Photosynthetically active radiation and carbon gain drives the southern orientation of Myrtillocactus geometrizans fruits

Abstract

The equatorial orientation of reproductive structures is known in some columnar cacti from extratropical deserts. It has been hypothesised that photosynthetically active radiation (PAR) interception is the main reason for this orientation, because of its key effect on nocturnal CO uptake. However, there are no studies addressing both the effect of PAR and its consequence, carbon gain, on fruit orientation. Accordingly, we tested whether PAR and carbon gain could explain the southern fruit orientation of Myrtillocactus geometrizans, an inter-tropical columnar cactus. We studied three populations of M. geometrizans in Mexico. For each population, azimuth of fruits, total daily PAR, nocturnal acid accumulation (NAA) and fruit production were measured. The relationships between rib orientation and number of fruits, as well as total daily PAR, were evaluated using periodic regressions. The effect of total daily PAR and NAA on number of fruits was assessed using generalised linear models. During spring, mean fruit orientation had a south azimuth for three populations. Likewise, rib orientation had a significant effect on fruit production, with the south-facing ribs having the maximum number of fruits. Total daily PAR was highest in the south-facing ribs, at least for those in the northern and central populations. Furthermore, during spring, there was a significant positive effect of total daily PAR and NAA on fruit production. Our results provide strong evidence that the higher carbon gain in equatorial ribs, through a highest interception of PAR, would be the responsible factor for equatorial orientation of fruits in an inter-tropical columnar cactus.

The Assessment and the Within-Plant Variation of the Morpho-Physiological Traits and VOCs Profile in Endemic and Rare Salvia ceratophylloides Ard. (Lamiaceae)

“…These results explained the phenotypic plasticity response to the local conditions [52,53] because preliminary results showed a low genetic variability of S. ceratophylloides populations [23]. It has been observed that the within-plant phenotypic variation responded to the microhabitat environmental heterogeneity or finegrained (small-scale) environmental variations [9,11,14,15] rather than macro-geographical or coarse-grained environmental variations [17,54,55]. In this respect, we hypothesized that the S. ceratophylloides individuals in the Mo site, characterized by a significant within-plant variation of the leaf morpho-physiological traits, could face with a higher microhabitat en-vironmental heterogeneity, especially for light intensity and/or temperature gradients (the most important abiotic stresses affecting the leaf growth), than Pu site.…”

“…Based on earlier works of the Winn [9,10] and De Kroon's hypothesis [11], which dealt with plant phenotypic variation at sub-individual level (i.e., organ or module), the 'withinplant' rather than "among-plant" phenotypic variation could represent the major source of population-level diversity in several functional traits [12,13]. Recent works pointed out the multiple ecological aspects of the 'within-plant variation' such as the improvement of the exploitation of the heterogeneous-distributed resource [14,15], the adaptation to biotic and biotic gradients [16], the spreading of the ecological breadth of species and individuals [17,18], the increase of the functional diversity of populations [17], and the alteration of plant-antagonist interactions [19][20][21][22]. However, no quantitative characterization of the within-plant variation in endangered and rare plant species has been assayed yet.…”

Floral orientation in Eulychnia acida, an arborescent cactus of the Atacama Desert, and implications for cacti globally

“…, Ponce‐Bautista et al. ). Eulychnia acida , evaluated in the present study, falls in the latter group of cacti.…”

Lifetime genealogical divergence within plants leads to epigenetic mosaicism in the long-lived shrubLavandula latifolia(Lamiaceae)

“…Depending on its magnitude and spatio-temporal patterning, this subindividual phenotypic variance can have multiple ecological effects. These include optimizing the exploitation of limiting resources such as light, water or nitrogen (Osada et al, 2014;Ponce-Bautista et al, 2017;Mediavilla et al, 2019), altering the outcome of . CC-BY-NC-ND 4.0 International license perpetuity.…”

“…Depending on its magnitude and spatio-temporal patterning, this subindividual phenotypic variance can have multiple ecological effects. These include optimizing the exploitation of limiting resources such as light, water or nitrogen (Osada et al ., 2014; Ponce-Bautista et al ., 2017; Mediavilla et al ., 2019), altering the outcome of interactions with animals (Sobral et al ., 2013, 2014; Shimada et al ., 2015; Wetzel et al ., 2016), driving selection on reproductive traits (Austen et al ., 2015; Dai et al ., 2016; Arceo-Gómez et al ., 2017; Kulbaba et al ., 2017), and enhancing tolerance of environmental unpredictability (Tíscar Oliver & Lucas Borja, 2010; Hidalgo et al ., 2016). Because of these ecological effects, subindividual variability can eventually influence the fitness of individuals and become itself a target for natural selection, since plants not only have characteristic trait means but also characteristic trait variances and spatio-temporal patterns of subindividual heterogeneity (Herrera, 2009, 2017; Kulbaba et al ., 2017; Harder et al ., 2019).…”