Quantitative analysis of abscisic acid in needles of Abies alba Mill. by electron capture gas chromatography

Abstract

Summary. The amount of abscisic acid (ABA) in needles of silver fir from a natural location was investigated with regard to position in the crown, damage, seasonal variation, and needle age. Because of problems of quantification of ABA in coniferous needles, which contain numerous secondary plant products, a method for reliable determination of both isomers cis-trans-ABA (c-ABA) and transtrans-ABA (t-ABA) was developed. By means of gas chromatography (GC) using an electron capture detector (ECD) and a programmed temperature vaporizer (PTV) injector complete separation of both compounds was achieved. Two different pairs of fir were investigated -in each case a damaged and a healthy tree. Needles from both trees from the first and the second pair collected in September contained 500-1100 ng c-ABA/g fresh weight (FW), and the concentrations of t-ABA varied from 400 to 700 ng/g FW. Investigations from the second pair show highest amounts of 2900 ng/g Fw c-ABA and 1800 ng/g FW of t-ABA in May and June. For the first pair a higher c-ABA content was found in needles from the top of the crown than in those from the middle and the base. This difference could not be confirmed in the analysis of the second pair. Because of the strong natural deviation no statistically significant difference between the healthy and the damaged tree was found. The first pair of firs examined showed a higher t-ABA concentration than the second one. In this case the highest amount was found in the top of the crown. Methodical mistakes during the clean-up procedure and in quantification by gas chromatography could be excluded. The presence of c-and t-ABA in the purified extract was corroborated by mass spectrometry. With regard to the seasonal variation both isomers of ABA show an unequivocal trend. The maximum concentration is achieved in May to June, whereas the content is minimal inCorrespondence to: H. Ziegler August/September. In any case the level of t-ABA is lower than that of c-ABA. No correlation between the amount of ABA and the needle age could be established.

Seasonal changes in needle water content and needle ABA concentration of Japanese red pine, Pinus densiflora, in declining forests on Mt. Gokurakuji, Hiroshima prefecture, Japan

“…In fact, in our preliminary experiments during which irrigation was stopped for 1 week, concentration of ABA in needles of 10-year-old P. densiflora seedlings exceeded 2,000 ng/g −1 DM, and WC of the needles decreased. However, Kraus and Ziegler (1993) showed that the maximum concentration in needles of silver fir (Abies alba) was achieved in May to June whereas the content was minimal in August/September. This results is similar to our results although they could not detect significant correlation between the amount of ABA and the needle age.…”

Augmentation of abscisic acid (ABA) levels by drought does not induce short-term stomatal sensitivity to CO2 in two divergent conifer species

“…The possibility of a missing or inactive signalling pathway in the stomata of conifers leads to the final explanation for the contrast between the angiosperm and two conifer species: a fundamental difference in stomatal control by ABA between the two lineages. A limited number of studies have investigated ABA f in conifers using physicochemical methods ( Kraus and Ziegler, 1993 ; Hoffman et al , 1999 ; Kong et al , 2009 ). These studies all indicate that ABA f in conifers, including Pinaceae ( Kraus and Ziegler, 1993 ; Kong et al , 2009 ) and Taxaceae ( Hoffman et al , 1999 ) species, were typically >400 ng g −1 fresh weight under well-watered conditions.…”

“…A limited number of studies have investigated ABA f in conifers using physicochemical methods ( Kraus and Ziegler, 1993 ; Hoffman et al , 1999 ; Kong et al , 2009 ). These studies all indicate that ABA f in conifers, including Pinaceae ( Kraus and Ziegler, 1993 ; Kong et al , 2009 ) and Taxaceae ( Hoffman et al , 1999 ) species, were typically >400 ng g −1 fresh weight under well-watered conditions. This is in contrast to angiosperm species under similar unstressed conditions for which ABA f is typically <100 ng g −1 .…”

Evolution of the Stomatal Regulation of Plant Water Content

“…The third requirement relates to the speed of ABA synthesis over a timeframe that matches apparent ABA-driven stomatal responses. In terms of changing soil water deficit (over days), this condition is met in all vascular land plants ( Kraus and Ziegler, 1993;Hoffman et al, 1999;Kong et al, 2009;McAdam and Brodribb, 2013), but only in angiosperm does ABA synthesis appear to occur over a timeframe that corresponds to the dynamics of stomatal response to VPD .…”