scholarly journals Variation in Phosphorus Availability, Root Architecture Attributes, and Onset of Storage Root Formation among Sweetpotato Cultivars

HortScience ◽  
2020 ◽  
Vol 55 (12) ◽  
pp. 1903-1911
Author(s):  
Arthur Villordon ◽  
Jeffrey C. Gregorie ◽  
Don LaBonte

The primary objective of this work was to generate species-specific information about root architectural responses to variations in inorganic phosphate (Pi) availability at the onset of storage root formation among six sweetpotato (Ipomoea batatas) cultivars. Three Pi levels were used: 0 (low Pi); 0.17 (medium Pi); and 0.34 (high Pi) g/pot triple super phosphate (0N–46P–0K). The check cultivar ‘Bayou Belle’ (BB) consistently showed evidence of storage root formation at 15 days in adventitious roots (ARs) grown across three Pi levels and two planting dates (PDs). Storage root formation was also detected in ‘Orleans’ (OR) and ‘Beauregard’ (BX), but it was less consistent relative to BB. In general, BB had the lowest adventitious root (AR) number relative to the other cultivars, but the magnitudes of difference varied with Pi availability and PD. With the first PD, BX had a 45% higher AR number compared with BB in low Pi conditions; however, there were no differences in the second PD. Within cultivars, BX and Okinawa grown in low Pi showed combined 17% and 24% reductions in primary root length (PRL) relative to roots grown in high Pi. BB had a higher lateral root number (LRN) and lateral root density (LRD) across Pi levels, corroborating prior data regarding the association of these root architectural attributes with the onset of storage root formation. The experimental data support the hypothesis regarding the existence of genetic variation for Pi efficiency in sweetpotato and that some well-documented Pi-efficient root traits like high LRN and LRD are indirectly selected for in-breeding programs that focus on early storage root formation and stable yields across environments.

HortScience ◽  
2021 ◽  
pp. 1-7
Author(s):  
Arthur Villordon ◽  
Jeffrey C. Gregorie

The primary objective of this work was to generate species-specific information about root architectural adaptation to variation in boron (B) availability at the onset of storage root formation among three sweetpotato [Ipomoea batatas (L.) Lam] cultivars (Beauregard = BX; Murasaki = MU; Okinawa = OK). Three B levels were used: 0B (B was omitted in the nutrient solution, substrate B = 0.1 mg·kg−1), 1XB (sufficient B; 0.5 mg·kg−1), and 2XB (high B; 1 mg·kg−1). The check cultivar BX showed evidence of storage root formation at 15 days in 0B and 1XB, whereas cultivars MU and OK failed to show evidence of root swelling. The 1XB and 2XB levels were associated with 736% and 2269% increase in leaf tissue B in BX, respectively, relative to plants grown in 0B. Similar magnitudes of increase were observed in MU and OK cultivars. There were no differences in adventitious root (AR) count within cultivars but OK showed 25% fewer AR numbers relative to BX across all B levels. 0B was associated with 20% and 48% reduction in main root length in BX and OK, respectively, relative to plants grown in 1XB and 2XB. 2XB was associated with a 10% increase in main root length in MU relative to plants grown in 0B and 1XB. 0B was associated with reduced lateral root length in all cultivars but the magnitude of responses varied with cultivars. These data corroborate findings in model systems and well-studied crop species that B deficiency is associated with reduced root growth. These data can be used to further understand the role of cultivar-specific responses to variation in B availability in sweetpotato.


Plants ◽  
2020 ◽  
Vol 9 (5) ◽  
pp. 612 ◽  
Author(s):  
Veronica Santoro ◽  
Michela Schiavon ◽  
Francesco Gresta ◽  
Andrea Ertani ◽  
Francesca Cardinale ◽  
...  

The hormones strigolactones accumulate in plant roots under phosphorus (P) shortage, inducing variations in plant phenotype. In this study, we aimed at understanding whether strigolactones control morphological and anatomical changes in tomato (Solanum lycopersicum L.) roots under varying P supply. Root traits were evaluated in wild-type seedlings grown in high vs. low P, with or without exogenous strigolactones, and in wild-type and strigolactone-depleted plants grown first under high vs. no P, and then under high vs. no P after acclimation on low P. Exogenous strigolactones stimulated primary root and lateral root number under low P. Root growth was reduced in strigolactone-depleted plants maintained under continuous P deprivation. Total root and root hair length, lateral root number and root tip anatomy were impaired by low strigolactone biosynthesis in plants grown under low P or transferred from low to no P. Under adequate P conditions, root traits of strigolactone-depleted and wild-type plants were similar. Concluding, our results indicate that strigolactones (i) control macro- and microscopic changes of root in tomato depending on P supply; and (ii) do not affect root traits significantly when plants are supplemented with adequate P, but are needed for acclimation to no P and typical responses to low P.


