Programme of senescence in petals and carpels of Pisum sativum L. flowers and its control by ethylene

Abstract

The role of ethylene in the control of senescence of both petals and unpollinated carpels of pea was investigated. An increase in ethylene production accompanied senescence, and the inhibitors of ethylene action were effective in delaying senescence symptoms in different flower verticils. Pollination did not seem to trigger the senescence syndrome in the corolla as deduced from the observation that petals from pollinated and unpollinated flowers and from flowers whose carpels had been removed senesced at the same time. A cDNA clone encoding a putative ethylene-response sensor (psERS) was isolated from pea flowers, and the pattern of expression of its mRNA was studied during development and senescence of different flower tissues. The levels of psERS mRNA paralleled ethylene production (and also levels of 1-aminocyclopropane-1-carboxylic acid oxidase (ACO) mRNA) in both petals and styles. Silver thiosulfate treatments were efficient at preventing ACO and psERS mRNA induction in petals. However, the same inhibitor showed no ability to modify expression patterns in pea carpels around the anthesis stage, suggesting different controls for ethylene synthesis and sensitivity in different flower organs.

Cellular and subcellular localisation of glutamine synthetase and glutamate dehydrogenase in grapes gives new insights on the regulation of carbon and nitrogen metabolism

“…The predominance of GS in the cytosol of the floral receptacle of fully developed flowers is somehow logical, since they behave as sink organs in which an active recycling of N coming from both senescing corollas and stamens is occurring after pollination and before fruit set (Orzaez et al 1999). Although the role of GS1 during N remobilisation has not yet been clearly assessed, it has been established that, during senescence, source aerial plant organs contain high levels of GS1 in the cytosol (Hayakawa et al 1994;Watanabe et al 1994;Pe´rez-Rodriguez and Valpuesta 1996;Brugie`re et al 2000).…”

Expression of ethylene receptors Dl-ERS1-3 and Dl-ERS2, and ethylene response during flower senescence in Delphinium

“…Thus, we inferred that these ethylene receptors, Dl-ERS1-3 and Dl-ERS2, were ERS-type ethylene receptors. The deduced amino acid sequences of Dl-ERS1-3 had 75%, 75% and 70% identity to Oryza sativa ERS1 (Os-ERS1, AF01397) (Yau and Yip, 1997), Pisum sativum ERS1 (Ps-ERS1, AJ005829) (Orzaez et al, 1999) and Lycopersicon esculentum ETR1 (Le-ETR1, AF043084) (Lashbrook et al, 1998), respectively. The deduced amino acid sequence of Dl-ERS2 had 74%, 71%, 71% and 71% identity to Vigna radiata ERS1 (Vr-ERS1, AF098272), Nicotiana tabacum ERS1 (Nt-ERS1, AF03992) (Terajima et al, 2001), Dianthus caryophyllus ERS2 (DC-ERS2, AF03470) (Charng et al, 1997) and Lycopersicon esculentum Nr (U38666) (Wilkinson et al, 1995), respectively.…”

Transglutaminase activity during senescence and programmed cell death in the corolla of tobacco (Nicotiana tabacum) flowers

“…In most flowers, pollination acts as a signal leading to disposal of the petals, even though in short-lived flowers senescence is controlled by an independent endogenous programme completed by cell death. 37 Plant hormones such as ethylene and its immediate precursor, 1-aminocyclopropane-1-carboxylic acid, cytokinins, and abscisic acid as well as other factors seem to regulate petal senescence. 36,38,39 In fact, the gene`defender against apoptotic death', Dad-1, is an evolutionarily conserved inhibitor of animal PCD which is downregulated by ethylene.…”

“…In order to evaluate the anti-senescence effects of PAs, detached flowers were treated with exogenous spermine (SM) and, for comparative purposes, with an inhibitor of ethylene action, silver thiosulphate (STS), previously shown to delay senescence in flowers. 37,43 In order to establish a correlation between TGase activity and rate of senescence, glutamyl derivatives of PAs were monitored.…”