scholarly journals Reducing Phenanthrene Contamination in Trifolium repens L. With Root-Associated Phenanthrene-Degrading Bacterium Diaphorobacter sp. Phe15

2021 ◽  
Vol 12 ◽  
Author(s):  
Hui Zhao ◽  
Yujun Gu ◽  
Xiangyu Liu ◽  
Juan Liu ◽  
Michael Gatheru Waigi
Keyword(s):  
White Clover ◽  
Trifolium Repens ◽  
Root Surface ◽  
Seed Soaking ◽  
Degrading Bacterium ◽  
Free Treatment ◽  
Polycyclic Aromatic ◽  
Clover Root ◽  
And Performance ◽  
Root Surfaces

Some root-associated bacteria could degrade polycyclic aromatic hydrocarbons (PAHs) in contaminated soil; however, their dynamic distribution and performance on root surface and in inner plant tissues are still unclear. In this study, greenhouse container experiments were conducted by inoculating the phenanthrene-degrading bacterium Diaphorobacter sp. Phe15, which was isolated from root surfaces of healthy plants contaminated with PAHs, with the white clover (Trifolium repens L.) via root irrigation or seed soaking. The dynamic colonization, distribution, and performance of Phe15 in white clover were investigated. Strain Phe15 could efficiently degrade phenanthrene in shaking flasks and produce IAA and siderophore. After cultivation for 30, 40, and 50 days, it could colonize the root surface of white clover by forming aggregates and enter its inner tissues via root irrigation or seed soaking. The number of strain Phe15 colonized on the white clover root surfaces was the highest, reaching 6.03 Log CFU⋅g–1 FW, followed by that in the roots and the least in the shoots. Colonization of Phe15 significantly reduced the contents of phenanthrene in white clover; the contents of phenanthrene in Phe15-inoculated plants roots and shoots were reduced by 29.92–43.16 and 41.36–51.29%, respectively, compared with the Phe15-free treatment. The Phe15 colonization also significantly enhanced the phenanthrene removal from rhizosphere soil. The colonization and performance of strain Phe15 in white clove inoculated via root inoculation were better than seed soaking. This study provides the technical support and the resource of strains for reducing the plant PAH pollution in PAH-contaminated areas.

scholarly journals Investigations into suitability of Trifolium occidentale as a host plant for two common pasture pests

2014 ◽  
Vol 67 ◽  
pp. 250-255
Author(s):  
P.J. Gerard ◽  
K.M. O'Donnell
Keyword(s):  
Host Plant ◽  
White Clover ◽  
Trifolium Repens ◽  
Stress Factors ◽  
Strong Preference ◽  
Choice Test ◽  
Sitona Lepidus ◽  
Clover Root ◽  
And Performance ◽  
Trifolium Occidentale

Western clover (Trifolium occidentale) is a diploid perennial clover that is reported to be one of the progenitors of white clover (Trifolium repens) The ability to produce hybrids between T repens and T occidentale provides an opportunity to introduce factors to improve white clover tolerance to common stress factors A series of assays was undertaken to compare the feeding and performance of two contrasting pests on two T occidentale lines and two T repens cultivars Clover root weevil (Sitona lepidus) adults showed a preference for T repens but this diminished if weevils had been previously exposed to T occidentale Weevil longevity feeding levels and oviposition were comparable over 32 days indicating T occidentale is a host plant for adult S lepidus Clover flea (Sminthurus viridis) showed a strong preference for T repens over T occidentale in a choice test and higher feeding levels on T repens in the nochoice test

Colonization and performance of a pyrene-degrading bacterium Mycolicibacterium sp. Pyr9 on root surfaces of white clover

Chemosphere ◽  
2021 ◽  
Vol 263 ◽  
pp. 127918
Author(s):  
Jie Yang ◽  
Yujun Gu ◽  
Zhigao Chen ◽  
Yao Song ◽  
Fengfei Sun ◽  
...  
Keyword(s):  
White Clover ◽  
Degrading Bacterium ◽  
And Performance ◽  
Root Surfaces

Phosphate responses of some Trifolium repens×T. uniflorum interspecific hybrids grown in soil

2014 ◽  
Vol 65 (4) ◽  
pp. 382 ◽  
Author(s):  
S. N. Nichols ◽  
J. R. Crush ◽  
L. Ouyang
Keyword(s):  
White Clover ◽  
Trifolium Repens ◽  
Interspecific Hybrids ◽  
Root Surface ◽  
P Uptake ◽  
Sand Culture ◽  
Interspecific Hybridisation ◽  
Growth Responses ◽  
Root Tips ◽  
Soil P

