Effect of abscisic acid on photosynthetic parameters during ex vitro transfer of micropropagated tobacco plantlets.
Abstract
The aim of this research was to determine whether exogenous abscisic acid (ABA) applied immediately after ex vitro transfer of in vitro grown plants can improve their acclimatization. Tobacco (Nicotiana tabacum L.) plantlets were transferred into pots with Perlite initially moistened either by water or 50 A mu M ABA solution and they were grown under low (LI) or high (HI) irradiance of 150 and 700 A mu mol m(-2) s(-1), respectively.
Endogenous content of ABA in tobacco leaves increased considerably after ABA application and even more in plants grown under HI. Stomatal conductance, transpiration rate and net photosynthetic rate decreased considerably 1 d after ex vitro transfer and increased thereafter.
The gas exchange parameters were further decreased by ABA application and so wilting of these plants was limited. Chlorophyll (a+b) and beta-carotene contents were higher in ABA-treated plants, but the content of xanthophyll cycle pigments was not increased.