2002 ◽  
Vol 127 (2) ◽  
pp. 178-183 ◽  
Author(s):  
Makoto Nakatani ◽  
Masaru Tanaka ◽  
Masaru Yoshinaga

A late-storage root-forming mutant (`KM95-A68') of sweetpotato [Ipomoea batatas (L.) Poir.] was characterized to clarify the genetic and physiological mechanisms of storage root formation. This mutant originated from a somaclonal mutation of `Kokei No. 14'. Storage roots of `KM95-A68' are rare and, when formed, develop 2 or 3 weeks later than those of `Kokei No. 14' from which it originated. Morphological characteristics of the canopy and leaf photosynthetic rates of `KM95-A68' were similar to those of `Kokei No. 14'. No apparent differences were observed in the anatomy of root cross sections of `KM95-A68' and `Kokei No. 14'. An apparent increase in the root zeatin riboside (ZR) levels were observed in `Kokei No. 14' at storage root formation. Root ZR levels differed between `Kokei No. 14' and `KM95-A68'. The onset of increase in root ZR levels was delayed by 2 or 3 weeks in `KM95-A68' in comparison to `Kokei No. 14'. Maximum root ZR levels in `Kokei No. 14' were 2.2 times higher in comparison to `KM95-A68'. This appeared to be a factor in delayed storage root formation of `KM95-A68'. Results of reciprocal grafts of `KM95-A68' and `Kokei No. 14' indicated that the late storage root-forming characteristic of `KM95-A68' is a characteristic that arises from the root itself.


2021 ◽  
Author(s):  
◽  
Ruth Laura Wood

<p>As part of Wellington Zoo’s current management philosophy to reduce the number of species and increase enclosure size, quality and appropriateness for those remaining animals, the zoo’s colony of hamadryas baboons (Papio cynocephalus hamadryas) was relocated within the zoo to a purpose-designed and more naturalistic exhibit. The primary objective of this investigation was to determine group and individual responses of five of these baboons to their new enclosure. In so doing, this investigation was intended to address the shortage of quantitative, species-specific information on environmental enrichment for Papio baboons (Kessel and Brent 1996). The data collection method used in this investigation consisted of fifteen-minute focal sampling of each of the five focal animals in the two months before and the month following the colony’s relocation. For the purposes of this investigation, these focal samples were initially analysed together, prior to each focal animal being considered independently. Analysis of data extracted from these focal samples included consideration of: • The overall occurrence of individual behaviours between the former and new enclosures; • Additions to the animals’ behavioural repertoires upon relocation; and, • Time the animals spent alone and interacting socially. Upon the colony’s relocation, changes in the combined focal animals’ behaviour were anticipated as a result of greater space, areas of privacy, and increased environmental variation. Focal sampling revealed increasingly naturalistic behaviours, including a reduction in vacuum and vestigial behaviours, and an increase in speciestypical behaviour. Results also indicated that the combined focal animals experienced unexpectedly low levels of “agonistic” (i.e. aggressive) behaviour in both enclosures. However, there was a reduction in some associated behaviours upon the colony’s relocation. This included a decline in male rivalry over females. Differences in the responses of individual focal animals to relocation were also anticipated. Of particular interest were results indicating an increasing similarity of individual roles within one-male units to those of free-ranging hamadryas baboons. These roles were associated with both age and sex. This study raises implications for improving the current management of the Wellington Zoo colony and other captive hamadryas baboon colonies. These include emphasising the importance of appropriate husbandry and feeding schedules. It also raises implications for the future management of other captive Papio baboon colonies in terms of enclosure redesign. These include the benefit of incorporating naturally occurring environmental factors, such as natural leaf litter. This study is also of value from a management perspective as a baseline for future investigations. Such investigations could include long-term monitoring of this colony’s use of environmental enrichment in the new enclosure and consideration of the animals’ behaviour as the colony is encouraged to expand.</p>


