Some important biochemical changes orchestrating flower development and senescence in Nicotiana plumbaginifolia Viv. and Petunia hybrida Vilm. flowers

Abstract

ABSTRACT A comparative study of some biochemical parameters and expression patterns during flower development and senescence in Nicotiana plumbaginifolia and Petunia hybrida was carried out to ascertain the differences between the two important ornamentals. Lipid peroxidation (LPO) was found to increase throughout flower development and senescence in P. hybrida whereas in N. plumbaginifolia it decreased towards flower opening and showed a sharp increase towards senescence. Membrane stability index showed a marginal decrease towards senescence in the flowers of both the plants. Activities of the antioxidant enzymes (superoxide dismutase, catalase, ascorbate peroxidase, and lipoxygenase) increased up to the open flower stage (stage IV) and decreased thereafter towards the senescent stage in the flowers from both the plant species. The pre-senescent stages in flowers from both the plants did not show up the detection of ethylene in the petal tissues on gas chromatograph while as a climacteric rise in the ethylene concentration was exhibited by the senescent stages of both the flowers under study. mRNA-transcripts of senescence associated gene DAD1 were found to accumulate in the open flower stage (stage IV) in N. plumbaginifolia and those of ETR1 and SAG12 were found to accumulate in the open flower stage (stage IV) in P. hybrida.