التفاصيل البيبلوغرافية
| العنوان: |
Cadmium in New Zealand pasture soils: toxicity to Rhizobia and white clover. |
| المؤلفون: |
Wakelin, SA, Cavanagh, JAE, Young, S, Gray, CW, van Ham, RJC |
| المصدر: |
New Zealand Journal of Agricultural Research; Mar2016, Vol. 59 Issue 1, p65-78, 14p |
| مصطلحات موضوعية: |
PASTURES, CADMIUM, SOIL composition, WHITE clover, RHIZOBIACEAE, SOIL microbiology |
| مصطلحات جغرافية: |
NEW Zealand |
| مستخلص: |
A survey of 26 pastures was conducted and soil and plant material analysed for total cadmium (Cd) and phosphorus (P), and soils further analysed for a variety of edaphic properties. Background Cd in pasture soils ranged from 0.06–0.85 mg Cd kg−1soil (mean of 0.23) and correlated closely with total P (R2 = 65.5;P < 0.001), while weaker relationships with Olsen P, nitrate-N and calcium were evident. Cadmium in the pasture dry matter had no correlation to underlying soil total Cd (P = 0.113) or soil P (P = 0.75). Strains ofRhizobiumspp. were isolated from a reference soil high in Cd (Morrinsville; 1.34 mg Cd kg−1soil) and a mid-range Cd soil (Whataroa; 0.32 mg Cd kg−1soil). The IC50of these strains, along with the commercial inoculant for white clover (Rhizobium leguminosarumbv.trifoliiTA1), to Cd were tested using a respiration sensitive assay (MicroRespTM). Rhizobia from the Whataroa soil had significantly greater tolerance to Cd than those from Morrinsville soil (P = 0.008). We propose a general stress-tolerance mechanism has evolved in the rhizobia from Whataroa, conferring metal co-tolerance. The Cd IC50ofRhizobiumTA1 was 3.06 ppm, but levels of respiration inhibition were evident at lower concentrations. Given the importance of the legume:rhizobia symbiosis to New Zealand's pastoral sector, determination of ‘no observable effect concentrations' is required forRhizobiumspp., pasture legumes and, most importantly, the establishment and function of symbiosis (nodulation and N2fixation, respectively). [ABSTRACT FROM AUTHOR] |
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| قاعدة البيانات: |
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