Similar articles

Abstract: leaf senescence is often caused by water deficit and the chimeric gene p_SAG12-IPT is an auto-regulated gene delaying leaf senescence. Using in vitro leaf discs culture system, the changes of contents of chlorophylls, carotenoids, soluble protein and thiobarbituric acid reactive substance (TBARS) and antioxidant enzymes activities were investigated during leaf senescence of P_SAGl2-IPT modified gerbera induced by osmotic stress compared with the control plant (wild type). leaf discs were incubated in 20%, 40% (w/v) polyethylene glycol (PEG) 6 000 nutrient solution for 20 h under continuous light [130 µmol/(m²·s)]. The results showed that the contents of chlorophylls, carotenoids and soluble protein were decreased by osmotic stress with the decrease being more pronounced at 40% PEG, but that, at the same PEG concentration the decrease in the transgenic plants was significantly lower than that in the control plant. The activities of superoxide dismutase (SOD), catalases (CAT), ascorbate peroxidase (APX), guaiacol peroxidase (GPX) and dehydroascorbate reductase (DHAR) were stimulated by PEG treatment. However, the increases were higher in p_SAG12-IPT transgenic plants than in the control plants, particularly at 40% PEG treatment. Lipid peroxidation (TBARS content) was increased by PEG treatment with the increase being much lower in transgenic plant than in the control plant. It could be concluded that the increases in the activities of antioxidant enzymes including SOD, CAT, APX, GPX and DHAR were responsible for the delay of leaf senescence induced by osmotic stress.

[1] Allen, R.G., Balin, A.K., 1989. Oxidative influence on development and differentiation: an overview of a free radical theory of development. Free Radic. Biol. Med., 6(6):631-661.

[2] Alscher, R.G., Erturk, N., Heath, L.S., 2002. Role of superoxide dismutases in controlling oxidative stress in plants. J. Exp. Bot., 53(372):1331-1341.

[3] Aziz, A., Larher, F., 1998. Osmotic stress induced changes in lipid composition and peroxidation in leaf discs of Brassica napus L. J. Plant Physiol., 153(5):754-762.

[4] Behera, S.K., Nayak, L., Biswal, B., 2003. Senescing leaves possess potential for stress adaptation: the developing leaves acclimated to high light exhibit increased tolerance to osmotic stress during senescence. J. Plant Physiol., 160(2):125-131.

[5] Bradford, M.M., 1976. A rapid and sensitive method for the quantitation of micogram quantities of protein utilizing the principle of protein-dye binding. Anal. Biochem., 72(1-2):248-254.

[6] de Haan, J.B., Cristiano, F., Iannello, R., Bladier, C., Kelner, M.J., Kola, I., 1996. Elevation in the ratio of Cu/Zn-superoxide dismutase to glutathione peroxidase activity induces features of cellular senescence and this effect is mediated by hydrogen peroxide. Hum. Mol. Genet., 5(2):283-292.

[7] Dertinger, U., Schaz, U., Schulz, E.D., 2003. Age-dependence of the antioxidative system in tobacco with enhanced glutathione reductase activity or senescence-induced production of cytokinins. Physiol. Plant., 119(1):19-29.

[8] Dong, H.Z., Li, W.J., Tang, W., Li, Z.H., Zhang, D.M., Niu, Y.H., 2006. Yield, quality and leaf senescence of cotton grown at varying planting dates and plant densities in the Yellow River Valley of China. Field Crops Res., 98(2-3):106-115.

[9] Foyer, C.H., Lelandais, M., Kunert, K.J., 1994. Photooxidative stress in plants. Physiol. Plant., 92(4):696-717.

[10] Gan, S., Amasino, R.M., 1995. Inhibition of leaf senescence by autoregulated production of cytokinin. Science, 270(5244):1986-1988.

[11] Gan, S., Amasino, R.M., 1997. Making sense of senescence. Plant Physiol., 113(2):313-319.

[12] Guo, Y.F., Gan, S.S., 2005. Leaf senescence: signals, execution, and regulation. Current Topics in Developmental Biology, 71:83-112.

[13] Huguet-Robert, V., Sulpice, R., Lefort, C., Maerskalck, V., Emery, N., Larher, F.R., 2003. The suppression of osmoinduced proline response of Brassica napus L. var oleifera leaf discs by polyunsaturated fatty acids and methyljasmonate. Plant Sci., 164(1):119-127.

[14] Jandrew, J., Clark, D.G., 2001. Selectively induced nutrient deficiency in transgenic P_SAG12-IPT, P_SAG13-IPT and P_SAG12-Kn1 petunias. HortSci., 36:518-519.

