scholarly journals Exogenous Melatonin Application Enhances Rhizophagus irregularis Symbiosis and Induces the Antioxidant Response of Medicago truncatula Under Lead Stress

2020 ◽  
Vol 11 ◽  
Author(s):  
Xiangyu Zhang ◽  
Huijuan Zhang ◽  
Haoqiang Zhang ◽  
Ming Tang
Keyword(s):  
Medicago Truncatula ◽  
Antioxidant Response ◽  
Rhizophagus Irregularis ◽  
Exogenous Melatonin

scholarly journals Root growth and presence of Rhizophagus irregularis distinctly alter substrate hydraulic properties in a model system with Medicago truncatula

2020 ◽  
Vol 457 (1-2) ◽  
pp. 131-151
Author(s):  
Richard Pauwels ◽  
Jan Jansa ◽  
David Püschel ◽  
Anja Müller ◽  
Jan Graefe ◽  
...  
Keyword(s):  
Medicago Truncatula ◽  
Mycorrhizal Fungi ◽  
Hydraulic Properties ◽  
Water Retention ◽  
Pore Space ◽  
Moisture Stress ◽  
Model System ◽  
Rhizophagus Irregularis ◽  
Root Penetration ◽  
Mycorrhizal Plants

Abstract Aim We investigated how substrate hydraulic properties respond to the presence of arbuscular mycorrhizal fungi (AMF) in root-containing and root-free substrate zones in a Medicago truncatula-Rhizophagus irregularis model system. Methods Before planting, two compartments constructed from standard soil sampling cores (250 cm3) were implanted into non-mycorrhizal and mycorrhizal pots containing a sand-zeolite-soil mix. One compartment allowed root penetration (1 mm mesh cover) and the other only hyphal ingrowth (42 μm mesh cover). After eight weeks of growth under maintenance of moist conditions, the cores were subjected to water retention measurements. Additionally, we measured water retention of bare substrates before and after drying events to check for successful maintenance of moist conditions in pots. Results Drying of bare substrates decreased water retention, but planting at least sustained it. The parameters of water retention models responded linearly to root morphological traits across mycorrhizal and non-mycorrhizal substrates. Hyphae-only colonization comparatively affected the course of water retention in ways that suggest increased pore space heterogeneity while maintaining water storage capacity of substrates. Conclusions Hence, water contents corresponded to different substrate matric potentials in non-mycorrhizal and mycorrhizal pots. We conclude that changes to water retention in AMF colonized substrates can contribute to a widely observed phenomenon, i.e. that mycorrhizal plants differ in their moisture stress response from non-mycorrhizal plants.

Beneficial contribution of the arbuscular mycorrhizal fungus, Rhizophagus irregularis, in the protection of Medicago truncatula roots against benzo[a]pyrene toxicity

Mycorrhiza ◽  
2017 ◽  
Vol 27 (5) ◽  
pp. 465-476 ◽  
Author(s):  
Ingrid Lenoir ◽  
Joël Fontaine ◽  
Benoît Tisserant ◽  
Frédéric Laruelle ◽  
Anissa Lounès-Hadj Sahraoui
Keyword(s):  
Medicago Truncatula ◽  
Arbuscular Mycorrhizal Fungus ◽  
Mycorrhizal Fungus ◽  
Arbuscular Mycorrhizal ◽  
Rhizophagus Irregularis

scholarly journals Arbuscular Mycorrhizal Fungi Increase Pb Uptake of Colonized and Non-Colonized Medicago truncatula Root and Deliver Extra Pb to Colonized Root Segment

2021 ◽  
Vol 9 (6) ◽  
pp. 1203
Author(s):  
Haoqiang Zhang ◽  
Wei Ren ◽  
Yaru Zheng ◽  
Yanpeng Li ◽  
Manzhe Zhu ◽  
...  
Keyword(s):  
Medicago Truncatula ◽  
Mycorrhizal Fungi ◽  
Biomass Accumulation ◽  
Arbuscular Mycorrhizal ◽  
Am Fungi ◽  
Rhizophagus Irregularis ◽  
Root Segment ◽  
Shoot Biomass ◽  
Split Root System ◽  
Long Term Impact

Arbuscular mycorrhizal (AM) fungi establish symbiosis and improve the lead (Pb) tolerance of host plants. The AM plants accumulate more Pb in roots than their non-mycorrhizal counterparts. However, the direct and long-term impact of AM fungi on plant Pb uptake has been rarely reported. In this study, AM fungus (Rhizophagus irregularis) colonized and non-colonized roots of Medicago truncatula were separated by a split-root system, and their differences in responding to Pb application were compared. The shoot biomass accumulation and transpiration were increased after R. irregularis inoculation, whereas the biomass of both colonized and non-colonized roots was decreased. Lead application in the non-colonized root compartment increased the R. irregularis colonization rate and up-regulated the relative expressions of MtPT4 and MtBCP1 in the colonized root compartments. Rhizophagus irregularis inoculation increased Pb uptake in both colonized and non-colonized roots, and R. irregularis transferred Pb to the colonized root segment. The Pb transferred through the colonized root segment had low mobility and might be sequestrated and compartmented in the root by R. irregularis. The Pb uptake of roots might follow water flow, which is facilitated by MtPIP2. The quantification of Pb transfer via the mycorrhizal pathway and the involvement of MtPIP2 deserve further study.

Effects of ageing and exogenous melatonin on pituitary responsiveness to GnRH in rats

Reproduction ◽  
2000 ◽  
pp. 151-156 ◽  
Author(s):  
E Diaz ◽  
D Pazo ◽  
AI Esquifino ◽  
B Diaz
Keyword(s):  
Body Weight ◽  
Reproductive System ◽  
Plasma Concentrations ◽  
Pituitary Hormones ◽  
Female Rats ◽  
Control Groups ◽  
Melatonin Treatment ◽  
Exogenous Melatonin ◽  
Reproductive Axis ◽  
Effect Of Age

The effect of age and melatonin on the activity of the neuroendocrine reproductive system was studied in young cyclic (3-5 months-old), and old acyclic (23-25 month-old) female rats. Pituitary responsiveness to a bolus of GnRH (50 ng per 100 g body weight) was assessed at both reproductive stages in control and melatonin-treated (150 micrograms melatonin per 100 g body weight each day for 1 month) groups. After this experiment, female rats were treated for another month to study the influence of ageing and melatonin on the reproductive axis. Plasma LH, FSH, prolactin, oestradiol and progesterone were measured. A positive LH response to GnRH was observed in both control groups (cyclic and acyclic). However, a response of greater magnitude was observed in old acyclic rats. Melatonin treatment reduced this increased response in acyclic rats and produced a pituitary responsiveness similar to that of young cyclic rats. FSH secretion was independent of GnRH administration in all groups, indicating desynchronization between LH and FSH secretion in response to GnRH in young animals and during senescence. No effect on prolactin was observed. Significantly higher LH (3009.11 +/- 1275.08 pg ml(-1); P < 0.05) and FSH concentrations (5879.28 +/- 1631.68 pg ml(-1); P < 0.01) were seen in acyclic control rats. After melatonin treatment, LH (811.11 +/- 89.71 pg ml(-1)) and FSH concentrations (2070 +/- 301.62 pg ml(-1)) decreased to amounts similar to those observed in young cyclic rats. However, plasma concentrations of oestradiol and progesterone were not reduced. In conclusion, the results of the present study indicate that, during ageing, the effect of melatonin is exerted primarily at the hypothalamo-pituitary axis rather than on the ovary. Melatonin restored the basal concentrations of pituitary hormones and pituitary responsiveness to similar values to those observed in young rats.

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