

Mark E Westgate 1,2,3,2, John S Boyer 1,2,3
PMCID: PMC1066786  PMID: 16663527

Abstract

Recent evidence from leaves and stems indicates that gradients in water potential (ψw) necessary for water movement through growing tissues are larger than previously assumed. Because growth is sensitive to tissue ψw and the behavior of these gradients has not been investigated in transpiring plants, we examined the water status of all the growing and mature vegetative tissues of maize (Zea mays L.) during high and low rates of transpiration. The ψw measured in the mature regions of the plant responded primarily to transpiration, while the ψw in the growing regions was affected both by transpiration and growth. The transpiration-induced potentials of the mature tissue formed a gradient of decreasing ψw along the transpiration stream while the growth-induced potentials formed a gradient of decreasing ψw from the transpiration stream to the expanding cells in the growing tissue. The growth-induced gradient in ψw within the leaf remained fairly constant as the xylem ψw decreased during the day and was associated with a decreased osmotic potential (ψs) of the growing region (osmotic adjustment). The growth-induced gradient in ψw was not caused by excision of the tissue because intact maize stems exhibited a similar ψw. These observations support the concept that large gradients in ψw are required to maintain water flow to expanding cells within all the vegetative tissues and suggest that the maintenance of a favorable gradient in ψw for cell enlargement may be an important role for osmotic adjustment.

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Selected References

These references are in PubMed. This may not be the complete list of references from this article.

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