Role of Phi Cells Under Abiotic Stress in Plants

Root development and structure in seedlings of Ginkgo biloba

“…If organisms from the gymnosperms, including Ginkgoales, to the angiosperms possess phi cells in their roots, then many plant species, including model organisms like Arabidopsis of the Brassicaceae, surely have the genetic basis for phi thickening since other members of its family possess phi cells. Future researchers may try to induce phi cell development in such plants, or species closely related to phi cell‐containing species, to better understand the genetic basis and possible functional importance of this trait (see Fernandez‐Garcia, et al, 2014).…”

“…While Gerrath et al (2005) showed that certain environmental conditions do not affect phi cell production in other gymnosperms, this finding was limited by differences in overall plant growth among their conditions; other researchers examining phi cells in angiosperms have found differences in their production across various environmental conditions (see Soukup et al, 2004; Fernandez‐Garcia et al, 2014). In addition to the response of phi cells to environmental conditions, questions of the constitutive nature and function of phi cells were partially addressed by Gerrath et al (2002, 2005) and by others for angiosperms.…”

“…In addition to the response of phi cells to environmental conditions, questions of the constitutive nature and function of phi cells were partially addressed by Gerrath et al (2002, 2005) and by others for angiosperms. However, phi cells have never received the kind of attention given to the usual barrier layers of the root cortex; this oversight has begun to change in recent years (De Melo, 2011; Fernandez‐Garcia et al, 2014).…”

“…Whether phi cells have retained a meaningful function, their presence in many gymnosperms (e.g., Cycadales, von Guttenberg, 1941; Cordaitales, Strullu‐Derrien et al, 2009) and various angiosperms (e.g., Orchidaceae, Idris and Collings, 2015; Geraniaceae, Haas et al, 1976; Rosaceae, Weerdenburg and Peterson, 1983; Scrophulariaceae, Bona and Morretes, 2003; and Brassicaceae, Fernández‐García et al, 2014) across the evolutionary tree (e.g., Mathews, 2009) suggests that the genetic basis for this trait has been preserved over the course of evolutionary history. If organisms from the gymnosperms, including Ginkgoales, to the angiosperms possess phi cells in their roots, then many plant species, including model organisms like Arabidopsis of the Brassicaceae, surely have the genetic basis for phi thickening since other members of its family possess phi cells.…”

The Induction and Roles Played by Phi Thickenings in Orchid Roots

“…However, the term is now used to encompass all patterned bands of secondary thickenings in the root cortex [1]. Initially observed in gymnosperms [2], these structures have been described in more than 100 plant species from 16 families, including both monocots and eudicots (reviewed in [1,3,4]). As phi thickenings are present in diverse taxa, the basic capacity to generate a phi thickening has either evolved multiple times during the evolution, or it has been conserved for a very long period of time.…”