2021 ◽  
Author(s):  
◽  
Ruth Laura Wood

<p>As part of Wellington Zoo’s current management philosophy to reduce the number of species and increase enclosure size, quality and appropriateness for those remaining animals, the zoo’s colony of hamadryas baboons (Papio cynocephalus hamadryas) was relocated within the zoo to a purpose-designed and more naturalistic exhibit. The primary objective of this investigation was to determine group and individual responses of five of these baboons to their new enclosure. In so doing, this investigation was intended to address the shortage of quantitative, species-specific information on environmental enrichment for Papio baboons (Kessel and Brent 1996). The data collection method used in this investigation consisted of fifteen-minute focal sampling of each of the five focal animals in the two months before and the month following the colony’s relocation. For the purposes of this investigation, these focal samples were initially analysed together, prior to each focal animal being considered independently. Analysis of data extracted from these focal samples included consideration of: • The overall occurrence of individual behaviours between the former and new enclosures; • Additions to the animals’ behavioural repertoires upon relocation; and, • Time the animals spent alone and interacting socially. Upon the colony’s relocation, changes in the combined focal animals’ behaviour were anticipated as a result of greater space, areas of privacy, and increased environmental variation. Focal sampling revealed increasingly naturalistic behaviours, including a reduction in vacuum and vestigial behaviours, and an increase in speciestypical behaviour. Results also indicated that the combined focal animals experienced unexpectedly low levels of “agonistic” (i.e. aggressive) behaviour in both enclosures. However, there was a reduction in some associated behaviours upon the colony’s relocation. This included a decline in male rivalry over females. Differences in the responses of individual focal animals to relocation were also anticipated. Of particular interest were results indicating an increasing similarity of individual roles within one-male units to those of free-ranging hamadryas baboons. These roles were associated with both age and sex. This study raises implications for improving the current management of the Wellington Zoo colony and other captive hamadryas baboon colonies. These include emphasising the importance of appropriate husbandry and feeding schedules. It also raises implications for the future management of other captive Papio baboon colonies in terms of enclosure redesign. These include the benefit of incorporating naturally occurring environmental factors, such as natural leaf litter. This study is also of value from a management perspective as a baseline for future investigations. Such investigations could include long-term monitoring of this colony’s use of environmental enrichment in the new enclosure and consideration of the animals’ behaviour as the colony is encouraged to expand.</p>


2021 ◽  
Vol 22 (14) ◽  
pp. 7305
Author(s):  
Leonardo Bruno ◽  
Emanuela Talarico ◽  
Luz Cabeiras-Freijanes ◽  
Maria Letizia Madeo ◽  
Antonella Muto ◽  
...  

Coumarin is a phytotoxic natural compound able to affect plant growth and development. Previous studies have demonstrated that this molecule at low concentrations (100 µM) can reduce primary root growth and stimulate lateral root formation, suggesting an auxin-like activity. In the present study, we evaluated coumarin’s effects (used at lateral root-stimulating concentrations) on the root apical meristem and polar auxin transport to identify its potential mode of action through a confocal microscopy approach. To achieve this goal, we used several Arabidopsis thaliana GFP transgenic lines (for polar auxin transport evaluation), immunolabeling techniques (for imaging cortical microtubules), and GC-MS analysis (for auxin quantification). The results highlighted that coumarin induced cyclin B accumulation, which altered the microtubule cortical array organization and, consequently, the root apical meristem architecture. Such alterations reduced the basipetal transport of auxin to the apical root apical meristem, inducing its accumulation in the maturation zone and stimulating lateral root formation.


1970 ◽  
Vol 23 (5) ◽  
pp. 1125
Author(s):  
RD Linke ◽  
NG Marinos

A 24�hr pregermination application of morphactin to seeds of P. sativum was found, particularly at the higher concentrations used (1-30 mg/l), to stimulate primary root elongation but partially inhibit the initiation and growth of laterals. The latter effect was accompanied by the production of undifferentiated outgrowths at the base of the primary root and a shift of the region of lateral root formation towards the tip.


2007 ◽  
Vol 20 (2) ◽  
pp. 207-217 ◽  
Author(s):  
José López-Bucio ◽  
Juan Carlos Campos-Cuevas ◽  
Erasto Hernández-Calderón ◽  
Crisanto Velásquez-Becerra ◽  
Rodolfo Farías-Rodríguez ◽  
...  

Soil microorganisms are critical players in plant-soil interactions at the rhizosphere. We have identified a Bacillus megaterium strain that promoted growth and development of bean (Phaseolus vulgaris) and Arabidopsis thaliana plants. We used Arabidopsis thaliana as a model to characterize the effects of inoculation with B. megaterium on plant-growth promotion and postembryonic root development. B. megaterium inoculation caused an inhibition in primary-root growth followed by an increase in lateral-root number, lateral-root growth, and root-hair length. Detailed cellular analyses revealed that primary root-growth inhibition was caused both by a reduction in cell elongation and by reduction of cell proliferation in the root meristem. To study the contribution of auxin and ethylene signaling pathways in the alterations in root-system architecture elicited by B. megaterium, a suite of plant hormone mutants of Arabidopsis, including aux1-7, axr4-1, eir1, etr1, ein2, and rhd6, defective in either auxin or ethylene signaling, were evaluated for their responses to inoculation with this bacteria. When inoculated, all mutant lines tested showed increased biomass production. Moreover, aux1-7 and eir1, which sustain limited root-hair and lateral-root formation when grown in uninoculated medium, were found to increase the number of lateral roots and to develop long root hairs when inoculated with B. megaterium. The ethylene-signaling mutants etr1 and ein2 showed an induction in lateral-root formation and root-hair growth in response to bacterial inoculation. Taken together, our results suggest that plant-growth promotion and root-architectural alterations by B. megaterium may involve auxin- and-ethylene independent mechanisms.


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