scholarly journals Growth, Rhizosphere Carboxylate Exudation, and Arbuscular Mycorrhizal Colonisation in Temperate Perennial Pasture Grasses Varied with Phosphorus Application

Agronomy ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 2017
Author(s):  
Sangay Tshewang ◽  
Zed Rengel ◽  
Kadambot H. M. Siddique ◽  
Zakaria M. Solaiman
Keyword(s):  
Specific Root Length ◽  
Arbuscular Mycorrhizal ◽  
Differential Growth ◽  
Pasture Production ◽  
Tall Wheatgrass ◽  
Pasture Grasses ◽  
Mycorrhizal Colonisation ◽  
Phosphorus Application ◽  
Carboxylate Exudation ◽  
P Supply

Phosphorus (P) fertiliser is applied regularly to the nutrient-poor sandy soils in southwestern Australia to elevate and/or maintain pasture production. This study aimed to characterise differential growth, root carboxylate exudation, and mycorrhizal responses in three temperate perennial pasture grasses at variable P supply. Tall fescue (Festuca arundinacea L. cv. Prosper), veldt grass (Ehrharta calycina Sm. cv. Mission), and tall wheatgrass (Thinopyrum ponticum L. cv. Dundas) with five P rates varying from 0 to 100 mg P kg−1 soil were evaluated in a controlled environment. Rhizosphere carboxylate exudation and mycorrhizal colonisation were assessed. Veldt grass produced the maximum shoot dry weight, highest agronomic phosphorus-use efficiency at low P supply, as well as the highest specific root length and shoot P content at all P rates. Across species, the maximum shoot weight was obtained at 20 and 50 mg P kg−1 soil, which differed significantly from the two lowest P rates (0 and 5 mg P kg−1 soil). Phosphorus application influenced carboxylate exudation, with plants exuding acetate only in the zero P treatment, and citrate and malonate in the P-supplemented treatments. In all three species, acetate and malonate were the major carboxylates exuded (37–51% of the total). Only tall wheatgrass released trans-aconitate. Citrate and malonate concentrations in the rhizosphere increased with P supply, suggesting their important role in P acquisition. Phosphorus applications reduced arbuscular mycorrhizal colonisation and increased root diameter as the P rate increased. Root carboxylate exudation in low-P soil played a role in mobilisation of P via P solubilisation, but the role of exuded carboxylate in soils well supplied with P might be diminished.

scholarly journals Nitrogen and Potassium Fertilisation Influences Growth, Rhizosphere Carboxylate Exudation and Mycorrhizal Colonisation in Temperate Perennial Pasture Grasses

Agronomy ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 1878
Author(s):  
Sangay Tshewang ◽  
Zed Rengel ◽  
Kadambot H. M. Siddique ◽  
Zakaria M. Solaiman
Keyword(s):  
Sandy Soil ◽  
Tall Fescue ◽  
Festuca Arundinacea ◽  
Dry Weight ◽  
Mycorrhizal Symbiosis ◽  
Shoot Dry Weight ◽  
Pasture Grasses ◽  
Mycorrhizal Colonisation ◽  
Low K ◽  
Carboxylate Exudation

Optimisation of potassium (K) use efficiency in pastures on sandy soil is challenging. We characterised growth response, root carboxylate exudation and mycorrhizal colonisation in three perennial pasture grasses: tall fescue (Festuca arundinacea L.), veldt grass (Ehrharta calycina Sm.) and tall wheatgrass (Thinopyrum ponticum L.) in two glasshouse experiments with: (1) four K rates (0, 40, 80 and 120 mg K kg-1 soil), and (2) four N and K treatments (no N and K (–N–K), 81 mg N kg-1 soil but no K, 80 mg K kg-1 soil but no N, and N at 81 and K at 80 mg kg-1 soil (+N+K)) in low-K sandy soil. Veldt grass had the highest shoot dry weight and shoot P content, but the lowest mycorrhizal colonisation. Potassium fertilisation had no significant impact on exudation of citrate and oxalate. The K0 plants had significantly lower exudation of acetate and total carboxylates than K40 plants. The +N+K plants had maximum shoot growth at both harvests (30 and 60 days after sowing (DAS)) and highest N and K shoot contents at 60 DAS. The –N–K plants exuded maximum amounts of citrate and malate at 30 DAS, but at 60 DAS tall fescue had the highest rhizosphere concentrations of citrate and malate in the +N+K treatment. At 60 DAS, mycorrhizal colonisation was significantly lower with than without N and K fertilisation. We concluded that pasture grasses could yield well even in inherently low-K soil without external K fertilisation and mycorrhizal symbiosis. However, the +N+K plants had the highest yield and root carboxylate exudation.

