Flower development in the passion fruit Passiflora edulis requires a photoperiod‐induced systemic graft‐transmissible signal

Abstract

Different organisms use gradual seasonal changes in photoperiod to correctly time diverse developmental processes, such as transition to flowering in plants. Florigen is a systemic signal formed in leaves exposed to specific environmental cues, mainly photoperiodic, and capable of triggering flower induction in several species. Here we show that in Passiflora edulis, a perennial climbing vine, flower initiation occurs throughout the year; however, without long photoperiods, flower primordia show arrested growth and differentiation at an early stage. Our results support the existence of a positive, systemic, graft-transmissible signal, produced in mature leaves under LDs, that is required for normal flower development beyond sepal formation. Our results also suggest that Gibberellin acts to inhibit flower development. We provide evidence for genetic variation in the response to short photoperiods. A genotype capable of forming developed flowers under short photoperiods produces a positive graft transmissible signal allowing normal flower development under short days in a cultivar which normally aborts flower development under these conditions. We believe these findings contribute towards discovering the chemical nature of this interesting mobile signal involved in flower development.

Mini-grafting of adult Passiflora edulis Sims f. flavicarpa Deg. scions onto vegetatively propagated adult rootstocks of P. mucronata Lam.

“…passiflorae isolates (Veloso et al, 2014;Preisigke et al, 2015). In the Passiflora genus, grafting presents a reliable approach to study the transmission of positive signs involved in flowering induction in P. edulis (Nave et al, 2010). As a propagation method, grafting may greatly contribute to the P. edulis f. flavicarpa species by combining with rootstocks that are resistant to soil illnesses, mainly Fusarium.…”

PEP1 of Arabis alpina Is Encoded by Two Overlapping Genes That Contribute to Natural Genetic Variation in Perennial Flowering

“…Most temperate perennial species flower seasonally and the phases of flowering and vegetative growth are clearly separated. Interestingly, in perennials the environmental cues that regulate floral initiation also have an impact on the duration of the flowering episode either by regulating the growth of flower buds [4] or the return to vegetative development [5], [6], [7]. Genetic variation also exists for these traits so that individuals of the same species flower either for a restricted period or for a more prolonged time [4], [8], [9].…”

“…Interestingly, in perennials the environmental cues that regulate floral initiation also have an impact on the duration of the flowering episode either by regulating the growth of flower buds [4] or the return to vegetative development [5], [6], [7]. Genetic variation also exists for these traits so that individuals of the same species flower either for a restricted period or for a more prolonged time [4], [8], [9]. In addition, differences in activity of flowering genes can contribute to the divergence in life history between plant species, including the distinction between annual and perennial life cycles [5], [10], [11], [12], [13], [14], [15].…”

Effects of Temperature and Ethylene Response Inhibitors on Growth and Flowering of Passion Fruit

“…are popular in many subtropical and tropical countries. The results of previous studies have shown that the flowering of passion fruit is enhanced by appropriate regulation of environmental factors, such as photoperiod (Menzel and Simpson, 1988;Nave et al, 2010), temperature (Menzel et al, 1987), water content (Menzel et al, 1986;Staveley and Wolstenholme, 1990), and the application of plant growth regulators including aminoethoxyvinylglycine (AVG) and silver thiosulfate (STS) (Barbosa et al, 2001;Reis et al, 2003).…”