Previous studies in sand culture suggested that some white clover (Trifolium repens) × T. uniflorum interspecific hybrids were more tolerant than white clover of low external phosphate (P) supply. Here, P acquisition and growth responses were determined in soil for two T. repens × T. uniflorum backcross hybrids and their parental white clover cultivar, grown in a glasshouse pot experiment at Olsen P of 6, 7, 9, 14, or 20 mg P kg–1 soil. Growth of all of the clover entries responded strongly to increasing soil P levels, and one hybrid clover grew, on average, 17% better than the white clover control cultivar at Olsen soil P 9–20 mg kg–1. Internal P concentrations and shoot growth per unit P absorbed did not differ among the clovers. Instead, improved growth of the hybrid resulted from a greater ability to acquire soil P. This hybrid had the longest, most frequently branched roots. Frequent branching and growth of root tips into fresh soil would reduce the limitations to P uptake imposed by slow diffusion of P to the root surface. The results confirm previous observations that interspecific hybridisation is a useful strategy for increasing the range of P responsiveness in breeding populations for white clover.

scholarly journals Relationship between Sitona lepidus larval numbers and white clover seed production

2001 ◽  
Vol 54 ◽  
pp. 141-146
Author(s):  
P.J. Gerard
Keyword(s):  
Seed Production ◽  
White Clover ◽  
Trifolium Repens ◽  
Negative Impact ◽  
Early Flowering ◽  
Sitona Lepidus ◽  
Clover Root ◽  
Second Year ◽  
Clover Seed ◽  
Seed Crops

Plots of two cultivars of white clover (Trifolium repens) Grasslands Prestige (smallleaved early flowering) and Grasslands Kopu (largeleaved later flowering) were established in coldframe beds Clover root weevil (Sitona lepidus) larval numbers were manipulated to obtain winter larval densities ranging from 0 to over 1000/m2 Increasing winter larval densities increased Prestige seed production (g/m2) when harvested on 28 December and 10 January and the trend was still evident on 24 January No such relationships were found in Kopu for the early and middle harvests but at the late harvest increasing winter larval densities had a negative impact on seed production The results indicate that the effect of clover root weevil larvae on second year clover seed crops may vary substantially between cultivars and may even be positive rather than negative

Effects of ratio of white clover to grass in silage and concentrate supplementation on intake and performance of ewes in late pregnancy

1987 ◽  
Vol 1987 ◽  
pp. 76-76
Author(s):  
R.J. Orr ◽  
T.T. Treacher
Keyword(s):  
White Clover ◽  
Trifolium Repens ◽  
Crude Protein ◽  
Late Pregnancy ◽  
Crude Protein Content ◽  
Fresh Weight ◽  
Concentrate Supplementation ◽  
Grass Silage ◽  
Voluntary Intake ◽  
And Performance

Widespread adoption of sheep systems based on mixed swards of white clover and grass may result in conservation cuts with a high proportion of clover, which will affect the intake of the silage or hay. The effect of proportion of clover in silage on voluntary intake was measured by offering mixtures of clover and grass silage with clover proportions of 0, 0.20, 0.40 and 0.60 with (S) and without (U) a ration of 600 g fresh weight per day of a barley, soya and fishmeal concentrate to 78 Finn Dorset ewes. The concentrate was formulated to have a crude protein content (CP) of 160 g per kg DM with 30 g per kg DM derived from fishmeal. The silages were made separately in 1984, with formic acid added at approximately 3.51 per tonne, from uninterrupted spring growths of perennial ryegass (Loliua perenre cv. Melle) cut on 16 June and white clover (Trifolium repens cv. Blanca) cut on 17 July and both were chopped. Mixtures of the two silages were made for each individual ewe separately each day, immediately prior to feeding.

Effect of sward surface height of mixed swards of ryegrass/white clover on the intake and performance by ewes and their twin lambs

1987 ◽  
Vol 1987 ◽  
pp. 37-37
Author(s):  
R.J. Orr ◽  
P.D. Penning ◽  
A.J. Parsons ◽  
T.T. Treacher
Keyword(s):  
Lolium Perenne ◽  
Perennial Ryegrass ◽  
White Clover ◽  
Trifolium Repens ◽  
Continuous Variable ◽  
Stocking Rate ◽  
Animal Performance ◽  
And Performance ◽  
Grass Sward