Experimentally altered rainfall regimes and host root traits affect grassland arbuscular mycorrhizal fungal communities

2019 ◽  
Author(s):  
Coline Deveautour ◽  
Suzanne Donn ◽  
Sally Power ◽  
Kirk Barnett ◽  
Jeff Powell
Keyword(s):  
Fungal Community ◽  
Community Assembly ◽  
Root Length ◽  
Specific Root Length ◽  
Root Traits ◽  
Arbuscular Mycorrhizal ◽  
Fungal Communities ◽  
Rainfall Regime ◽  
Precipitation Regimes ◽  
Rainfall Regimes

Future climate scenarios predict changes in rainfall regimes. These changes are expected to affect plants via effects on the expression of root traits associated with water and nutrient uptake. Associated microorganisms may also respond to these new precipitation regimes, either directly in response to changes in the soil environment or indirectly in response to altered root trait expression. We characterised arbuscular mycorrhizal (AM) fungal communities in an Australian grassland exposed to experimentally altered rainfall regimes. We used Illumina sequencing to assess the responses of AM fungal communities associated with four plant species sampled in different watering treatments and evaluated the extent to which shifts were associated with changes in root traits. We observed that altered rainfall regimes affected the composition but not the richness of the AM fungal communities, and we found distinctive communities in the increased rainfall treatment. We found no evidence of altered rainfall regime effects via changes in host physiology because none of the studied traits were affected by changes in rainfall. However, specific root length was observed to correlate with AM fungal richness, while concentrations of phosphorus and calcium in root tissue and the proportion of root length allocated to fine roots were correlated to community composition. Our study provides evidence that climate change and its effects on rainfall may influence AM fungal community assembly, as do plant traits related to plant nutrition and water uptake. We did not find evidence that host responses to altered rainfall drive AM fungal community assembly in this grassland ecosystem.

Sex-specifically responsive strategies to phosphorus availability combined with different soil nitrogen forms in dioecious Populus cathayana

2021 ◽  
Author(s):  
Xiucheng Liu ◽  
Yuting Wang ◽  
Shuangri Liu ◽  
Miao Liu
Keyword(s):  
Root Length ◽  
Root Length Density ◽  
Specific Root Length ◽  
P Uptake ◽  
Root Tip ◽  
P Availability ◽  
P Deficiency ◽  
Populus Cathayana ◽  
Leaf P ◽  
P Supply

Abstract Aims Phosphorus (P) availability and efficiency are especially important for plant growth and productivity. However, the sex-specific P acquisition and utilization strategies of dioecious plant species under different N forms are not clear. Methods This study investigated the responsive mechanisms of dioecious Populus cathayana females and males based on P uptake and allocation to soil P supply under N deficiency, nitrate (NO3 −) and ammonium (NH4 +) supply. Important Findings Females had a greater biomass, root length density (RLD), specific root length (SRL) and shoot P concentration than males under normal P availability with two N supplies. NH4 + supply led to higher total root length, RLD and SRL but lower root tip number than NO3 − supply under normal P supply. Under P deficiency, males showed a smaller root system but greater photosynthetic P availability and higher leaf P remobilization, exhibiting a better capacity to adaptation to P-deficiency than females. Under P deficiency, NO3 − supply increased leaf photosynthesis and PUE but reduced RLD and SRL in females while males had higher leaf P redistribution and photosynthetic PUE than NH4 + supply. Females had a better potentiality to cope with P deficiency under NO3 − supply than NH4 + supply; the contrary was true for males. These results suggest that females may devote to increase in P uptake and shoot P allocation under normal P availability, especially under NO3 − supply, while males adopt more efficient resource use and P remobilization to maximum their tolerance to P-deficiency.

scholarly journals The Phosphate Inhibition Paradigm: Host and Fungal Genotypes Determine Arbuscular Mycorrhizal Fungal Colonization and Responsiveness to Inoculation in Cassava With Increasing Phosphorus Supply

2021 ◽  
Vol 12 ◽  
Author(s):  
Ricardo Alexander Peña Venegas ◽  
Soon-Jae Lee ◽  
Moses Thuita ◽  
Deusdedit Peter Mlay ◽  
Cargele Masso ◽  
...  
Keyword(s):  
Mycorrhizal Fungi ◽  
Arbuscular Mycorrhizal ◽  
Field Trials ◽  
P Uptake ◽  
Fungal Colonization ◽  
P Availability ◽  
Terrestrial Plants ◽  
Soil Microbial ◽  
Arbuscular Mycorrhizal Fungal ◽  
P Supply

