caa a22 4500 463171926 CHVBK 20180406164815.0 cr unu---uuuuu 170326e20071201xx s 000 0 eng 10.1007/s00344-007-9016-5 doi (NATIONALLICENCE)springer-10.1007/s00344-007-9016-5 Plant Growth Regulators and Induction of Leaf Senescence in Nitrogen-Deprived Wheat Plants [Elektronische Daten] [M. Criado, Irma Roberts, Mariela Echeverria, Atilio Barneix] The sequence of events and the signals that regulate the remobilization of nitrogen (N) reserves during senescence induced by N starvation were studied in leaf 3, the last fully expanded leaf, in 17-day-old wheat (Triticum aestivum L.) plants. The first event observed was a rapid decrease in the isopentenyl adenosine (iPA) concentration during the first 24 h of N starvation. No differences in t-zeatin riboside and dihydrozeatin riboside concentrations were observed until the end of the assay. During the following 6 days, a decrease in soluble amino acids, chlorophyll, and protein, as well as an increase in soluble sugar concentration and endoproteolytic activity, could be observed. At day 3 of the experiment, the abscisic acid (ABA) concentration in the leaves of N-deprived plants started to increase. After 6 days of N deprivation there was a rise in oxidative stress, as indicated by the increase in malondialdehyde concentration, as well as a decrease in the activities of antioxidant enzymes catalase and ascorbate peroxidase. To analyze interactions with leaf development, the first, second, third, and fourth leaves were studied. iPA concentration decreased in all the leaf stages, including leaf 4, which was not fully expanded. A linear correlation between iPA and protein concentration was determined. These results suggest that the sharp fall in iPA could be the earliest event that induces protein degradation during the development of senescence induced by N deficiency, and that only later is ABA accumulated and oxidative stress developed. Springer Science+Business Media, LLC, 2007 Abscisic acid nationallicence Cytokinin nationallicence Nitrogen deprivation nationallicence Oxidative stress nationallicence Senescence nationallicence Wheat nationallicence Criado M. IBYF-CONICET, Facultad de Agronomía, Universidad de Buenos Aires, Av. San Martín 4453, C1417DSE, Buenos Aires, Argentina aut Roberts Irma IBYF-CONICET, Facultad de Agronomía, Universidad de Buenos Aires, Av. San Martín 4453, C1417DSE, Buenos Aires, Argentina aut Echeverria Mariela IBYF-CONICET, Facultad de Agronomía, Universidad de Buenos Aires, Av. San Martín 4453, C1417DSE, Buenos Aires, Argentina aut Barneix Atilio IBYF-CONICET, Facultad de Agronomía, Universidad de Buenos Aires, Av. San Martín 4453, C1417DSE, Buenos Aires, Argentina aut Journal of Plant Growth Regulation Springer-Verlag 26/4(2007-12-01), 301-307 0721-7595 26:4<301 2007 26 344 https://doi.org/10.1007/s00344-007-9016-5 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s00344-007-9016-5 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Criado M. IBYF-CONICET, Facultad de Agronomía, Universidad de Buenos Aires, Av. San Martín 4453, C1417DSE, Buenos Aires, Argentina aut NATIONALLICENCE 700 1- Roberts Irma IBYF-CONICET, Facultad de Agronomía, Universidad de Buenos Aires, Av. San Martín 4453, C1417DSE, Buenos Aires, Argentina aut NATIONALLICENCE 700 1- Echeverria Mariela IBYF-CONICET, Facultad de Agronomía, Universidad de Buenos Aires, Av. San Martín 4453, C1417DSE, Buenos Aires, Argentina aut NATIONALLICENCE 700 1- Barneix Atilio IBYF-CONICET, Facultad de Agronomía, Universidad de Buenos Aires, Av. San Martín 4453, C1417DSE, Buenos Aires, Argentina aut NATIONALLICENCE 773 0- Journal of Plant Growth Regulation Springer-Verlag 26/4(2007-12-01), 301-307 0721-7595 26:4<301 2007 26 344 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer