TY - JOUR

T1 - Changes in stomatal behaviour in the calcicole Leontodon hispidus due to the disruption by ozone of the regulation of apoplastic Ca2+ by trichomes.

AU - de Silva, D. L. R.

AU - Mansfield, T. A.

AU - McAinsh, Martin

PY - 2001/11

Y1 - 2001/11

N2 - Regulation of the concentration of Ca2+ in the apoplast of plants is essential in order to allow Ca2+-dependent processes, such as Ca2+-mediated signal transduction in stomatal guard cells, to function correctly. This is particularly important for plants growing with high levels of Ca2+ in the rhizosphere. Recently, we have shown that in two calcicoles, Leontodon hispidus L. and Centaurea scabiosa L., trichomes play a key role in this regulatory process. Ozone is known to have a marked effect on plant Ca2+ homeostasis. Therefore, we have examined the effect of this pollutant on the regulation by trichomes of apoplastic Ca2+ in the calcicole L. hispidus. Treatment with 100 nl l-1 ozone resulted in a reduction in stomatal conductance of approximately 25% in plants grown with 15 mM Ca2+ in the rhizosphere. Analysis of total Ca2+ levels revealed that these changes in stomatal behaviour reflect a decrease in the ability of trichomes to sequester Ca2+. The amount of Ca2+ present in the trichome tip cell was reduced by approximately 38%. This was accompanied by an increase in the levels of Ca2+ in the guard cells and other tissues of the leaf. These data suggest that ozone has a detrimental effect on the ability of trichomes to regulate the concentration of apoplastic Ca2+ in L. hispidus, resulting in altered stomatal behaviour, and hence gaseous exchange, possibly due to the disruption of guard-cell Ca2+-mediated signal transduction. This has important implications for the growth and survival of plants growing in Ca2+-rich soils.

AB - Regulation of the concentration of Ca2+ in the apoplast of plants is essential in order to allow Ca2+-dependent processes, such as Ca2+-mediated signal transduction in stomatal guard cells, to function correctly. This is particularly important for plants growing with high levels of Ca2+ in the rhizosphere. Recently, we have shown that in two calcicoles, Leontodon hispidus L. and Centaurea scabiosa L., trichomes play a key role in this regulatory process. Ozone is known to have a marked effect on plant Ca2+ homeostasis. Therefore, we have examined the effect of this pollutant on the regulation by trichomes of apoplastic Ca2+ in the calcicole L. hispidus. Treatment with 100 nl l-1 ozone resulted in a reduction in stomatal conductance of approximately 25% in plants grown with 15 mM Ca2+ in the rhizosphere. Analysis of total Ca2+ levels revealed that these changes in stomatal behaviour reflect a decrease in the ability of trichomes to sequester Ca2+. The amount of Ca2+ present in the trichome tip cell was reduced by approximately 38%. This was accompanied by an increase in the levels of Ca2+ in the guard cells and other tissues of the leaf. These data suggest that ozone has a detrimental effect on the ability of trichomes to regulate the concentration of apoplastic Ca2+ in L. hispidus, resulting in altered stomatal behaviour, and hence gaseous exchange, possibly due to the disruption of guard-cell Ca2+-mediated signal transduction. This has important implications for the growth and survival of plants growing in Ca2+-rich soils.

KW - Apoplastic Ca 2+

KW - Calcicole

KW - Leontodon (calcicole)

KW - Ozone

KW - Stomate

KW - Trichome

U2 - 10.1007/s004250100674

DO - 10.1007/s004250100674

M3 - Journal article

VL - 214

SP - 158

EP - 162

JO - Planta

JF - Planta

SN - 0032-0935

IS - 1

ER -