Mixed swards of perennial ryegrass (Lolium perenne cv. S23) and white clover (Trifolium repens cv. Huia) were maintained at sward surface heights (SSH) of 3 (GC3), 6 (GC6) and 9 cm (GC9) by continuous variable stocking to examine effects on sward and animal performance. In addition, a pure grass sward of S23 was kept at 6 cm (G6) and fertilized with 14 applications of 30 kg N per ha at fortnightly intervals, beginning on 25 March. The swards were sown in August 1983, cut twice in 1984, in May and June, and then grazed thereafter. Fertilizer was applied to the seedbed at 40 kg N per ha, 20 kg P205 per ha and 20 kg K20 per ha. In March 1984 and 1985, 20 kg per ha each of P205 and K2O were applied to all plots.Dry sheep grazed the paddocks (0.69 ha) to the required SSH's with grazing starting on 4 April, 9 April, 12 April and 24 April for treatments GC3, G6, GC6 and GC9, respectively. On 24 April, two days after lambing, core groups of 8 Scottish Halfbred ewes with twin lambs were put on the plots. Additional ewes, kept on swards similar to the treatment areas, were used to adjust the stocking rate to maintain the SSH's. These were measured three times each week with 200 readings per plot.

scholarly journals Clover root weevil biocontrol distribution in the North Island - release tactics and outcomes

2010 ◽  
pp. 85-89
Author(s):  
P.J. Gerard ◽  
D.J. Wilson ◽  
T.M. Eden
Keyword(s):  
Technology Transfer ◽  
White Clover ◽  
Trifolium Repens ◽  
Biocontrol Agent ◽  
Postal Survey ◽  
Far North ◽  
The North ◽  
Field Samples ◽  
Clover Root ◽  
Microctonus Aethiopoides

Clover root weevil (CRW) has become one of New Zealand's most serious pasture pests. An Irish ecotype of Microctonus aethiopoides has been released and established as a biocontrol agent. Since early 2006, field samples have been taken to monitor its spread and establishment. The biocontrol agent has established well at sites where 1 000-2 500 parasitised CRW were initially released, except in the Far North, and is spreading at around 15 km/year. Industry field personnel assisted with distributing 2 000 mini-releases (10 parasitised CRW) to areas where CRW was causing damage. One hundred farmers were sent a postal survey and feedback from 59 respondents showed the mini-release approach was successful in terms of distribution of the parasitoid, technology transfer and funder recognition. Based on natural spread from many of the release sites, it is predicted that the parasitoid will be present on most North Island farms by the end of summer 2010/2011. Keywords: Microctonus aethiopoides, biocontrol agent, white clover, Trifolium repens

scholarly journals Establishing white clover (Trifolium repens) in high pest density regions

2008 ◽  
Vol 61 ◽  
pp. 248-255
Author(s):  
J.L. Brock ◽  
J.P.J. Eerens ◽  
A. Rahman ◽  
D.J. Wilson
Keyword(s):  
White Clover ◽  
Trifolium Repens ◽  
Seedling Establishment ◽  
Dairy Farms ◽  
Field Trials ◽  
Fallow Period ◽  
Clover Root ◽  
Pest Density ◽  
Clover Content

Four field trials were conducted on commercial dairy farms in Waikato and Manawatu to develop guidelines for reestablishing white clover into vigorous grass pastures Treatments were designed to (1) determine the minimum clover fallow period needed to minimise clover pest populations and (2) identify options for reintroducing white clover Tribenuron proved damaging to grass and results for thifensulfuron were variable Dicamba was effective in removing clover and the length of clover fallow required to remove clover root weevil larvae appeared to be 68 months Glyphosate applied at sowing reduced pasture cover significantly for up to 10 weeks but seedling establishment was improved by 50100 The reintroduction of clover was better in autumn than spring but no treatment resulted in increased long term clover content of the pasture This was due to both poor emergence and survival of clover seedlings facing severe competition from resident well established grass plants

scholarly journals Long-term effects of pastoral fallowing on the distribution and performance of white clover (Trifolium repens L.) in a hill country pasture

1996 ◽  
Vol 6 ◽  
pp. 75-78 ◽  
Author(s):  
Z.N. Nie ◽  
I. Valentine ◽  
A.D. Mackay ◽  
D.J. Barker ◽  
J. Hodgson
Keyword(s):  
White Clover ◽  
Trifolium Repens ◽  
Dry Matter ◽  
Dry Matter Yield ◽  
Long Term Effects ◽  
Hill Country ◽  
Trifolium Repens L ◽  
And Performance

Previous work found that white clover (Trifolium repens L.) yield initially decreased, but subsequently increased following a pastoral fallow. The objective of this research was to quantify the response in herbage production and stolon characteristics of white clover up to 4 years after fallowing. Four treatments were used: fallowed 1990/91 (F4), fallowed 1991/92 (F3), fallowed 1993/94 (F1) and non-fallowed (F0). The fallowing period was between September and May. White clover dry matter yield (between 15/12/94 and 18/5/95) was significantly greater for the treatment F4 than F0 (P

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