Molecular understanding of postharvest flower opening and senescence

Abstract

Flowers are key organs in many ornamental plants, and various phases of flower development impact their economic value. The final stage of petal development is associated with flower senescence, which is an irreversible process involving programmed cell death, and premature senescence of cut flowers often results in major losses in quality during postharvest handling. Flower opening and senescence are two sequential processes. As flowers open, the stamens are exposed to attract pollinators. Once pollination occurs, flower senescence is initiated. Both the opening and senescence processes are regulated by a range of endogenous phytohormones and environmental factors. Ethylene acts as a central regulator for the ethylene-sensitive flowers. Other phytohormones, including auxin, gibberellin, cytokinin, jasmonic acid and abscisic acid, are also involved in the control of petal expansion and senescence. Water status also directly influences postharvest flower opening, while pollination is a key event in initiating the onset flower senescence. Here, we review the current understanding of flower opening and senescence, and propose future research directions, such as the study of interactions between hormonal and environmental signals, the application of new technology, and interdisciplinary research.

Rapid clearance of cytokinin controls transition from cell division to expansion during petal development in rose (Rosa hybrida)

“…Based on our previous results, we de ned stage 0 as " oral bud revealed" and stage 2 as "sepal completely unfold." Microscopy observations indicated that division of petal cells almost stops at stage 2, while cell expansion drove petal growth from stage 2 onward [29][30][31] The above dataset revealed that the abundance of microRNA159 (miR159) exhibits a sharp drop in petals from cell division (stage 0) to cell expansion (5 days after stage 0) (Fig. 1A) 19,30,32 .…”

“…Organ growth requires coordination between cell division and cell expansion 27,28 . In petals, cell division mostly ceases before anthesis, and ower opening is largely attributed to cell expansion [29][30][31] . To understand the underlying mechanism of the transition between cell division and cell expansion, we previously conducted a transcriptome deep sequencing (RNA-seq) analysis of short RNAs and transcripts from petals to investigate gene expression pro les during the cell division and expansion phases.…”

Recent progresses in molecular postharvest biology

“…Two research articles in the collection report the most recent findings that AtNAP promotes leaf senescence by activating the gene of cytokinin oxidase 3 (that degrades senescence-inhibiting plant hormone cytokinins) (Hu et al 2021) Flowers are "food for the mind, ' and senescence of flowers limits vase life and reduces aesthetic appreciation. In this special collection there are one review article (Sun et al 2021) and one research article (Zou et al 2021) representing the frontiers in flower senescence research. Many flowers, especially cut flowers such as rose, undergo opening and senescence processes after harvest.…”

An Aux/IAA Family Member, RhIAA14, Involved in Ethylene-Inhibited Petal Expansion in Rose (Rosa hybrida)

“…Larger flowers are valuable in terms of both evolution and the economy. Changes to internal and external cues of the flower opening process can be responsible for alterations in the flower size [ 1 ]. However, the regulatory mechanism of flower opening is far from clear.…”

“…Cell expansion, a vital factor that shapes the morphology of plant organs and enables their optimal growth in response to environmental cues [ 6 ], depends largely on a coordination of cell wall metabolism, cell turgor, and cytoskeletal reorganization [ 7 ]. Ethylene can promote flower opening in many ornamental plants [ 1 ]. In rose, ethylene accelerates flower opening while inhibiting petal expansion [ 5 , 8 , 9 ], and its regulation of flower opening is through the upregulation of gene-encoding ethylene receptors [ 8 , 10 ].…”