TY - JOUR

T1 - Stomata of micropropagated Delphinium plants respond to abscisic acid (ABA), CO2, light and water potential but fail to close fully.

AU - Santamaria, J. M.

AU - Davies, W. J.

AU - Atkinson, C. J.

PY - 1993

Y1 - 1993

N2 - Morphological and physiological characteristics of micropropagated plants of Delphinium cv. Princess Caroline were studied. Leaves produced in vitro showed poor control of water loss which appears to result from restricted responses by stomata and not from poor cuticular development. Stomata of leaves produced in vitro were larger and more frequent than those produced during acclimatization. Despite the fact that stomata from isolated epidermis of leaves produced in vitro reduced their apertures when exposed to turgor-reducing treatments, they did not close fully. This, together with high stomatal frequencies might explain the poor control of water loss shown by intact leaves produced in culture when exposed to dry air. While leaves from acclimatized plants showed almost complete closure with ABA, low water potentials, darkness and CO2, stomata from leaves produced in vitro reduced their apertures when exposed to those factors, but only to a limit. Therefore, stomata from leaves cultured in vitro seem to be partially functional, but some physiological or anatomical alteration prevents them from closing fully. Stomata from leaves produced in vitro were particularly insensitive to ABA which appears to be partly associated with the high cytokinin concentration in the culture medium. In the long-term, this stomatal insensitivity to ABA might contribute to plant losses when micropropagated plantlets are transferred to soil.

AB - Morphological and physiological characteristics of micropropagated plants of Delphinium cv. Princess Caroline were studied. Leaves produced in vitro showed poor control of water loss which appears to result from restricted responses by stomata and not from poor cuticular development. Stomata of leaves produced in vitro were larger and more frequent than those produced during acclimatization. Despite the fact that stomata from isolated epidermis of leaves produced in vitro reduced their apertures when exposed to turgor-reducing treatments, they did not close fully. This, together with high stomatal frequencies might explain the poor control of water loss shown by intact leaves produced in culture when exposed to dry air. While leaves from acclimatized plants showed almost complete closure with ABA, low water potentials, darkness and CO2, stomata from leaves produced in vitro reduced their apertures when exposed to those factors, but only to a limit. Therefore, stomata from leaves cultured in vitro seem to be partially functional, but some physiological or anatomical alteration prevents them from closing fully. Stomata from leaves produced in vitro were particularly insensitive to ABA which appears to be partly associated with the high cytokinin concentration in the culture medium. In the long-term, this stomatal insensitivity to ABA might contribute to plant losses when micropropagated plantlets are transferred to soil.

KW - Micropropagation

KW - stomatal physiology

KW - dehydration

KW - PEG

KW - ABA

KW - BAP

KW - darkness

KW - CO2

KW - Delphinium

U2 - 10.1093/jxb/44.1.99

DO - 10.1093/jxb/44.1.99

M3 - Journal article

VL - 44

SP - 99

EP - 107

JO - Journal of Experimental Botany

JF - Journal of Experimental Botany

SN - 1460-2431

IS - 1

ER -