[15] Lascano, H.R., Antonicelli, G.E., Luna, C.M., Melchiorre, M.N., Gómez, L.D., Racca, R.W., Trippi, V.S., Casano, L.M., 2001. Antioxidant system response of different wheat cultivars under drought: field and in vitro studies. Aust. J. Plant. Physiol., 28(11):1095-1102.

[16] Li, W.X., Zhang, M., Yu, H.Q., 2006. Study on hypobaric storage of green asparagus. J. Food Eng., 73(3):225-230.

[17] Lichtenthaler, H.K., 1987. Chlorophylls and carotenoids: pigments of photosynthetic biomembranes. Meth. Enzymol., 148:350-382.

[18] Ludewig, F., Sonnewald, U., 2000. High CO₂-mediated down-regulation of photosynthetic gene transcripts is caused by accelerated leaf senescence rather than sugar accumulation. FEBS Letters, 479(1-2):19-24.

[19] McCabe, M.S., Garratt, L.C., Schepers, F., Jordi, W.J.R.M., Stoopen, G.M., Davelaar, E., van Rhijn, J.H.A., Power, J.B., Davey, M.R., 2001. Effects of P_SAG12-IPT gene expression on development and senescence in transgenic lettuce. Plant Physiol., 127(2):505-516.

[20] Mignotte, B., Vayssiere, J.L., 1998. Mitochondria and apoptosis. Eur. J. Biochem., 252(1):1-15.

[21] Nakano, Y., Asada, K., 1981. Hydrogen peroxide scanvenged by ascorbated specific peroxidase in spinach chloroplast. Plant Cell Physiol., 22(5):867-880.

[22] Nickel, R.S., Cunningham, B.A., 1969. Improved peroxidase assay method using Ieuco 2,3,6-trichlcroindophenol and application to comparative measurements of peroxidase catalysis. Anal. Biochem., 27(2):292-299.

[23] Pastori, G.M., Rio, L.A., 1997. Natural senescence of pea leaves, an activated oxygen-mediated function for peroxisomes. Plant Physiol., 113(2):411-418.

[24] Patra, H.L., Kar, M., Mishre, D., 1978. Catalase activity in leaves and cotyledons during plant development and senescence. Biochem. Physiol., 172(4):385-390.

[25] Shalata, A., Tal, M., 1998. The effect of salt stress on lipid peroxidation and antioxidants in the leaf of the cultivated tomato and its wild salt-tolerant relative Lycopersicon pennellii. Physiol. Plant., 104(2):169-174.

[26] Shibanuma, M., Kuroki, T., Nose, K., 1990. Stimulation by hydrogen peroxide of DNA synthesis, competence family gene expression and phosphorylation of a specific protein in quiescent Balb/3T3 cells. Oncogene, 5(7):1025-1032.

[27] Stewart, R.C., Bewley, J.D., 1980. Lipid peroxidation associated with accelerated aging of soybean axes. Plant Physiol., 65(2):245-248.

[28] Sun, Y., 1990. Free radicals, antioxidant enzymes, and carcinogenesis. Free Radic. Biol. Med., 8(6):583-599.

[29] Thomas, J.C., Smigoli, A.C., Bohnert, H.J., 1995. Light-inducible expression of ipt from Agrobacterium tumefaciens results in cytokinin accumulation and osmotic stress symptoms in transgenic tobacco. Plant Mol. Biol., 27(2):225-235.

[30] Toit, E.S., Robbertse, P.J., Niederwieser, J.G., 2004. Temperature regime during bulb production affects foliage and flower quality of Lachenalia cv. Ronina pot plants. Scientia Horticulturae, 102(4):441-448.

[31] Turtola, S., Rousi, M., Pusenius, J., Yamaji, K., Heiska, S., Tirkkonen, V., Meier, B., Riitta, J.T., 2006. Genotypic variation in drought response of willows grown under ambient and enhanced UV-B radiation. Environmental and Experimental Botany, 56(1):80-86.

[32] Wang, J., Letham, D.S., Cornish, E., Stevenson, K.R., 1997. Studies of cytokinin action and metabolism using tobacco plants expressing either the ipt or the GUS gene controlled by a chalcone synthase promoter I developmental features of the transgenic plants. Plant Physiol., 24(5):661-672.

[33] Zhu, Z.J., Gerendas, J., Bendixen, R., Schinner, K., Tabrizi, H., Sattelmacher, B., Hansen, U.P., 2000. Different tolerance to light stress in NO₃^- and NH₄⁺-grown Phaseolus vulgaris L. Plant Biol., 2(5):558-570.