TY  - JOUR
A1  - Ballach, Hans-Joachim
A1  - Oppenheimer, Simone
A1  - Mooi, Jan
T1  - Reactions of cloned poplars to air pollution: Premature leaf loss and investigations of the nitrogen metabolism
T2  - Zeitschrift für Naturforschung, C
N2  - Young poplar cuttings (Populus nigra L. cv. Loenen and P. maximowiczii Henry x P. nigra L. cv. Rochester) were exposed for six weeks in open-top chambers to realistic concentrations of pollutant mixtures: 1) control; 2) SO2/NOx; 3)O3/ NOx and 4)SO2/O3/NOx. In this sequence of fumigation variants, the degree of influence of the various parameters of the nitrogen metabolism and of premature leaf drop increased very frequently compared to the control plants, P. nigra L. proving to be the more sensitive species.
The elevated Kjeldahl nitrogen content of the fumigated leaves was accompanied by either an increase in free amino acids or in total protein or, in the case of particularly large rises (SO2/O3/NOx variants), by increases in both substance groups. Proteolytic processes as a cause of the elevated content of free amino acids could be excluded to a large extent. A diminished de novo synthesis of proteins obviously led to a shift in the amino acid/protein relationship. In the younger fumigated leaves, the total concentration of free amino acids exceeded the values of the older leaves. The elevated amino acid content of the fumigated leaves was produced to a high degree by the glycolate pathway and the Krebs cycle. The increased turnover of the carbon skeletons was connected with a drastic starch degradation, especially in the older leaves.
The interaction of the amino acid and carbohydrate metabolisms is probably an important regulator in the promotion of rapid growth of young leaves in order to compensate premature leaf loss.
KW  - Populus nigra L. cv. Loenen
KW  - P. maximowiczii Henry x P. nigra L. cv. Rochester
KW  - Air Pollutants
KW  - Nitrogen Metabolism
KW  - Premature Leaf Drop
Y1  - 2014
UR  - http://publikationen.ub.uni-frankfurt.de/frontdoor/index/index/docId/79928
UR  - https://nbn-resolving.org/urn:nbn:de:hebis:30:3-799280
SN  - 0939-5075
SN  - 1865-7125
VL  - 47.1992
IS  - 1-2
SP  - 109
EP  - 119
PB  - Verlag der Zeitschrift für Naturforschung
CY  - Tübingen
ER  -