A vast majority of terrestrial plants are dependent on arbuscular mycorrhizal fungi (AMF) for their nutrient acquisition. AMF act as an extension of the root system helping phosphate uptake. In agriculture, harnessing the symbiosis can potentially increase plant growth. Application of the AMF Rhizophagus irregularis has been demonstrated to increase the yields of various crops. However, there is a paradigm that AMF colonization of roots, as well as the plant benefits afforded by inoculation with AMF, decreases with increasing phosphorus (P) supply in the soil. The paradigm suggests that when fertilized with sufficient P, inoculation of crops would not be beneficial. However, the majority of experiments demonstrating the paradigm were conducted in sterile conditions without a background AMF or soil microbial community. Interestingly, intraspecific variation in R. irregularis can greatly alter the yield of cassava even at a full application of the recommended P dose. Cassava is a globally important crop, feeding 800 million people worldwide, and a crop that is highly dependent on AMF for P uptake. In this study, field trials were conducted at three locations in Kenya and Tanzania using different AMF and cassava varieties under different P fertilization levels to test if the paradigm occurs in tropical field conditions. We found that AMF colonization and inoculation responsiveness of cassava does not always decrease with an increased P supply as expected by the paradigm. The obtained results demonstrate that maximizing the inoculation responsiveness of cassava is not necessarily only in conditions of low P availability, but that this is dependent on cassava and fungal genotypes. Thus, the modeling of plant symbiosis with AMF under different P levels in nature should be considered with caution.

scholarly journals Efficacy of Bio-inoculants Arbuscular Mycorrhizal Fungi and Phosphorus on Micronutrient Status of Leaves and Soil in Litchi (Litchi chinensis Sonn.) Layers in Nursery Condition

2020 ◽  
pp. 122-129
Author(s):  
Priyanka Kumari ◽  
R. R. Singh ◽  
Ruby Rani ◽  
Mahendra Singh ◽  
Uday Kumar
Keyword(s):  
Mycorrhizal Fungi ◽  
Copper Content ◽  
Soil Nutrient ◽  
Arbuscular Mycorrhizal ◽  
Nutrient Status ◽  
Nutrient Content ◽  
Time Duration ◽  
Litchi Chinensis ◽  
Significant Difference ◽  
Phosphorus Application

Litchi (Litchi chinensis Sonn.) originated from South China, it is sub-tropical evergreen fruit crops, especially grown on the marginal climate of tropics and subtropics. It is delicious juicy fruit of India having excellent nutritional quality, pleasant flavoured, good amount of antioxidant and vitamins C, vitamin B-complex and phytonutrients flavonoids. It has a great potential to earn foreign exchange in the national and international market through export. Arbuscular mycorrhizal (AM) infection is a common association between plant roots and microorganisms. It is responsible for increasing plant nutrient uptake and also increases in macro and micronutrients in leaf. Therefore, the present work has been analyzed macro and micro nutrients from soil and leaf, after 60, 90 and 120 days after inoculation of two bio-inoculants with phosphorus (SSP) including nine treatments with three replications. After 120 days of inoculation both the species of mycorrhizal combination with phosphorus application were very effective. Highest Copper content is (10.99 ppm), Zinc (33.17 ppm), Iron (121.47 ppm) and Manganese (15.33 ppm) was recorded in case T5 (G. mosseae 10 g + Phosphorus 50 mg kg-1 of soil) which is gradually increases. The soil nutrient content gradually decreased with time duration but no- significant difference was found among treatments after 120 days inoculation. After 120 days potting result was found that the Copper content is (1.70 ppm), Zinc (3.07 ppm), Iron (7.80 ppm) and Manganese (4.00 ppm) was recorded in case T5 (G. mosseae 10 g + Phosphorus 50 mg kg-1 of soil).this research was undertaken to find out whether Arbuscular mycorrhizal (AM) infection and phosphorus affect the micro-nutrient status of soil and leaves in nursery stage.

Development of an organomineral fertiliser formulation that improves tomato growth and sustains arbuscular mycorrhizal colonisation

2021 ◽  
pp. 151977
Author(s):  
Hue T.T. Ngo ◽  
Stephanie J. Watts-Williams ◽  
Ashleigh Panagaris ◽  
Roslyn Baird ◽  
Michael J. McLaughlin ◽  
...  
Keyword(s):  
Arbuscular Mycorrhizal ◽  
Mycorrhizal Colonisation ◽  
Tomato Growth
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